Yes the idm will interchange
From 94.5-2003
Obs idm 100v
E99 sd idm 110v
99And up 120v
So any 7.3 powerstroke idm will interchange

 

I recently bought a 97 that had receipts saying the old owner complained of it going into idle mode and having the same problems as what your describing, it was the throttle pedal assembly because the receipt says they tested one off a different truck and it stopped going into idle mode so they put a new assembly in it...hope the info helps!

 

Thanks for the replies guys. The idm I got is the obs 100. The last thing I changed was the TPS and the IVS, still have the problem. Sure would like to find an old big block truck that I could trade. This gremlin is getting to me.

 

^^^^ Unless you go way back in time, a gasser will have more electronics for potential problems like this. And if it's a simple main power issue, that's pretty-much the same between gassers and diesels. If you're looking to avoid electronic/electrical gremlins, consider an IDI. They're astonishingly simple and straightforward.

 

Maybe you could try running a wire directly from battery power through a toggle switch to the pcm for testing purposes.


I just had a thought: Have you checked the pcm ground at all? If the pcm loses its ground, it would act just like it lost power.

 

Yes madpouge, I found a 1972 f250 the other day, but it wasn't for sale. It was so nice to see a fuel line spark plug and a air filter. I was wondering about the idi's. That would probably be cheaper than a cummins conversion. Phil, I have checked all the grounds I can find. There are a few power grounds, but I don't know if some of those would cause the WTS light to come on. Oh yea, I swapped the IDM, didn't help. Thanks for the help guys. Charlie

 

[QUOTE=csj992;15763130] That would probably be cheaper than a cummins conversion.




Yes, but far less satisfying...

 

Hey guys, I was wondering if any of y'all knew what told the PCM to turn on the WTS. I noticed that there is a lead from the IDM that goes to the PCM on pin 14. It is also labeled vpwr. I was wondering if loss of power on this pin could cause the WTS light to come on and also cause the PCM to go to idle mode.

 

WTS run time is determined by EOT, and it only comes on at initial power-up of the PCM. If your WTS light is coming on while you're underway, and the engine is dropping to idle at the same time, most likely it's from a brief interruption in main power to the PCM. If this happens, you should be able to let off the pedal, then press it again, and normal engine ops will resume.

The wire you mention is from the PCM to the IDM, not vice-versa. The PCM controls the IDM.

 

Yes madpogue, that is exactly what happens. The wire I am talking about is going to pin 14 labeled vpwr. I see the idmenableout on pin 70 which looks like it energizes the IDM relay closing the contact and sending voltage toward the PCM. Madpogue, I see where I said IDM in my previous post where I should have said IDM relay. Sorry about that. Screwed up again. That vpwr lead I am talking about goes to the IDM pin 14 NOT the PCM. What is your opinion on running 12 volts from battery to the two vpwr leads going to the PCM, to check and see if that fixes the loss of pwr?

 

The IDM relay shouldn't have any effect on PCM power. PCM power interruptions like this are usually a loose connection at the maxifuse, an ignition switch issue, or issue with wiring to the ignition switch and/or maxifuse.

 

Hey madpogue, If I told you that my failures occur more frequently at running temp than they do when truck is cold would that lead you in any direction?

 

Pull your engine compartment fuse box a take a peek underneath. Look for burnt spots, especially on fuse #22 and fuse #9. I believe there are some major wire junctions under there that can corrode too.

 

Thanks Jim, Sounds like a good idea. That is the only part of the wiring that I haven't wiggled trying to duplicate the fault.

 

I was just wondering what info I can get from the OBD2. madpouge thinks I am loosing power or a ground to my pcm causing it to go into the idle mode. I was wondering if there is some sort of computer or scanner I could hook up to the OBD2 that would tell me what I was loosing and what pin on the pcm was loosing it. Thanks, Charlie