Fueling Problem...VP?

Ok folks. Here's the skinny on my truck. I have been fighting this problem for months now off and on and haven't found a solution yet.

Problem: When accelerating at a moderate pace, my truck bucks and jumps between 20 and 30 PSI like it is either losing boost or losing fuel or the juice mod is wigging out.

What I've done so far: I started by pressurizing the intake from the turbo with a homemade jig. I had a very small leak on a intake manifold bolt and fixed that. So now, I don't think I have any boost leaks to speak of so now I'm thinking it is a fueling problem. My pump wire is tappd and the LED's are responding as expected on the Juice module.

My VP44 was replaced under warranty at 55K along with my LP and the truck is at 95K miles now. I put the Vulcan Big Line Relo kit and my LP pressures are 16-17 idle, 13-14 cruising, and 10-11 WOT on 5-5.

The truck runs fine in town when boosting up to 20 psi between shifts and seems to hit 43 psi (my wastgated max) when on the soot pedal hard on 5-5. My Juice module doesn't show to be "backing down" as the back-down drops to 0% after a few minutes of warm up. My gauges all read great. Boost maxes 42-43, EGT maxes 1150-1200, and so on. The computer has not shown any codes thus far.

My injectors were bought used and were never pop tested, just dropped into the truck.

Any thoughts? I am at the end of my knowledge as far as trouble shooting. Is there anyway to tell if it is the VP44 or a way to test to see if it is getting weak? Is waiting for a trouble code the only tale of a failing pump?
Why would the truck run great when poking around, when flooring it hard, and then run like crap when in the middle of the trottle?

Please HELP! :thankyou2: :bang

You check for codes? Has it behaved like this the whole time with the Edge?

No codes. The very first time I pulled a trailer with it, it did it once or twice in that range. I had 12,000 of hay on a 24 ft flatbed running 70 down the highway for 2 hours. Some told me that it was turbo bark. They said my turbo was making more air than the motor could pass when getting on the throttle at below 2000 RPM...which makes some sense. It only did it when loaded at first and now does it all the time. I have learned to drive differntly to avoid the "bark" when shifting gears, but this jumping and bucking of the entire truck just over 20 psi has to stop!

Any other ideas? I have thought about sending my Edge module in to test but they want the whole wire harness. I really don't want to jerk that sucker out of there. I can surely test it with a DMM no?

I'd try to improve the wot psi's..... your idle psi is what i'd like to see at wot- or better.....

and on this bucking and jumping issue- almost sounds like an APPS/TPS issue?

RacinDuallie said:

I'd try to improve the wot psi's..... your idle psi is what i'd like to see at wot- or better.....

and on this bucking and jumping issue- almost sounds like an APPS/TPS issue?

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I'd like to throw a cummins campaign pump in for $65 and see how that works. With a little girl on the way in April, daddy has had his "truck" money banned for a while...and that is fine. Anything I get now has to be "affordable". Ya right, diesel performance and affordable in the same sentance!:hehe:

And APPS/TPS. Throttle Positioning Sensor? What is APPS? I haven't thought of that. I had it off several times to put injectors in and junk. Maybe I screwed it up? Any chance of a "what to check for" pargraph? I have the technical maunal for an '01 truck on CD that matches my '02 for the most part, but the stupid thing never gives me enough detail to actually test anything. It just says "replace".

I sure wish one of you "diesel race junkies" lived close. I'd just come let you drive it. I have a hard time explaining what it does. Once it crosses 20, the boost reads 22...25...23....26...21...if I keep the pedal about half way down. Now, if I hit the pedal hard from the git-go, it goes...15...22...43....43....43...43..

yea i think u got a problem on ur hands. i'm here w/ Woodruff Diesel.we are located in southern ohio. u can call us at (937)987-2177, or go to our website @ www.woodruffdiesel.com to get any other information. we would be glad to help u in any way as possible.

woodruff diesel said:

yea i think u got a problem on ur hands. i'm here w/ Woodruff Diesel.we are located in southern ohio. u can call us at (937)987-2177, or go to our website @ www.woodruffdiesel.com to get any other information. we would be glad to help u in any way as possible.

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I sure wish someone would move a good diesel shop down here to Okie land. You all are SO FAR away!

Well look who it is!!! I honestly have no clue what else to look for either....the only thing that I can think is maybe toss in your old injectors ( if you still have them ) and see what happens. Then you can rule them out if it still does it or if that cures it.


~Nick

I like the idea of tryin to reset the TPS (Throttle Position Sensor) It sounds like it's fueling then defueling causing the rise and drop in the boost pressure. Can you hear the turbo spool and despool as your pressure rises and drops. You can try resetting the TPS by unhooking your batteries over night and see if that helps. Has the problem got worse over time, I know you said that it started when towing but has it got to the point where it happens all the time, or worse every time it happens?

this is kind of funny but i was driving to mobile on saturday pulling my 20ft gooseneck bout 7k on the bed an my truck started bucking/cutting out so i pulled over on the side looked over everything boy i mean i was pissed but guess what i found the relocation wire that came off of the old lift pump somehow maybe got some moisture or such in it an had a bad connection we fixed that she runs fine . maybe check the power goping to the pump maybe shorting out.

I'm gonna say reset the APPS and see what happens then, you have good FP to the IP and everything else (to me) you have described sounds like the IP is working fine.

Is this on the stock turbo?? I ask because we have an almost identical setup and I have never had the problem you describe. If you are still on the stock turbo I would rule out turbo surge, I have had the goat pushing 30+PSI in 6th at 17-1800RPM with a load behind it with no problems.

Ok, where's the "multi-quote" button? op:

Yes, Nick, it is me! :rockwoot:

Bad_cummins': Yes, once I cross about 20 psi, I can hear the turbo barking and loosing the boost. The pressure wigs out between 20 and 30 like...22...25...23...26....27...until I either jam the pedal to the floor or let off it. I can ease into the pedal from the start and get the boost gauge to go slow like 10...13....16...17....19....21....then it goes to crap. If I floor it from the get go, it goes 8....14.....25.....37....43....43....43....

02 Doge 4x4 5.9: My LP pressures are good so I don't know about the wire shorting. 16-17 idle, 13-14 driving, and 10 min WOT.

Billysgoat: RacinDuallie has briefed me on the reset and I'll try that tonight when I get home. I have an Industrial Injection 62/14 Phat Shaft turbo and this sucker makes a metric butt load of air, I just can't keep it coming. It seems to me that I don't have enough fuel to keep the exhaust turbine spining so I lose what I have. Does that make sense? I'm supposed to have this :ft: and I'm getting this :st:

I have also noticed my smoke is a little grey'er than usual. Where's my fuel?

I'd see about pulling those Jammers out and re-installing the stockers..... Just to rule the Jammers out, if there is a change then send your Jammers out to get pop tested/matched....

What sucks is that I don't have the stockers anymore! I traded them for a good deal on the Jammers. That is what I get for buying used....

Does it only do this with the Juice on? Is it temp related in any way? Once you start getting the surge, can you go wide open throttle, and clear it up? What max EGT are you seeing?

Paul

paulb said:

Does it only do this with the Juice on? Is it temp related in any way? Once you start getting the surge, can you go wide open throttle, and clear it up? What max EGT are you seeing?

Paul

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I guess you mean by "juice is on", it is on 1 thru 5 and not on the stock setting of 0? I don't guess I know what you mean by "on". Yes. I have tried it on levels 1 thru 5 and the lower levels seem to do it worse. The harder I push it, the better it is. I can punch it to the floor and cure everything. Or I can putt-putt around and not see the problem. It is the mid-range that sucks. My max EGT only exceeds 1200 once I cross 100 mph and have my foot on top of the valve cover. This turbo runs really cool. Usually when getting on it harder than normal I only see 1050 or 1100 max. My max setpoint on my attitude mod is set for 1350 max and 45 psi max. That might also be good info. I am viewing the "back-down" percentage on my screen right now and only see a backdown when cold and when I start reaching my set points. It is on 0% most of the time when I have my problems.

Yeah, 0 is what I meant. It's off on the drag comp... Sorry. Your EGT's are well in check. I would adjust the wastegate (or adjustable boost elbow if you have one), to lower the boost a little, and see if you can get it farther from the surge line, in the mid range boost. I would try setting it for a max boost of about 38psi, and give that a try.

Paul

If it only does it with the juice on then maybe the box is bad. I had to send my comp in due to it changing settings and other odd things. Try turning the juice off altogther and see if that helps. Edge has kind of gotten shotty since they have been bought out. They do a good job with warrenty work though, just another option$.02 , good luck:Cheer:

Ya. I called them about sending the box in and having it tested. They said they'd be happy to test if for me....but wanted the wiring harness too! Horse hockey. I sure don't want to pull that SOB out! It took me long enough to get the dang thing plugged into the MAP sensor and junk...being a rookie and all. I can probably do it faster now, but that would still suck. I may pull the box and have them look at it if they'll take just the box. I did have them update my attitude one day after I put it in. It had old firmware on it and kept dropping the boost option on the display. Who bought them out? I did not know that. They just sent me a new one and I swapped them out. I wish they'd put a connector on the back of the attitude module so you could swap them without pulling the cable through the dang firewall each time. That would be a good addition.

I may try unpluggin the harness all together and driving the truck without the entire Edge box and wires. Then I'd know to look elsewheres. I just haven't had a few hours at night to pull the truck in the shop. I'm still building baby furniture for the room.....honey-do's you know....Argh!

Even though it's a pain in the butt, I'd yank the harness and send the whole thing in. It may take awhile but it'd be worth it to see if that's the problem.....it'll save a bunch of headache.