Engine/Transmission (1998.5 - 2002) Need Advice on Engine Problem

[StevenWalker]

Recently, I had been driving my truck down the interstate for about two hours, the truck suddenly lost power then just as suddenly regained power. It did this off/on/off/on situation for about 15 seconds the first time. It was as if some turned the ignition off then on rapidly. Then a few miles later it did it again. The episode lasted a little longer. After reaching my destination, the truck sat and cooled off, the problem seemed to go away. On the return trip, the off/on/off/on problem occured again after about an hour.

During these episodes my fuel pressure drops momentarly from about 13 psi down to about 5 or 6 psi. When the engine catches again, the pressure goes right beack up.

It I disconnect my Edge EZ and ran it as stock. The problem still occured, but much less frequently and the duration was much shorter. I scaned the truck for codes and there were none.

So, has anyone got any ideals on what might be going on or where I should look next?

Thanks for your input.

 

[NWhitney]

lift pump

Is your Fuel PSI going down just as or slightly before you are loosing power? Sounds as if your lift or transfer pump is on the way out and starving your VP for fuel and thus your truck is "bucking". Check your Fuel Filter for blockage (I am assuming that your fuel psi is from the side of the VP inlet). Your Edge would be asking for more fuel and would make the problem worse, so that is why it got better when you took it off.

 

[StevenWalker]

The fuel pressure seems to go down with the engine loosing power. The lift pump in high on my list of suspects.

Steve

 

[StevenWalker]

I forgot to add that I changed the fuel filter and checked the fuel for water. The old filter looked good and there was no water in the fuel. If, as I supect, it is the lift pump, then the next question is to replace it with the original style or go with an after market type. Since the truck is close to stock, I'm not looking for high volume or pressure.

Steve

 

[blacksheepdiesel]

Need to know where you take the fuel pressure reading from, before or after the fuel filter.

Godspeed,
Trent

 

[Curious Dave]

I would suggest stopping by a local parts store and getting a Holley blue pump. You can get everything you need to make it work at one store and it will be plenty of pressure to keep you going. You will need a filter and some barbs but you can set it up rather quickly.

 

[fox]

It could be the edge box, or " dead pedal" Which doesn't always set a code.

If so the VP could be going out.

 

[icman95]

A friend and TDR member had many LP problems before I got into modding my truck. So, one day while it was in the dealer for something else, I asked them to flow check it just to make sure. They thought I was nuts because I wasn't having any symtoms, but I just wanted to play it safe. Turns out that it was only putting out 1/2 volume and pressure of stock specs. An "I told you so" was a pleasure to give the service manager as he shook his head. As a temporary fix I had them replace it with the same kind and as soon as possible I put on a FASS system.



Moral of the story is that if it is the LP, don't even think of putting an exact replacement on. What a piece of junk! It doesn't really matter what brand of aftermarket system you put on, but do something other than the OEM part. Again-if it is the LP. That was my first thought, but of course there are other things it could be (the aforementioned pedal sensor, etc)



Good luck.

 

[StevenWalker]

I want to thank everyone for your input. The advice has been very good. Thanks for taking the time to help me out.

Steve

 

[NWhitney]

To check your lift pump extend your current fuel filter drain hose and catch it in a bucket. Open Valve and Bump key so fuel pump runs without engine on. Check amount in bucket over run time (30 sec I think) with specs ( I can't remember, if you do a search you should find it on TDR somewhere)

 

[MJReynolds]

A friend of mine just had a problem with his 02 truck that turned out to be the throttle position sensor (TPS) or APPS. Basically the truck lost power as the computer cut the engine to idle. Do a search for "dead pedal" or APPS and you'll find a bunch of information on this particular failure.

 

[DFerverda]

I would start with the cheapest way out. Disconnect both batteries and turn on the headlights, (to drain the cap) clean all battery posts and the cables. Also check and clean all the engine grounds you can find, just pull em off and use some sand paper to clean them up and use some dielectric grease and put them all back.
After your done and your batteries are hooked back up,(turn off headlights) reset your apps (tps).
Turn on the key but do not start or crank the starter, slowly push the go peddle to the floor and slowly let it up, turn off the key and then start the truck.
A bad ground can give you those symptoms, it takes you about an hour, but it is free to do and it fixed mine when it acted like that.
Good luck

 

[AllianceDiesel]

if its a external fuel pump (not in tank) than you check pressure, if the lift pump is in the tank you check flow.



Remember injection pump codes won't turn the check engine light on but will still throw the code, you have to do the key trick to see what codes are stored.

 

[fox]

Pressure and flow are connected!!! I know you are following the rules, but still if one drops by 50% the other does also.

 

[AllianceDiesel]

see I thought so too but I was talking to a guy from the star center (lead cummins guy) and I asked the same thing and he said you can have flow put no pressure and pressure and no flow. then when I started working on locomotives I heard the same thing from an instructor during training, I guess I just go by what the specs tell me.

 

[fox]

A garden hose open ended has flow but no pressure. Pinch it closed, there is no flow but good pressure.

With our fuel systems, if the pump is dieing both flow and pressure drop. There is no open or closed event.

 

[John - K5AWO]

Don't over look that the fuel pump may be loosing power to make it run. ???

Does the voltmeter on the truck show a drop when this happens?

I've had ignition switches go bad in the past.

Look for any connections and be sure they are clean and tight.

 

[PaulWeber]

engine problem

i chased the same problem for 3 yrs. after going to cummins and the dealership no help#@$%!. i found the semi-flexable fuel line from the truck frame rigid line to the lift pump inlet to be sucking air in hot weather. (never had the problem in the winter) i replaced the factory slip on line with 3/8 fuel line w/ 2 clamps on each end hope this helps