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Discussion Starter #1 (Edited)
Hi,

i'm new to this forum, i'have a 87 corvette with l98 TPI engine
and i have a big problem


the engine start and have a good idle but when i accelerate the engine dead .
"check engine soon" light stay on .

i have read the code stored and no code (12 12 12 12 12 12..)
i don't understand
i have set the TPS to 0.54 v and the distributor seem fine
 

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Welcome to DC! :buhbye:

Does the check engine light stay lit when the engine is running?

Have you cleaned the throttle body lately?

Has your fuel filter been changed recently?

Can you rule out any vacuum leaks?
 

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Discussion Starter #3
yes, the check engine light stay lit when the engine is running.

i'have not cleaned the throttle body lately.

the fuel filter hasn't been changed lately , i don't know where is located??

i'have verified vacuum piping and : no leaks anywhere;)

excuse me because my english isn't very good;)
 

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Discussion Starter #5
today ,i have found a code :34 mass air flow circuit.

the problem is constant because the check engine light stay light

play with maf connections don't cure the problem

:(
 

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Ahhh, Code 34 is good to know here. :thumbsup:

You'll need to check the Throttle Body. The best way to tell if your TB needs cleaning is unscrew the IAC from the bottom of the TB and check it's condition. If its carboned up, take the TB off and clean it. The fuel filter is located on the passenger side just behind the wheel well.
 

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Discussion Starter #7
the throttle body needs cleaning :it's black carboned :surprised

do i need change the fuel filter?
 

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It is likely the 2 MAF relays located on the firewall behind the battery they are cheap at $15 each. I did mine and 4500 miles later no SES light...
 

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Discussion Starter #10
i have interchanged the two maf relays connectors (the two relay are the same) and: no change

sunday, i will clean the throttle body and change the fuel filter

i'dont need to change the maf sensor????

:huh:
 

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The shop manual says if you unplug the MAF and conditions improve, replace the sensor. If they do not improve the MAF is good, it could be a dirty TB. When you unplug it you should get a code 33. If you get code 34 again then the wiring or ECM are at fault.
 

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Discussion Starter #12 (Edited)
yes , the check engine light stay off when the engine is running.
:cheers: :thumbsup:

the throttle body was very dirty and the IAC valve was black carboned : cleaning and no code stored

but same problem , the engine start and have a good idle but when i accelerate the engine dead .
:rolleyes:

I have the new fuel filter tuesday :( and the problem is the fuel filter
I have dismounted and put off three time.
the engine is a lot more smooth when i accelerate ,he misfire only after 3000 rpm

there is another filter near the fuel filter? a second fuel filter???

i change the two or not??


thanks :thumbsup:
 
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