Engine/Transmission (1998.5 - 2002) Bothersome 2nd gen, need trouble shooting help.

[Hescomp]

Hi All.

This is one of those problems that are hard to do a thread search on. Redirects are welcome.



I have a 1999 2wd drw 3500 Ram. It has had 4 Fuel pumps and 1 injector pump.

Since my trouble began I have replaced a fuel pump and the boost sensor in the head.

While driving on the freeway at a steady pace at about 150 miles into the trip the truck starts to surge like a large long head wind. The boost gage will climb to 10 psi then to 5 psi. The change in psi is on about 2 second intervals. If I keep steady petal it will continue to cycle like this. I have tried adjusting my speed, it will go away for a minute or so then return. I have pushed the trailering selector on the shifter and ran at 2500 rpm for a mile and switched back. This seems to makeit go away for a little while. The best way toget it to go away is to stop at McD's for 20 min then get back on the freeway. It then is good for another 150 to 200 miles.

This last time I made 3 SHORT stops during the first 150 miles and when the trouble began the OD said exatly 150.

The rpms do not fluctuate.

My feul presure gage is junk and don't have the extra 250$ for a good one. Gotta put food on the table ya know.

This is very frustrating. I am curious as to what I could be damaging letting this go unsolved.

This is all without a load.

Any ideas are welcome and appreciated.

I am currently working in Louisville and Live in Michigan.

Thanks

 

[fox]

You need to know what the fuel pressure is when this happens.

Gauges could save you a injection pump.

Stop buying those awful carters and get an aftermarket lift pump.

The bad thing they did was design the VP-44 to draw fuel. It continues to run with low fuel pressure and the pump doesn't cool. This destroys it over time.

A class action lawsuit should have come against them to force a fuel pressure gauge. But, it would only have been another junk source of trouble.

 

[B.G. Smith]

Are you towing anything or have a topper on the truck? I had the same 99 and best I remember on level highway it would do less than 10 psig boost at 70 mph with no load. Since the rpms don't change could it be the wastegate actuator gone bad???? Could also be fuel starvation but I would think that would change the rpm. How long since the fuel filter changed? Look at the air box inlet from under the fender and make sure there's nothing obstructing the air flow. You mention the trailer towing selector, are you talking about the OD off button?? bg

 

[Hescomp]

Reply

I just replaced the Fuel Filter and the air Filter about 1k miles earlier while having the issue with no effect.



I have an empty bed, nothing in tow.

Boost is right around 10 while at 70mph. usually just under.

Yes it was the selector on the shifter that I used.

I put a new Mopar boost sensor in. There isn't a MAP sensor on this truck. Some books call it a map sensor but it is the same cavity as my boost gage.

Batteries are 1 year old.

I have no issues running around town, It moves out nice with the edge chip in it. Passing and cruising it runs great.



I put a new fuel pump in (It is mounted with the remote mount kit from Geno's) just before this trip. 2. 5 miles on the tank of fuel before driving 150 miles. The last pump was less than a year old and I dn't think it was bad because it did not change anything.



At 150 miles out it starts messing up. This trip after I sat at McD's for 20 minutes, got back on the freeway and went almost 200 miles before any trouble. I stopped and filled up at Pilot and drove the 50 miles left with no issues. (at 19 mpg one tank will go over 300 miles. )



It is a very puzzling issue.



Heat would stay with it with the small times of my stops.



Thank you for the Replys.



I will get a good gage as soon as I can. Pay dropped 20%, kinda hard to justify a gage now unless i loose another VP.

 

[BDaugherty]

MAP stands for manifold absolute pressure. It's the same thing as boost. Just more technical terminology.



I was thinking MAP sensor, but since you replace it already let's move on.

Do you have any codes?

Have you disconnected the Edge to see if it changes your problem?

Also, I agree that you need to see your fuel pressure while the problem is happening. Fuel starvation is know to cause "bucking" in 24V trucks.



quote: I will get a good gage as soon as I can. Pay dropped 20%, kinda hard to justify a gage now unless i loose another VP.

A gauge could have saved you from buying 1 or more of the 4 lift pumps. 1 lift pump costs the same as several gauges. Not to mention it's a good troubleshooting tool... . much cheaper than thowing parts at it.

 

[DCreed]

Try driving with the filler cap off to see if the vent is not working on the tank. You may be getting a vacuum in the tank that will go away in minutes but is only a problem when pulling steady.

 

[Hescomp]

1 There are no trouble codes and no light. I think I did the trouble code check correctly.

2 I get lift pumps for 125$ and I bought 2 the last time so it was easy to check the pump this time. The best price on a good gage was about that and higher.

3 I never would have thought of the tank vent, Thanks I'll keep that in mind this weekend while driving to Michigan.

4 I have now had the oppertunity to talk with a Cummins repair shop and they mentioned it could be the VP heating up because of the fuel on the market now as well as posibly the waste gate starting to fail.

5 I plan on trying to disconnect the Edge Chip if this trip does not work out. I hesitate with that as I am 8 hours from home and my fuel gage quit so I am relying on miles driven. The last time i took the chip out I went from 17mpg city to 10mpg city. No clue what would happen on the freeway. I bought the truck with the chip already installed.



Another thing C said might help is dumping a quart of Dextron in the tank to lube the VP.



I will moniter this again this weekend on my way home. I will try to find a place local to get a better gage as well.



Thank you again for all the ideas. I will post what I find and hopefully have a Fuel PSI at my next Posting.

 

[fox]

One more thing, the lift pump will run but not always pump fuel. Don't trust it for sound= fuel pressure.

A scanner is a must--or smarty- to read the codes.

 

[Hescomp]

Well we will see what Cummins says about it.

The place I am working at deals with a Cummins dealership in Jeffersontown Kentucky.

After this thread and the guys from the dealership I let Them talk me into letting the dealership look into the problem. (everything pointed to the posibility of a major problem) Dealers are expensive but I would rather not risk blowing something on the way home. So we will see what they have to say tonight.

 

[Hescomp]

Update:

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[ttbird]

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[Hescomp]

Thanks ttbird