Duck Hunter

All right guys, need your help here. First off, I don't know that this is the forum for this post, so if it's not please feel free to move it where it should reside. Here's the question I got:

Was crusing at around 75 mph the other day, with the cruise on. I had my 5 stage power chip clicked up on the second notch (which is where we always run, about 50 extra hp). All of a sudden the truck started runnining really rough and kind of jumping a bit and losing power. I pulled over real quick and as I decelerated the truck started blowing quite a bit of white smoke out the tailpipe. The check engine light came on right as the problem happened. I had just gotten fuel 10 miles earlier.

I checked the engine and looked under the truck. No visible problems, no leaks or fluid or anything that I could see. Got back in the truck and started it. It started and ran fine. I turned around and headed back to the town I was by (about 3 hours from home on a trip). I went to the dealership but they didn't have time to look at it and didn't have any idea. I went to a Cummins repair shop and they told me to go across the street because there was a Dodge Cummins expert over at that shop. Went over to this shop and the guy, really nice guy, took my truck in right then and started working on it. I have been having some issues with the chip doing odd things. Sometimes all of the lights on the chip will light up, or random lights in a sequence that you can't have (like 1st, 3rd and 5th stage), and the chip wouldn't be working, but it never caused any problems. I explained this to the mechanic, who was very familiar with chips and such. The diagnostics came back with errors that said the fuel line had been spliced into and such. The chip is spliced into the fuel line before the fuel injector pump I suppose. As I understand it from the mechanic, most of the chips work the same way, they're spliced into the line and they essentially "fool" the truck's boost pressure, making it think it's got boost when it doesn't or something to that effect. They guy was definately anti-chip, which I guess most mechanics are. The question I have is this: Are all of the chips spliced into the line before the pump? I have the exact error codes that came back from the diagnostics, and the explanation, but they're at home - it had something to do with the line and VP44. The mechanic, however, said that these error messages would come back even if there wasn't a "problem" - that they will come back with all chips like this even if the truck is running fine. I can post error codes and explanation when I get home. I ran the truck without the chip on for about 1,000 miles on the rest of my trip and the truck ran fine, just like stock. I am guessing there must be something wrong with the computer in the chip box or something along those lines. I have a call into the shop and they are checking with the manufacturer on replacing the box or switching chips. Need you general feedback, thoughts and such regarding chips, etc. Thanks a lot guys, looking forward to your great feedback, like usual.

Thomas

Ramflasher

Well, it sounds to me like you have a chip gone bad...but, it could be something even simpler. How are the connections on the VP44 and elsewhere? How is the ground connection doing?

If all of that checks out, then swap out the box for a new one. Most places warranty them fairly well.

(I'm thinking it may be your ground wire)

2nd...not all boxes for power have to connect to your VP44. The mild boxes do not, the wild ones do.

Duck Hunter

Ramflasher -

Thanks for the response. We checked the ground and connections, all were good. I'm guessing that it may be the box. I figured most of the "wild" (100+ hp) chips had to be connected there, but wasn't sure.

Everyone -

I promised, here are the scanner codes and info on them:
P0251(M) - Fuel injection pump mechanical failure fuel valve feedback circuit - Problem sensed with fuel circuit internal to fuel injection pump.
P0253(M) - Fuel injection pump fuel valve open circuit - Problem sensed with fuel circuit internal to fuel injection pump.

That's what the mechanic highlighted on the print out here gave me, not sure that it helps or matters, but trying to provide as much info as possible.

Thomas

Fishin2Deep4U

I agree that it might be first in the connections. Next, call the box manufacture and get some troubleshooting advice.

Also, you can check your own codes by cycling the key three times, off to run. Don't go to start.

If the box is good, connections are good, maybe the VP44. You never know. Also, what is your fuel pressure??

Dave

Ramflasher

One other thing to remember...don't have a friend come over and just swap the boxes on your truck. Unless it is the same year. I forget which years, but they are not all interchangeable.

I don't think you have huge worries, cause it ran normal for about 1000 miles without the box...There have been several instances of bad boxes...you would not be the first...

Duck Hunter

Fishin-
Not sure what the fuel pressure is, or how to check it honestly. I'm new to these diesels, although I really like them thus far. However, I would assume the fuel pressure is good since I've put over 1,000 miles on it without the box turned on and not had a problem.
I have already sent the manufacturer an e-mail, although I'm sure they're closed until Monday, so hopefully I'll hear something back from them. I've also got a call into the supplier of the chip (the person who sold it to me) to see what he has to say.

Ramflasher-
What do you mean by not just switching out the boxes? If the company says, "It's a bad box, what year is your truck . . . blah blah blah . . . we'll send you a new box" wouldn't that be all right? Surely I don't have to switch out all the wiring and such if I'm going with an identical box? I know that the 2001, with this box, is specific to the year - but as long as I got a box for an '01 I should be all right, right?

Thomas

marksmith

I think ramflasher is referring to changing out boxes if you have a 98.5 and a buddy has a 2002. They are a little different (I thought the harness was the only thing different) so if you plug the different one in they might not be compatible. If the manufacturer sends you a new box for your year truck you should be fine.

The fuel pressure everyone is talking about is the supply pressure from the lift pump to the injector pump. It will run fine with little or no FP but it will take out the VP. You need to get a guage and check it once in a while (I have mine plumbed into the cab so I can watch it all the time) It is sometimes the only way you can tell they are bad. I replaced my first one at 20K and my second one is getting weak @ 34K so it is definately something to check into. Genos sells guages fairly cheap. I think your year you have the option of using one of two ports on the top of you fuel filter to measure pre- or post filter pressure. I recommend post filter so you know how much the injector pump is getting. If you do a search on FP guage installs I am sure you will get enough reading to last you a week.

Any more questions holler
Mark

Duck Hunter

Mark,

How difficult, on a scale of 1-5 (one being easy) is it to install a fuel pressure gauge on these trucks? Also, where can you "periodically" check the fuel pressure and why type of tool (does it have a name), should I use to check it? Thanks a lot - sorry for the ignorance.

Thomas

marksmith

If your truck is the year where the ports are still on top of the filter housing I would rate it about a two. You thread a tap into the port attach a 1/8 NPT grease gun hose to a sender then run the wires into the cab to the mounting spot. Keyed power and ground are the only other things needed. There is other (less expensive) methods to check it periodically. This requres hooking up to the filter housing like a permanent guage, but you run it out the hood and duck tape it to the windshield so you can read it while cruising down the road. I believe you can get this guage at www.sourceautomotive.biz give him a call at 1-866-211-1533. He'll do everything in his power to answer any questions you have.

Hope this helps
Mark

marksmith

I just checked his site and he has a FP guage for sale for $50 it comes w/ everything you need to check the FP at the schreader valve on the vp44 (its the silver one at the end of the line from the filter) Comes w/ a six foot hose and a 2.5inch guage.

Give em a holler

Mark

Ramflasher

Marksmith...that is exactly what I was trying to say! Maybe I should have worded it differently...but...

In addition to the underhood connections, it is my understanding that you can not simply change boxes from year to year, either...there are slight programming changes. Whether this is due to HO/non HO, or whatever, I do not know.

I have one of Rip's fuel gauges, and it works well.

Duck Hunter

Mark,

Thanks for the info, I'll get one of those gauges on order! What should normal fuel pressure (psi) run?

Thomas

marksmith

"Normal" is 15-16 idling, 12-14 cruise and no less than 8 WOT. If you have fueling mods that will change. I can pull mine down to 6-7 w/ brand new pump. You mostly are looking to keep at least 6-7 lbs at all times.

Mark

HOHN

Good advice all around. I would add that not all years have the Schrader valve at the VP. no matter, there are many number of ways to get your FP readings.

I would recommend a mechanical gauge. The senders on electric gauges tend not to last. Install is easy. Making it look good is the hard part. I went shadetree with a homebuilt plywood dash box for now-- it works and it's cheap.

You ought to install your FP gauge ASAP. Fuel pressure is the single weakest link on a 24V truck (lift pump).

Justin