2nd Gen Non-Engine/Transmission Lope @ Idle? Lemon-Law

[Greg Boardman-RIP]

My friend has a 99 that has had a lope at idle since it was around

15,000 miles old. It now has under 60,000 and has been to the dealer a number of times for the same thing. Six months ago He had the vp44 replaced under warranty to fix this. Didn't work.

Six months before that they reflased computer, didn't work.

A year before that the reflashed computer(both) and installed new injectors. It still has the problem and has been in the dealers parking lot for about two weeks. They have changed both computer programs, Map sensor, IAT sensor, Crank positioning sensor, and now the lift pump. Still is loping when hot.

I am friends with the tech at the dealer and he said he is at a loss. What do you guys think? Where to go from here. The truck owner is starting to think about the lemon law. Who does he contact for that? Any help would be greatly appreciated..... Thanks, Greg

 

[RustyJC]

If it were mine, I'd push for DaimlerChrysler to cut a purchase order to take the thing over to a Cummins shop for analysis. Couldn't hurt... .



Rusty

 

[Oxjockey]

Chrysler can buy the truck back as a Lemon buy back, but I'm not sure how that works. He'd have to research the law in his state to figure out what needs to be done. I know in some states, there are steps you have to take before using the law, as well as be within certain mileage limitations.



Bryan

 

[Taz]

Hrm... could a lope be caused by incorrectly adjusted valves??

 

[Cummins4Life]

How extreme is the "lope" mine does it in park + or - 50 or so rpms. It seems to get a little more pronounced after a long run down the freeway.

 

[Greg Boardman-RIP]

C4Life,

It is alot worse than +or- 50 rpm's. Yes it does get worse after a hard pull down the road. It seems more like a stumble not a lope. Like it is lacking fuel. I thought the lift pump would cure it for sure. This is the second one

 

[fest3er]

Seems the truck has the could-be's. First, determine the 'qualities' of the stumble as exactly as you can. Is it regular or irregular? That is, does it seem to miss in the same spot, but not necessarily all the time? Does the RPM always drop first, then increase? Does it happen only on idle, but go away when you push the go pedal a bit? Is it related to the A/C compressor engaging? Are the heater relays still in good condition ( a long shot, granted)? Is the system voltage stable?

Possibilities:

• crank position sensor is flaky when hot. If it is at all accessible, try spraying something cold on it (water might work, pressurized can of air or other cooler might work, too).
• electronics in the ECM are flaky when hot. Try cooling it down when the problem rears its head.
• electronis in the PCM are flaky when hot. Less likely, since the PCM is mostly inside the truck.
• Are fuel pressures OK?
• Are there any flaky/corroded electrical connectors?
  
  That's all I can think of at the moment, in the line of could-be's.
  
  Fest3er

 

[Greg Boardman-RIP]

Originally posted by fest3er

Is it regular ? Yes



That is, does it seem to miss in the same spot? Yes

Does the RPM always drop first, then increase? Yes



Does it happen only on idle, but go away when you push the go pedal a bit? Yes



Is it related to the A/C compressor engaging? No



Are the heater relays still in good condition ( a long shot, granted)? That is a good one?



Is the system voltage stable? Yes





That's all I can think of at the moment, in the line of could-be's.



Fest3er [/B]

Thanks for your help. I hope this makes it a little clearer for you Fest. The truck is at his house now and still idles rough and has a jump like a lope in a cam. dealer said it will be fine... ... ... They have had this truck for 63 days over a three year period to fix this problem. Still no fix

 

[lberch]

Has anyone dropped the fuel tank and cleaned all the grunge thats probably covering the pickup membrane? I had the same exact problem (Miss / Stumble @ idle) and I did and enormous amount of troubleshooting and parts replacement only to find out that I had a restricted fuel pickup.



LB

 

[Pit Bull]

Originally posted by lberch

Has anyone dropped the fuel tank and cleaned all the grunge thats probably covering the pickup membrane? I had the same exact problem (Miss / Stumble @ idle) and I did and enormous amount of troubleshooting and parts replacement only to find out that I had a restricted fuel pickup.



LB

I bet it is the fuel tank and pressure after it is warm. Tell them to drop the tank like iberch has suggested and clean everything up.

 

[Archive]

Fuel restriction will kill the power up high- but not effect the idle.



IMO, it's sucking air.

 

[Gary - K7GLD]

Since everyone else is guessing...



Wonder if the idle speed could be too low - or the ECM thinks it is, and the ECM is cycling the fuel system to make adjustments? Might try simply increasing idle speed a small amount - or replacing the ECM?

 

[Greg Boardman-RIP]

Originally posted by TopFuel

[

IMO, it's sucking air. [/B]

Thats what I think too. Or maybe a bad or poor seating valve.

 

[Greg Boardman-RIP]

QUOTEOriginally posted by lberch

Has anyone dropped the fuel tank and cleaned all the grunge thats probably covering the pickup membrane? I had the same exact problem (Miss / Stumble @ idle) and I did and enormous amount of troubleshooting and parts replacement only to find out that I had a restricted fuel pickup.



Fuel pressure at idle is 12, wot is 9 Restricted fuel pickup would effect fuel pressure, Right?

 

[Big_Daddy_T]

There is lemon law advice on the net if you do a search. I think this is how it goes. If it is a major problem like runability or complete failure if they do not rectify the problem in three attempts it is legally a lemon. Some states have good lemon laws some do not. Alaska comes to mind. I believe in some states that it has to be the original owner even if its under warranty. Sounds kinda dumb to me. Look up your state lemon law and see what you come up with. I know folks on there 5th transmission under warranty. Id say enough is enough its obviously junk.

 

[lberch]

Greg:



What convinced me to go into the tank was my observations of two mechanical fuel guages. One pre-filter and one on the injection pump. First time I hooked them up I had 13 psi pre & 10 - 12 psi at the pump. The reading at the pump was very erratic, bouncing all over the place so the 10-12 is an estimate. People who say erratic readings at the pump are normal and caused by pump pulses are incorrect (IMO).

When my engine would stumble (drop in RPM) my pressures both pre and at the pump would pulse up.

To add further, I must have replaced my fuel filter 10 times during my trooubleshooting and right after I would change it, I would have perfectly steady readings at both locations for about 5 minutes and then the pressure at the pump would start to bounce.

After I dropped my tank and cleaned the membrane, both pressures are rock steady at idle and every tank of fuel gets Stanadyne and shot of biocide, that was 3 months ago and it hasn't missed since then. If you want to read more on my trooubleshooting escapades, just do a search under lberch, there are only a few. Good luck! BTW it is not a big job or a PITA to drop the tank.



LB