87 fiero gt

  • Thread starter Thread starter deadfiero87gt
  • Start date Start date
D

deadfiero87gt

I have an 87 pontiac fiero gt v6. i just did a head job on it. the engine idles beautifuly. the issue im having is the car wants to run rich and then lean and when driving it i have an issue in 4th and %th gears with it cutting out and backfiring. the cat does not want to run above 3000 rpm in these to gears after it warms up. any help would be great im going crazy. it has a code for mass air flow but i dont think that my car has that sensor. please help.
 
Honestly, and I am not critiquing your work or anything, But, it sounds to me like you put something in backwards when you did the heads. It would throw off a mass air flow code if you do have the sensor, and, it would explain why the car won't go past 3K rpm's in 4&5. The air and exhaust isn't traveling through properly then it'd back the enigne up causing it to burn lean and then it would 180 and go rich and once the excess fuel is forced out it would run lean again till it had build up again.


This is in no way the solution to your delima it is purely a possibility. Please before redoing all that work wait for a senior member to answer and always get a second opinion from someone who is standing there with the car.

Edit: I was wondering will your car run past 3K rpms in 4&5 when it's still cold? (I know exactly what you want to do, rebuild the head and then run it hard while it's cold)
 
Last edited:
help

yes the car runs ok kinda dogish when its cold but does ok till the engine warms up to operating temp. it seams to consume alot of fuel. when i first put it together i was gettin about 100 miles outta the first quarter tank now i get about 70 out of a half a tank. thank you
 
deadfiero87gt said:
yes the car runs ok kinda dogish when its cold but does ok till the engine warms up to operating temp. it seams to consume alot of fuel. when i first put it together i was gettin about 100 miles outta the first quarter tank now i get about 70 out of a half a tank. thank you
Click to expand...


Yeah I'm gonna say that you might really want to pull the heads back off and re-check your work to make sure that everything was put in the right way. Something just really says cam to me.
______________________________
 
How did it run before the valve job?
When you installed the heads did you adjust the rocker arms properly?
It sounds like the rockers are not adjusted correctly.
You don't need to pull the heads, Just the valve covers and re-check the rocker are settings.

If you follow this link: http://www.fieronews.net/fusion/downloads.php?cat_id=13
You can download the 1986 GM factory service manual. This will have detailed instructions on adjusting/setting the rocker arms for the 2.8L V-6 engine.

If it ran badly before the valve job, It could be a clogging catalytic converter.

Fiero's use a MAP sensor (Manifold Air Pressure) not a MAF sensor.
 
You must log in or register to reply here.

Share this page

Back
Top