G
Guest
·This has been an ongoing problem that has seemingly run me dry of possible solutions. I have a VPC (B chip) and AFR on a '94 SP60 6 speed. Basically the car is completely untunable because once we make any modifications on the VPC and AFR, the A/F changes a short time later.
I noticed that Lance at Toymoto had connected the VPC a little differently than the mkiv tech article stated that the vpc should be spliced into the wires on the ECU (I don't have a harness) [I cant get the exact colors of the wires because mkiv is down for some reason right now]. I think the wire from the VPC was yellow. Anyhow, the ECU wire that the yellow VPC wire should have been spliced into was cut and the end from whatever sensor that it was receiving a signal from was left undone. I tried splicing it like the mkiv tech article stated, but unfortunately it did not solve any of my problems.
I have heard a number of different proposals as to what was causing this.
One such proposal was that splicing an AFR into the harness instead of using a GCC can cause interference and prevent the VPC from operating correctly.
Grant thinks that it could be the result of a malfunctioning throttle position sensor (Those engine codes were thrown once).
I thought that it could be the O2 sensor, but the car is terciometric (cant spell it, 14.7 a/f) while cruising. This would also seem to rule out a malfunctioning FJO unit.
I have heard of some single's going lean in the midrange when the stock fuel pump is left in the 9/12v mode. Apparently some people have solved this problem by hardwiring the fuel pump to 12v. I will be trying this tomorrow, however, the car was previously wired to 18v (B&M power plus) and all that did was cause the car to go extremely lean on long trips (possibly by overheating the fuel pump). I later removed the B&M unit and the problem only happens now on even longer duration trips. I will probably be getting dual walbro's in an effort to eliminate any possibility of the fuel pump being the weak link.
I am really at a loss here. Lance at Toyomoto was the one who I paid to complete the install and get the car running right; however, he failed on a number of things (crummy boost source for EBC/wastegate [fixed by me and Grant], wrong settings on AFR [fixed by me and Grant], forgetting to bead the intercooler piping [fixed by Lance after I was stranded on I75], etc.).
I would really appreciate it if anyone had anything at all to offer.
Cheers.
I noticed that Lance at Toymoto had connected the VPC a little differently than the mkiv tech article stated that the vpc should be spliced into the wires on the ECU (I don't have a harness) [I cant get the exact colors of the wires because mkiv is down for some reason right now]. I think the wire from the VPC was yellow. Anyhow, the ECU wire that the yellow VPC wire should have been spliced into was cut and the end from whatever sensor that it was receiving a signal from was left undone. I tried splicing it like the mkiv tech article stated, but unfortunately it did not solve any of my problems.
I have heard a number of different proposals as to what was causing this.
One such proposal was that splicing an AFR into the harness instead of using a GCC can cause interference and prevent the VPC from operating correctly.
Grant thinks that it could be the result of a malfunctioning throttle position sensor (Those engine codes were thrown once).
I thought that it could be the O2 sensor, but the car is terciometric (cant spell it, 14.7 a/f) while cruising. This would also seem to rule out a malfunctioning FJO unit.
I have heard of some single's going lean in the midrange when the stock fuel pump is left in the 9/12v mode. Apparently some people have solved this problem by hardwiring the fuel pump to 12v. I will be trying this tomorrow, however, the car was previously wired to 18v (B&M power plus) and all that did was cause the car to go extremely lean on long trips (possibly by overheating the fuel pump). I later removed the B&M unit and the problem only happens now on even longer duration trips. I will probably be getting dual walbro's in an effort to eliminate any possibility of the fuel pump being the weak link.
I am really at a loss here. Lance at Toyomoto was the one who I paid to complete the install and get the car running right; however, he failed on a number of things (crummy boost source for EBC/wastegate [fixed by me and Grant], wrong settings on AFR [fixed by me and Grant], forgetting to bead the intercooler piping [fixed by Lance after I was stranded on I75], etc.).
I would really appreciate it if anyone had anything at all to offer.
Cheers.