Intermittent no start

jspecteggy · Sep 30, 2015

I got a new to me 96 psd, it has always had somewhat of a lazy/long crank but it was running fine until one weekend after sitting for about 4 days would not start. I noticed the fuel bowl did not seem to be losing fuel, the bowl was about 1/3 full and there was fuel in the valley. So after ordering all the seals, o-rings and hoses from the internet it started fine and ran fine for a few days and got rid of all of the leaks in the valley and the pedestal.

I let it sit for a day without driving it, went to crank it the morning after and it wouldn't start until I unplugged the ICP (had oil in the plug) which one would think would point directly to the ICP except that the next morning when I go to crank it with the ICP still unplugged it doesn't want to start again. I keep trying until I get it started, plugging and unplugging the ICP and eventually hitting the gas pedal while cranking got it started. I'm a little stumped and don't really want to throw parts at it more than I already have.

When I plug the ICP after it is running I dont' feel any change in idle or anything. CPS is new, the GPR had full voltage on both posts with key on, the batteries have checked good multiple times at different parts stores.

Does anybody have any additional suggestions? Would bad injectors cause this? UVCH? I'm hoping its not the pump since I just had everything apart in the valley.

pdumont01 · Sep 30, 2015

Probably a bad ICP, shouldn't have any oil coming though sensor pins.

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jspecteggy · Sep 30, 2015

But if it was the ICP it should start every time with it unplugged correct? Cause it's definitely not doing that. I just went to start it after it sitting for 24 hrs, and it wouldn't start again. I had to crank it a few times and eventually I depressed the gas pedal a bit and it seemed like it was about to start and I stopped cranking, cranked it up again while getting on and off the gas pedal and it started up.... This leads me to believe it's something fuel related..

pdumont01 · Sep 30, 2015

If you can hear the injectors clicking but not firing then its a fuel problem, can you observe the ICP pressure pid while cranking? With fuel it would not just quit it would slowly die out and make horrible fuel knock.

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jspecteggy · Sep 30, 2015

I don't have anything to read the sensors with. Yea it doesn't die slowly or anything like that, it's just the first start of the day that's the problem because after that it'll crank right up every time. Idle doesn't change at all when I plug the ICP back in after its running and I can start it with it plugged in after I get it cranked up the first time

pdumont01 · Sep 30, 2015

Really without monitoring what's going on its a shot in the dark. No one you know has a scanner? My friend had something similar that turned out to be his regulator, make sure the nut is tight and the wires look OK.

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jspecteggy · Sep 30, 2015

A friend of a friend's has a scan gauge I'm gonna try to borrow and check the numbers of the ICP and IPR. I'm gonna check the fuel bowl after it sits overnight again to see if it's full

pdumont01 · Sep 30, 2015

I'd be very surprised if it was a fuel issue. Good luck let us know what u find

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jspecteggy · Oct 1, 2015

Who knows maybe it's a glow plug system issue or maybe bad injectors? I'm gonna try to check the ICP and IPR numbers with that scan gauge.

pdumont01 · Oct 1, 2015

All injectors wouldn't go bad at once, usually it would be running rough, as for glow plugs they shouldn't be an issue until it gets colder out. You never know though

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gnxtc2 · Oct 1, 2015

What is the cranking ICP?

You really need to hook up some type of scanner to properly diagnosis the no start issue otherwise you are just throwing parts at it.

Billy T.
[email protected]

jspecteggy · Oct 1, 2015

Update: plugged in the block heater today for about 3 hrs and went to crank it. Fired right up. Checked the glow plug relay and the post that is supposed to be energized with the key on is not displaying 12v..

pdumont01 · Oct 1, 2015

Hopefully that's all it is.

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jspecteggy · Oct 2, 2015

gnxtc2 said:
What is the cranking ICP?

You really need to hook up some type of scanner to properly diagnosis the no start issue otherwise you are just throwing parts at it.

Billy T.
[email protected]

Idk honestly man, I'm waiting on a buddy's friend to let me borrow a scan gauge. I don't have anything to read the sensors with. I'm going to ohm out the glow plugs tomorrow and see what they're reading.

Patrick Feeley · Oct 2, 2015

Here are some tips:

For checking the injector/glowplug wiring: From each valvecover gasket connection's outermost pins (2 per connector) to ground you should get 0.1 to 2 ohms (indicates good plug and wiring). From each valvecover gasket connection's center pin to each immediately adjacent pin, you should get around 3 ohms (indicates good injector solenoid and wiring). You should not get any continuity from any of the outer pins to the 3 inner pins (indicates no shorts between injector and glowplug wiring). You should also get 0 to 1 ohms from each of the external harness connectors outer pins back to the Glowplug Relay's large terminal on the GP side (indicates good wiring from external connections back to the relay).

To check the glowplug relay (GPR), measure the voltage drop across the GPR's large terminals. While the GPR is active (up to 1.5 to 2 minutes after the key is turned to Wait-to-Start) put your meter leads on the large terminals (one lead on one large terminal and the other lead on the other large terminal). The measures how much voltage is being "lost" across the relay. A reading of 0.3V or more indicates a bad relay.

Cheers!

jspecteggy · Oct 2, 2015

I checked the glow plugs through the harness connectors today and I think I have some bad plugs. The readings I got are as follows, passenger side: 1- 0.6Ω, 3- 1.8-2.0Ω, 5- 0.6Ω, 7- 0.8Ω. Driver's side were: cylinder 2- 0.8Ω, 4- 1.2Ω, 6- 0.9Ω, 8- 0.6Ω. I didn't have any Ω between the 2 outer pins and the 3 center pins. The relay is a brand new Motorcraft relay, I'll check voltage drop across it anyways though. The relay only stays energized for about 1 minute though. Is there a way to check the under valve cover harnesses?

jspecteggy · Oct 3, 2015

I had checked the starter at O'Reilly's with their portable battery tester and it checked good. Took it off the truck and took it inside to get tested and it was doing all sorts of weird crap on the tester and it tested bad. Replaced it with their Ultima Mitusbishi reduction gear starter and the truck cranked faster than it has since I have had it. I'm guessing plugging in the block heater that one time made it easier on the starter since everything was warm already so it made it appear like a glow plug issue.

Thanks for all of the help and guidance! Hopefully she stays running this nice and leak free.