Engine/Transmission (1998.5 - 2002) Boost comes and Goes????

[RMcNee]

Ok this has been doing this for awhile now... only when I'm on a trip though,,,,heres whats goin on... this weekend took a 375 mile round trip... everything is fine till about 180 miles... . got the cruise set at 75 nice level eastern montana road, and all the sudden the acc. pedel goes to the floor and i have only about 6psi boost and i'm losing speed... this has done it before but its only on trips... ive had it in but it wont do it with someone just taking it out to the interstate for a quick trip... so i kill the cruise... put the clutch in... rev it up a couple of times and then let the clutch out and i got boost again... right up to 25 or so cause i'm getttin back up to speed... . couple of miles down the road... same exact thing... . FP is 12, pyro is 600, boost drops to about 5 with the pedal to the floor... then i do the same thing and i get boost back..... this time it actually did it once when i was trying to pass someone... lost all power so had to get back behind them??? ANY IDEAS??? i dont have any codes comin up. . and other than this she runs hard as hell... i am running a edge ez... could this be with that ?? thanks for any info... Russ

 

[Mundgyver]

Pull the EZ and see how it does. If it does it again, then you might want to look at your fuel and throttle. Throttle positioner might be a problem with a developing dead spot. If not then maybe the EZ is the problem.

 

[cerberusiam]

The boxes sometimes cause inexplicably strange behaviour. Sometimes its the box, other times its a component problem.



Have you:



Checked both batteries to make sure they are good



Checked all the grounding points



Reset the APPS



Checked crank position sensor connections





It sounds suspiciously like the infamous "dead pedal" syndrome which means you probably have a VP44 with one foot in the grave. No codes means it simply hasn't failed hard enough to get the ECM's attention. How did you check for codes?



Are you towing when this happens or running empty? Many times the IP failure just won't show until you load it and really work the crap out of it.



Since your boost is dropping it probably means it is defueling for some reason. The APPS is a good place to start and make sure it does not have a dead spot. The next step would be look closely at the IP and see if you can't produce a failure with a code.

 

[RMcNee]

Thanks for the info... will check the apps today and see what happens... . If i unhook the EZ do i need to take out the elbow that came with it for the waste gate? thanks

 

[Mundgyver]

Nope, just leave the elbow in.

 

[SnoKing]

You will defuel if you do not cut the boost back to around 20 lbs. Sets code also I think.

SNOKING

 

[nps]

SNOKING is right. If you want to test the EZ, then leave the wastegate elbow installed, leave the EZ plugged in between MAP connector, and just pull the EZ connector to the data bus. This way the boost fooler still works, but the EZ is not adding anything to the VP44.



I do this every year for my annual emissions check. Also is a good way to regain your appreciation for the EZ - you'll think you are pulling a 20K trailer with the EZ unhooked.

 

[Mundgyver]

I don't have a defueling problem with my elbow installed and the Edge removed and I have never set any codes in this configuration Am I missing something, cause my truck runs just fine and I can hit 30 lbs of boost. No codes show up on my Roadrelay either. This is without the Edge installed.

 

[RMcNee]

Well i reset the APPS again yesterday, cleaned all the battery post and terminals again, double checked the EZ connections, so I guess I'll have to wait till i get out on the road again... like i said it doesnt do it till i'm on a decent trip, last weekend it didn't start till i was 180 miles into... thanks for the info... . Russ

 

[shouldbeonmyboat]

Greetings, I am new to the group. I wanted to let you know that I am having the same problem your having. I have a 2002 2500 HO with the 6 speed manual. My symptoms started just as yours but has now migrated to starting when it is cold. The only difference is that I have no modifications to my rig. Can you tell me if you have determined it to be the pump? This forum is great isn't it?



Live long ...



Mark

 

[Mundgyver]

I am wondering if you might have what is known as a floating ground. This would be a ground connection that is not tight. Could be simple as a loose nut or screw at the ground point or maybe a ground wire that is broken but still making contact and vibrates out when the rig is in motion. Also are the connectors to the ECM tight and dry meaning that no moisture has entered and started carroding the pin connection. Just food for thought here.

 

[DF5152]

any updates just got back from a long trip my truck started doing the same thing on the way home.

 

[AHire]

My truck was acting the same way. Im looking for a vp44 now.

 

[shouldbeonmyboat]

Based on the information I got from the rest of you I went to the dealer and confirmed that it is still under warranty. I did find out too that there is a $100 deductible. Oh well, better that paying for the whole thing. I will be taking it in next week but don't know of any 5 star diesel dealers near Troutdale, Oregon. I will update this thread when I get her repaired.



Live long ...

 

[RDBuck]

I just had warranty work done on my 02 for the lift pump and vp44-same symtons as you describe but it did throw the 0216 code. However there was no $100 deductible that your dealer mentioned-I would ask to see where the warranty states that information.