743power

I just swapped a 97 gsr motor into a 94 ls. Everything is fine except when I try to use a chipped p28, the car wont rev past 4000rpm, like its in limp mode. When I use the stock ls ecu, it works fine. I'm trying to figure this out, and its really bugging me. The only thing I can think of is that the knock sensor is not sending a signal to the ecu. I tapped into the red/blue wire on the passenger side shock tower harness and ran it to D3, if my memory serves me. The problem is that I was using the ecu pin from an obd2 ecu harness and they are different than the obd1 ones. Any answers to my many questions?

Newman

When it doesn't rev past 4000, usually the chip is bad, or the install was done incorrectly - especially when your stock ECU works. The car will still run just like normal w/out the knock sensor, but it'll make the ECU pull back on the timing and eventually throw a code. But it will still allow you to rev it past 4000 rpms. Might want to check the P28 itself and whoever did the chip install and to check the ERPOM and the soldering job.

743power

is there any visible way to inspect the erprom with the chip off for damage or loose connection? What should I look for? Any pics?

redhcsi

a p28 doesn't use a knock sensor

eg6ajk

make sure the chips you're inserting are pointing the right way or where pointing the right way otherwise they are PITA, most will burn out. if thats fine. then the other problem could be the distributor sensor difference. I have noticed that some 94-5 cars require a 94-5 type ECUs otherwise you won't rev past 4k and get a code 15 (Ignition output signal).

if that keeps happening check if you have a wire at A11 and/or A24, if either is present then add it in and splice it to the other.

otherwise, email me and will go from there.

743power

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eg6ajk &raquo;</TD></TR><TR><TD CLASS="quote">make sure the chips you're inserting are pointing the right way or where pointing the right way otherwise they are PITA, most will burn out. if thats fine.

if that keeps happening check if you have a wire at A11 and/or A24, if either is present then add it in and splice it to the other.</TD></TR></TABLE>

What do you mean by the chips being in the right way. When I got the ecu, the writing on the chip read right when the lid was off and the chip was on the lower right hand corner.