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Discussion Starter · #1 ·
A friend and I received a 1999 v6 5-speed firebird that has been sitting a while (tag expired in 2017) due to what we were told was a leaking intake gasket. before we tore it apart we checked to see if we could get it to crank/fire up. it was stubborn to even try to crank but we finally got it and it did run but misfired and was leaking water from the intake which confirmed the leak. car was able to move under its own power so i pulled it back into the shop and it sat until we got parts for it.

we finally got it back together the other night and the old gaskets were the crappy plastic ones that leak and it definitely looked bad. we were only able to get it to crank on its own ONCE, and it wouldn't even start on its own. it ran on its own before no problem after we put gas in it (had an empty tank). unless the gas has already gone bad then I'm not sure why it wont now. it ran off brake clean, its getting plenty of fuel to the rail. but the main issue is the no crank. starter is getting full voltage, nothing from the signal wire when we turn it and it doesn't crank, i can jump the starter just fine and it works. clutch safety switch? ignition switch? no security light flashing or anything. column is loose and the car does have 233k on it... any help would be greatly appreciated.

i apologize for the long post, i like to be detailed as i can....
 

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So the Security light illuminates when you turn the key on and goes out a few seconds later when the self-check is over? As does the Check Engine / Service Engine light? ...sometimes, "no light" doesn't mean "no problem". There could be a burned out bulb, or, maybe one of the few issues that sets a code but doesn't trip the warning lamp.

Battery voltage is above 12v? The engine is NOT hydro-locked? After sitting, when key turns from off to run, do you hear the fuel pump prime?

If I had to begin somewhere with this, I'd pull the plugs first and make sure there isn't coolant in the combustion chambers. I may move on to testing the crank position sensor next as it was "misfiring".

Did you check for spark? Have you placed an actual gauge on on the fuel rail to take a pressure reading after prime?

Most importantly, since it ran before you fixed it, and now doesn't run after you fixed it, you have made 110% sure everything you removed is reinstalled in it's proper place, and securely connected/seated? ...then you looked over everything you went near and made sure nothing was bumped or disconnected accidentally during the process? Sorry, gotta ask.

The fuel tank being empty is a good thing, and a bad thing. It's good because ethanol was probably the last thing in the tank and not only does ethanol have nowhere near the shelf life E0 has, it likes to absorb water. Nasty stuff. New OEM pumps won't last 18 months sitting in ethanol unless it's of course it's a pump designed for ethanol, which, ours are not. On the other hand, what little ethanol may have been left in the tank (if there was any at all) could have still taken out the fuel pump, or at the very least, weakened it and it's either not strong enough, or that time it started after sitting was coincidentally it's last hurrah.

Just because there is pressure at the rail doesn't mean there is enough pressure at the rail. Injectors could be plugged, or stuck open flooding it out... Hell, the fuel filter could be shot allowing a gradual build of pressure over time, but not enough to actually maintain pressure once an injector opens.

Could be so many things, but, since it was more or less fine before you laid hands on it, that's the place to begin. We ask two questions in Tech Support. "When was the last time it worked?" ...and "What did you do after that." Very rarely it is not something they did without realizing. Guilty myself. 100 times over. Go over every inch of your work, verify it, then look to areas around where you worked. Do it two to three times. If after that you don't spot something out of place or not properly connected, check spark, check fuel pressure (with a gauge), diagnose crank position sensor. ...and at the very least, new fuel filter while you're at it.

If you have a way to pull codes, try to do so. There may be something there. It's most likely there isn't, but sometimes there is and it's the very last place we look to because "no light".


Good luck, and welcome aboard!
 

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Discussion Starter · #3 ·
security light illuminates as well as all the other lights for the system check and they all turn off minus abs, seat belt, and airbag lights. no codes present either. I didn't see any signs of it ingesting coolant/water before hand and definitely isn't now. it wasn't smoking before, no milky oil, etc. engine still turns freely when i jump the starter as i mentioned and still runs off brake clean so its fine there. battery voltage was 12+, even swapped out for a battery from a known running vehicle that was also around 12-13 volts.

i didnt hook up a gauge but the fuel pump is audible and can hear air escaping the more we primed when we first hooked everything back up. removed return and feed fuel lines at the rail to confirm, fuel was coming out of the return, had enough pressure in the feed to make a mess all over me lol.

only thing we changed otherwise was fixed a vacuum line that was broken going to the FPR, and the gaskets, triple checked all connections or anything that would prevent it to run or at least try, we replaced the injector o-rings but that is helping not harming lol.

i even unhooked it and tried just for kicks, didn't make a difference of course, no fuel came out either so FPR is in theory working correctly. gas didn't smell varnished but i guess its possible it could be contaminated or something.

we never disconnected the coil, made sure the injectors were plugged in, map sensor, MAF, throttle body, coolant sensor, IAT, EGR, etc etc etc etc. it has a access panel from when the fuel pump was done before and i even put my hand on it and can feel it working as well as it humming. we have fuel, pressure, nothing has changed anywhere besides the age of the fuel (2-3 weeks max?) and the new parts. we do have a new filter so i guess we can go ahead and throw it on with more fresh gas for kicks. it definitely has spark and can run since again it runs basically off bottle feed still. even double checked firing order etc. made sure all connectors were in still, we stared at the thing for an hour trying to figure it out.
 

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That's a head scratcher. When you said "I'm not sure why it wont now. it ran off brake clean, its getting plenty of fuel to the rail." I took that as "it won't fire now at all" since ran is past tense. What you intended then is "I'm not sure why it wont run now. it runs off brake clean, its getting plenty of fuel to the rail." ...different scenario altogether. :)

So it runs with some form of fluid being sprayed into the intake. OK, same page now.

That still doesn't explain fuel delivery. You're delivering the fuel source with the air charge. Injectors not opening, starter not turning, that sounds like VATS to me but there would be a light for that, and you know that the lamp is good.

How exactly are you starting it? Turn the key to run and jump the starter as fluid is sprayed into the intake?

If it was a neutral safety switch, I could see that shutting down the starters circuit, but can't see how it would affect fuel delivery. I would expect the engine to crank and fire simply by jumping the starter (which it sounds like you did too).

If it was a bad crank position sensor, it would crank and either not start or start and run rough due to misfires. ...and there should/would be a code.

VATS failure will shut down the fuel pump after prime. Sometimes, the engine even cranks. In these cases, the engine at least fires, but dies within seconds due to lack of fuel delivery.

If you're 100% sure it's not a VATS issue, rent a NOID Light kit from Advance Auto/AutoZone (or buy one) or use/make a test light to check the injectors to see if they are getting power and the signal to open from the PCM. That's all I got. For grins, maybe clean the resistor on the key and spray some electrical contact cleaner into the key barrel?

I almost wonder if the VATS module hasn't failed in such a manner that there's no code or lamp for it. VATS is the only thing I can think of that would prevent the starter and injectors from working at the same time. If not VATS, then maybe the PCM itself because "The VATS module controls the starter enable relay and the fuel disable parameter in the ECM "
 

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Discussion Starter · #5 · (Edited)
I guess i was saying "ran" because it technically was yesterday not today lol

I was initially thinking VATS, but i remember watching the light, and as you said it should still do something... Maybe this weekend i can go back over there and i can verify for sure that the light goes off and doesn't flash or stay on. in the meantime ill see if i can test the injectors some way or another.

also seems strange, if it is VATS, that it wouldn't only just occasionally crank and run? to be fair it only did it once after we fixed everything, but my friend manning the key, didn't keep cranking once it did crank on its own.. "i should've let it prime" and assumed it would crank again....

if it is VATS or the PCM, whats involved in doing that, do i have to get it reprogrammed if i replace one or the other, or can i remove it or bypass it or anything? not as familiar with GM's VATS. hence why i really dont want to deal with anything that involves it if i can...

Forgot to mention as well, when attempting to crank, i hear what sounds like a relay clicking, but no lights dim, or change when attempting to crank (attempt meaning, turning the key to start, but doesn't crank/nothing happens)
 

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There is a good knowledgebase for these cars called shbox.com Check it out sometime. I'm going to direct you to one of the VATS pages at that site. It explains the system rather well, as well as discussing methods to bypass/defeat/disable the system.

4th Gen LT1 F-Body Tech-PassKey/VATS

Just skimming over it real fast, under Normal Operation I see they mention the TDM (theft deterrent module) enabling the starter and telling the PCM to enable the injectors. What surprised me though is they begin the paragraph with "The TDM (or BCM) ..."

You have a BCM. BCM's are known issues with these cars (my '93 doesn't have one). Usually when the BCM begins failing it's intermittently manifested in the window and radio circuits. ...this module could be the culprit in you case. If so, good news is the BCM can usually be repaired. It's often just a solder joint that needs reflowed. I don't think they're but $50 to replace either. Could be wrong, but I don't recall them being a high dollar item or hard to acquire.

I've only really dealt with VATS by bypassing my key (unplug key barrel harness at steering column and short the two wires "computer side" with a properly spec'd resistor). I have not had to deal with the TDM, I don't have a BCM, and none of the other modules or bits in the system has given me issue. knocks on wood. My barrel wore out, VATS couldn't read the key, I gave Pontiac several hundred to replace the key barrel (and key), 6 months later, same $#!%. So I bypassed the key barrel. Any key with the correct cut will start my car now. Not very "anti-theft".

As the problem has somewhat of an intermittent nature, BCM's are known to fail with intermittent issues, the problem appears VATS related, the BCM is apparently part of VATS on later models, and you have a BCM, I'm going to keep a finger pointed at VATS.

Unfortunately, even if I'm 100% correct here, anything past this is well out of my scope. Sorry. I have ZERO experience with 6 cylinder 'birds, LS 'birds, or any OBD2 system. What our vehicles share in common is all I can speak to and even then, not with much authority.

I would definitely be looking at the Body Control Module now though. In my mind, it fits the scenario and symptoms, if indeed it is part of VATS.

Hope this gets you pointed towards where you need to be.

Oh yeah, the loose steering column. My wrist-pin is worn pretty badly too. Try different positions and pull down on the wheel. With mine, most positions are so sloppy just the weight of your hand lowers it up to 3". However, there is one spot, just one, where the column is "tight" enough to feel normal and not move around. Maybe you'll have a similar spot?
 

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Discussion Starter · #7 · (Edited)
That's very helpful ill try to look into some of that stuff more, and its all been very helpful for sure, VATS, BCM, etc do seem to be the logical culprit here with the symptoms in question. ill try to do more digging, diagnosing, etc. this weekend and see what i come up with.

Also, seems possible it could be the BCM, the windows work intermittently, which it says it controls. which is funny since when we first picked it up my friends uncle who gave us the car said the windows worked, but they didn't when we tried but did the other night-ish. I'm thinking its BCM/TDR/TDM related at this point since those control starter signal and fuel injector firing. ill probably try to clean the key, cylinder, and check the key cylinder connections and wiring etc while im at it
 

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1994 Firebird Formula 381ci LT1 / TH400+GV O/D
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The Shoebox VATS article covers the differences between models with (96+) and without a BCM. The TDM is incorporated in the BCM.
 

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Discussion Starter · #9 ·
That makes sense, and was kind of the theme I was getting with their wording and when looking for a VATS bypass, which I think I’m going to do as well as maybe bypassing the key signal depending on what I find and what happens.
 

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Discussion Starter · #10 ·
Alright well i have a not so great update. we're getting quite stumped and annoyed at this point. got a VATS bypass, seems to be connected correctly from checking wiring diagrams multiple times, checking for power, and the fact it lights up when its connected correctly. we also had it cranking quite regularly before we installed it, got a new battery because the one it had was just bad and not holding a charge. after we did that, wouldn't crank again. so we figured well we should have fuel now with the bypass so we tried push starting it, nothing. it would just coast in gear. so we still somehow have no fuel? and still an intermittent cranking issue. this has to be some of the most overcomplicated and annoying electrical/security setup i've ever seen or dealt with...
 

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Without reading thru this whole thing again, have you scanned the PCM for codes? There is a code (P1626) for failure of the PCM to receive the fuel enable signal from the BCM.

Have you ever actually measured the fuel pressure?

Did you use a ‘noid light to verify the injectors are getting the ground pulse from the PCM to fire the injectors?

Are you using the 50Hz signal out of the fuel enable signal bypass, as opposed to the 30Hz signal (capability incorporated to allow the device to be used on 93 and earlier models)?
 

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If I'm reading the shbox website correctly, there are two parts to the bypass you are attempting. One bypasses the BCM/TDM which enables fuel, and the other bypasses the TDR (Theft Deterrent Relay) which enables the starter. I see no mention of how you handled the TDR.

Directly from SHBOX.Com:

What to do if you no longer want the VATS
You must do these things if you don't intend to have any of the components operational:
  • Bypass the TDR (to allow starter operation)
  • Purchase a bypass module or have the computer reprogrammed to ignore the need of the signal from the TDM [BCM] (to allow fuel to the injectors)
 

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The BCM (or TDM) reads the key. If it matches, is sends a ground to the TDR and the 50Hz fuel enable signal to the PCM. If the starter cranks the engine, the key detect is OK, and he just needs the 50Hz bypass module. I'm assuming he is calling the “bypass” the 50Hz module. But I could be wrong. I didn’t read all those lengthy posts in detail.
 

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Discussion Starter · #14 ·
Well I was referring to “no fuel” as in no injector power via the bypass, so yes it was to bypass the fuel enable relay circuit, and yes it’s 50Hz

again, I can check pressure but there would be no reason for that to change in such a short time and so significantly, and when I’m still getting pressure on both sides (in/out) meaning there’s enough pressure that the FPR is returning fuel.

I realize there’s also a need to bypass the TDR or starter enable switch but I guess that’s kind of what I was expecting an answer for when I said it’s still an intermittent issue. As I have no idea where the starter enable switch is. Also, while yes I still have no crank, if I have it connected correctly (99% sure I do), the fuel enable circuit should be bypassed, and with the key in “run” should be able to start by jumping the starter or push starting it (since it is a manual after all) correct??
 

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Discussion Starter · #15 ·
My best guess for the intermittent starter signal is just the resistor in the key or the switch have a crappy connection or something so it doesn’t “satisfy” the BCM/TDR so to speak. In which case I suppose I need to find a way to rewire the starter relay, bypass the SER/TDR, or something of that nature to solve THAT part of my issue.
 

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Are the terminals ("bumps") on the sides of the resistor pellet worn down? (I too have not read through this entire thread again.)
 
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