Engine/Transmission (1994 - 1998) Need help--on a road trip and I've lost power

[Warhorse]

This just started yesterday afternoon: I'm on a trip through Wyoming and Colorado; yesterday I was driving through some hills and found I had very little power. At 2000 rpm I was making only 45 mph going up hill, with only 8-9 pounds of boost, accelerator pedal on the floor. It seemed like the more I put my foot into it, the less power I made. Also, acceleration was practically nill. After stopping for awhile at Fort Bridger, I got onto Interstate 80 and things seemed to be fine. Today started out o. k. , but this afternoon the same thing happened again. I recorded this data while I was driving: on a fairly gradual hill, I was able to maintain 60-64 mph (that's all) with the pedal on the floor, while the boost varied between 5-10 pounds. Rpm was 1750. The boost would go up to 10, then drop to 5, then back up to 10, then back to 5, and so on. On a steep hill, the best I could do was 35 mph at 1750 rpm. Boost varied between 4-8 pounds, again going up to 8, then dropping to 4 and back again.

On accelerating from a dead stop, the turbo usually spools up to 19 pounds really fast; now it goes up to 11-15 and drops back to 4 right away, and the truck is gutless until the boost slowly comes back up to a maximum of 11 pounds. It almost seems like the boost is leaking out somewhere. Truck is a '97 2500 4x4, auto trans, no egr, and about 233,000 miles (egr manifold was replaced with a non-egr manifold about 6 weeks ago). Any help would really be appreciated. I am headed from Rawlins Wyoming to Grand Junction, Colorado tomorrow (mostly downhill), where I will be until next Saturday.

Thanks!

Paul

 

[Warhorse]

Forgot to mention--no smoke is visible during acceleration or at any other time. I do not know the trans temp or the egts, as I haven't installed those gauges yet.

Thanks!

 

[AMink]

Start with the cheap stuff==check all the clamps on your intercooler hoses. Loosen them, wiggle the hoses, then clamp 'em back down. If that all is good, there might be cracks in the hoses, or maybe a leak in the intercooler itself. Good luck!

 

[wcjp]

Agree on checking all boost hoses. Also, change out the fuel filter in case of bad fuel.

 

[SKnapp]

yup sounds like a leak, in a hose or intercooler. also check air filter. also look at turbo to see if any broken fins.

 

[KYOUNG]

More than likely its your Fuel Filter!!!!!

 

[Vaughn MacKenzie]

I doubt it's a boost leak, that would result in quite a bit of smoke, which Paul says he doesn't have.

Like Kyoung says change the fuel filter, gotta have a good one to cross Wyoming on I-80!

 

[bighammer]

I would think a boost leak would be obviously noisy. You'd also blow a good bit of smoke, so I guess I'm thinking along the lines of fuel starvation-- Either a weak lift pump, or overflow valve, or something causing defueling at the higher RPMs (AFC or lever catching under fuel cam plate)

 

[bighammer]

Did it really have EGR, or was it just the CA models? I'm not familiar with that.

(been driving the 3rd gen too much and not much of the 12 valves is familiar anymore)

 

[Missouri Mule]

Warhorse, you wouldn't happen to have a exhaust brake?

 

[fest3er]

The next thing is to check the manifold-to-AFC boost line and the AFC itself. If the AFC is not working right, it won't let you have much fuel and won't let you build much boost, and, thus, you'll have little power.

 

[bighammer]

AFC boost line kinked or disconnected?

Timing slipped? If you stand on it in N does it go up to 3k?

Wastegate opening somehow? Faulty wastegate actuator?

In thinking about the wastegate, I started to wonder does a boost leak necessarily make smoke? The wastegate is a boost leak too. One difference is, you wouldn't HEAR it.

All I know is when my hose slipped off, it was LOUD. If an intercooler were splitting at the seam, would be that noisy? Something else to look at?

 

[Warhorse]

Thanks for the help everyone! I made it to Grand Junction, so now I have more time to examine things. Here's what I did: I have a vegetable fuel system installed on my truck, which is completely independent of the diesel fuel system up to the lift pump. So this morning before I left Rawlins I bought about seven gallons of vegetable oil and put it into the veggie tank, then left for Grand Junction. I figured that if my power problem disappeared on the veggie fuel, I must have a bad diesel filter. As it happened, when I switched to veggie oil, performance was back to normal: boost back up to 19 pounds when I mashed the pedal, no problem going up hills, and so on. So, because I only had a limited amount of veggie oil, I used diesel on the flatlands and downhill, and veggie while going up hills! I bought a filter in Craig, Colorado, and will install it tomorrow. I will also carry a spare from now on!



Bighammer--California trucks were equipped with an egr in 1997; I bought a 49-state manifold from someone on this board, installed it, and blocked off the opening on the exhaust manifold. The air inlet on the egr manifold is about the size of a quarter!



Missouri Mule--I don't have an exhaust brake (but I'd like to get one).

 

[CumminsPower98]

Sounds like you got it covered. I always carry a spare filter or two and have had to change one on the road. I also have a fuel pressure gauge so I was able to see it dropping and getting pretty low before I really lost much performance. This happened in Wyoming this past winter but it had nothing to do with WY fuel as I have never had a problem with that. I think it was just my fuel system being cleaned by the ULSD since I hadn't been running it long at that time and the filter was completely black with fewer miles than previous filters.



For future reference if you are having fuel issues also check the fuel solenoid. They can wear from lots of use and come apart in the flex joint as mine just did and caused a no start situation. I also saw this happen on a buss a few years ago. I was in Indiana when mine came apart a few weeks ago so I just removed it and ran a wire from there to home, fixed it and continued on to CA to deliver my trailer. Of course the electronics can also screw up.

 

[fox]

You may have algae in the main diesel tank. Thus, it is starving for fuel. Been there done that. treat it soon or it gets real bad.

 

[Howard Durand]

I haven't seen this written anywhere but I was told by a friend, who is a retired mechanic, that the new diesel formulation does a real good job of cleaning out any tanks that it happens to be in. That crud winds up in the fuel filter making it necessary to change filters more often.

 

[Warhorse]

Final report--changed the fuel filter yesterday, and everything is back to normal. I'll be carrying a spare filter from now on, and I think I'll invest in a filter relocation kit. Getting that filter out and back in again is a real pita!

Thanks to everyone for their help and suggestions.

Paul

 

[Missouri Mule]

Howard Durand, the charastic of USLD cleaning things out has been in the TDR magizine and on this web site.