80SC CIS problems

gpn · 09-13-2006, 07:52 AM

I am having a frustrating issue with my 80SC track car. It is a 3.2 SC(98mm P?C's), which I still run CIS on. Lots of mods, a 2100# car. Rebuilt engine last winter and it ran fine for two events. I am unable to get power past 5500 or so rpm under load. Here's what we have done so far.

1. Replaced plugs, new coils, tried my spare MSD, new distributor cap and rotor, even tried a friend's distributor and his coils (we have twin plug Andial conversion), nothing
2. Replaced the old fuel pump to the surge tank, and the one to the engine, cleaned the K&N filter out of the cell, put a new one in the back, blew out all the lines. Fuel pressure is good, pressure regulator good, auxilary warmup valve works, no apparent vacuum leaks. Sensor plate moves freely, cold start valve works, but sometimes need to lift the sensor plate get a good squirt to start. Replaced the accumulator, it got a little better, not much.
3. I put on a different auxilary air valve regulator last night. My firiend's SC which runs fine has a pulsing vacuum at the warmup regulator line from AAV, mine just pulled constant vacuum. Will try tonight to run it and see what happens.

This is a Euro SC intake, I have run it in this configuration for ten years, never a burp until now.

The engine will run all the way up to 7000 with no load. Anybody with any ideas, I need it before I take the 12lb sledge to something I will regret.

Thanks in advance for any support.

Gary Nichols
Batavia, Ohio
nichols.surveying@fuse.net

ruf-porsche · ruf-porsche's Garage

Quote:

Originally posted by gpn
Sensor plate moves freely, cold start valve works, but sometimes need to lift the sensor plate get a good squirt to start.
Thanks in advance for any support.

Gary Nichols
Batavia, Ohio
nichols.surveying@fuse.net

For the cold start issue, your sensor plate is probably set to high, when the engine try to start in the morning, air is entering between the gap in the sensor plate so the sensor plate doesn't move up. If the sensor plate doesn't move up the upper chambers of the FD does not get gas. This in turn does not pass gas along to the injectors, hence HARD starting problem.

As for no power under load, I would start by doing a comnpression check of all the cylinders. Since you change every parts that could be causing a problem, the problem may lie within the engine itself.