10-24-2007, 01:37 PM
Join Date: Jan 2007
Location: Newnan, GA
Total Cats: 27
This may be a long read, but I want to cover everything.
My car suddenly started having an issue Monday night when entering boost, it acts like the fuel gets cut off, then on, then off, basically hesitation, stutter, whatever you want to call it. When it cuts fuel (feels like I slam into a brick wall), AFR goes completely lean, and then goes over to 11.9-12.5, and bounces back and forth as long as I stay on it.
During idle and cruise, AFR is 14.6-14.9. Acceleration is completely normal (and strong even) as long as I stay out of boost, if I even touch 2 psi, this happens.
I did a seach on here, and went through some of the same troubleshooting methods others have tried. Checked wires (Magnecor 8.5mm), replaced plugs (NGK BKR6E-11 at .035" gap, which is how they've always been gapped with no problems), checked my grounds (had an issue where the wire from the battery broke at the grounding point in the trunk, but fixed that), checked all of the vacuum lines, intercooler piping, everything is how it always is.
Also, I've not done anything to the car lately except a tranny and differential oil change, and the last major modification was the DO Water Injection kit, and at the moment, I've turned the controller start point all the way up so it's not spraying at all. But when it was set, it operated correctly, and had done so for the few weeks it's been installed. Had it set up to come on at 5 psi, and set the shutoff on the progressive controller way over to 25psi so that it was not spraying too much since I haven't had a chance to get everything tuned. AFR stayed within normal reading boundaries during this time.
Fuel pressure readings are still consistent with what they have always been, so that leads me to believe that the Walbro pump and the fuel filter (which was replaced about 18k miles ago are ok). Just put a fresh tank of gas in it today with no change.
I'm wondering if the stock o2 sensor needs replacement, because it still sends readings to the Link as I have not had the opportunity to hook up the AEM UEGO to the Link. But if it was bad, wouldn't my idle and cruise AFRs be crappy?
Anyway, car is a 1995 w/ FMII turbo kit and Link EMS. 12 psi at the moment, have had it up to 15psi with no issues. I had the Link hooked up to a Palm M500 (PLink program) a while back, but the Palm became nonresponsive about a 6 weeks ago, so I unhooked it and haven't used it since. So no changes to ECU settings could have been made, and I never had the chance to change anything with it hooked up anyway because I hadn't gotten a chance to really sit down and mess with it.
Any ideas will be great! Thanks in advance!
Last edited by RotorNutFD3S; 10-24-2007 at 02:18 PM.