Engine/Transmission (1998.5 - 2002) misfire

[aptacek]

I have a misfire on my 01 2500 4x4 QC dodge pickup.



Symptoms prior to pump change. 1. 216 code 2. dead pedal in various positions. 3 a "stumble" when starting truck, causing a "limp mode" until

2-4 miles of driving then fueled fine and have normal operation characteristics. No miss problems at this time



Changed the VP 44, test drove worked great, had a small fuel leak, appeared to be coming from the rubber coupling on the return line by the fuel filter

area. Put a hose clamp on, drove it and appeared to be fixed. Drove the truck back home from my buddies place, ~175 miles, when I pulled up to the

stoplight in town, noticed a miss. Pulled into a parking lot and saw

fuel dripping. Got the truck home to my shop and saw #2 cylinder high pressure line leaking bad,removed the injector line set, saw the scratch in the connector tube. Bought a new connector tube and figured better get a new line. Re installed and leak was gone, then #1 had a small leak, that one I resolved by polishing the ferrule end of the line and re-seating the connector tube and high pressure line connection. No more leaks still a miss.

Tried to isolate miss, by cracking lines, could not get to #6 until I buy more

cheap wrenches, and cut, grind, bend etc to make them work in the difficult place to crack the connection. Don't have a scan tool that can do

a cylinder cutout test. Here is the "curve" in this dilemma. If the truck is under load, (in gear at a stop sign) no apparent mis. I can use the power

braking technique to simulate hiway load no problem it even breaks the one tire loose in the shop. I let off the throttle and it starts the miss again.

Have an idea why the load simulation seems to cure the problem.

The only mods are the edge box w/ attitude, the pump wire has not been tapped yet and the box is set to "0" stock level. Truck has ~ 87000 miles

Any feedback on this would really help

Thanks

Andy

 

[DavidC]

I would try disconnecting all but the power and ground to the box first. Put the wiring back to stock and eliminate the box to see if it is affecting the system.



Dave

 

[AllianceDiesel]

yeah I have seen boxes mess with trucks before even when they were at stock, completly remove the box and see if that helps, it might be something simple

 

[JLandry]

Andy,

If disconnecting the Edge computer doesn't solve the problem, I'm tempted to wonder if you have an injector not completely closing... like maybe a contaminate is preventing the internal needle from seating all the way? I believe the injector would still function, but fuel delivery wouldn't be precise and could cause a miss at idle.

Any Dodge dealer (or someone with a DRBIII scan tool) would be able to isolate which cylinder is the culprit in a few minutes.

BTW, where are you located in case someone in your area can help? Please fill in your profile and signature info.

Good luck,

John L.

 

[AllianceDiesel]

im pretty sure you can't kill an injector on a 2nd gen with the drb, you can on the third gens since they are electronic

 

[Bob4x4]

The drb can kill cylinders on the 2nd gen 24v. I like to use a flare nut crows foot on # 6



Bob

 

[AllianceDiesel]

huh never knew it could, guess I never had a truck that needed to have the injectors killed on a 2nd gen, I wonder how that works, has to be something inside the vp44?

 

[Bob4x4]

Yup inside the VP. Another interesting thing is the misfire code on the vp trucks... ..... it doesn't ever come on in my experience but I have had many not firing right.

 

[EBung]

I dont think it can shut off just one injector though. Isnt it 1-6,2-5,3-4?

 

[Bob4x4]

I have done one 1 at a time,the only question is what version software is loaded on the drb 3 some were numbered by cylinder and some by firing order.

If I found one weak I would go back old school and crack a line.



Bob

 

[JLandry]

I dont think it can shut off just one injector though. Isnt it 1-6,2-5,3-4?

With a DRBIII, you can most definitely kill one (or more) injectors at a time... I have one and have done it many times.



You can also increase and decrease the engine rpm without touching the throttle to aid in trouble shooting.



A DRBIII is a very helpful tool to have. They can be rented directly from Miller SPX (www.spx.miller.com).



John L.

 

[aptacek]

I finally got back to working on the truck. I pulled off the edge box. No change. Cracked #6 cylinder injector line had fuel squirting and a change in the engine operation. Talked to a diesel instructor at the local community college, he said, sounds like you have a leaky injector. I have pulled the injectors and will take them to local diesel pump shop, they will test them and let me know the results along with an estimate on fixing them. All of the injectors have alot "coking" on them, and the holes are difficult to see. Maybe this has something to do with the poor fuel economy prior to the pump change, (14-15 mpg on the hyway). I'll post the results on the injectors, and hopefully it fixes the problem.



Andy