Freaky problem. ideas please.

[Rickerbucks]

I have a 383 b2b blower LT1.

This is a new motor. I was running around the last few days and I had two WIERD problems. The first time I was running well and then suddenly, BAM, it is running pig rich. So rich it stalls the car at idle. Now at the time I had fan problems and I put it down to be overheated. The car cooled off and I was able to get home. I fixed the fan and no problem.

Three days later and I'm slowly improving the tune and BAM, its running stupid LEAN. Its bucking and stumbeling and I have to increase the VE map by about 15 points accross the board to get it to run well enough to get home. i pulled the plugs and they indicate running rich.

I should also point out that I have been burning a disturbing amount of oil and I'm hoping that the rings will eventually seat better. Would the oil have fouled plugs or the O2 sensor?

I have a log and the (good) tune available - the one that causes the lean condition. I cannot SEE any arching plug wires and I replaced the four easiest plugs. (its a sob to change plugs on my motor especially with headers). I also changed the oil.

Any hints guys? the only tables I MIGHT have fooled with before this happened was the throttle follower map and the map that is suppose to help with tip-in.

Another question. Originally i had a lot of popping on deceleration and the afr read lean. I fattened the BOTTOM of the VE tables to get to the 13.0 afr I want BUT I'm not sure that was the correct way to do it. Anyone able to advise?

One more Q? I also pulled the O2 sensor to clean it. I used WD40. A friend just told me that oyu will ruin a STOCK o2 with WD40. Please tell me I'll be alright?

 

[bruce]

Oil Burning generates carbon flakes in the exhaust which will coat the inner workings of the O2 sensor and ruin it.

Assembling the motor with anything that has any TRACES of silicone will kill the O2.

If the propellant in the WB40, or the WD itself, has any silicone in it, you for sure killed the sensor.

Your randomness of having problems sounds like silicone. If the motor is comtaminated with it from assembly, it'll take a LEAST a few hundred miles to clear the silicone out of the system.

Using lots of oil, I wouldn't even install the WB until that's fixed.

 

[bobc455]

What is your voltage when this happens?

In my car, there is a relationship between the fans coming on and running rich...

-Bob Cunningham

 

[Rickerbucks]

Just updating this in caes any one finds it during a search.

It appears that a 'loose' plug wire was the culprit of the lean / normal tune problem.

Still not sure about the burning oil issue. I have been told by the engine builder to run it up and down the freeway to try and get the rigs to seal. I have done that a couple of days but not really sure if that has helped much. Another friend told me it was about 2 months before his burning oil problem got solved with just driving.

Back on the road after fixing a header leak and making GOOD progress. Getting the 'cruise' driveability is proving to be more of a challenge.