'99 I30 cranks but has no spark or fuel, bad ecm ?

[pmkls2]

Okay, this post is for a co-worker's vehicle so I will list as much info as I can. He went to start the car one morning and it cranked but wouldn't start. He had it towed in to us here ( I work at a cadillac dealership ) and we have taken a look at the car but can only guess what's wrong. All fuses and relays check good. The fuel pump does not have power to it and it will run if you apply 12 volts. We tried starting the car with power on the pump but it doesn't have spark either. A technician tried the security relearn procedure but it didn't help. We also tried pulling codes from the ecm with a matco scanner, but it won't communicate with the ecm. At this point all we can figure is the ecm has gone bad. Any suggestions ?

[maxnix]

I'd try another OBD II scanner measure FP pressure just before the injector manifold feed.

[pmkls2]

It has no fuel pressure at all, the pump will not ever get power. The pump will run, but only if we apply 12v to it. I have another scanner to try, but the car has no spark either which is more than coincidence

[pmkls2]

I checked with another scanner and still no communication. I'm leaning toward the ecm given all of the symptoms, but would like to see if anyone else thinks that

[pmkls2]

We also had a guy fron the nissan dealership next door come and try to scan for codes and he couldnt communicate with the ecm either. I've checked just about everywhere and can't find an ecm at all except for at infiniti and on ebay.

[SteveTheTech]

If you cannot get a scan tool to communicate the primary assumption is usually an internally failed ECM.

You need to do a few things before throwing an ECM at this car.

First pull the intake piping and under the throttle plate remove the two screws for the IAC solenoid and inspect for any coolant puddled in there. A failed IAC valve will take out an ECM with little to no advanced warning. You need to also remove the connector for blue corrosion inside the connector (possibly from a leaking windshield seal or heater core box). If the IAC valve has no sign of coolant and the ECM has no sign of corrosion, check the EC harness on the passenger side bulkhead.

If the IAC valve coolant tube ruptures it can provide a faulty ground through the ECM frying the IC. If it turns out to be something simple like corrosion on the ECM, or a break in the signal wires in the EC harness it can easily be fixed. If it turns out that coolant is in the IAC valve the ECM needs to be replaced as well as the IAC valve. Also there have been a few motor mounts that short out and take ECMs with them. That's not as easy to check though.

Good Luck.

[pmkls2]

We pulled the ecm out yesterday to get the code off of it when checking the availability of a used unit and there isn't any corrosion on the connector there. The owner of the car has also been told by a few other people that it is most likely a bad ground and one place to look was in the main harness on the passenger side bulkhead. There is somebody with some experience with these cars stopping by to check some of the possible ground faults he has seen in the past and I'll mention the IAC valve as well. I have done as much as I can on the car as I am no longer a tech, I retired the tools about 4 months ago and now I'm a service advisor so my time is limited in the shop. I've been trying to oversee as much as possible on the diagnosis as I have more knowledge on nissans than any of the other techs although my knowledge amounts to very little lol. Anyhow, thanks very much for the info. When all is said and done I will post what was found and what it took to correct the problem.

[fixer]

DOES THE SECURITY LIGHT STAY ON WHEN YOU crank the engine. If it stays on then you need to find a good key that is already programmed to the car. If you dont have another key you may have to take it to the dealer to make a new key and program it. The nats system will turn off the fuel pump and works together with the ecm. ck that first . if youn replacve the ecm you will have to program all the keys again anyways.

[Hope_I_Can_Fix]

did you ever figure out what the problem was?