Alright. So about about 6 months ago, I bought my 99 EM1 with a full ctr swap. Everything is there harness, P72 ecu, and all the grounds. It ran great until a couple weeks ago. It wouldn't start. And when I went to turn the key the check engine light came on. Then after letting it sit for a couple hours and it starts right up. Then a couple days ago it randomly shuts off while I'm driving. I checked all my fuses and put in a new main relay but no change. I have researched, but no one out there seems to have the same exact problems. What should I check next? Any suggestions?

 

Pull the cel.... it should still be there.

 

A P72 ECU is from a USDM GSR. You have the wrong ECU for your swap. The "correct" ECU for a CTR/B16B is "PCT," which is a JDM ECU.

 

@Chris: Yeah I know. I need to get my P72 chipped on a PCT map, but that shouldn't be affecting my swap like it is. I can't pull the codes because some days it will show the CEL, and some days it won't. Should I just buy an entirely different ECU?

 

pull the code while the car is running.

 

Check the ignition coil in the distributor.

If that checks out, before going out and buying a new ECU, go over the entire engine harness and check for any loose/bad connectors. Check the ECU connections also.

I know you said you checked your grounds but make sure all three (valve cover, transmission, thermostat housing) have zero corrosion on the ends and are making good contact with the metal on the engine and chassis.

When you say it doesn't start, does it crank at all?

 

It will crank and occasionally start, but once it fires the idle will be insanely low and will have no throttle response. Then after 30 seconds it dies.

 

I went to pull the codes last night and my codereader would not connect to the car. Could this be because I have a P72 ECU? Should I get my ECU tuned on the PCT basemap and then try to diagnose the problems?

 

It also has after market injectors(not sure what size). Could that be causing my issues?

 

Yea got the same issues u have. They must of used a different harness or used the stock harness that the car had,is it a SI body? Plus the harness has a short start ur car and move the ecu around and see if the car idles diferent

 

It is the stock harness, I can tell because there are some sensors that have no where to connect. (ex intake manifold) And yeah it's the SI body. Tried to move the ECU around. Didn't make much of a difference.

 

Yea i have the same issues my car turns off for no reason,plus my cluster acts up right before it turns off. Is it a 0bd2 to obd1 using jumper. Plus look to see if they used a Si harness or a ex harness and just cut the wires. Mine i know i have a short in my harness the shop that did it did a shitty job. Bought mine swapped as well and have put a lot of time working the bugs out of it.

 

Also move the wires or tap the ecu and see if it jumps,sometimes mines does it and sometimes it doesnt. My knock sensor and my intake sensor are also not plugged in. Shity swaps.

 

it's probably got an obd1 ecu or jdm. either way a code reader won't work. you have to jump the connector above the ecu. there's plenty of writeups on it.

 

i have an obd2b pct ecu. lmk if you're interested.

 

check the calibration on your tps sensor, youd be suprised what an off tps can do.