firstxj

So, I thought it was my fuel pump but now I am thinking I have a bigger problem. specs: 95 4.0

Motor will turn over but wont fire up. I checked the coil and nothing is coming out of it. Before replacing it I decided to check and see if anything is coming into it and from what I can tell, nothing is. I unplugged the wire coming into the coil and hooked it up to a meter. Got nothing on it. I tried both sides of the plug. Any ideas?

builtnotbought89'

Try unplug the icm from the distributor & try to start it! I know it sounds crazy but it worked on my 89 & started with a rough idel then just pluged it back in & she was fine!

firstxj

Ok, maybe this is a stupid question but what is the ICM?

firstxj

I went out and looked and there was only one wire coming out of the distributor that wasn't a plug wire or the coil wire. So, I unplugged that and replugged it back in and nothing. Any other ideas?

Carl48

You should have battery voltage at the coil on the dark green/orange wire while cranking. Crank the engine for 5 seconds while monitoring this voltage, if the voltage appears for a couple of seconds then goes away, this is usually a sign of no crank position sensor signal. If the voltage never appears, trouble could be the PCM or ASD relay.

firstxj

Sorry for my lack of knowledge, I have always owned old cars/trucks, but what is the PCM or ASD relay? I am not farmiliar with these "abbreviations". Thanks for all your help guys.

Carl48

PCM is the Powertrain Control Module (computer), ASD is automatic shutdown relay. Try cranking the engine while monitoring the voltage to the coil and report what happened.

firstxj

With the help of my wonderful wife we checked the voltage on the green/orange wire and had 0. I swapped the relay with my electric fan relay, which I know is good, and still 0. Any other possibilities or does this mean it is the PCM? Which I hope it is not because they dont seem to be cheap. Also, where is the PCM located? Under the dash on the passenger side?

Carl48

If you are using a digital voltmeter, be aware that they may not instantly register the presence of voltage. If you see even the slightest indication on the meter display when you first start to crank the engine, there may be a momentary voltage present. An analog (needle) style voltmeter or even a 12 volt test light would be a better choice here. The reason is that if there is no crank position signal to the computer (PCM), the computer will shut down voltage to the coil within one or two seconds which may not be enough time for the digital meter to register. Make absolutely certain that there never is any voltage at the coil during cranking before going further and condemning the PCM. In other words, try it again just to be sure.

firstxj

The voltmeter I am using is a pretty nice one and reads instantly but I will get a test light and check it that way, thanks for the tip. If this is still the case, any other ideas?

Carl48

Check fuse #14 (20 amps) in the power distribution center fuse box under the hood. Check fuse #2 (30 amps) also. In fact, while you are at it go thru all the fuses under the hood and under the dash just to be sure. btw, the computer is located on the driver side under the hood above the wheel well just outboard of the air cleaner box but don't worry about that (yet).

firstxj

I checked every fuse under the hood and under the dash and all were good.

Carl48

Well, double check the voltage to the coil with a 12 volt test light as mentioned when you get a chance. btw, do you hear the fuel pump kick on for a couple of seconds when you first turn the key to the "run" position before cranking the engine?

firstxj

I will run to AZ tomorrow and grab a test light and post up with the restults.

Yes, the fuel pump is coming on and the fuel rail has pressure.

Carl48

OK. The reason for the fuel pump question is because the fuel pump relay is driven by the PCM in parallel with the ASD relay...just a quick way to test things.