Data log is in post 5
Hello fellas. I have been having an issue that causes my car to spike suuuper lean and I can't find the cause. The car jerks and bucks as you would expect it to. It's almost as if I am hitting revlimit, but I'm not. It happens most of the time around 5800-6500 RPM. I have found others that have this issue online, but none of them are turbo and none have MS.
First I was having issues with my IAT, and I thought that was related. The DIY pigtail from MegaSquirt kept coming unseated. I replaced the sensor before I realized this. Eventually I bought a pre-made 6" pigtail from them and since I have had 0 issues with the IAT. That works fine now.
Recently my o2 died for my LC-1. I replaced that tonight and everything looks peachy from there.
Here is a screen shot of where the issue happens. I went through every single sensor there was to make sure nothing funky was going on. I couldn't find anything.
1. I have 100% fixed the Air Temperature Sensor. That is not causing the lean spike at high RPMs.
2. New o2 Sensor - so that isn't causing it either. Now my computer and gauge are a mere 0.2 - 0.4 off as far as I can tell.
3. The car is still jerking and spiking lean at very high RPMs. The previous two shifts before this one here generated no issues. Smooth sailing.
So, the wideband isn't the issue. The IAT isn't the issue. The tune can't be the issue.
Is it possible, that even though my injectors aren't even close to their limit (550ccs at only 7lbs of boost) they are giving up and not injecting fuel at all for a split second?
The problem is intermittent. I can go whole days without the issue, then it will suddenly crop up again. It is not related to the weather at all, or my driving style.
What am I doing wrong?!
And thanks in advance!
INFO about car:
95 Running MSPNP2
BEGI S4 Turbo Kit (mostly) with GT2560
Rather New NGK Wires
MSM Plugs with the stock gap (.040?)
550cc injectors - TLFPerformance - under warranty.
No MAF, only IAT.