roadtrip120

Note; i will be posting my datamaster file shortly
http://www.students.wtamu.edu/~jy785...run%20test.uni

I installed headers two days ago, the true duals were welded on early today. last night the car race a new best at the track with open headers. 13.3 at 103mph. the car feels real strong at WOT only. It acts like it stubmles driving around town( note- not spark related). Come to find out the O2's go from 700-800( not where they should be) to 13-120( very very lean) only for a second but enough to feel and notice. Earlier today she(car) was running good driving around town, O2's were around 900 ish. I have nitrous on the car not sure if that caused all this or not. The pcm was pulling a MAF system fail a week or two ago, it went away for a while till this fuel system too lean code started showing up. Then the MAF code comes back now and again. I put another MAF out of my 96 chevy z-71 truck, into my z-28 , it still pulled a lean and maf code.

Car halls at Wot, no fuel stumble or lean conditions at WOt o2's at 900's

Any ideas why the pcm is pulling fuel lean codes??(besides the fact that the o2's are in the double digits)
Fuel pump?
Electrical?
Nitrous?
MAF bad and the trcuk one didn't show?
Just a piece of crap?

roadtrip120

Forgot

The first time the light came on was right after i race a gsxr 600. with my 150 shot, after that i guess it seemed to drive funny/ fuel stumble, or go lean all of a sudden

Injuneer

If you post the logs as a ".csv" file, rather than the DataMaster ".uni" format, anyone can look at them. Only DataMaster owners can open .uni files.

roadtrip120

datamaster has a free trial

What does fuel in the vacume line of the fuel presure regulator mean??


Fuel presure is fine at idle

smoknta

If you can pull the vacuum line of the regulator and get fuel out the vacuum port, the fuel pressure regulator is bad.

shoebox

Your point is??

It would be arrogant presumption if you are suggesting someone go to the trouble to download and install a program they might not want on their computer, just to look at your file. Especially when you could export it as a .csv, as suggested, so nearly anyone with a spreadsheet program could look at it.

If that is not what you meant, then I presumed too much.

TobyZ28

If ya post the CSV ill have a look at it

roadtrip120

I'll be able to post it around 5:00pm,
i didnt realize it was that easy to export as csv

roadtrip120

Here it is is csv form

http://www.students.wtamu.edu/~jy785...drag%20run.csv


Notes

816 stumble
1440 stumble
1911 2nd gear to 5th race
4756 stumble for 5 sec
5447 stumble

Im thinking the opti sensor that controls the injectors is going out. Im going to hook up a test light to the injectors in a bit, and see if there is an unusual pattern at idle.

95Z-Cross-Eyed

You said you just installed new headers. I done this as well. I have read several post about when you burn in headers they can cause an O2 to go bad. I had this happen on one of mine. it got real lazy after I put the new motor in and installed a new set of denso O2's when I also installed some new coated hooker long tubes. I think its something to do with the coating. My O2 got real lazy at idle and will throw a code at times. Just food for thought.

Mike

roadtrip120

But if you look at the file you will notice that the O2's only drop after the injector duty cycle and pulse width fall or drop to "0". Something is wrong with the not enough fuel at small amounts of time.

Im thinking opti, but its an expensive quess.

Has anyone else had problems with the opti not sending signals to the injectors???

Injuneer

I'm glad you said it, Rob. Offer to help and you get that kind of a response. I have a comple Excel system set up for analyzing the data, so why would I want to play with DataMaster? 100's of people have managed to take the time and send a .csv file so I could look at it.

roadtrip120

Have you had time to look at the csv file yet?

Any reason why the injectors drop out for a sec then come back??

TobyZ28

If your car is running remotely ok, then your oxygen sensors are very messed up and your opti is probably ok.
If your car is running absolutley horribly almost all the time its your opti messing up timing and your oxygen sensors are also probably shot.
I'm guessing its your O2's from what I could tell in the CSV
Mind you the injectors showing no signal for brief periods of time seem really weird. Happens only when your O2's are about to go really really lean.
Your MAF looks fine to me....

roadtrip120

Should the car still perform if i unplug the O2's?? I dont realy have the money to buy new O2's.