dodge 2.2 turbo II odd efi problem, intermittent rich condition

[Jeff Deifik]

I have a 1987 shelby csx (dodge 2.2 intercooled turbo).
I have the shelby stage II computer, and a rebuilt engine with
mostly turbo II parts inside, with a super-60 cam, turbo, 20% bigger 
than stock injectors, and a super-60-like head. About 10k miles on engine.

While getting a smog check everything was ok at idle, but at 2000 rpm there
was an intermittent rich condition. After some digging around, some blow-by
was found. A leak-down test was performed, as well as a compression check.
The leakdown was 5% in all cylinders, except #3 was 14-15 percent.
The compression test was 135, 125, 125, 150 dry, and 145, 150, 150, 155 wet.
There was also some valvetrain noise. When the valve cover was removed,
there was visible wear on some of the cam lobes. I have heard that no super-60
cam seems to survive beyond 10k miles, due to the aggressive profile, or a 
bad heat treatment. The engine was torn down, and the #3 cylinder wall was
found to be worn smooth, while all the other walls looked fine.

I think that the intermittent rich condition may have been confined to the
#3 cylinder, which may have washed the oil from the cylinder wall, causing
the wear, and the bad leakdown.

I was wondering what might cause this intermittent rich condition.
The injectors had less than 20k miles on them. The o2 sensor had less than
20k miles on it. I run unleaded gas. The engine showed no fault codes.
I had a new cap & rotor and ignition wires & sparkplugs.

I am not sure which cam lobes were getting flattened.
Could a flattened cam lobe cause the intermittent rich condition?
It looked like the top of the lobes had been flattened, which I would guess
would be bad for high rpm use, but should be pretty harmless otherwise.
I don't recall which lobes were flattened, but roughly 4 of the lobes
were showing signs of wear. I can find out.

I will be getting 13% bigger than stock injectors, which I have heard are 
fine for 15 lbs of boost, and which should improve the part throttle fuel
injection metering. I will get a milder cam, and a high volumn oil pump.
I wish to figure out what was causing the intermittent rich condition, so I
don't have to rebuild the motor again at 10k miles.

I will probably also build a o2 led monitor to check for the rich condition.

	Jeff turbo Deifik
	jdeifik at weasel.com		turbo at weasel.com