Archived Problem after KDP (tab method) fix

[GeoVeo]

I was in a minor front-end collision in which the bumber, radiator, intercooler, trans cooler, a/c condenser, etc. were damaged. It was minor enough that I was able to drive the 100 miles back to the house with no problems. I arranged with the dealer’s body shop to let me in there to do the KDP tab fix while the above-mentioned parts were removed.



After I left they called and said they started it (don’t ask me why) while these parts were still off and it ran real rough and smoked. I went back and found no diagnostic trouble codes indicating any problems. When I tried to start it, it would not fire – I didn’t let it crank long. The only thing I could think of was (although neither the shop manual nor the TDR thread discussing the tab method made any mention of it) maybe the engine speed sensor required proper orientation with the vibration damper. Before removing the damper I had made some marks but thought maybe I had somehow goofed. I removed the damper and turned it 90 degrees and the truck fired right off and seemed to run ok. Now they call me back and say its running rough again.



My question is, would the PCM make the truck act like this with the intercooler, etc. off or do I have something more serious going on (like – where did I leave my wedding ring)? I used a torque wrench during assembly. I would think if the PCM was the cause it would show a code.



Any help would be greatly appreciated.

 

[illflem]

About the only thing you could mess up to cause running problems during the tab fix is the gap on the engine speed sensor. I don't know the specs offhand, maybe someone else can chime in. Do know you are supposed to use a non-magnetic feeler gauge. Wiring could also be messed up from the wreck.

 

[Dieselnerd]

A matchbook cover or a double business card will set the gap pretty well.

 

[GeoVeo]

Thanks for the replies. The gap on the engine speed sensor (ESS) is 0. 049 - 0. 051. So you're saying the ESS would cause this behavior? From what I get out of the service manual, the ESS drives the tach, supplies inputs for the cruise control, the generator field, and along with the VSS & TPS, controls auto trans shift points.



If a faulty ESS could cause this, I have, for sometime now, noticed that setting the cruise doesn't always take. Perhaps it decided to misbehave in other ways now?



The manual refers to a Powertrain Diagnostics Procedures manual to test the ESS - I don't have that manual. Maybe I can get the dealer to check it for me.



Thanks, again.

 

[Joe G.]

You probably should clean the connector and seal it with some dialectric grease. If it's corroded or dirty or wet you could get these symptoms.

 

[Extreme1]

You truck is mechanical, the ESS can't affect the way it runs.



I would suspect that if you drive it every day and now it sits for a few before being run that your fuel return line is starting to head south. It might start hard and run a little rough but it should smooth out after a little while. Make sure the body shop isn't doing anything wierd (like cycling the heaters too many times).

 

[GeoVeo]

I replaced the fuel return line Jan 2001 with diesel rated hose, but I'll give it and the supply line another look. Other items that have recently been replaced include: fuel filter, overflow valve and pre-heater/filter screen cleaned. I'll try to determine if they are doing anything wierd when they start it.



From the responses I've received, I guess having the intercooler out of the loop (hence, no boost) has nothing to do with it sometimes running rough and making it hard to start. I was hoping someone would say: no boost = no good.



I'm going to take a day off tomorrow and apply your suggestions. I really appreciate the responses! GeoVeo