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Discussion Starter #1 (Edited)
Hi All,

I recently changed out my injectors due to cold start issues. 1999 F250 7.3l superduty. Here is a little background info...Before I did anything the truck ran fine once it was warm, but it smoked like hell at any cold start temp below 50 degrees. I had all AD injectors coming out of the truck. The new injectors set had 7 AD's and 1 AE for cylinder 8. The provider said that the AE injector was matched with my VIN.

I moved forward with the swap despite the discrepancy. After the new injectors were installed it started hard and was running rough. So I pulled the non matching AE injector and put in a reman'd AD in cylinder 8. It runs with a little bit more power now with all AD injectors, but it still starts hard and has quite a bit of vibration. Definitely not running as well as it was with the original injectors.

I ran a scan on the truck to see about fault codes. No fault codes came up that had any relation to the engine or it's sensors. Then I ran a buzz test and cylinder contribution test. Each test gave me a different fault code. Here are the results...

Buzz test results - Injector Driver Module.
===DTC P1298===
Code: P1298 - Injector Driver Module Failure
Module: Powertrain Control Module
Diagnostic Trouble Code details
Injector Driver Module Failure

Contribution test results - Cylinder #2
===DTC P0266===
Code: P0266 - Cylinder #2 Contribution/Balance
Module: Powertrain Control Module
Diagnostic Trouble Code details
Cylinder #2 Contribution/Balance
This DTC may be caused by :
Internal engine components
Possible causes are:
Fuel Injector
Valve train assembly
Compression rings

Since i didn't have this issue before the injector swap, I'm skeptical that the IDM is bad. Regarding the contribution test, I did all the procedures regarding removing oil/fuel from the cylinders before buttoning up the valve covers and hope I didn't harm the #2 cylinder. But at this point I have to wonder.

How serious is the contribution test results. Is that something a simple valve adjustment could fix or do I need to pull the head and inspect the cylinder for damage. Remember, the truck ran fine before the injector swap. Or, should I drop $350 on an IDM and hope the truck runs well enough until I can get the valve/cylinder looked at.

thanks for any input.
Adam
 

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I would suspect a defective replacement injector before a base engine issue, such as valve train.

The IDM failure code is probably a fluke. I've had that come up a few times, but have never had an IDM problem.

You could swap the #2 injector to another cylinder and see if the contribution fault follows it. If you put rebuilt injectors in, I would definitely suspect them.

Your injector provider is incorrect. Unless the '99 went in for the "cackle fix" and someone changed the #8 injector, it would have 8 AD injectors. The change to the AE in #8 required a PCM flash as well, and if not done would affect how it runs.
 

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Really? The AE on #8 is not stock and requires a pcm update? Somehow I thought it was. Would that have anything to do with a #4 and #8 cct failure? Now I need to double check what I have.

Sent from my Pixel using Tapatalk
 

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Discussion Starter #4
Really? The AE on #8 is not stock and requires a pcm update? Somehow I thought it was. Would that have anything to do with a #4 and #8 cct failure? Now I need to double check what I have.

Sent from my Pixel using Tapatalk
QuercusRubra, why are you hijacking my thread?
 

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I would suspect a defective replacement injector before a base engine issue, such as valve train.

The IDM failure code is probably a fluke. I've had that come up a few times, but have never had an IDM problem.

You could swap the #2 injector to another cylinder and see if the contribution fault follows it. If you put rebuilt injectors in, I would definitely suspect them.

Your injector provider is incorrect. Unless the '99 went in for the "cackle fix" and someone changed the #8 injector, it would have 8 AD injectors. The change to the AE in #8 required a PCM flash as well, and if not done would affect how it runs.
klhansen, to be clear, I put in all AD reman'd injectors and it still runs rough. I will try putting one of the old AD's in the number 2 cylinder and see what result I get back. However, when I do a buzz test with all AD's, they all buzz.

is there a way to bench test the injectors on the truck? off the truck? I worry that I'll swap a bad injector with another bad injector.
 

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Really? The AE on #8 is not stock and requires a pcm update? Somehow I thought it was. Would that have anything to do with a #4 and #8 cct failure? Now I need to double check what I have.
On a '99 from the factory, the injectors would be all AD's. The AE injector was introduced in the 2000 MY, IIRC.

QuercusRubra, why are you hijacking my thread?
His question is on topic, so not a hijack. We share info here. :smile2:

What I meant by swapping injectors, was to swap the #2 with another already installed in the engine that didn't show up as a code on the Contribution Test.
The buzz test only checks the injector solenoid and circuits for continuity, although you can get an indication by listening to the sound for a weak buzz which might indicate a worn pintle valve or reduced clearance in the injector armature plate.
The hydraulic end of the injectors is tested using the contribution test. But as you saw, there are other things that can affect cylinder contribution which checks the power of each cylinder by monitoring minute engine RPM fluctuations.
 

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bomhour:
Just out of curiosity, how many miles were on the original injectors when you pulled them? Did you obtain the new/reman'd injectors from a reputable supplier? (You don't need to name them specifically, unless you're comfortable with that. Not trying to hang anybody here...)
Sometimes a shody reman' job can lead to bigger problems than just leaving in the old sticks.

Hopefully not in your case...

~Al
 

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Discussion Starter #8
thanks for the replies. I ended up pulling the vc on the driver side again after ohm'g all the injectors and getting a low number on 6. I had another injector wire harness from the injector kit. I th threw that in and fired it up. It still started really hard, but it ran a lot smoother once started. I took it down the highway at 75mph and all was good with power, acceleration, sound and smoothness. I think it was a harness issue causing the IDM fault. I started it up again once I was done with the test drive and it fired right up.

I think it just needed to purge some air in the system before it wanted to start like usual. I'm headed up to the mountains tomorrow. If i have any issues I'll check back in and let you all know. But for now, I think the issue is solved.

thanks for everyone's replies...even QuercusRubra :)
 
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