Engine/Transmission (1998.5 - 2002) Engine Miss

[pcarlson]

I have a miss at idle when the truck is still warm and has sat for a couple hours. An overnight sit and it idles fine and after your driving it idles fine. Power on the go seems unaffected, she still pulls and scoots. The miss will shake the truck. Doesn't seem to matter about outside temps either.



I just put in some power service and there are no codes.



Possible causes??

 

[AKAMAC]

Try cracking the injector lines when it is missing. This will eliminate/identify a bad one.

If you can identify the cylinder missing at idle and verify fuel to injector then a call to seller is required. Hopefully it is that simple.

 

[pcarlson]

I will have to try that this weekend. Be one of the first EDM's to go bad as I haven't seen to many problems on here about them. Post results later.

 

[NPloysa]

Not sure if this is the same as you are experiencing, but mine misses a bit too, but only on certain fuel. If I fill up at a truck stop, the fuel is fine, any other small place that doesn't get a lot of volume and fuel rotation, seems to make it miss. So if you don't find anything with the injectors, try a fuel change to see if it goes away.

 

[Ncostello]

I've dealt with this for years. New injectors didn't help. Tried many tricks and all the suggestions including sensors, additives, and checking all wire connections. Cummins determined throught the use of the INSIGHT diagnostics that groups of two injectors were not at 100% delivery. Check it again later and a different group of two were not at 100%. They do this by running the engine on all possibilities of two cylinders in pair through electronic control. My last straw is the VP44. I have no reason to believe there is anything wrong with my VP (sort of)... so I got another here at home awaiting a major malfunction.



I think something in my VP is broke but its not major enough to kill it yet. And I think I know what it is but only dis-assembly will tell.

 

[NPloysa]

I've dealt with this for years. New injectors didn't help. Tried many tricks and all the suggestions including sensors, additives, and checking all wire connections. Cummins determined throught the use of the INSIGHT diagnostics that groups of two injectors were not at 100% delivery. Check it again later and a different group of two were not at 100%. They do this by running the engine on all possibilities of two cylinders in pair through electronic control. My last straw is the VP44. I have no reason to believe there is anything wrong with my VP (sort of)... so I got another here at home awaiting a major malfunction.



I think something in my VP is broke but its not major enough to kill it yet. And I think I know what it is but only dis-assembly will tell.

Possibly! But I have heard of ongoing problems even after VPs being replaced. Maybe it is in the ECM?

 

[RCrawford]

I replaced my VP44 last Dec. Before that the engine was smooth as silk. After the replace, the engine started to miss some, not on a regular bases thow. Some times it runs perfectly. The Insight program didn't show anything, so i'm going to run it till something shows up. Later,R. C.

 

[pcarlson]

Well cracking the lines did nothing but make a bit of a mess. The bugger will only miss when its still warm, i. e. after sitting 4-8 hours. The morning their is no miss or a quick stop and go at a store, no miss either. When it misses there is no mistaking it as it shakes the truck as the motor really shacks side to side. If you put it in gear when it does this it calms down and if you drive a half blocks and stop the miss is gone.



Driving and under load there is no miss I can detect and it pulls the 5er just fine. MPG seems unaffected and I have run two bottles of power service through it already and that seems to have had no effect. Fuel pressure is 15-16 idle and 13-14 cruising.



To me I believe it is electrical verses mechanical. Any other inputs. My VP was replaced about 20-25k ago.

 

[SConklin]

I have the same kind of problem. I have replaced the drag comp, ecm, and boost sensor recently for other reasons, but none of them cured the miss. Replacing the ECM made it milder, but I don't think it was because it's an ECM problem. I just think it's pushing through more fuel at idle maybe, which seems to dampen it anyways when it's working even just a little more. I suspect it's the VP44, or injectors. I have a VP44 tester, and it didn't show up when it did that, but then again, I had to shut the truck off to hook it up, and that always seemed to cure the miss temporarily anyways. I'm going to be swapping the VP44 soon anyways. We'll see what happens. If that doesn't work, I'll check the injectors, and maybe the APPS. Let me know if you get it fixed. I'd be interested to hear how, since it sounds like you have the same problem as me.



Skyler

 

[pcarlson]

I'll keep checking it out and see what I find. If I find something I'll post it.

 

[djacy99]

I have the same problem. I was under the motor and just happened to see the balancer rubber was dry rotted. I will be changing it Monday. I don't understand why it only does it when hot. I don't know if this is the fix but you might check yours.

 

[pcarlson]

This weekend I replaced the fuel filter and reset the APPS. Fuel pressure might have gained . 5 psi cruising and its still 15 at idle. I figured while I was under there I would unplug the EZ connections, clean and reconnect and lastly I reset the APPS. Started up and ran fine, drove it around and power seemed fine like always. Let it sit for a couple hours and started it up and there again was the miss!! This miss shacks the engine side to side that the truck shacks. Drove down the drive way and back and the miss is gone. Miss at idle is not there if you restart and will only be there if it sat for a couple hours.



This is getting annoying for nothing else. I like to diagnose and fix. This has me a little baffled.

 

[AKAMAC]

I know it's a PITA to swap but I can loan you a set of stock injectors to put back in to diagnois the miss, if you have sent back yours as cores. I know how you feel about doing it yourself. If they don't fix the problem then your out 5 or 6 bucks for shipping and an hour or two of your time. If it works then you can use them till replacements arrive.

Mike

 

[obert]

Well, I bet the stock Injectors dont help. This little bug has shown up here several times and nothing has ever come out of it.



My truck has had this problem scince the VP was replaced almost 80k ago. With the manual shift the apperance is slightly different. Always at operating temp, only after stopping and sometime slowly clears up as the truck idles. Sometimes the miss is more like a solid dead cylender, sometimes its very random and intermittent.



It was fine on the old VP, and all mods, repairs, and adjustments have had absolutly no effect.



I'll be watching this thread, PLEASE someone shed some light on this one.

 

[mhenon]

Engine miss!!

Hard to say what this problem might be. I was thinking maybe the APPS or Crank Position Sensor. Before you start buying and replacing parts though you might try uncoupling "all" electrical plugs and coat them with a di-electric grease. Also, check "all" of your grounding cables. There's a few of them located around the truck so you'll have to find them. I un-hooked all of my ground straps awile ago... ground off the painted surfaces... and reinstalled the grounds with a coat of conductive grease (not dielectric grease this time).

If it turns out to be a bad ground or corroded contact pin you'll have saved youself some cash. If not... . they probablely needed it anyway.

Good luck. . hope you figure it out.



Mike

 

[pcarlson]

I think I should explain the miss better. I think the miss would be best described like a "Gasser with a Big Cam". It lopes and only when cold or haven sat for hours. I was originally thinking valve adjustment but that should be when hot verses cold? I was also thinking a temp sensor or cam/crank sensor.



All my connections have the dielectric grease but I will check all the ground connections. The symptoms just started like a switch on/off and not a gradual change over time just getting worse, so that is why I was leaning electrical.

 

[obert]

There are alot of connections to go through in that engine harness. Honestly I fell bad about having not fixed this one-- Iv'e chased down worse than this at work, but my "factory training" doesnt involve on-hwy. equipment.



I do want to agree with that electrical conection (or ground) problem. My miss shows similar to pcarlson's, but mine doesnt show at stone cold engine, but does taper off to smooth after some idle time.



An unrelated failure took the crank sensor this summer-- that was replaced with no change to this miss thing. On a side note, if you ever jump into your idling rig and see the check engine MIL on and the tach at 0, DO NOT turn off the engine untill you are sure the truck wont need to be moved for a little while.

 

[Cattletrkr]

This weekend I replaced the fuel filter and reset the APPS. Fuel pressure might have gained . 5 psi cruising and its still 15 at idle. I figured while I was under there I would unplug the EZ connections, clean and reconnect and lastly I reset the APPS. Started up and ran fine, drove it around and power seemed fine like always. Let it sit for a couple hours and started it up and there again was the miss!! This miss shacks the engine side to side that the truck shacks. Drove down the drive way and back and the miss is gone. Miss at idle is not there if you restart and will only be there if it sat for a couple hours.

Is the APPS the same as what the dealer calls the "bell crank sensor"? If so, how do you reset it? Dad's is throwing code 0122.



thanks

 

[pcarlson]

APPS- is the accelerator pedal position sensor.