Starts and idles. Dies as soon as throttle is hit (Page 1/3)
ChuckR JUL 29, 09:29 PM
Good afternoon. This past Friday my Fiero stranded me. It was running fine, then it started sputtering a bit on acceleration. I got it to my destination and turned off the car. About 2 hours passed and I went out and the car would start and idle then die as soon as the throttle was given. You could smell gas very strong. This says to me that it is flooding. In my research I have seen O2, MAP, and coolant temp sensor listed as causes. Now it will start and idle for a few seconds and die. Car is the 2.8 88 GT. Any help or suggestions would be appreciated. Tomorrow I will go out and jump the ALDL to see what trouble codes flash, if any. Also the EGR was deleted physically, just not sure if it was in the computer. It was running fine for a full week. As long as I have had this car... I will start figuring out hoe to test the MAP. I did try unplugging the O2 to see if the computer would revert to base code. That didnt have any effect. The PO says he put new injectors and fuel regulator on the car since it sat for 8 years. He did give me a box that has a brand new EGR and tube (braided from the fiero store) I am not sure if the Solenoid is still there or not, I need to figure out where it is supposed to be located. I read that the vacuum line to the MAP sensor can get clogged with carbon. I went to locate the lines and it seems they run under the intake and disappear. does it connect under the intake? Thanks in advance for any help!

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"HICCUPP" 1988 2.8 GT Ocelot SS exhaust

Patrick JUL 29, 09:44 PM

Put a fuel pressure tester on there... to not only see what the fuel pressure is while the pump is running, but also to see how quickly it drops when power is cut from the pump.
Doug85GT JUL 30, 12:42 AM
Start the car then shut it off. Pull the vacuum line off of the fuel pressure regulator. If you smell gas in the vacuum line, it means the FPR diaphragm has a hole in it and needs to be replaced.

Check your timing if you can. If for some reason your distributor got loose and moved a lot, it can cause similar problems. I would take the cap off and make sure the rotor and everything on the inside is still in decent shape. I have seen rotors come apart but usually when that happens the engine won't fire at all.
ChuckR AUG 06, 09:15 AM

quote
Put a fuel pressure tester on there... to not only see what the fuel pressure is while the pump is running, but also to see how quickly it drops when power is cut from the pump.



Ok finally got around to this, I had birthdays and life...

Key at on position 24 PSI. Key in off position 22 PSI after a couple minutes.
Cranking 30 PSI
Car quit starting...
holds 28 PSI after 10 min.

Also took off MAP and cleaned with MAP cleaner (pretty sure this is just an electronic connector cleaner that CRC has labeled MAP to charge more... no change, car did start and idle for about 30 seconds and did respond to throttle. No longer starting again. Car was cold and sitting for days before this attempt to start. now will crank and sputter with no start, still smell gas. Not sure if MAP cleaner was the ignition source on the start and run. I think maybe I am getting a cold spark, next I am checking the Ignition. Any other ideas would be welcome. The Factory service manual is not as through as I hoped it would be compared to newer cars...
ChuckR AUG 06, 09:48 AM

quote
Originally posted by Doug85GT:

Start the car then shut it off. Pull the vacuum line off of the fuel pressure regulator. If you smell gas in the vacuum line, it means the FPR diaphragm has a hole in it and needs to be replaced.

Check your timing if you can. If for some reason your distributor got loose and moved a lot, it can cause similar problems. I would take the cap off and make sure the rotor and everything on the inside is still in decent shape. I have seen rotors come apart but usually when that happens the engine won't fire at all.



I figure since I am holding fuel pressure for over 10 minutes there isnt a hole in the FPR diaphragm. I am will be checking ignition next. I feel like this maybe where the problem is. I think the start and run I had was due to the cleaner that I used in the MAP lines and I get a stutter after a long time cranking, so I am thinking maybe the engine is flooding due to miss timed / cold spark.
ChuckR AUG 06, 11:53 AM

quote
Originally posted by ChuckR:


I figure since I am holding fuel pressure for over 10 minutes there isnt a hole in the FPR diaphragm. I am will be checking ignition next. I feel like this maybe where the problem is. I think the start and run I had was due to the cleaner that I used in the MAP lines and I get a stutter after a long time cranking, so I am thinking maybe the engine is flooding due to miss timed / cold spark.



I should have done this first... I have a code 33, 34 - MAP sensor issue.. I also have 42 EST Fault.

It did start again, ran for a few seconds and died again and will not restart.

The MAP codes may be from when I had the MAP unplugged to gain better access to the fuel pressure valve and cranking to get a pressure reading. Being unplugged should give those codes I would think. Also plugs look good except covered in gas from flooding. Wires are new, cap and rotor are new. Now the original owner has installed an MSD coil and it is wired in aftermarket not with a standard weather pack connector. Now all of these look to be wired well using spade wire connectors. I take it that the Ignition module is the black box under the cap that has 2 wire harnesses plugged into it? One of which is going to the coil the 2nd passes under the intake. How do I test the IM? From what I have read it sounds like it could be the IM not working, or the ECU or bad wiring. Could it jumping timing on the distributor cause this?

Here is the timeline:

Car running well for 1 week. Friday afternoon throttle started to bog while driving. If pedal pumped it would push through and accelerate with a lot of sputter. giving gas hard seemed to flood it. Parked car for a few hours, came out to diagnose and it would idle but as soon as you touch the throttle it would die. Get car towed home, car will not start. Leave sitting for about 2 weeks and that brings me to now with all I have already described. I dont want to start throwing parts at it blindly. That will get expensive fast. top of my mind would be MAP, Ignition Module, and TPS maybe??
Gall757 AUG 06, 11:58 AM
MSD again..................

do some searching on this site about MSD ignition systems; very likely part of your problem.

also note, the Fiero has a non intuitive throttle setup where you actually 'clear' the fuel by depressing the gas pedal....the opposite of carburetor cars. The computer decides how much fuel to send based on sensor information, so a bad sensor can make the car appear to be flooded.

[This message has been edited by Gall757 (edited 08-06-2019).]

Patrick AUG 06, 03:10 PM

quote
Originally posted by ChuckR:

Key at on position 24 PSI. Key in off position 22 PSI after a couple minutes.
Cranking 30 PSI
Car quit starting...
holds 28 PSI after 10 min.

I figure since I am holding fuel pressure for over 10 minutes there isnt a hole in the FPR diaphragm. I am will be checking ignition next. I feel like this maybe where the problem is.



Those fuel pressure readings are way too low.

I'm not trying to give you a bad time, but when you went through the trouble of testing the fuel pressure (as advised to do), did you not also look up what the readings were supposed to be?

What is an acceptable fuel pressure "range" for the V6?

[This message has been edited by Patrick (edited 08-07-2019).]

fierofool AUG 06, 05:06 PM
I agree with Patrick. The pressures are too low. Just as a possible cause, change your fuel filter and see if the pressure rises before assuming it's the fuel pump.
ChuckR AUG 06, 06:13 PM

quote
Originally posted by Patrick:

Those fuel pressure readings are way too low.

I'm not trying to give you a bad time, but when you went through the trouble of testing the fuel pressure (as advised to do), did you not also look up what the readings are supposed to be?

What is an acceptable fuel pressure "range" for the V6?




I did read on it but I must have looked at bad information as I thought the 24 PSI holding was normal and since I couldnt get it to run the 32 sounded ok... . I will change fuel filter and see what shakes loose at worst I am out 5 bucks.
To clearify it should be at 45 PSI not running and drop when it is running to around the PSI I had while cranking?

I am still going to take care of those spade connections by soldering and heat shrinking then taping.

So if it is low pressure why does it smell like gas and flooding? Also when I pulled spark plugs they were soaked in gas.