Okay, I have been searching through the forums looking for reasons that my car would run rich. I read about the o2 sensors and checked mine. I found that the insulation on three of the wires for the right o2 sensor had been burnt(on the engine bay harness.) Put it on the lift droped the y pipe out the way and put some electrical tape on the wires and some new wire loom. I tied the wires away from the headers and put everything back together. I drove the car home and it seemed to do better so I hooked up the laptop and ran a data log on it. We noticed that the long term and short term fuel corrections were both running rich. I raised the fuel pressure to 55lbs and ran another data log on the car. It did great untill it went into a closed loop and then everything went to hell. I am new at fuel injected performance and I am not sure of everything but I am thinking that I may have a bad o2 sensor on the right bank. I read a reply that injuneer posted on the board about switching the sensor but I have not had a chance to do this. I would like to post the data logs that I have when the fuel pressure was at 55 and then when I backed it back down to 43.5 but I am not sure as to how to post them. My wife is mad as hell and says if we dont get the car lined out soon she is going to sell it and I dont want this to happen so please someone help us with this problem. If there is anything that any of you need to know just ask and if I know I will quickly reply. Thanks in advance for any and all help.

 

What size injectors? Do you have a tune?

 

I have 42 pound injectors and Bryan at pcmforless just did my tune.

 

I have seen a lot of mail order tune running rich lately. I wonder what could be happening to make them off so much. I would contact him and see what he thinks. Was it running rich before the tune?

 

Yeah I went from 26lb injectors to 42lb injectors because the previous owner had pulled the vaccum referance of the adjustable pressure regulator so the pcm thought the engine was always at wide open throttle. I had Bryan do the tune because he had done the original tune.

 

Removing the vacuum line from the FPR does not tell the PCM anything. The PCM has no way of knowing if that line is connected or not, no way on knowing what the fuel pressure is, etc. Not having the vacuum line connected means that under conditions where there is high intake manifold vacuum, the differential pressure between the rails and the manifold will be greater than the 43.5psi flow rating pressure of the injectors. That means the injectors would be flowing about 8-9% more fuel than the PCM is expecting them to flow, causing the long term fuel corrections to go below 128.

In any case there is nothing in that scenario that would force you to switch from 26 #/HR to 42 #/HR injectors. This doesn't make any sense at all.

What exactly are the long term fuel corrections for various cells? It hard to understand what you mean when you say "We noticed that the long term and short term fuel corrections were both running rich". Are you saying the BLM's were dropping below 128 to correct a rich condition, or do you mean the BLM's were elevated well above 128, causing a (possible false) rich condition.

You can not post attachments directly to the forums. You have to upload the data files to a free FTP site, then provide us with the link. If you upload the files, more people can open them if you put them in ".csv" format. If you have Datamaster, there is an option to "export" the file in .csv format. If you use the standard .uni format, only people with Datamaster can look at them, and my copy of Datamaster is not in the computer I'm using until Tuesday.