Engine Miss

[DGerth]

Gentlemen,
A conundrum if you will. I have a 01 CTD 6spd, 50hp injectors with an engine miss. Our yearly road trip to AZ,
started to miss badly and deteriorated as we progressed. Found a good shop and decided the hi pressure pump was the culprit, original had 285k mi on it. Had injectors tested and were good. Fuel pressure 16-17lbs when it was missing, no codes at that time, no smoke. R&R'd the pump and life was good for 3,200miles. Now the miss is back! Codes P0234 & P1693, over boost and ECM/PCM detected a DTC, Power is also down. The pump is reman and the builder will test but if nothing is amiss, will charge for another pump not under warranty. Truck runs good unladen, again, no smoke when missing. Is the turbo at fault, perhaps a sensor on the turbo? ECM/PCM bad or on the way out? Thoughts, ideas are good!
D gerth

 

[petersonj]

Is the "miss" exactly the same as the "miss" before replacing the VP44? If it is the same, then the problem could lie elsewhere. Also, can you describe the "miss" in more detail - i.e., is the miss a single cylinder miss? is the miss affecting all cylinders, is it at cruising speed / idle / under heavy throttle?, etc.
.
Need as much info on the truck as well - auto or manual transmission, past repairs / parts, programmer, etc.

- John

 

[DavidC]

Any engine mods/fueling boxes besides injectors ?

 

[DGerth]

Any engine mods/fueling boxes besides injectors ?

There are no other mods to the truck. The miss occurs under load at between 1500 and 1700 rpms, goes away at higher rpms. Has three gauge pod, boost, fuel, egt.

 

[Alan Reagan]

Sounds like an electrical issue on the control line. I had a similar issue where the truck would start missing at around 1500 rpms, especially noticeable when pulling a long hill.
The dealership replaced injectors, and various other parts to the tune of about $10,000 worth of warranty work. Nothing changed. I was sent to another dealer for a second opinion. Within 45 minutes, the tech showed me where there was a noise spike on the fuel load line. That spike coincided with the fan clutch engaging and disengaging and was causing the engine to miss. The fan clutch was replaced and the problem disappeared.

Someone with a data bus analyzer (dealer probably) needs to look at the control lines and see what's going on before any more parts are replaced.