Alright guys, my bad luck continues (thats right Huck). Driving through town yesterday my truck hesitated slightly, then the CEL came on. The truck started running rough, shaking, which was worse at lower RPM. I limped it home last night then went to my buddy's shop to have the codes read today. Everything was pointing towards another bad IDM. This would be the third IDM failure in about 5 years. So we borrowed a brand new IDM from another friend. The new IDM still had the rough running, and the problem seemed to be isolated to injector #4. So we put the old IDM back in and it got much worse. Now it seems as if 3 or 4 injectors are acting up. Here are the codes currently:

P1274
P1293
P1294
P0541 - AIH is deleted so this is normal

We ran a CCT, which won't completely run because of the missing AIH, but it did throw 3 more codes:

P0266
P0272
P0284
P0541 - still the AIH code

I drove the truck home (about a mile) very slowy with very little power.

A buzz test flagged injector #4.

This is an '03 motor, so the UVCH shouldn't be loose. Also, the difference in running with the different IDMs has us stumped. The truck acts up on both IDMs but noticeably worse on the old IDM.

There is no noticeable smoke due to the poor running.

This is evrything I can think of right now. If y'all have more quesitons I'll be happy to try and answer them. I really appreciate any help.

 

Oh yeah, fuel pressure is good, right at 70 which is where I have it set. Also, I swapped out my black CPS with a grey one and no change.

 

sorry to hear it...

you say its not the connections but what about chaffed wires?

 

Everything outside of the valve covers looks good.

 

Maybe an injector solenoid is causing a bank to shut down but you are getting codes for both sides so idk. Wouldn't hurt to ohm I to C at the valve cover 9 pin. Look for consistent readings. A low reading on a solenoid can cause the bank to shut down.

G - G - I - I - C - I - I - G - G

G = glow plug
I = Injector return
C = Injector common feed

 

Bob,
Out of curiosity, did you happen to check the wiring at the IDM connector while you were swapping IDMs? (I've attached the GB tech bulletin 103 in case you don't already have it...)

The original die-electric grease in my connector had long since dried out and turned into some weird sort of dry fish scale looking junk. I had to clean it out with electrical parts cleaner while using a small pipe cleaning brush to get it all cleaned out. Engine ran real nice after that. (Just throwing it out there in case you haven't already cleaned your connector...)

If you are sure your external wiring is ok, then it's time to look under the driver's side valve cover and see if #4 is firing. It's possible you have a solenoid problem on that injector and it's taking down the whole bank from time to time. If that was the case, then a different IDM could be more or less sensitive to the bad solenoid (just throwing out ideas...)

Did #4 sound way different during the buzz test?

 

Thanks for the suggestions guys. #4 did sound different during the buzz test. Can someone point me towards more detailed instructions for testing the soleniod?

 

Just read through the tech bulletin above and it is very informative. I am going to look into doing those tests, unfortunately I may not be able to get to it until this weekend now due to work and lack of light when I get home in the evenings. Any other information is still greatly appreciated.

 

You just unplug the 9 pin connector at the valve cover. Then set the meter to ohms and put one lead on I and the other on C. Look for consistent readings like I said above. You'll probably see around 3.4 ohms. If you see .5 ohms or more less than the other readings that might be the issue.

 

The ohm test is a good place to start but there could be other issues going on that won't show on an ohms test. I had a loose armature plate once and it caused my injector to shut down because the solenoid couldn't operate the poppet valve correctly.

If it were me, I think I'd run through the following steps:

1. Ohm the injectors at the exterior valve cover connector. If readings are good, then work back towards the IDM while checking the harness.
2. If injectors readings are suspect, then open up the valve cover and see what you find.
3. Check UVCH connector for positive connection
4. Start engine and watch oil discharge
5. Note: While cranking to start, watch #4 to see if it's bleeding oil vs regular dumps.
6. If you suspect a bad solenoid, you can swap it out with a nearby injector and see if the problem follows the solenoid or the injector

If you have multiple injectors out on that bank, then unplug #4 and see if the others begin working.

Good luck.

 

That's what I would do. Reps if I could.

 

Thanks guys, makes sense. I tried to start with the plug outside of the valve cover, but my multi-meter is jacked up. I will get a new one and try to do these tests then.

 

Ok guys, I got a decent multi-meter today, so depending on what time I get home tonight I am going to run some of these tests. I want to make sure I understand what you're saying though. For #1 above, I disconnect the plug on the outside of the valve cover and then I check the resistance (ohms) on the loose plug going back to the IDM or on the end that is mounted to the valve cover?

I hope that question makes sense. If not I will try to think of another way to explain it.

Thanks again.

 

Another question I have, is it possible that my remanufactured IDM harmed an injector solenoid somehow?

 

on the valve cover harness to test the injectors