CEL does not come on, truck won't start. checked relays.

[V Maxima]

Hey everyone, this is my first post here. I've been lurking on and off. I'm trying to get a 98 5.0 running again after a couple years of it just waiting for someone to use it. A few weeks ago, I tried starting it up and I'd get the engine to crank but not start. I sprayed some carb cleaner into the intake and it would start and then die, so I figured it was the fuel pump. I replaced the fuel pump. And it started and ran beautifully (ignoring the leaking EGR pipe) but I found a radiator leak. So I replaced all the cooling components except the water pump. No more leaks but it won't start now.

Now I can't get it to start again. It cranks but it doesn't run. I did a search and found to check the CEL if it comes on with the "key on but the ignition off." That is what I see, so I checked the relay for the PCM on a 12V power source and they are functional. I also visually checked the fuses.

How do I trouble shoot this further? I hope it isn't the fuel pump again. I have the Haynes manual but it doesn't help at all.

Thanks in advance. I really appreciate it.

 

[V Maxima]

I just found a post from a search on "PCM". I'm going to test tomorrow.

http://www.explorerforum.com/forums/showthread.php?t=257954&highlight=pcm

 

[BrooklynBay]

Jump the connection in the PCM relay socket. The coil in the relay could be good, but the contacts could be bad.

 

[V Maxima]

Did a quick test early this morning, jumping the contacts at the PCM relay socket. I got a bunch of other relays activating when I placed the jumper. I tried to stat the truck, but still same symptoms of no cel at any time, and then cranking but not starting. So I guess the PCM is still getting power but the CEL bulb is out????!?!?

Going to go get some starting fluid or carb cleaner to try to start the truck. And then I'm going to test the fuel pump side of things. If it ends up being the fuel pump I'm cutting a freaking access hole.

 

[BrooklynBay]

Test the wiring connected to the PCM to see if it's getting any power. It might have a bad ground connection or a blown fuse.

 

[marragtop]

If you think the PCM is working, check for power at the inertia switch connector. If you have power there then the problem is between the inertial switch and fuel pump. I'm assuming you do not hear the fuel pump prime when you turn the key to on. Correct?

 

[V Maxima]

How do I check power at the PCM? Or do I check the power for the PCM at the relay? I also see some diodes, should I even bother with those?

I cannot hear the fuel pump, should I be able to hear the pump regardless of the brand of pump that's in the tank? I'm having trouble checking for power at the inertia switch. Do I jumper and then check voltage across the jumper while I turn the ignition to on? If I can check the fuel pressure at the rail will that be sufficient for checking the function of the pump?

Sorry for all the questions. I've never had to trouble shoot something like this before. And once again I really appreciate all the help guys.

 

[BrooklynBay]

The fuel pump can't turn on unless the PCM turns on. The PCM has a bulkhead connector. Use a test light or a DMM to check the pins in the connector for power. A schematic diagram would tell you which wires are hot (+).

 

[V Maxima]

I am getting power at both the PCM and the inertia switch. I tried spraying carb cleaner (as starting fluid) into the intake and then starting the truck, but still no go. I'm now thinking it may be an immobilizer problem. I checked and the 98 Explorer should still crank but not turn over if there is a problem with the PATS. I'm not sure how to pinpoint that it is indeed a problem with the immobilizer.

I might pull the gauge cluster to check that the CEL bulb is out. This is pretty frustrating. I kind of wish it was just the fuel pump again.

 

[celly]

I might pull the gauge cluster to check that the CEL bulb is out. This is pretty frustrating. I kind of wish it was just the fuel pump again.

Why not just turn your key? All your dash lights come on then. It's the idiot proof and simple way to check to see if your CEL bulb is working.

 

[V Maxima]

The CEL light does not illuminate, thats what led me to initially believe my PCM was out. But I get power at the PCM.

 

[celly]

The CEL light does not illuminate, thats what led me to initially believe my PCM was out. But I get power at the PCM.

My point was that ALL bulbs that are working should illuminate when you turn your key regardless of whether the function being monitored is working or not. If the light doesn't illuminate, then your bulb is burned out. Don't pull the cluster just to check the bulb. The key method is MUCH quicker.

 

[2000StreetRod]

Drain the tank?

. . . I'm trying to get a 98 5.0 running again after a couple years of it just waiting for someone to use it. A few weeks ago, I tried starting it up and I'd get the engine to crank but not start. I sprayed some carb cleaner into the intake and it would start and then die, so I figured it was the fuel pump. I replaced the fuel pump. And it started and ran beautifully (ignoring the leaking EGR pipe) but I found a radiator leak. . . . Now I can't get it to start again. It cranks but it doesn't run. . . .

Did you drain the fuel tank and replace the fuel filter before trying to start the vehicle? The fuel would be bad after sitting for a couple years.

 

[V Maxima]

I found out that there is a parasitic draw on one of the fuses in the cabin. I'm going to figure what is causing this, as this could be a short causing all my problems.

Regarding the CEL bulb, I'm just going to leave it and assume that it is the bulb, per celly.

 

[V Maxima]

I did replace the fuel filter with the fuel pump and all the fuel.

 

[budwich]

The CEL light does not illuminate, thats what led me to initially believe my PCM was out. But I get power at the PCM.

Please tell us how many power points you found at the PCM????

I assume your truck has a computer controlled fuel regulator (no return line)... please confirm as the testing is a bit different. However, IF is the "old standard" fuel return type, you should be seeing fuel pressure on the fuel line.

Go back to basics.... of course, you checked all your fuses right????

 

[V Maxima]

I only tested the 12V going to the PCM from the PCM relay. I checked the voltage at the pin on the connector. But this is all moot now, because I pulled the cluster and the CEL bulb is indeed blown. I haven't replaced the bulb yet, but if the bulb ends up working and the light functions as it should if the PCM is getting power. Then I am left with either the fuel pump or the PATS system.

I didn't get to find the parasitic draw on the system. I removed the fuse in the engine bay which apparently is the fuse for the fuse box inside the cabin, and now there is no more current draw. So until that starts again, I can't use that to help find my problem. I'm going to be cutting an access panel sometime this week so I can pull the pump, test it, and inspect the wiring.

Budwich, I did check all my fuses, first visually and then with a meter. Everything was ok there. I'm not really sure what kind of fuel regulator this truck has. It is a 98 5.0 if that tells you anything. I was going to check the fuel pressure, but I can't find where to attach the gauge.

 

[budwich]

thanks... replacing the cel light will help you alot in getting further along. For your info though, the power coming from the PCM relay is only ONE source of power for the PCM... there are a number of sources... all of which have to be there for the unit to function correctly. Again, hopefully the light will help in this matter. As for fuel, you should see a fuel connection point on the fuel rail somewhere which can be carefully and momentarily released to "spray" a small amount of fuel in the air... be very careful. The connection point looks like those used for the air conditioning system.

Does your anti-theft light flash then go out???

 

[V Maxima]

Thanks again for the help guys. I'll check for the fuel rail tomorrow morning. The anti-theft light does blink when the truck is locked. With the key on the ON position the light will turn solid and then turn off. I've done a little more research and it seems that that is properly functioning.

 

[5litreford]

What about the fuel cut-off switch. I think I read that it's at the front passenger footwell. Needs to be reset sometimes. I would guess after a fuel pump replacement.