So last week I was driving down the road and my truck just killed ended up being the IDM. I changed that out today and followed the instructions to let it run for 15 mins maybe go for a drive it said. So when I started it up it ran like *** and shock like crazy so after about 5 mins of listening to it sound bad i decided lets try a little drive maybe it would work its way back to normal and right once i put it in first and let out the clutch it killed. So when i started it back up and tried to drive forward i had to keep a steady foot on my gas pedal while i was letting out the clutch. What could this be i just changed the glow plug solenoid and the CPS.

 

Well there are a few different things it could be.

First thing I would check is the valve covers gaskets/pigtails and under valve cover gaskets. If any of those appear burnt/discolored then you should change those out for sure.

If you didn't do this test before installing the IDM, I would highly recommend doing it now. Just unplug the IDM connector and use a multimeter:

GB Remanufacturing - Tech Bulletin #103

This will let you be able to test the circuits to the injectors from the IDM. If any of the resistances are off, you will know there is something wrong (wiring/UVCH/pigtails/ possible injector solenoid.)

Also, what brand CPS did you go with? Everyone and I mean EVERYONE recommends NOT getting a parts store CPS. Get it only from Ford or International. They cost around 35 bucks there.

The parts store CPSs are extremely unreliable and have been known to fail less than a few months after getting them or even be bad out of the box. I don't know why the quality control is so bad on them, but 100% of the reading I've done insists on avoiding parts store CPSs.

 

Yea i bought the CPS from Ford and i was kinda researching bad idle and someone said the IPR could that be the case if the IDM checks out?

 

I'm no expert on these systems yet but I suppose it is possible. They can get stuck open or have the o-rings fail not allowing the proper flow of oil which in turn will mess with the injection system. I would try and see if the tin nut holding the IPR electrical part is on and tight.

I'm not really sure how to check an IDM without a specific special scan tool. From what I read is they usually work fine, or don't work at all.

The experience I had with the two I had that failed were:

- The first one cut out one bank of injectors for about 30 seconds, then they came back on like nothing happened. The next day, only one bank of injectors started up when I ran the truck and they finally came back about 8 minutes of driving (I had to get home.) The next time I tried starting the truck if never did so I replaced the IDM.

- The second IDM just up and failed but only after I was parked. everything seemed great, I parked at Chick-fil-a and ate. Then when I went to start, it wouldn't start at all.

I'm now on my third IDM in less than 1 month. I did heavy diagnosing to see what may have been the cause but don't really know for sure. I have read that fluctuating voltage (caused by a bad alternator or batteries going bad) or bad grounds can sometimes be the culprit behind IDM failures. I had some shoddy grounds, a burnt alternator plug, and a battery on its last leg so I'm hoping that cured my IDM failure.

If you truck was running totally fine before the IDM failed, and putting a new one in didn't make it run well, I would try to get the IDM checked out. I would highly recommend testing the resistances of the injector circuit first, and trying to physically see if the wiring to the injectors is good.

If possible, you can take your "new" (I'm assuming it's used) IDM and plug it into another truck with a 7.3 (if anyone you know has one.) If your IDM is bad, it will make their truck run bad or not start at all. You won't have to worry about messing up their truck either.

 

Ok ill definetly test the one i have. Thanks

 

Oh and when you test the resistances, that's on the plug side, not the actual IDM. I am not sure how to go about testing the IDM itself besides plugging it into another persons truck!