Like a CPS failure but Not. Engine just dies

[tlutman]

I'll take a crack at it. If it is like turning off the ignition with all relays de-energizing, than it would not seem to be the ICP, CPS, IPR, or any other sensor. They sent info to the PCM, which controls everthing according to what they send. They do not control the relays. Your ICP might have been bad to begin with, and the truck will run without, not well , but will run.

Have you payed particular attention to anything that DOES work when this happens? Any dash lights, heater fan, radio, etc. It does sound like an electrical problem, be it a ground or power wire. The PCM controls alot of relays, including the fuel pump and IDM, which would be like shutting the truck off. Try taking a good look at the PCM relay and ground for it. Try wiggling it, tapping on it, grabbing the wire harness there and move it to try to recreate the problems.

[klhansen]

Hmm, that is strange. I agree it's a gremlin, and you need some gremlin exterminator spray. [img]/forums/images/%%GRAEMLIN_URL%%/grin.gif[/img]

If you can hang a voltmeter on the ignition switch "run" output wire and observe that, it may tell you something. It could be that your ignition switch is going bad. If the voltage drops when the engine cuts out, then you've got your gremlin. That wire controls all the "hot in run" circuits, so would kill the fuel pump relay, PCM and IDM power relays, ect. if it lost voltage.

That's where I'd start anyway. :shrug:

[WaveEater]

tlutman,
I agree it just doesn't seem like a sensor,but at the same time it doesn't happen on rough roads or during vibrations which would make me believe it's not a connection issue. I do though hear the relays under the dash click off when it dies.

Everything on the cluster still works except the tach and oil pressure instantly drops to 0. Radio and everthing else is not affected.

never had a ses light come on abnormally

[arisley]

Have you tried replacing the fuel pump relay?

[klhansen]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: WaveEater</div><div class="ubbcode-body">tlutman,
I agree it just doesn't seem like a sensor,but at the same time it doesn't happen on rough roads or during vibrations which would make me believe it's not a connection issue. I do though hear the relays under the dash click off when it dies.

Everything on the cluster still works except the tach and oil pressure instantly drops to 0. Radio and everthing else is not affected.

never had a ses light come on abnormally </div></div>

Sounds more like the ignition switch all the time.

4 separate circuits come out of the switch that are hot in "run".

ckt 10400 Red/Black - powers DRL, Vacuum pump, Speed control, backup lamps
ckt 297 Black/Light Green - powers wipers, lights, radio
ckt 1000 Red/Black - powers PCM & IDM relays, Inst cluster, GEM, trip computer, Idle validation switch, AIC
ckt 687 Grey/Yellow - powers ari bag, flasher, ABS, HVAC, Trailer tow relay.

If ckt 1000 is intermittent, then the PCM would shut off when it drops out, meaning the SES wouldn't work, Fuel pump relay would drop out, tach would quit working, etc. Just like you had shut off the key. All the other circuits could still be powered.

Wouldn't necessarily take a rough road to cause the switch to open a circuit. Could be heat buildup across a burnt contact, etc.

Don't write it off without checking. A test light hooked to that circuit would be a good indicator.

[Mach1]

Heres your problem, I have seen/repaired 3 of them now, The ICP plug needs to be replaced.

The ICP plug will become saturataed with oil and it loses it connection, I have seen a couple get water in them and it corrodes the electrical connection, YOU HAVE to change the connector, I cut mine off and got one from Ford, and soldered it on and heat shrink the wires.

If you lock close at the plug connector terminals you will see corrosion on the terminals, you can scrap them with a toothpick or Xacto knife..

What technically happens is the ICP loses connection with the PCM, and dosen't give the PCM a ICP parameter, so the PCM says that is out of range and then shuts down the engine.

Have seen this a couple of times, especically when its high humidity out...

[B727capt]

I agree with Mach1. Years ago I read here where a Ford mech said these trucks come in all the time with these exact symptoms. He recommended putting permatex on top of the ICP plug where the wires go into the plug. Water and dirt go down in the plug from the top and make for a bad connection over time.
I had a problem with my 02 6 months ago where the thing would just quit going down the highway. Like turning the key off. Thought CPS at first and changed that. After a week of the problem, I bought AE and found cranking oil pressure was only 165 and not the 500 psi the injectors need to start. It was the coil part of the IPR. After the motor got hot, it quit. After it cooled off for an hour, it would start and run 10 minutes. Bought a new IPR and that did the trick. Placed the old coil part of the IPR on a buddy's truck to confirm, and his quit too. Found a new IPR on eBay for 105.00.
Bill

[WaveEater]

Thanks I put a couple LEDs on the red/black wires to check and see if the voltage drops out at the switch. It sounds like the most logical solution so far.

I can't see why it would be a bad ICP connection When unplugging the whole connector makes no difference. I could see that it may have possibly been shorting out across the oil in the plug, but now the plug is dry there is no way corrosion would cause a short, only an open.

IF it was the IPR or the fuel pump or fuel pump relay it would run rough and sputter before dieing and it would have to be running first of course

[Mach1]

Let me explain a little further, when you unplug the connector, the PCM sees no input and defaults to limpmode, which I believe is 800 psi, enough to limp home. When the PCM sees a high/low resistance, it says something is out of the normal range and shuts the engine down. Then there is the resistance within the range and the truck drives normally.

TECHS use this method to diagnose ICP problems (under certain conditions), If they think it is ICP related(before getting the Computer out to diagnose) some will unplug the harness to see if it will start.

This problem is getting more and more common as the wiring harness loosens up and moisture penetrates the connector and corrodes the wire terminals..

Tip--unplug yours and look very cafefully at the terminals.
Or put the AE software on there and monitor the ICP.

[puttputtwannabe]

Do you have a chip? Could be a bad connection.

[slowpoke]

I just finished replacing the last part of my particular series of issues (see previous post in this thread), and everything seems fine. I have replaced the glow plugs, the inside-the-valve-cover harness (it needed it 'fer shur'), the valve cover gasket, the outside-the-valve-cover-gasket wiring harness (which came with the glow plug relay, or whatever it's called, already installed), the intake system rubber (with the adapter kit), and a new CPS. So far, so good. I plan on replacing the ICP when I can, and I will post the parts list and prices when I am confident that the system is good and all is well (finally). Mine is a '97, and I am told that it is a transition year. The first run at an external harness was priced at $950, but my parts man at Ford (thanks, Ray) talked to an old mechanic and got a new reference that brought that price down to around $500 with the relay in the harness. I buy from International when I can, but sometimes there is no other option.

[nu2ford]

Something to try.....worked on a 95 Jimmy with the exact symptoms (relays click when the truck stalled, would reboot the PCM while driving, sometimes a complete stall, sometimes flashing airbag/SES/Batt lights and no power and then would magically go away).

Spray your ignition key and lock with WD40 and work it back and forth in the ignition. You wouldn't believe the crud that accumulates in the ignition switch amongst the tumblers and all.

Only ever had to do it once, never had the problem again.

[basutoland]

i have a truck that is starting to quit going down the road...reading all the possibilites ...this truck had its ignition key assembly fooled with to silence the warning bells.. did you guys ever go in there to silence the bells ?? could it be that messing in there [ignition switch] is coming back to haunt ?? i remember when the silencing of the warning bells thing was the thing to do and the means of doing it became better and better as the understanding of how it worked increased.

[F350_6]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: aridzone</div><div class="ubbcode-body">i have a truck that is starting to quit going down the road...reading all the possibilites ...this truck had its ignition key assembly fooled with to silence the warning bells.. did you guys ever go in there to silence the bells ?? could it be that messing in there [ignition switch] is coming back to haunt ?? i remember when the silencing of the warning bells thing was the thing to do and the means of doing it became better and better as the understanding of how it worked increased. </div></div>

Several possibilities and not enough info. Start a new post and tell us all you can and we'll see if we can get it fixed for you.