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First, this car is supposed to run a 24 hour race with Chumpcar this Saturday. It has to be in the trailer Friday, hence my urgency.
I have some threads elsewhere on this board but an old problem just resurfaced today. In essence, its running on what seems to be 2.5 cylinders.
First, the car has new spark plug wires, new spark plugs (gapped .034) and a new fuel injector wiring harness. It has a new fuel pump and a new fuel filter. I have a fuel pressure gauge on the rail that shows 39psi with the vaccumn line disconnected and plugged.
It idled fine tonight. I took it out for a short boosted run and it dropped a cylinder or two. It did this at my last race as well.
I pulled the intercooler and put my shop-vac hose from the turbo to the throttle body so I could shoot temperatures on the exhaust manifold. When idling, cylinders 1 and 2 were around 400 degrees. cylinder 3 was around 300 degrees, and cylinder 2 was around 200 degrees. The spark plugs looked good but I put new ones in anyhow, same issue.
I have proper plug wire routing. 1-3-4-2
The funny part is, the car will be sitting there idling terrible, then for a split second it runs fine, then it goes back to dropping cylinders.
Cylinder 1 and 2 seem to be fine. Cylinder 4 seems to be dead. I can't figure out why cylinder 3 seems to be half-live.
I have ordered in a new distributor and TFI module, since the problem does seem to be electrical. Any thoughts on whether this will solve the problem. I still can't rationalize out why the distributor would fire cylinder 1 and 2 but not 4, and maybe half of 3. You can't fire half a cylinder, so I'm thinking that maybe 3 is being fired terribly out of timing.
The car has an old cap and rotor on it. I have ordered in a new one, but the car will shock you senseless if you try to pull a wire off when running which makes me think it isn't that. Which reminds me, if you pull the spark plug wire off any of the cylinders, insert an old spark plug and start the car and ground the old plug, you do get spark out of all the cylinders, which would seem to negate it being a bad distributor or TFI, unless those, when they go bad, would make the car run, but badly out of timing.
I didn't check the TPS voltage, because it seems to me that if the TPS was off, all 4 cylinders would be off. If I'm wrong, let me know.
I'm out of time and ideas and need help fast. Any thoughts?
I have some threads elsewhere on this board but an old problem just resurfaced today. In essence, its running on what seems to be 2.5 cylinders.
First, the car has new spark plug wires, new spark plugs (gapped .034) and a new fuel injector wiring harness. It has a new fuel pump and a new fuel filter. I have a fuel pressure gauge on the rail that shows 39psi with the vaccumn line disconnected and plugged.
It idled fine tonight. I took it out for a short boosted run and it dropped a cylinder or two. It did this at my last race as well.
I pulled the intercooler and put my shop-vac hose from the turbo to the throttle body so I could shoot temperatures on the exhaust manifold. When idling, cylinders 1 and 2 were around 400 degrees. cylinder 3 was around 300 degrees, and cylinder 2 was around 200 degrees. The spark plugs looked good but I put new ones in anyhow, same issue.
I have proper plug wire routing. 1-3-4-2
The funny part is, the car will be sitting there idling terrible, then for a split second it runs fine, then it goes back to dropping cylinders.
Cylinder 1 and 2 seem to be fine. Cylinder 4 seems to be dead. I can't figure out why cylinder 3 seems to be half-live.
I have ordered in a new distributor and TFI module, since the problem does seem to be electrical. Any thoughts on whether this will solve the problem. I still can't rationalize out why the distributor would fire cylinder 1 and 2 but not 4, and maybe half of 3. You can't fire half a cylinder, so I'm thinking that maybe 3 is being fired terribly out of timing.
The car has an old cap and rotor on it. I have ordered in a new one, but the car will shock you senseless if you try to pull a wire off when running which makes me think it isn't that. Which reminds me, if you pull the spark plug wire off any of the cylinders, insert an old spark plug and start the car and ground the old plug, you do get spark out of all the cylinders, which would seem to negate it being a bad distributor or TFI, unless those, when they go bad, would make the car run, but badly out of timing.
I didn't check the TPS voltage, because it seems to me that if the TPS was off, all 4 cylinders would be off. If I'm wrong, let me know.
I'm out of time and ideas and need help fast. Any thoughts?
1987 Turbo Coupe