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#825687 SCAN9495 - Free Scanning Software for 94/95 LT1 (OBD-1)

Posted by GaryDoug on 19 January 2013 - 06:44 PM

Too many distraction for a while, but now I'm past the first step, getting a platform to use. Here is a photo of a minimal OBD1 adapter that you can make yourself. Nothing new here. I stole this one off the web and made it from parts I had already. It works just fine with Freescan and Datamaster (which I keep on a re-storable old PC for perpetual use...) on the 94 PCM from a Z28. Not sure how well they work on a newer PC using a USB-to-serialport adapter. One's on order, so I will find out.

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#823163 SCAN9495 - Free Scanning Software for 94/95 LT1 (OBD-1)

Posted by GaryDoug on 12 December 2012 - 02:11 PM

I just bought a used 1994 Formula PCM for $53 and will use it to try to make an OBD1 scan app. According to my Tech2 clone, it is working. I can use that with a data sniffer to see how it requests the data. Give Freescan a try too.

For what it is worth, the guy has another one for sale for the same price, in case anyone needs a spare: http://www.ebay.com/...=item4abf73be35
Not sure if it is a Pontiac or Camaro though, without the VIN.

EDIT BY ADMIN - This thread describes the developement of SCAN9495. This software is available in a free download, and will scan the PCM, ABS and SRS (air bag) systems. Gary has also come up with sources for ready-made and D-I-Y interface cables. It's worth reading through the entire thread to see how it was developed, the various updates, and the solutions to interface problems that some people have found (and Gary has solved) with various PC operating systems. For anyone in a hurry, here's the link to the software, user manual, etc.

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Posted by GaryDoug on 07 July 2011 - 01:28 PM

Some resources:

These books are in .pdf format, in multiple parts. There is a free-ware pdf utility program there if you need one, which can be used to merge the sections into original size.


(These are not links - just a list. Click on the link at the very bottom of this post for access to the folder containing all these items.)

1996 - 1997 should be very similar

Exploded parts diagrams for 1982 - 2002 models.

Wiring diagram downloads for 1999 - 2002 models.

Double click on a filename to start the download for that file.This site has a good amount of ads and some popups, but doesn't require you to install anything, just click on the "close" or "X" of each unwanted popup. Pay attention to not click to close the file download popup message. After the file download, close the browser download page to start on the next file. The files are pure pdf with no added items.

[EDIT]All of the above are now available in a single folder.


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#476628 "Performance Chips"

Posted by Injuneer on 12 April 2010 - 10:33 AM

The PCM is hard coded to produce an A/F ratio of 14.7:1 in closed loop. That's the level required for the catalytic converter to work, and produces reasonable fuel economy. "Closed loop" is the PCM's method of controlling A/F ratio at part load conditions. When you go WOT (its actually a table ot throttle position vs. RPM) the PCM richens the mixture. The typical target A/F ratio for WOT is 11.7:1. That's too rich. You will generally get better results with something in the range of 12.8 - 13.2:1. Its easy to alter the target A/F ratio for WOT in the program tables.

Once you get the PCM to operate at the correct target A/F ratio, the PCM looks at the mass air flow, divides by the target A/F ratio, and then calculates the injector pulse width required to delivere the required fuel flow. In order to calculate the pulse width, the PCM has to be programmed with the correct injector flow rating. Stock programming is 24.9 #/HR.

The problem with using larger injectors than it's programmed for is that the engine may run rich in closed loop, and will run pig-rich at WOT. The excess fuel may be enough to wash the lubrication off the cylinder walls, and cause ring damage. The fuel can also dilute the oil, causing bearing damage. In closed loop (part load driving) the O2 sensors will help the PCM correct the excessively rich mixture, but the PCM can only "subtract" about 15% excess fuel using the long term fuel corrections. The 30 #/HR injectors are adding 20% excess fuel, more than the PCM can adjust for.
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#468635 Working under a car.

Posted by Pete W on 28 March 2010 - 05:55 AM

Folk's, we just had a member from another car club gut crushed and killed while working under his truck, the jack collapsed and the axle stand shifted pinning him and taking his life.

I cannot tell you how many times I have ripped guys heads off after seeing their car's up in the air and not even remotely jacked up properly, supported, not on level ground, no wheel blocks etc and no parking brake being used!

Please take this seriously and use caution to extreme level's always, never jack up your vehicle and get immediately under it,check for stability and safeness as this can be a one time option.
I am going to find as many articles as possible to link here and I urge you to read them and or watch them and appreciate anyone with a lot of knowledge to offer their advice on this important subject.

Having a cool car,truck project can be fantastic but having your surviving wife sell it to support her and your kids is not!



I know there are folks here that have done extensive repairs and building of cars who would have great insight and safety tips, please add your thoughts to this post and always remember most accidents are caused by rushing or improper care, sometimes what you do a lot makes you too confident and in fact careless which can take your life.

Jacking a car is so dangerous I would add a disclaimer to this post that no one should consider anything posted here as gospel to raising,lowering and supporting your car, it is always your responsibility to use the best of your knowledge, the best in jacks and support stands, blocks and utmost care.

If you are not going to invest in best quality jacks, stands, blocks etc then take it to a garage period. :12EMOTICHEERS:
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#838105 Should i buy this 1970 firebird 350 for $3000?

Posted by WHITE-68 on 21 March 2013 - 04:41 PM

:angrysoapbox: You would really try to profit off the people that were helping you in the 1st place? I could see asking 3k.. But I almost think its an insult to ask 5k from the very people that helped you with it in the first place? Your original thread was "should I buy this" It looks like you have bought it, but now don't have time so your going to try and profit off it.. I think I will close the thread. If you have new issues open a new topic. Please be courteous and don't disrespect the people that helped you.
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#827558 SCAN9495 - Free Scanning Software for 94/95 LT1 (OBD-1)

Posted by GaryDoug on 12 February 2013 - 07:48 PM

Update: Ordered 4 USB-to_Serial port adapters, received 3 so far. Only one will work with Freescan. It is a Sabrent model CB-FT1K, which has the FDTI chip. That IC device is well recognized as reliable and well documented, especially for supporting non-pc baud rates like the 8192K. Anyone wanting to use the DIY circuit with a newer PC and a USB port should look for an adapter saying it has the FTDI chip. Here is the Sabrent one: http://www.amazon.co...ref=pd_sxp_f_pt
The other two devices were the Trendnet TU-S9 and a Chinese no-name product. Both of those devices use the Prolific chip and do not work with Freescan.
Right now I am using the Sabrent device with my DIY 2-transistor circuit (mentioned above) on a Windows 7 PC running Freescan and connected to 94 Z28 PCM and am getting good data. Total cost so far is $13 for the Sabrent adapter and about $10-$15 for the interface circuit. Now that I can use the newer pc, I can more easily begin developing my own program (maybe?).
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#818765 Firebird in barn for 33 years

Posted by steve1861 on 05 October 2012 - 05:09 PM

Here are some pictures of the '68 Firebird barn find, and here's my take on the whole story. Hope you enjoy it!

Ever since I rode in my first convertible with my babe I fell in love with the freedom that a convertible gives. So I had to have one. I wanted the best of both worlds, a classic car and a convertible. But I never settle for less than the best, and I needed an original and rare car that I could refinish back to its original state. I wasn't looking for perfection, I need something to occupy my free time during the week in the winter months that were pending. I searched for over a year to find the right car. I searched in various states, various websites and took many roadtrips only to find that what was described as the perfect car for me, was not nearly as perfect as they depicted. I was getting frustrated and anxious that I would not find what I wanted.

Looking through Craigslist, getting alerts about new posts, endless searches all over the place….fruitless. One night as I continued my search, I came upon a newly posted ad:

1968 Firebird convertible. Matching numbers. Phone number. Price.

No pictures, no further description. No email. I called him as soon as I saw it, it was located in Vermont. I offered him his asking price plus $1000 over, and made arrangements to be there first thing Saturday morning. The calls were already pouring in to him, and I wanted to beat them. A neighbor had offered him 4500, but he chose not to sell it to him because he didn't want to see it driving around his neighborhood.

So we packed up and headed to Vermont on Saturday morning, trailer in tow. Now reality is setting in. What if it's totally rotted? What if it's not matching numbers? What if what if… but it didn't matter . Babe had a feeling that it was going to be a great surprise, that I would find something to be excited about when I finally saw it. I was hesitant still. Driving up route 107 to Barnard. We're making bets about what the color is, what condition it might be in, and who is this person we're about to meet. We get about 10 minutes away, and turn onto a side road. It is a very steep hill up a one-lane dirt road. Reminiscent of a horror movie… I was feeling that it was going to be a one of a kind find. In all places, never thought it would be in the hills of Vermont.

We pull up to a ramshackle shack, with abandoned cars all around. The firebird was there. Most people would have seen something destined for the junkyard. The top was ripped off, tires were flat, missing headlights, back window totally gone. But through my eyes I saw a 1968 Firebird convertible right on the showroom floor. I can see the potential in everything. Verdoro green. Original paint. 90% rust, but the color shown through. Still had the registration sticker and plates on it from 1980, the last time it was on the road.

The owner, Jim, walked out. Softspoken. Come to find out, he was the 2nd owner of this car. He worked for a Saab dealership, and this car was traded by a customer, and he bought it at age 17. $10/week payments out of his paycheck.

Looked for the matching numbers. The horsepower matched up. The VIN on the engine was not visible. But Jim guaranteed the engine was original, and I just had a feeling that it was true. This car was the one for me. I had to be content to verify the matching numbers when we got it home. Original interior, original paint, untouched since it left the factory. It had mag wheels added. Third week in May 1968.

Jim said he had a picture of the car, the last day he drove it. He gave us that picture and said we could keep it. Here's Jim in his car in 1977:
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There were a couple of dents, Jim told us how they got there – two were from a deer and one was him backing into a sign.

Jim said the car was recently taken out of a barn that was ready to collapse. So it's truly a barn find, that I've always dreamed about!

Loaded it on the trailer, drove back to town, and all eyes were on the Firebird on the trailer. Even though the top was blowing in the wind, and the tires were flat, it was still a sight to behold. You can see the history in this car, even though it's not in prime condition, there is potential to bring it back to life. Which is exactly what I will do.

We stopped for lunch, parked across the street. We noticed a man and his wife walking around the trailer, looking and smiling at the car. They spent quite a long time, just looking and looking. The wife took a picture of the man standing next to the car. And so it begins…

We pull into the south house. Determined to find the matching numbers, I called a buddy that knows about these things. He suggested look at the bottom of the engine, behind the water pump hose outlet. And that's where I found it. I snapped a photo so we could see it clearly. It's about restoring history. The car becomes my canvas, and I can create something from nothing. I can see beauty in everything.

To me, these classic cars represent the simplicity of life during those times. War was going on, but peace back home. We cherish those times.
Every time we sit in these cars, it's not about the noise the engines make or the horsepower, it's about a memory of simpler times, and an effort to get it back again.
Feeling the past. Reliving the dream.

This car meant a lot to Jim. He chose to not drive it anymore because he knew he was getting reckless and was going to hurt someone or himself. And Jim informed us that he has only a short time left on this earth, as he has terminal cancer. I want to dedicate this restoration project to Jim Clark.

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#463286 Rust and Pitting

Posted by MacDuff on 16 March 2010 - 08:36 PM

Cut out the bad metal, replace with new metal. Weld and then finish grind it until its smooth, maybe apply a slight skim coat of body filler if needed, then sand, prime and paint. That's the only way to do it in my opinion if there is a substantial amount of holes. That way you get rid of any chance that the rust will come back sooner than expected and the repair will be like factory, if not better when done right. If there's only some small holes, you may be able to get away with welding and grinding the holes if the metal isn't too thin. You could weld the holes shut then apply the rust converter and then topcoat the converter if you want to. It all depends on how far you want to take it, and what you want the final result to be. Some people like to half-@ss it cuz no one's ever gonna see it, but I don't really understand that type of thinking. If you're gonna spend the time and energy to go in and fix a problem, why not do it the right way the first time? Also, I don't think fiberglass is a recommended repair method for body work, unless its on a fiberglass car or part. :beer:

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#423216 Picture Tribute to my good friend Jay

Posted by 1tinindian on 13 December 2009 - 02:16 PM

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That's right guys, Jay did wear long pants ,but after all, this was in March...LOL!
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Please keep adding to this thread in honor of our fallen friend Jay!

I miss you buddy!

And don't forget to give to the Chip-in box at the top of the page, as every dollar given means the world to Liz and the girls
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#856057 How to align Body Panels and Doors.

Posted by raguza123 on 21 April 2013 - 04:29 PM

Body Panel adjustments


Begin with the B pillar with weather stripping in place.(door glass fit adjustment is another critter entirely):

Bolt hinges to doors and snug. Center bolts within adjustment range.

Bolt door/hinge assembly to A pillar and snug. Center within adjustment range.

Carefully close door fully, with striker pin removed.

Loosen lower hinge to pillar or door to hinge bolts as needed to set gap evenly at the rockers, then retighten all.

Now set distance from door to quarter and horizontal tilt by loosening one hinge from pillar at a time and "walking it" so you didn't lose your door height. Go for about a quarter of an inch gap at the bottom and back of the door. Having help helps.

Now set the top to bottom tilt of the door. Loosen hinge to door bolts and adjust inward and outward as needed for a flush fit from top to bottom at the quarter (or rear door). Here again walk it to avoid losing height it's hard to raise the door with hinges snug.

At this point you should have similar gaps on each side between the windshield posts and the top front corners of the door skins. Your door should fit the quarter and rockers evenly.

Install and set the striker position now. Do not use the striker pin adjustment to pull the door up or down into place when latched. the pin's job is to be where the latch wants to meet, not the other way around. The pin must hit the latch dead center, and should not contact the latch anywhere but on the claws. Use the striker pin's shim pack to adjust how far it extends forward into the latch and avoid dragging. I prefer light oil to heavy grease, only inside the latch. No lubricant belongs on the striker pin or latch claws faces.

Tighten all door and hinge bolts. Still good? Moving on....

Place a fender and start all bolts.

The big rear top bolt facing upward is the first to tighten(Guys with cowl panels and exposed wipers may have to remove those for access). shim the height so that the major upper body line approximately lines up to the door and snug the bolt.

Next bolt is the big one by the master cylinder or heater, facing forward. Set the door to fender distance with the shims here then snug the bolt. You may have to loosen that top bolt again to let it move.

Now use a shim pack under the big bolt at the bottom rear of the fender if needed, to set the bottom of the fender level with the rocker when tight. Most importantly, match where the contour or molding there will line up. tighten.

At this point, confirm that your core support is centered:

Choose symmetrical reference points at the cowl such as first big fender bolt, then measure in an X pattern to a fixed point like a hole or contour on the core support. Alternatively, you could determine the exact center of the core support and just measure from those fender bolts to that mark. If you have a quarter inch or less of difference in the measurements from side to side, you shouldn't have big trouble. If the discrepancy is larger than that, it's possible your frame is bent but in most cases the core support mounts can be loosened at the frame and moved slightly, to "square up" the engine compartment. Sometimes you got to slot a hole a little here or there to allow adjustment.

Got that all square? Got all the bolts started? Wheel well bolts and fender brace bolts are all installed but not tight? OK, Lets move on:

Go back where you left off before measuring, and do what you can to fine tune the fender to door gap now. Hard to reach those hinge to pillar bolts with fenders on so hope you nailed em. Make adjustments, but never assume you have it licked until the bolts are all tight. Keep in mind that the rear top and bottom bolts "pinch" the fender a little, and can affect how far out it sticks in the middle. Be sure to carefully check for clearance along the front edge of the door opening and closing during gap adjustments, and bear in mind that GM was more concerned that the moldings line up than the actual panel edges, in many cases on the full framed cars.

Got happy door gaps now? Close easy and don't rub? Got all rubber bumpers and seals that support the hood in place? Cowl guys put it back on now, with the rubber.

OK, Lets grab the hood.

Remove the striker pin for now. Install the hood hinges to fenders, center them within the range adjustment and tighten. Not snug, tight.

Bolt hood to hinges, in the center of the mounting slots and tighten.

Carefully close hood, watch the back corners so they don't rub. If it is significantly off center at the back, you screwed up the hinge. You are urinating directly into the breeze until you get a good one with a good spring. Hard to fix'em.

Now that you see how the hood sits, open it and adjust the front to rear position by loosening the bolts and repositioning them in the hinge slots then tightening. You are not only adjusting the front to rear position of the hood, but also centering the hood's front to the rest of the car.

Does the hood lineup now(or how is the to grille header gap)? Cowl-having' guys can move the cowl. Got your front fender bolts at the core support loose? Make'em just finger tight, and pull the fender out as far as it goes.

OK lets put the striker back like it was and latch it.

Latch good now? Move the latch and or striker so that the aim is centered, if not. Just get it to close. Here again, just like on the door, we don't want the latch really pulling it one way or the other. we just want an easy click and secure latching. Don't mess with worn out latches unless you like wearing a hood.

If that's not working and it's way off, the core support needs to move in relation to the frame. Loosen the mounts there and slide it over then retighten. Don't be surprised if you have to slot a hole somewhere to get it just right. If everything is unbent, you should be able to use the side to side travel of just the fender front bolts to establish good hood side gaps now. Remember, all the factory rubber bumpers around the hood have a purpose here.

Work with those things until you can close it and have good side gaps, then move on to fine-tuning the latch tension. Use the adjustable stoppers to set the height of the hood corners, then adjust the striker pin length until suitable tension is generated to secure the hood and to pop it open easily. A little slam action should be required to close it.

Now it looks great but the back of the hood sticks up, right?

Well now that the doors, fenders and core support are in the right places, that's easy. If you have good hinges and springs, the hood hinge to fender bolts are where you adjust this.

The hood has to close at the same time as the hinges, to rest properly at the rear. Adjust the tilt, or clock position of the hinge in relation to the fender to fine-tune it. To lower the rear of the hood, begin by loosening the rear hinge bolt(s) and leaving the front tight. Now gently lift the hood past fully open and retighten. That moved the rear end of the hinge(and the pivot point) down. Better but not enough? You guessed it, leave the rear tight and loosen the front, over-open the hood again to pull the hinge front slot up against the front bolt and retighten while holding. You will know right quick if you are going the wrong way but you will also know when you found the sweet spot. Most old hinges and springs have too much slop and sometimes that requires a little push down by hand to fully seat the hood after closing. A few potholes do the same thing. Again remember all the stoppers and bumpers around the perimeter are what holds that heavy hood in place. If any of that is missing, it can adversely affect your overall fit. Also don't forget to tighten anything because loose threads rust fast!

I always backtrack during the process, particularly if any of the parts are replacements. If your render gaps change a little in one place when you adjust another, that's normal and that's why I say don't count your chickens until everything is tight and all the rubber is there. Anyone who follows this procedure and has further questions, Please feel free to inquire. Pictures are most helpful in these situations.

One note about door hinges... do not oil detent roller faces! Oil the pins and bushings, the detent roller spring contact points, and the roller itself but do not lube the roller face or detent bar. Friction is required for them to work properly, so just keep that part clean. If lubricated, the roller can skip over the detents and create flat spots, and this tends to saw off the end of the rollers pin overtime.
  • Formula71, WHITE-68, cwi inspector and 1 other like this

#827831 SCAN9495 - Free Scanning Software for 94/95 LT1 (OBD-1)

Posted by GaryDoug on 16 February 2013 - 03:06 PM

Update: Now have the ability to request and receive selective data from the 94 Formula PCM. It's a long datastream of stuff. I just have to sync with it so it can be automated and more usable.
  • Injuneer, Jaysz28, WHITE-68 and 1 other like this

#827111 Happy Birthday Jerry (Cheats)

Posted by Formula71 on 06 February 2013 - 02:56 PM

I couldn't decide what to get you Jerry.


Posted Image Posted Image Posted Image

some of your favorite tequila

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I knew you were trying to watch what you were eating so I knew cake was out

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Maybe a new car

Posted Image Posted Image

but while trying to choose between all of those, I ran out of time, so I guess I'll just have to say Happy Birthday. Hope you have an awesome day.
  • sixth_sense676, firebird_madness, 84 T/A and 1 other like this

#656045 Fred (injuneer), thanks for all your great information

Posted by djfirebird93 on 04 June 2011 - 03:39 PM

I'd like to thank everyone on firebird nation for all their great information, especially Fred (injuneer). Its nice to have a forum with friendly people who are always helping out, and 9 times out of 10, the information helps solve the problem. Thanks everybody!
  • 1993TransAm, Formula71, CF_TransAm and 1 other like this

#610355 "Performance Chips"

Posted by Injuneer on 27 January 2011 - 12:15 PM

Inlet air temperature is only used to set fuel on engines that run in speed-density mode. That means they have no MAF sensor. If your engine has an MAF sensor, the purpose of the sensor is to directly measure the mass air flow rate (#/HR, grams/sec, etc.) into the engine. As I noted above, if the PCM knows the mass air flow rate, all it has to do is divide the mass air flow rate by the target A/F ratio, and that result is the mass of fuel (#/HR) required to produce that A/F ratio.

In speed-density, the PCM has to go through some more complex calculations to arrive at the mass air flow rate. First, it has to calculate the volume air flow rate. It does this by multiplying the displacement X RPM/2 X the volumetric efficiency (VE). There's the first problem with speed-density. The volumetric efficiency is the ratio of the actual air flow into the cylinders to the theoretical air flow into the cylinders. The better the engine breathes, the higher the volumetric efficiency. A stock engine might have a VE of 80%. That accounts for pressure loss and temperature increases between the intake manifold and the cylinder. A well built engine can approach 100% VE. A highly specialized engine like a NASCAR cup engine, which operates in a very narrow RPM range can actually see a VE in excess of 100%, due to the ability to design the intake system to take advantage of the intake pulse flow, by tuning the length of the intake runner to amplify the pulse flow, providing a mild "supercharging effect".

So now we need to know the VE of the engine, in order to program the PCM. The manufacturer measures this directly from a test engine. Then he programs a table of VE as a function of RPM and engine load. If you change anything that affects the engine's breathing - intake, exhaust, cam, heads - you need to develop new VE tables. And even after you have the revised VE tables, the PCM isn't done with the calculations. Now it knows the VOLUME air flow (eg - CFM), but that's not what it needs. It has to calculate the MASS air flow rate. To do that, it uses the perfect gas law to calculate the density of the air (#/CF). To do that, it needs the inlet air temperature in absolute degrees (deg-Rankin, or deg-Kelvin) and the manifold absolute pressure (in psi, "Hg, etc.).

So there you are - the IAT affects the calculation of the mass air flow in a speed-density system. If you want to "fool" the PCM into leaning or richening the mixture, you could play games with the IAT sensor resistance. This is a popular thing to do in the speed-density 3rd Gen engines, because they are often programmed a bit lean, and richening the mixture, by telling the PCM the IAT is lower than it actually is will richen the mixture. The numbers I've seen used for a 3rd Gen is to tell the PCM the IAT is 57degF, and that corresponds to a resistance of about 4,500 ohms. Works for a 3rd Gen. Will NOT work for a 4th Gen. The only 4th Gen speed-density LT1 is already programmed too rich. The last thing you want to do is fool the PCM into thinking the IAT is lower than it actually is.

If you have a speed-density system, IAT will change the fueling of the engine. If you have an MAF sensor, it will not. The only 4th Gen V8 that had a speed-density system is the 1993 LT1. If you have a 94-97 LT1, or a 98-02 LS1 (or any of the V6 MAF engines), changing the IAT reading will not appreciably affect the fuel delivery. It will affect other things. One is the ignition timing. From my observations, it appears that if the IAT gets too high (say over 130degF) the LT1 PCM will pull about 3-degrees of ignition advance. That is perfectly logical, because as you heat up the incoming air, or run a higher coolant temperature, you increase the chance of detonation (knock), so pulling timing makes sense.

Probably way more info that you wanted, but to me explaining WHY something works or doesn't work is way better than simply typing "No".
  • CF_TransAm, Boyer, brarei200 and 1 other like this

#607023 National FBN Get together

Posted by CF_TransAm on 19 January 2011 - 07:41 AM

Here is an idea if your Firebird or T/A isn't running SHUT-UP, you don't have a say.. If its 500 miles or less I will be there, otherwise doubt it.. Just the way it is..

OK time for me to step in....... This is not all about cars!! This is about PEOPLE and If you want to drive your "daily driver" or even if you fly to the GTG you are welcome to come. :angrysoapbox:

Just remember that this is a club event and your a member and willing to step up and host it speak up!!
If your not a member and want to step up..... fill out an application and join...... but everyone is welcome to attend.
  • FBN Firebird Nation, 1tinindian, sixth_sense676 and 1 other like this

#518397 caught me a scum bag this morning.

Posted by hi_tek_rednek on 30 June 2010 - 12:57 PM

This morning on my way to work. I pull up to a red light in the right turn lane 2nd car back. While wait for the truck in front of me to go. A nissan plows this motorcyclist in the intersection. Then takes off. Well, there was just enough room for my bird to get between the truck and the car in the next lane. Everyone else had stopped and was getting out to help the biker. I fit my car thru and hammered it. The guy had about an 1/8th mile head start on me but within a 1/4 mile i was on his butt (Doing about 120mph at 6:30 in the morning is a rush.) until i could get his tag number. Just as i get it, he decides to make a left turn at about 100. Well he missed the turn and hit the median throwing him into oncoming traffic.(luckly there was none.) I hit the brakes and call 911. Let them know what kind of car, color, where he turned and the tag number. Had my buddy call his fireman friend to find out what happened to the biker. Was a girl on the bike and she only had minor injuries. She rolled good. (like a hotdog on a rotiserie.) No crazy flips or anything. Glad shes ok. She had on full leathers and a helmet. I hope they hang the scum bag for runnin. Bird ran him down good but now i have a crazy shake in the motor. I think its either the fuel pump, injectors or coil. Cause it comes and goes. But i dont care. Small price to pay for catching the azzhat.
  • 1tinindian, SoulTerror, sixth_sense676 and 1 other like this

#433780 3.73's and TrueTrac installed.

Posted by Mark42 on 12 January 2010 - 09:17 AM

Posted this earlier, but I think it got lost in the server move.

Was going to post in the drive train forum, but this is really a performance improvement, so I posted here.

My 98 Firebird V6 automatic coupe came with 3.08 gears and an open differential. This has proved to be very economical on gas, but not very performance oriented. Always feel like the car is lugging when the gas is depressed to go, and always having to downshift to pass.

So.... Had a local trans shop install the 3.73 Summit gears and Eaton Truetrac LSD. The Eaton Truetrac is an all gear LSD, no clutches involved, so it will not wear out with use. Install took longer than planned becuause after taking the car for a test drive, the shop pulled the pinion gear and reshimed to get a better wear pattern and less noise. I supplied all the parts: gears, LSD, gaskets, pinion install kit, and new Reluctor Ring (for 3 series carrier). Was quoted $300 for labor plus extra for broken parts and problems. Sounded fair to me so the shop got my business. The re-shim labor cost a bit and the total came to $385. Not bad for taking an entire day by an experienced old time hot rod builder.

Got past the 500 mile break in period and the gears have quited down a lot to the point of not noticing the slight noise they make. First thing I noticed was the car accelerates quicly with just a little throttle, and pulls very hard as the throttle is rolled on. Slam down the pedal and the Truetrac locks up and tires will just spin. :D The truetrac is really great. Lets me pull up my incline driveway in the snow with no problem, just a little tire spin and tail wag near the top of the hill. Couldn't even get half way with the old open rear. With the passenger side tires off the road in the snow and other other tires on pavement, a little gas will cause one tire to spin for a second until the TT locks and the car drives off nice and easy, no throwing snow/mud all over the car like my 96 Camaro would have with the clutch style LSD it had.

The Truetrac is also very quiet, and under normal driving does not seem to be causing drag on the inside tire. Spirited acceleration from a stop either left or right will cause the Truetrac to lock up and the inside tire to "scuff" the pavement. But it does it without out making any noise; no chatter or clunking noises from the rear.

The engine RPM's are 21% higher in 4th with the 3.73's than with the 3.08 and that really wakes the car up on the highway. Passing is a breeze as the car responds quickly to a little throttle, and downshifting makes it take off in a hurry.

All in all, the 3.73 gears make the car much more spirited to drive. Easy as pie to spin the tires, greatly improved off the line and passing acceleration and all around better feel. The Truetrac keeps the tires planted well, especially in the rain where single tire spin was a real issue.

The whole job, including a PCM update to correct for the speedo, parts and labor came to about $1000. I truely feel this is the single biggest performance upgrade you can make for the money. A cold air intake and stainless steel exhaust w/install will run about $1000 and will not give nearly the performance improvement the gears and LSD make.

I have not got the new PCM in the mail yet, probably in a few days. PCMforless.com claims about a 10-14 hp increase for the 3800 and 1-3 mpg improvement. Will wait and see how it pans out. Right now, accountning for the 21% increase in miles registering, the MPG is coming in at 25.5, compared to up to 27 for the 3.08 gears. Not a big economy hit, and hopefully the new PCM tune will make up for it.

Will keep you posted.

  • FBN Firebird Nation, Injuneer, CF_TransAm and 1 other like this

#431559 Donations

Posted by 79/6.6 on 06 January 2010 - 10:04 PM

I know, noone likes to ask for money!!! I know, even less like to give it away!!! There comes a time, when we ALL have to either ASK or in some cases GIVE. This site is a wonderful meeting place to find FREE information on how to fix your car. In some cases, how to fix other problems. More importantly it is a place to gather with GOOD FRIENDS. Lot's of us would not even be online much, would it not be for FBN. We would not enjoy lot's of the small things we take for granted.
I know for a FACT, that the ASKING in EVERY CASE has been for a most WORTHY CAUSE!!!
So I humbly ask, that any time a member of FBN ask's for a small donation..........GIVE
There are nearly 8000 members last time I checked, if everyone JUST gave $1.00, that would be a sum that would take care of most any need I can think of. I know I spend at least a $1.00 on worthless junk, at least once a day. There is strength in numbers folks!!! Let's ALL reach out and lend a helping hand, when asked... Think if it were us in a predicament, surely you would be most grateful for any help!!!

Hope everyone had a Great New Year, and has a wonderful rest of the year!!!
  • FBN Firebird Nation, CF_TransAm, Pete W and 1 other like this

#1193817 93 Firebird Optispark failure analysis

Posted by GaryDoug on 08 December 2014 - 08:40 PM

This topic is about the Opti that Tony ("ZumpTA") suspected was bad in his 93. He removed it when it was repeatedly failing after only a few minutes of run time.

I tested it on the bench in my "Little Shop of Horrors" and found the fault (hopefully). The Opti would fail after just a brief application of heat from a hair dryer. It fails at 38 seconds in the following video. Watch the scope display go "flatline" for both signals, and the DC current (red display) goes to zero on the power supply in the top right corner.

After the cap was removed, it no longer failed that way, but it did exhibit the same defect mode while being tapped with a screwdriver handle. It appeared that there was a loose connection that happened while the cap and other parts were slightly expanding under heat.

The loose connection was traced to the broken solder connection on one of the two small circuit boards that form the sensor section. This type of Opti has the sensor electronics installed in a large plastic mounting plate (shown below) mounted to the aluminum base, unlike some other ones that use a much smaller single circuit board.

Once the connection was re-soldered, the distributor was reassembled and tested for an hour at 160 *F. There was no failure. Nor was there any signal loss while tapping with the tool as before.

FBN member, Steve ("Birdman350") had the same type Opti with a similar defect last year, only it was the power connection that was intermittent. That is right next to the ground connection. Like this one, his also had no markings to indicate the manufacturer.

Attached Files

  • Injuneer, ZumpTA, 1993TransAm and 1 other like this