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check eng lght flashes and runs rough HELP!!

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Old Feb 20, 2011 | 02:42 AM
  #1  
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check eng lght flashes and runs rough HELP!!

ok i'm usually anti fuel injection but my 92 tbi has been sittin when i start it it runs rough and the check engine light flashes like crazy it has a new ecm, distributor and tps but i put them all in b4 it was parked about 2 years ago someone help please we've had the car since 92 and i want to just fix everything and use it as my daily driver cause my other car is just too much $$ to drive ever day any ideas anyone???
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Old Feb 20, 2011 | 10:14 AM
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Re: check eng lght flashes and runs rough HELP!!

Well you need to find out why it is flashing. You need to be able to read the computer code. You can buy a cheap OBDII and OBDI scanner from your local parts store to do this.

Only time my light has ever flashed on me is when I changed the computer's prom to a different one that didnt want to correlate with the computer. Other than that I have never seen mine flash.
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Old Feb 20, 2011 | 10:47 AM
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Car: 89 rs, 86 Trans Am
Engine: RS-V6... Trans Am-LG4
Transmission: RS-T5... Trans Am 700r4
Re: check eng lght flashes and runs rough HELP!!

Fuel filter. was it a steady flashing, or more like a random flickering? If it's random and the engine stumbles with the flickering, it's the fuel filter

No codes store for a bad filter, but you dont need a code reader. Your ecm already gives you codes with a paper clip

Last edited by 58mark; Feb 20, 2011 at 10:57 AM.
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Old Feb 20, 2011 | 11:55 AM
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Re: check eng lght flashes and runs rough HELP!!

Flashing check engine light is usually a failure of ECM or chip or chip installed incorectly etc... so i'm not sure you could read codes with the paperclip method...
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Old Feb 20, 2011 | 11:58 AM
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Car: 89 rs, 86 Trans Am
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Re: check eng lght flashes and runs rough HELP!!

That's why i asked if it was a flickering or a steady flashing. Big difference
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Old Feb 20, 2011 | 12:11 PM
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Re: check eng lght flashes and runs rough HELP!!

OK, I know what a steady flash is, and I can imagine what flickering looks like. Flickering to me would seem like a wiring issue. But your saying flickering is a normal function to indicate an error?
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Old Feb 20, 2011 | 12:14 PM
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Re: check eng lght flashes and runs rough HELP!!

More like it's the reaction of the ecm to being starved of fuel by a clogged filter. Happened to me, and my service manual confirmed it
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Old Feb 20, 2011 | 12:18 PM
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Re: check eng lght flashes and runs rough HELP!!

yeah its a flickering and a brand new ecm w/ less than an our of run time thanx alot guys i'm gonna change the fuel filter and see what happens it makes sense cause before my brother gave it back to me he ran it completely out of gas filter may have picked up some sh*t from the bottom of the tank
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Old Feb 20, 2011 | 12:21 PM
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From: Cary, North Carolina
Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
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Re: check eng lght flashes and runs rough HELP!!

Was there any gas additive/preservative added to the car before it sat 2 years? You just can't let gas sit for long periods, it turns into varnish, and eventually into sap (like tree sap). You have to add a preservative to the gas, and run the engine so it gets through entire engine to keep fuel lines/passages from gumming up.

As mentioned, you need a filter - more than likely it's clogged with varnish/sap.

You also need to add a can of SeaFoam to the tank, and run all that gas out, refill (1/2) tank and add another can and run that through. Might go through a couple filters doing this.

If the car is going to keep sitting, then add StaBil to the tank and run that for a few minutes to keep it from gumming up again.
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Old Feb 20, 2011 | 12:54 PM
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Re: check eng lght flashes and runs rough HELP!!

wow I have never heard about the filter either.
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Old Feb 20, 2011 | 01:09 PM
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Re: check eng lght flashes and runs rough HELP!!

Originally Posted by 58mark
More like it's the reaction of the ecm to being starved of fuel by a clogged filter. Happened to me, and my service manual confirmed it
Cool! Thanks! I always like to learn new things about these systems.
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Old Feb 20, 2011 | 03:47 PM
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Re: check eng lght flashes and runs rough HELP!!

changed filter it needed it too but still have problem it flashed a 1-2 code and 5-1 thats a prom error does anyone have one
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Old Feb 20, 2011 | 06:01 PM
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Re: check eng lght flashes and runs rough HELP!!

Flashing SES means that the ECM cant read the prom. The flashing is actually the ECM restarting each time it fails to read the prom. This means that the engine is running off of redundant fueling, which is just controlled by resistors using the sensor inputs to generate a temporary output to run the injectors.

Sounds like the ECM you have has a bad prom, or something else wrong with it.
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Old Feb 20, 2011 | 06:35 PM
  #14  
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Transmission: 94 t56
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Re: check eng lght flashes and runs rough HELP!!

yeah the ecm has less than an hour runtime on it it was a reman i put in like 2 yrs i used to work at the parts store so i'm gonna see if they will swap it for me even though warranty is out might still need a prom though like i said does any1 have one laying around
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Old Feb 20, 2011 | 08:50 PM
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Re: check eng lght flashes and runs rough HELP!!

warranty the ecm and see. make sure to have the battery disconnected when installing the new ecm. good luck.
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