About 6 weeks ago my car decided it wouldn't start. It had no spark, so I figured it was a broken ground wire. I figured out later that it also isn't sending a pusle signal to the injectors. I have swapped the pcm, swapped the harness for another I have, changed plugs just to be sure, and installed new cam and crank sensors. The fuel pressure is a steady 58psi. I even checked all the wires on the harness I removed and didn't find a problem with it. The engine cranks over fine. I even tried jumping it to make sure I had good voltage.

Any ideas.

 

I lost my PCM a few years age and replaced it with another one and it would crank but not start and i found that it was the PCM need flashed with the cars original tune because of the security system ,(it pacific to your car.) I had to take it to the dealer so they could flash with the vin number ,Plus the passive key II plays a part in it. And the BCM (body control module) also check all fusses in the car and under the hood.

 

Mine car is a conversion, with no BCM. The newest PCM has the same vin as the original one and for now a wait4me tune.

 

Anyone else?

 

Any DTCs? seeing RPM move in the scan tool when you crank it?

 

No DTC's at all on the first pcm, but I haven't checked this one yet, since the symptoms are the same. I am completly lost on this one.

 

did you check for voltage at the PCM while cranking?

 

Yes, I did it with the mounted battery and then when I was jumping it. What do you think is the minimum it needs to start and run?

 

If you aren't seeing RPMs, that sounds like the crank sensor isn't working for some reason. Check voltage and ground at the sensor, and check continuity for the signal wire between the sensor end and the PCM end.

 

put a scan tool on it and see what your cranking rpm is

 

I know the harness continuity is good. I just swapped the harness and checked every wire before I hooked it up. It was also good on the one I removed. I also just swapped the crank sensor and nothing changed, but I'll check again just to be sure.

 

i had the same problem after an engine swap, clip replacement on a 99 z/28 the small ground wire (on the f-body) that bolts up by the radiator support wasnt hooked up, and i had the same symptoms.

 

it needs atleast 12v going into the PCM on the IGN+ inputs, i had the same problem with my conversion (no spark) and it turned where i was taking my switched ignition from was dropping to 6v when i would crank it, but a faulty ignition switch could cause a similar problem... an easy way to check it is to get a meter and check the voltage @ the pink wire in the main ignition coil connector on either side while cranking the engine.

 

when then things don't make sense, it's usually because you are making bad assumptions. Assume nothing, test everything.

 

Well, I figured out what is causing it not to start. It's only putting .02 volts to the crank sensor. Now I just have to figure out what is causing that. I scanned it while cranking the starter and it wouldn't register any rpm's or injector pulses. I expect that to be because of the lack of voltage going to the crank sensor.

 

A quick update here. I took my the new pcm and my original harness to the work bench. Wired it up and couldn't get any power to the crank or cam sensor. Swapped in the original pcm and it had power. Put it back in the car and the damn thing started in less than two revolutions of the engine. Looks like I get to return the pcm for exchange. I have no idea why it wouldn't start in the first place, but it will now and that's all that matters. I'll have a spare pcm and automatic harness for sale in a couple of weeks.

 

Its most likely in the distrubtion block, my car had a similar issue so I replaced the gorund underneath and it was good as new.