No start...has me stumped

Swapped IDMs just to be sure and still no start. Checked everything over again. No signs of burnt wires. Did another buzz test with the original IDM and it passed. Had a friend crank the truck while I listened for the injectors....dead silence, no injector noise. Plus, have no white smoke out the tailpipe.

With the scanner hooked up, there is no pulse width.....hmmmm. Gotta break out the shop manuals for the schematics unless someone knows which wire goes between the PCM and IDM.

Any chance the PCM took a dump?

https://youtu.be/pVI3RAxZO0w.

Billy T.
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Swap IDM relay?

Fused link in wiring harness somewhere?

CTC DEEZUL said:

Swap IDM relay?

Click to expand...

I'll try it. But it passed the buzz test. Is the relay involved in the buzz test?

Strokersace said:

Fused link in wiring harness somewhere?

Click to expand...

Is there one?

After doing some reading, in an OBS truck the O PW reading means the PCM and IDM are not sync'd together. Anyone know how they get in sync?

Billy T.
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Yes but while cranking we're losing alot of volts that other wise we're dedicated to just buzz test.

They buzz strong?

Post video of buzz test

gnxtc2 said:

I'll try it. But it passed the buzz test. Is the relay involved in the buzz test?



Is there one?

After doing some reading, in an OBS truck the O PW reading means the PCM and IDM are not sync'd together. Anyone know how they get in sync?

Billy T.
[email protected]

Click to expand...

There should be fusible links coming off the starter relay.

So all this started with jumping out wires for the windows? Was he just jumping them out at the switch connector?
I would double check every fuse in the cab and under the hood also check those fusible links.

I just reread your first post. Is there any chance when he did the fuel pump that he switched the wires between the IPR and EBPV?

boggerr said:

There should be fusible links coming off the starter relay.

So all this started with jumping out wires for the windows? Was he just jumping them out at the switch connector?
I would double check every fuse in the cab and under the hood also check those fusible links.

Click to expand...

Yes, when he was jumping wires at the driver's window. It was stuck down and was troubleshooting if it was the switch or window motor.

I pulled every fuse and checked them.

boggerr said:

I just reread your first post. Is there any chance when he did the fuel pump that he switched the wires between the IPR and EBPV?

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The truck didn't start prior to the fuel pump change. He changed as part of his throwning parts at it without diagnosis it. But he said it was leaking anyway.

I'll double check to make sure.

He was driving it, the window wouldn't raise, parked it to fool with the window switch/motor and wouldn't start after playing with the window to raise.

Billy T.
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That is strange but I'm wondering if the first no start problem was cause of the key being on so long the GP's never cycled on and pretty much flooded the cyls out with fuel. Then they just screwed more stuff up throwing parts at it.

Maybe check the fuses with a test light just to be safe.

The wait to start light is on when you 1st turn the key, prior to trying to start it?

PCM pinout
http://www.diesel-dave.com/vehic/manual/vt1/vt118123.htm

Strokersace said:

The wait to start light is on when you 1st turn the key, prior to trying to start it?

Click to expand...

I wish it was that easy, but yes the WTS comes on and the voltage gauges goes down when you hear the GPS click.

Billy T.
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125 rpm is too low. The calibration parameters for minimum cranking speed is typically set to 150 rpm. If the pcm does not see 150+ rpm it will not signal IDM to fire injectors.

What is voltage while cranking? Weak starter or voltage drop.


If it shorted out anywhere while messing with the window switch, its possible that the pcm got messed up. Can swap a pcm to rule that out if you have one. But that low of rpm and it all of a sudden happening while messing with window has me thinking something shorted out or batteries are that low or starter is bad.

live life full throttle

Yea it looks like 9v cranking.

It starts off at 13.x. The more I crank it, the voltage starts dropping (killing the batteries).

I found this online:

When trying to diagnose hard start or no start issues a scan tool is needed to check and monitor the ICP (Injection Control Pressure), RPM (From the CMP) Vehicle Voltage during cranking and PW (Pulse Width) signal.

1. RPM, minimum 100 rpm cranking speed (When warm it should be over 180 rpm)
2. ICP, minimum required for starting 500 PSI if no rpm signal, ICP won’t go over 400 PSI
3. Voltage during cranking 7-10 volts minimum depending on year
4. Pulse Width; 0 ms means no sync, 1994-1997 .42 ms indicates that PCM and IDM are in sync (on 99-03 it should be .60 ms) and the PCM is waiting on the ICP to reach the minimum of 500 PSI. When min. ICP is reached PW should change to 1-6 ms
5. If any of the above doesn’t meet the minimum specification, solve the problem as-per the appropriate Ford Diagnostic Manual.

Billy T.
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lincolnlocker said:

What is voltage while cranking? Weak starter or voltage drop.


If it shorted out anywhere while messing with the window switch, its possible that the pcm got messed up. Can swap a pcm to rule that out if you have one. But that low of rpm and it all of a sudden happening while messing with window has me thinking something shorted out or batteries are that low or starter is bad.

live life full throttle

Click to expand...

I don't have a spare PCM otherwise I would try it. It's a PITA to take my PCM out as I have to remove the cab steps off my truck to remove the PCM.

Billy T.
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What about the other question?

live life full throttle

The video I posted shows all the parameters. The cranking rpm was over 150.

I'm with you that something got shorted out. The ignition had to be in the RUN position in order to jump out the window switch/motor which probably back fed something. I just gotta find out what shorted, if possible or the PCM took the hit.

I gotta trace out the FDSC circuit. Need to get my shop manuals.

Billy T.
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CTC DEEZUL said:

Yea it looks like 9v cranking.

Click to expand...

My truck gets down to 10.9-11.1 volts in the dead of winter with the glow plugs on and the truck cranks and starts no problem.

Billy T.
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