JP I think I would start with trying to find the where the added resistance is. It could be causing your issues still. Also pull the connector off your pcm and inspect it. You may have a dirty or bent pin.

 

Don't worry about the other threads. You've got enough on your plate with your own thread.

 

Hey thats a good find!! Because it answered my question about taxing the idm when running splits... Sweet!

 

agreed, you'd think there'd be error codes like crazy, but when i unplug the IDM and turn the key to run the PCM comes on fine and only shows 2 codes (read by my Aeroforce Interceptor). i forget the numbers, but i looked them up and they are the "keep alive memory code" which sets when you disconnect the battery, which i have done alot. and the "hey where'd my EBPV go?" code, which makes sense as i have none now.

so like, i said, the PCM powers up fine and throws no codes other than irrelevant ones. i can't say that all the internals (specifically the ones that control the IDM are OK, but i'd have no reason to think otherwise. As for the IDM, it will power up sometimes (after a bit of clicking), but then everything dies when i start cranking. i wonder if there'd be power enough to run an injector buzz test from the AF interceptor on one of these times it does power up. that would at least give me an idea of the IDM is OK or not...

as for damage during cranking. i don't believe i had the PCM or IDM in place at that time, though i honesly don't remember now. i do remember thinking that worst case, i'd be giving my batteries one hell of a load test. cranking sounded good and battery voltage never dropped below 10.5 or so during all the cranking, then would come back up by the trickle charger in a reasonable time. even now, with the GPs back in, i've cranked a few times and everything sounds strong.

but yes, something definitely could have been fried by my cranking - or perhaps even worse, bad grounds in the cab body or something during cranking. i'm just not sure how to dig in and test all that out right now. ...short of cutting up whole harnesses and visually inspecting for burned spots or something...

yeah, that's an oscilloscope reading from the IDM output. My father-in-law has an old oscilloscope i'd like to get my hands on, but last time i asked, he never answered...

 

It sounds like the PCM doesn't like your IDM. If the PCM operates correctly without the IDM, but with it, it goes nuts, I would almost wager that something is going on in the IDM. Would a no-touch voltmeter be able to read the connection between the PCM and IDM?


You might already have them, but it might help.




Looks like pin #26 is your IDM ground.
Sorry the PCM pinout got cut off on upload
Corey, glad I could give you an answer( inadvertently)!

 

Heres The PCM. Hope it gives you some ideas!

 

thanks, John - i appreciate it. i just printed them off myself at lunch today. its amazing what you can find on the internet!

and yes, i agree, the PCM seems to HATE my IDM right now. i just wish i knew why.

i'm really tempted to power the IDM separate from the PCM, but that seems almost guaranteed to fry one or the other given the current state of affairs.

 

I don't think the issue is your IDM at all. I think you have a draw in the system somewhere that is draining down the voltage low enough that the relay starts chattering like that. If you disconnect the wiring connector on the IDM, does the relay still chatter?

Has anything else changed in this equation aside from the R&R of just about everything and the SD wiring to the VC's? I'm just curious what has changed.

The only other thing I can think of (since I think you mentioned that your starter was getting weak) is whether you have disconnected the starter from the rest of the electrical system to see if that makes any difference.

I really think some power wire somewhere is partially shorted to ground, and when it gets power, it pulls down the system voltage enough that the coil on the relay drops out, then the voltage recovers and the coil comes back in, then the process repeats.

What about the e-fuel? Where are you pulling power from for that? If you're powering the e-fuel circuit through the fuel bowl heater wire, disconnect it and see what happens. If that's where you're pulling the power from for the relay, do you have the relay pulling power directly from the batteries (as you can't pull the power for the fuel pump from the fuel heater wire without causing issues).

It's got to be something simple. Sometimes it just takes a different set of eyes on the issue to see what you're too close to see yourself.

 

I still think it's the glovebox light. If your AF interceptor won't power on with that fuse out, that means it runs off that circuit. Right? I'm not sure if I read that right... Anyways, if that's the case, then I'd track down that resistance.

 

It's just me, but it looks like the IDM and PCM share a similar ground. Maybe trace those pins, and see if there is a break there?

 

How are you making out JP. We're all wondering what's going on.

 

I'm not... Decided to take the night away from the truck and research. ...started by making a new thread to maybe catch the eye of a pro PCM guy or something...

I'm really stumped.

Nate, I may be calling you tonight. Thanks for the offer

 

Give me a call man. Electronics are a part of my background so I'll offer any help I'm able. I'll be in class for a while tonight, so if you don't get me right away, leave me a message and I'll hit you back when I can.

 

yeah JP, call this guy. You'll glad you did. I was afraid to even use a voltmeter until Nate talked me through what each thing means and how the basics of electronic diagnosing these trucks works.

I hope you guys can find something. I feel your pain with the trouble. If I could be of ANY help, I would. The last time my truck wouldn't start and threw a CEL, it was because I had accidentally pulled the chip halfway off the PCM....it didn't like that very much.

 

oh, i will definitely call that guy! i think we've BS'd on the phone before over waste oil stoves and such. at least by email. this will be much more productive, i can only imagine.

Nate - i'm going to be doing some cleaning and re-clamping of all my battery clamps and connections tonight. if that doesnt do the trick, you're getting the call.

how late is too late?