|Originally posted by Rich Truett:|
So...I recently bought a 1988 Formula from the second owner, a retired GM engineer. Total mileage: 55,000.
The car appears to never had a tuneup. I replaced original spark plugs, cap, rotor, wires, etc.
None of the maintenance cured a nagging problem: When cold, the engine runs very, very rich and will not rev past 3,000 or so RPM.
The codes thrown were 34 and 42.
I replaced the 02 sensor, the coolant temperature sensor, the MAP sensor. I found and fixed three vacuum leaks, including the EGR tube, which was cracked. I cleaned the upper intake while it was off and the throttle body as well.
The previous owner did recently replace the Ignition Control Module (ICM).
Finally yesterday, on a whim, I replaced the ICM and lo behold the car runs perfectly now. steady idle at 900 rpm, starts nicely when cold.
A few remaining small items to fix, including the dreaded trunk-side exhaust manifold.
There is a tube that appears to just stick in the bottom part of the throttle body. I can see that producing a small vacuum leak. Is there supposed to be any kind of sealer/o-ring around this tube? On my car it just fits inside.
What is the best way to remove that trunk side exhaust manifold. You can't see most of the manifold bolt from either the top or the bottom of the car.
BTW: This is my first Fiero since the early '90s. Neat car.
Hi Rich, welcome to the forum.
About the throttle body...it has an o ring seated outside the metal tube to seal with-in the throttle body. The bottom of the tube goes into the lower
plenum. I suspect this is what your asking about. Like you mentioned you took the TB off for cleaning. That would of been the best time to
see the o ring seal inside. The o ring is seated in a groove in the throttle body. This...you need to have.
I hope you replaced the ICM with a new AC Delco unit. The aftermarket ICMs have a tendency to have a short life. Make sure to add some heat-sink
grease underneath the ICM and the 2 screws are very clean, or install new GM ones at 10$ / pr. I'm saying this to benefit you to have a trouble free ignition
system for years to come.
One pointer about the cracked manifold. Most folks don't know this, but don't open the deck-lid when its raining and the engine running. Try to avoid that.
The reason is the water from above falls on to the hot manifold and that gives a temperature shock to the steel and the manifold will crack over time.
Have fun with the car, and you did a good choice getting an 88.
88 GT, Loaded, 5-speed.
88 GT, 5-speed. Beechwood interior, All original.