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Reduced Engine Power Pontiac Firebird 2000 Rate Topic: -----

#1 User is offline   Hockeykid 

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Posted 21 October 2011 - 02:41 PM

Hello,
For the past few weeks the "reduced engine light" has turned on, and my car begins to loose its ability to accelerate. I can probably get it to go about 40 mph (tops), and it take a while of holding down on the peddle to get it this high (acceleration is VERY slow). Sometimes turning the car off and letting it sit for a minute will make the "reduced engine light" go away (although today this didn't work). I took the car to a mechanic and he informed me that the car's fuel pump is starting to go, and the reason it only happens after a while of driving is because it over heats (this seemed odd to me). So after the diagnosis I was able to drive it home (without getting the fuel pump replaced), I decided to call GM and I explained to them my issue and told them what the mechanic had said. Their response was: "That doesn't necessarily mean it's the fuel pump".

Right now I am at a loss, the mechanic said its the fuel pump, GM says it could be something else, and several internet searches bring up a few different reasons. Getting the fuel pump replaced is quite expensive, so I don't want to have to replace it if it is not the issue.

Hopefully someone on here can help give some further insight!
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#2 User is offline   98firebird 

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Posted 21 October 2011 - 03:54 PM

Try to look at every possibility before the fuel pump. You'd have to either drop your rear axle and suspension, or cut a hole in the sheetmetal to get to the tank from above



Here's a link to more info on this topic.
—Travel the road less traveled...
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#3 User is offline   GaryDoug 

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Posted 21 October 2011 - 06:35 PM

The "Reduced Engine Power" light is is an indication of a problem with the drive-by-wire throttle system which is composed of electrical sensors at the accelerator pedal and a throttle-body motor, instead of a cable linkage. The computer in the car detects incorrect readings with either the throttle body sensor/motor or the throttle pedal sensors, then reduces the engine power in order to prevent engine runaway conditions (similar to the ones Toyota has experienced in recent years). Note that your 2000 owners manual indicates that this light is only present in the V6 car, but not in the V8 car. This is because only the 2000 V6 car uses the drive-by-wire system. The 2000 V8 uses a conventional cable linkage, so there is no "Reduced Engine Power" mode necessary in that car.
Unfortunately, unless your mechanic carefully reads the computer error codes (if any), it is likely he will automatically replace the throttle body, which is somewhat expensive. The problem is somewhere between, and including, the throttle pedal and the engine throttle body, including all wires and connectors. If it were me, I would start checking the cables, connectors, and throttle sensors first (because they are less expensive).
See this You-tube video for an explanation of one possible fault causing this symptom. It was created for a later model GM truck, but is still somewhat relevant in understanding what is happening.

http://www.youtube.c...h?v=U2DjMcM_Quk

This post has been edited by GaryDoug: 21 October 2011 - 06:35 PM

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#4 User is offline   djfirebird93 

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Posted 21 October 2011 - 09:08 PM

Had the same issue. Pulled the connector, and there was a lot of moisture in the connector.

On the throttle body that is. The one with many many wires on it.
My bird is a working progress. New Marshall engine-forged pistons, upgraded rockers and stronger rods/bearings. Rebuilt transmission. New LSD. I wish money grew on trees :)
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#5 User is offline   Hockeykid 

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Posted 22 October 2011 - 09:06 PM

Thanks for the suggestions,I haven't had a chance to look at it yet. If it is the throttle body or the connector why does it only happen after a while of driving?
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#6 User is offline   GaryDoug 

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Posted 23 October 2011 - 04:49 AM

There is an electric motor in the throttle body that moves the throttle butterfly valve. That could be failing because of heat-related issues. As could any of the other components. You should get your car scanned for error codes. That might narrow down the problem. If you don't have a scanner, some auto parts stores, like Autozone, will do it for free. Write down all the code numbers, not just the descriptions
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#7 User is offline   WHITE-68 

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Posted 23 October 2011 - 06:29 AM

Had the same issue in a friends car and it was the pump! So not sure what codes its throwing like the other guys said, need to check those first.
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#8 User is offline   84 T/A 

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Posted 23 October 2011 - 07:53 AM

Advance auto will check all codes fro free, ive had a similar problem on a vehicle we used to own, it was the fuel pump. but always check the codes first, thats free, a new fuel pump isnt...LOL
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#9 User is offline   Hockeykid 

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Posted 24 October 2011 - 07:46 PM

Hey guys,
I took it over to the auto-parts store, and it came up as "Fuel Pump", but while I was there I decided to buy some throttle body cleaner. When I got home I removed the air flow sensor, the whole butterfly valve and engine chamber (I think that's the correct term) was black (probably from a back firing issue I had fixed month or so ago)! I've cleaned it out and am hoping that this was the issue, its about 11:45pm here so I haven't had time to take it out for a test drive but driving around for next few days will help me confirm if this was the issue or not.
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#10 User is offline   GaryDoug 

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Posted 24 October 2011 - 08:03 PM

Well there you go. Looks like the "fuel pump" guys were right. Kinda doubt a black throttle body would cause the problem....unless it was sticking. I guess you will find out soon enough.
You may be asking how to replace the pump next ;-)
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#11 User is offline   Hockeykid 

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Posted 24 October 2011 - 08:08 PM

Yeah,
hopefully not, but I'll keep this thread open just in-case ;) (Is it hard?)
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#12 User is offline   GaryDoug 

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Posted 24 October 2011 - 08:14 PM

 Hockeykid, on 24 October 2011 - 08:08 PM, said:

Yeah,
hopefully not, but I'll keep this thread open just in-case ;) (Is it hard?)


Very difficult if you do it the right way. Not so much if you do it the way I did, by cutting a hole in the floor above the tank. Anyway, that's for another day.
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#13 User is offline   WHITE-68 

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Posted 25 October 2011 - 04:36 AM

I wouldn't say "VERY" difficult, but the way Gary did it will suffice. As a matter of fact it's the new trend, and there is a thread on here to walk you through it. Now if I can just find that thread!
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#14 User is offline   GaryDoug 

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Posted 25 October 2011 - 05:14 AM

Well, I would have found it very difficult since my factory service manual specifies that you first remove the exhaust system from the converter back... and the entire rear axle assembly!! I read that several times before I said "no way am I doing that". Anyway, it's not much of a procedure to cut the hole. Just use a method where you are comfortable. I was paranoid of cutting a pipe, cable, the tank, or anything else I couldn't see; so I used tin snips and went very slowly. Mine is one of the ugliest jobs you will find online. The metal is soft and easy to cut by any method. I started the corners with a cold chisel and a 1/2" drill bit (again very slowly). I don't have a photo of the cover I made. I will do that the next time I have the carpet up. Always keep in mind that you are creating a possible safety hazard if you don't make a sturdy cover, since a rear end collision can cause raw gas to spray inside the cabin if the hole is left uncovered by anything substantial. Do an online search and you will find a plethora of information on this subject.

p.s. I was not replacing the pump, but was investigating an EVAP error code and wanted access to the tank connectors and pressure sensor.

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