How damaged were your chaffed wires? If some of the strands in the wires were broken, that can affect signal. Taping them up will stop/slow further chafing, but the wire may need to be repaired to operate property.

Also, which wires--meaning what wire numbers as indicated on the 42 pin connector.

 

ReefBlue - thanks for the feedback.

Its been awhile but the wires were not chaffed too badly. Some of the insulation had been rubbed but I don't recall seeing any copper. I'm pretty careful and retentive about my vehicle repair and trust myself that I would have done a better repair if I felt it was required. Good point though - I guess beyond the direct effect of chaffing it could be a corrosion issue.

I don't recall which wires were chaffed - checked them out, taped them up, put it back together but you've got a good point and I will check the colors/pin numbers next chance I get (16 month old son = 0 time!!)

On a general note do you have experience or knowledge on failed IDMs? From what I read they usually cause a no-start condition or a slew of other codes when they go bad. It seems like if the IDM was bad it would not run, but I don't know enough about them to say if they could have a partial failure like this.

Thanks again!

 

The idm can have a partial failure and the truck will still run. I had mine fail for no6 injector. By pulling the idm, you can check to see if the harness connector has got dirt in it and also try ohming out the whole circuit.

Normally, the idm is determined to be bad by the process of elimination. If the injector is good and all the harness/ connectors are good, then the issue must be with the idm

 

I would clear the codes and see what comes back. Those codes would point towards a bad idm but you wouldn't be able to start it or do a buzz test.

 

Thanks for the replies guys.

I hope to get a chance to pull the wheel liner and check the IDM connector as well as the wiring in the next couple of days.

Tinman - thanks for the knowledge. I've been pouring over the forums reading up on this and most guys said that the IDM would cause "big issues" when they go. Good to hear (well, good to have an answer at least, wish it was a little cheaper) that it COULD be the IDM. The expenditure would be less than preferable but completely worth it if resolved the issue

From what I can read/gather I'll:
- ohm the harness from the IDM to the 42 pin connector
- check Pin 26-BK/PK on the IDM connector for good ground
- Where does the IDM get its power from? I'd like to make sure its getting good power but I can't find the (+) on the connector pin out.

If the harness ohms out the way it should (to the 42 pin as well as good ground) I can only assume that its the IDM itself?

I've not had a CEL with this issue at all, the P1293/4 codes only surfaced when I ran the buzz test. Is it normal for these codes not to illuminate the CEL? I realize that codes above P1000 are manufacturer specific, can't be read by general code readers, etc. but wouldn't they still cause CEL illumination?

When I changed the o-rings I did crank the motor briefly to get the oil/fuel out of the piston dishes. I've heard that this can cause the 1293/1294 errors but it also causes other codes as well - no other codes found so I woudl assume that the 1293/4 codes would go away as well if they weren't current.

Thanks so much for all of the help guys!

 

I would suggest clearing codes and retesting. They could be residual codes which will remain stored until cleared.
Why only ohm to the 42 pin? I would ohm the entire circuit from the idm circuit. You can go two ways there. Each bank has a common high side, so you should have inf between them (checks for shorts between banks). Next is individual injector high to low, where you should see the individual resistance readings (checks for open/short for that circuit). Last, check from injector high to the other injector high sides on the same bank. You should see the sum of the individual injector resistance readings. (checks for short circuits between circuits)
The idm power comes in on pin 14, a DG/LG wire. Ground is pin 26 -BK/PK

I drove my truck 50mi to a dealership to buy an overpriced idm and changed it out in the parking lot. Problem was solved

 

Question – my CEL is not on. I know it works as it lights up during KO/self-test and did light when I unplugged the ICP as part of my troubleshooting. Should the P1293/4 code cause CEL illumination? I’m using the Car Gauge Pro app on my phone to run the buzz test – I trust it somewhat but not enough to pop for an expensive IDM at this point. I’ve searched forums but can’t find much info on the app and don’t know if others have had the same issue (is the 1293/4 an issue with the app). I would love AE but the $380 isn’t in the budget right now.

Checking the wiring harness: I’m new to the diesel world so please be patient with my ignorance. Injector high side – is this the center pin on the valve cover gasket connector? I’ve checked the gasket from the center pin to each of the injector pins and each came back within ohm-spec. It’s been awhile but I recall them being less than 5 ohms.
- Check between banks – Pin #23/PK-Y (feed left) to Pin #24/OG (feed right) on the IDM plug?
- Injector High to Low – the injector feeds to ground?
- Injector high to Injector High – IE from #2 to #4, 6, and 8 and the other permutations?
- For all the above I guess it’s best to check from the IDM connector and get the whole circuit in the loop, yeah?

Big question – if the Injector high sides were open would it even run the buzz test or start?

Once again, sorry for the lost post but I want to show appreciation for your help by giving thorough answers.

 

The injector system is broke down to 2 banks. Each bank has a common high (hot) side, and individual ground wires (low side). Don't think of that ground side as chassis ground. It's a closed loop from the idm, to the injector, and back to the idm.
You are looking for an intermittent problem, being an open common center-pin for both injector banks . If both banks were open, the truck would not start and you would not get an injector buzz.
If the truck was cranked with the harness connector unplugged, it would show as 1293/94 since the common wires were in fact open. The cel might not immediately come on, and wouldn't if the connectors were plugged back in but the code(s) would remain stored. That's why it's recommended to clear codes and retest before doing anything.

I won't get into the ohming thing (unless you just want to know) because it can be confusing as all get-out if you are unfamiliar with electronics.

 

Just a thought as everyone here is going thru this now too. Batteries lose power in the cold. At 32 degrees they are only at 55-65% When down to 0 they are only at 40%. I have 2 cars both needing batteries that a month ago tested great but in the cold now both test low. My batteries are old so I do not care about changing them. One is 13 years old.

These trucks need 11.5 v to run. The closer you get to 11.5 the more gremlins creap up. It sounds like you are very thorough but no mention on voltage off and voltage when running. Just a thought. This is the time of year for batteries.

Good luck. I am still chasing Gremlins with circuit faults and bad grounds. I just found my 4x4 went out and was ready to go crazy when i found the plug behind the switch fell out. Crazy huh. This is how simple the repairs can be. Before that it was the under hood fuse for running lights was stretched and flickering the running lights. For now I twisted the fuse ends and problem solved. Later I will solder in a new fuse holder.

 

Hey guys. Sorry to be a couple of days, weekend and preparations for the holidays have kept me away from the keyboard.

mtnsammy - good suggestions. I had called a local diesel shop and the guy told me the same info - that the IDM will cut off at 10.5 volts (although I've seen references to 11.5 as well). Mentioned that they had a truck come in that would shut off at 2k rpm. Ran completely fine otherwise, but once you revved it up to 2k would just shut off. Said they had replaced a bunch of stuff, injectors, IDM, etc. and the battery terminals were the culprit... I guess it would get up to the point where the IDM was demanding more than the corroded battery terminals could provide and it would shut down. I've learned alot through this adventure and can only hope I can pack it away into my memory bank!

So - on my side of the fence. Issue is fixed. Truck is back to running like a top, idling like glass (as much as they did new anyways), fuel mileage is back up... Was the HPx I had installed shortly after buying the truck. I never would have thought it the issue (well, obviously...) I don't want to mention any names since I've not contacted the manufacturer. But, while creeping around the motor with it running I happened to have my hand against the HPx and felt what I can only describe as hammering. Crazy thing is when I bought the HPx I recall thinking "if that was a brake line it would trap tons of air..." I had read the good reviews of the part and made sure that I followed the install instructions to a T - but I'll be d....ned if it wasn't it. After feeling the pulsating/hammering I took the HPx off and put my plugs back in - fired it up and within 10 seconds it was running/idling better. The annoying vibration coming up through my seat was gone, getting on the road the vibration in the steering wheel was gone, power was back, and no misfire-feeling at speed... I'll admit the idle is a bit louder but it runs 100% better.

So glad to have it fixed!! I'll be contacting the manufacturer of the HPx - its been too long to get a refund on it but I want to help others avoid the same issue. I know it takes some time to get the air out of the system but I had done TWO oil changes as well as put about 1500 miles on the truck with the HPx installed - more than fair enough chance I think. Looking at it there are some design flaws that would really cause it to trap air - should probably be revised. Unfortunately my $60 aftermarket "fun" part "good money" cost me over $600 in "bad money" ($140 o-rings from the dealer, $75 in u-joints, oil change, UVCH's + glow plugs, $200 pre-pump filter kit, various supplies, etc.) but its been a great learning experience and I guess the parts I've replaced would have had to been done anyways...

No idea why the buzz test gives me the 1293/1294 error. Something to keep in the memory bank if an issue arises again. The program I'm using is actually an app on my phone (car gauge pro) so it may very well be that hte app itself is causing the issue, or causing the ECM to read wrong and throwing the code.

Thanks again for all the help guys!!

 

How do you get the buzz test to run? I can't seem to figure it out.

 

What type scanner are you using?

Sent from my DROID X2 using AutoGuide.Com Free App

 

Drew - Car Gauge - its certainly not intuitive.

- To get it started you have to press the little plug button at the top of the screen.
- Select Ford as the vehicle make.
- Select Powertrain (the first one)
- Select Scan All when it says Select System Type (Ford)
- Select Full Auto Scan (All Pids)
- Choose your device/dongle/ELM
- Allow it to connect
- It will say Available ECU - mine said 10, I just picked it as it was the only option
- Wait for it to scan all the PIDS (and yes, do like I did and think about the battery, fuel pump priming, glow plugs glowing, etc. annoyingly while you wait)
- It will then ask you to save the PID list, just give it a name
- Now, from the Car Gauge home screen press the "settings" button in the top right (three little squares)
- Select OBD Menu
- Select Self Test
- Now select Fan, Outputs, Injector, Glow Plug, CCT, etc.

I tried the Key On Engine Running test and all it did was jump the idle around, make it misfire/run rough, and resulted in a P1000 (no ready). After this experience I didn't do any other tests besides the Buzz and CCT. I had heard about some dongles/apps messing with the ECU programming so I opted not to tempt fate.

I tried saving the PID profile but it never seems to work - gotta run through the entire process above each time you want to "run" the app.

Tinman - I'm not using a traditional scanner. I have a OBD II bluetooth Dongle (PLX Kiwi) and use one of two apps on my phone: Car Gauge pro as described above and Torque Pro. Car Gauge Pro is a PITA to use but does perform a buzz test and CCT. Torque is much more user friendly and gives you many more options/gauges/etc.

I would love to have AE but its a little out of my price range and I expect I would have bought it just to realize I have no idea how to use it. And, driving around with a laptop sliding around seemed like it would be an annoyance.

The PLX Kiwi dongle was $50 on ebay (on sale it seemed) and the apps were about $6. I used a spare 10 ft micro USB cable and picked up an auxiliary 12v outlet that had two USB ports on it (in addition to the traditional cig plug) for $10. I provided power to the 12v outlet with an ATM Add A Fuse powered off of a switched fuse in the underdash fuse panel/PTC or whatever the "just under the dash, no underhood" panel is called. I mounted the aux power under the steering column and ran the USB cable up the A-pillar, along the windshield under the headliner board to where the rear view mirror is. I used a flexible neck cell phone mount/holder and have it holding an old Android phone above the rear view mirror. Torque Pro has the option to "sleep" the phone when the OBDII adapter is not detected or the phone doesn't have power. I just leave the phone in the mount and it turns itself on and off with the ignition. I do have to manually turn off the Kiwi Dongle but its a small inconvenience. The nice thing about the Kiwi is that it has a physical on/off switch - other dongles you have to unplug.

Overall its definitely a budget setup but it was WAY less than a set of gauges, less than AE, can read pretty much any engine parameter from the PCM and also reads codes. You can have any number of gauges but I monitor Boost, EBP, EOT, Trans Fluid temp, HPOP pressure and IPR duty cycle with traditional looking gauges. In between the gauges I have digital "number" read outs for Engine Load, Throttle Position, Battery Voltage, IAT and TC slip. Running so many gauges makes it update a little slow (dongle can only handle so much and it is an older/slower phone) but it updates about 2x a second which is fine by my expectations. If I run just one gauge its about 13x a second.

Another nice thing about Torque Pro is that you can set alarms that will flash the gauges and also give an audible alarm if something exceeds the value you programmed.