This '88 has 40k miles on it - and was rotting in the sun for at least six years. I'm trying to recover it.
The first time I drove the car, the throttle response was terrible - even scary. After about 3/4 throttle, the car began to move. At no time did it have the responsiveness I expected. Think about a 36hp VW... uphill.
Today I installed a new TPS, cap, and rotor. Plugs and cables looked fine. Voltage on the low side of the TPS is about 0.5. Compression is about 100psi on the three accessible cylinders (I didn't go the extra mile). Idle cold is about 1100, less when warm.
I know the ECU takes time to "learn" new parts, but when I drove the car after the install there was no difference whatsoever. I warmed it up and tried it again. Same. The throttle problem persists. I inspected the linkage and see no obvious fault.
In its current state, the car cannot be safely driven to a shop for a smog check!
The fuse box has latches on the two sides. Squeeze the latches push up slightly and it will pivot down to vertical. There are two injector fuses. Each controls 3 injectors. Pull one and put it back and then try the other. You will need to give it some extra throttle to keep it running. If both fuses cause a signifigant loss in power/rpm than you know that each bank of injectors are working. If one does nothing and the other one kills it then look to see why one bank is not working (bad fuse most likely).
I put this test first since it is easiest.
Check the fuel pressure and make sure it is in spec.
Finally since the car sat for a long time, what I think is most likely is the fuel injector tips are plugged. You can soak them in injector cleaner and re-install them and that will most likely clean them.
My first guess would be ignition. You could eliminate the obvious and the least expensive by replacing the plugs and plug wires. If that doesn't improve it the next item to replace would be the ignition control module, which is fastened to the base plate on the distributor. ICMs cost more than plugs+wires, but they are the source of a lot of performance issues on the V6 Fieros.
If you replace the ICM, it would be strongly recommended to only use an AC Delco model ICM (AC Delco D1943A), and make sure you apply the entire packet of thermal grease to the underside of the ICM before you install it. Any new ICM should come with a small packet of thermal grease in the package.
Is the crap fuel still in it? Changing the fuel filter after sitting a long time is a must. Any old filters that has a chance to dry out has a chance of the filter element coming apart and sending crap through everything up stream.
I used a fiber optic scope to look up the rear end of the car, and didn't find anything.
I have not yet checked to see if the exhaust system runs hot, but will do so if cleaning the fuel system doesn't help. I'm about to pump out the old gas (yeah, I forgot to do that in the beginning) and change the filter. Hopefully the injectors are ok...
Had a similar problem after recovering a GT that had been sitting over 2 years. Car drove sluggish and lacked any pep. Changed plugs, new fuel pump and filters, new gas, etc. Still no improvement. Took to shop and mechanic believed engine was not "getting enough air" (whatever that means). He suggested installing a new catalytic converter. Put in a new converter and immediately the car ran like a stripped "___" ape. Super fun to drive now.
Took to shop and mechanic believed engine was not "getting enough air" (whatever that means). He suggested installing a new catalytic converter. Put in a new converter and immediately the car ran like a stripped "___" ape.
Engine has to breathe in order to run, which includes being able to "exhale".
This is a picture of the plugged cat from my '86 GT (from This thread.)
The car is in my garage, at home. The tank is now empty, and the 6-year old gas doesn't look too bad. HOPEFULLY, replacing the fuel filter will get it functionalk BUT:
I haven't found a safe way to get it into the air with enough clearance to provide access to the fuel filter. My small floor jack is insufficient..A friend is coming over with a much larger floor jack than mine - hopefully that plus jackstands will do the job. Is there a safe central jack point that will support the entire rear end of the car?
The way it is right now, it really cannot be driven. Once the car is running, I can drive to a local resource and put it on the ramp. At that time I'll drop the tank, blow out lines, drop some of fthe exhaust, etc.
Idles smoothly, though a bit high. Never misses, always feels smooth at any RPM.
But when the accelerator is depressed, nothing happens until it hits the 3/4 area, and even then it's sluggish right up to its maximum RPM - perhaps 2,000.
It's never gotten really hot since I first picked it up.
The next step is to get under the car, hopefully in the morning when Jackzilla gets here. I like the idea of pulling the TPS - I should have remembered that!! And, I'll be able to reach the tank and fuel filter. I have a very bad feeling about the pump, especially if there's a sock on it. It's been more than SIX YEARS without running.
No jack+helper until next week, so did some minor tasks on the car. Drove it around the block with the O2 sensor removed, and it's the same. Max rpm under load on level ground is under 2000. I still think it's fuel. I hate to think about a rotted tank - it's not an item easily found.
The (primary) culprit was ROTTEN FUEL. After draining the tank, flushing, and replacing the fuel filter, the car runs well. The exhaust is clear. This drive was the first to go over 30mph, and I'm happy to report that shifting and general drivability seems fine.
Thanks to the gurus here - and now, BACK TO THE PUNCH LIST
[This message has been edited by notaguru (edited 01-02-2014).]