Bob,
I know that you tested each injector for continuity, since that's how you found the open circuit to #4 injector.
I would suggest that you measure each injector lead for a ground. Do the same test you did for continuity, but this time instead of one probe on the "C" terminal, connect it to the negative post of a battery. You should get and open circuit reading at each test point. Any other reading would indicate a path to ground, such as a pinched wire.
Good luck, Nick
BTW, since you did find an open circuit on #4, that would cause the IDM to fire at in a high voltage condition, and cause it to burn out.

 

Nick, thanks for the advice. Sounds easy enough, but am I also checking Ohms on this test? Or something else?

 

You might want to leave your valve covers off until you talk to swamps. They should be able to help you figure out what is going on. I know they have done a lot work on IDMs and testing. That is where I found the information about the solenoids.

High-Performance IDMs by Swamp's Diesel Performance

 

Grant, I think you may be right. I have been reading through their info and they are all over the IDM modifications. If I can get a bit more performance out of all of this I will be ecstatic!

 

What bothers me is the frequency of IDM failures you seem to be having. This leads me to believe you have some sort of wiring issue. For the sake of discussion, if there was a bare spot on the #4 wire and it grounded out on something under the valve cover, then you would see a zero ohm reading prior to removing the vc. Then by simply plugging the connector back in, the wire could have moved away from the point where it was grounding out. At that point all your tests would be within spec and the engine would run great.

Under no circumstances should you see zero ohms on any of your solenoid readings. An unplugged connector should be quite the opposite (infinity) ohms. By any chance did you mean to post that you had an 'open' reading on #4 or did you in fact have zero ohms? If so, then that would be a closed circuit and something was grounded somewhere.

I wondered if maybe a bad IDM would give you a zero ohm reading but that can't be the case since you had the harness disconnected to take the readings...so that is why I am still suspecting something with the wiring under the valve cover itself.

Since you have the valve covers off still, I would inspect the wiring for something obvious, however even a crack in the insulation could fault to ground with the voltage involved so you might not even see it. At this point, all you can do it put a meter on pins 23 and 7 and then move the wires under the valve covers by hand and see if you get a any ohm reading at all. Anything less than infinity is a problem. Keep in mind that a zero ohm reading means absolutely no resistance what-so-ever so that is the same as a short to ground. An open circuit won't harm your IDM but a grounded circuit will.

I hate to spend money unnecessarily, but if you saw zero ohms before you popped open the valve covers then I'd be replacing the wiring harness and valve cover gasket as well. Especially since you are now on your 4th IDM.

 

Greg, you definitely have me thinking hard and I appreciate your help. I was not looking at the multimeter, my bro-in-law was while I held the leads on the contacts at the plug. What would an "open" circuit show in a multimeter? 0.L?

 

all I can really say is that the contacts all read about 3.4 ohms once the plug was reconnected.

 

Depends on the meter. One of my meters show a series of dashes "----" while the other shows "0.L"

 

Greg, I want to make sure you understand that I have only had what I consider 1 true IDM failure, and that was the original one. SInce then I had a reman that died within 6 months and the second reman is the one I have now. So its not like theyre high quality products.

 

I would wiggle the wires, especially #4 as you check the ohms.

 

wiggled the wires to death today

 

Let us know if you go with swamps moded IDM. Like to see what you think when done.

 

Just ordered the Swamps IDM. Hopefully will be here by the end of the week. I will let y'all know what I think! Thanks again for all the help!

 

Looking forward to your thoughts on the Swamps IDM, did you talk to Bill or Cody as to the effect if any on the tuning ?

 

No, but I found a thread on their forum where somone did the Swamps IDM after having the Pheonix chip. Also, the guys at Swamps said it wouldn't be an issue. I posted the question on the PHP forum. I won't run the two together until I get confirmation form Bill or Cody, but I will just send the chip in for a reburn if I have to. I've been wanting to make some changes to my tunes anyways.