Sudden Loss of Power?

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About a week and a half ago, my truck lost a significant amount of power. The first few times I noticed it, the truck seemed normal for the first few miles, then lost power. After a day or so, the power loss turned constant, always there.

My first thought was a leaky turbo hose, but I don't think this could be the problem, as the low power occurs under all conditions, including starting from a stop (i. e. low/no boost). This truck has never seemed like it had as much power from a stop as similar ones I test drove before I bought it (in late July), and you have to slip it a little more clutch now. I think the idle is a bit low as well, and it has never started without resting your foot on the accelerater.

My next thought was a plugged fuel filter, but I'm not sure how this would cause such a sudden power loss, and I don't think its hurting my milage like when the filter would get plugged on my 6. 2.

I haven't had a chance to thouroghly investigate the problem yet (its mid-term time), but I did check the intake tract to make sure I didn't suck up the cat (darn), and the filter didn't look too bad. I tried to wiggle the exhaust apart to see if it was plugged, but it wouldn't cooperated and I had to be somewhere.

The truck is bone stock with the exception of 255/85R16's, has 80,000 miles, and I adjusted the valves when I bought it (around 3000 miles ago). I plan on changing the fuel filter and checking the strainer in the next couple days.

Any advice would be greatly appreciated.

Pete

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'97 2500 CC 4X4 5spd Sport
'83 K5 Blazer 350 TBI (ex 6. 2), 39. 5 TSLs, 3" lift, Dana 60/GM 14 blt, Detroits

 

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Sounds like your cat needs a swim in the river!

 

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Pete, aside from the items you mentioned (fuel filter,strainer and turbo hoses) that I'd check ASAP, one additional easy to check item is the cat. Have someone stand at the back of the truck near the exhaust exit and shut the engine down. They should be able to hear the turbo spin down for a few seconds. If not I'd suspect a plugged converter. There have been many post on the removal, and benefits of killing the cat.

One additional easy, is to check for full travel of the throttle linkage. Have someone hold the pedal to the floor (engine off, unless you're braver than me) and see if you can pull the linkage back anymore by hand at the pump. Check the throttle cable while you're there. It could very well need replacing if it's the original.

Good luck, Ronnie

 

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Thanks Ronnie, I'll have someone turn off the truck for me so I can listen when I get home tonight. I've been contemplating straight pipe, but have some concerns as I live in an emmisions are. Does anyone know how long the emmisions warrenty is for? (My truck came with a gas owner's manual. ) I'll be sure to check the throttle linkage as well, but the way it drives I don't think this is the problem.

Pete

 

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Pete,the fedral emissions warranty is 8 years or 80k. In CA you also get 7 years or 70k to get it right if it fails a test. This from the '95 warranty booklet.

 

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pcorssmit,

There is another thing to check that is real simple to fix. The lever on the injection pump that the throttle linkage moves is fastened by two screws with 8mm heads. If one of them fell out it could act like you describe. They tend to get loose so the lever wobbles around.

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Joe George
Eureka, CA

'95 2500 CC auto 4X4,3. 54,Combo EGT/boost guage,custom switch panel,PacBrake,TST #5,BD valve body,Automatic motorhome steps on both sides,Foldacover hard bed cover,Cummins chrome kit,Black steel grill guard,Front hitch receiver

 

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Your gonna want to check out the cheaper fixes before going major so to eliminate any exhaust restrictions, may I suggest putting a test pipe in where the cat and muffler are feel the power and reward yourself with better fuel milage. Should cost under a $100.
Stephen's won ton dually in Sanger CA.

 

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Have your fuel pressure checked. The check valves are probably out in the supply pump.

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1998 CUMMINS Dodge Ram

 

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Stacked, is there any way to check the fuel pressure with out the special tool/adapter shown in the service manual? I've got a gauge, just not the adapter.

Thanks,
Pete

 

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I do not know of any other way. You can get that adaptor from Snap-On though. Best of luck.

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1998 CUMMINS Dodge Ram

 

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Well, I think I finally found the problem.

After checking all the items mentioned above, I think the overflow valve is shot. I never did actually take the exhaust off, but I checked the back pressure (pre cat) and it was minimal. As for the fuel pressure, I'm getting about 13 psi at idle, and the max is about 25 at redline (3000). The book calls for 17-22 at idle and 25-30 at 2500 rpm. If I pinch off the return line, it pins the needle on the gauge.

Does anyone know if the overflow valve is covered under warranty? If not, what is a good price for one?

Thanks, I'm anxiously awaiting the return of power.

Pete

 

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If youre getting 13 @ idle, and the book calls for 17, I'd say that's it.
I dont see why it shouldnt be covered? As long as youre under 100K Miles.
Keep us posted,(with prices too) my truck is doing similar stuff.

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98 Quad cab 4X4 2500 12 valve,5 speed,3. 54 rears, 8' bed. Boost and egt gauges but basicly stock except for a "properly adjusted" AFC. Cat in the garage. Uniden HR 2510, Texas Star 1200 amp. 59,000 Mi as of 10/21/00.
NRA life member. High power/IDPA.

 

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I just had my overflow valve replaced by the dealer. It IS a warranty item as long as the mileage is under 100k.

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1997 Dodge Cummins Turbo Diesel Dually
2L Custom Trucks Conversion

 

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If you are not under warranty, remove the overflow valve and measure the spring. It should be at . 500, if its not stretch it to . 550 and put it back in. That cured my power loss problem. Its not a permanent cure as the spring is still weak but you can find out if thats the problem without spending money on a maybe fix. Eventually the power loss will return but at least you know what it is. My local injection shop had the Bosch overflow valve for $60. 00.
Good Luck

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96 SLT Laramie CC 5spd, 3. 54, no muff, no cat, 5"turn down tip
80gal fuel capacity. BD Brake, EGT,Boost + fuel pressure gauges. Member NRA/USPSA

 

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I used a similar approach to how Deezul 1 did it. Instead of stretching the spring I put a washer behind it to get the length in spec. That should last a little longer than stretching it. So far, so good for about 10K miles.

 

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Thanks, I guess I'll try calling the dealer tommorrow. Anyone have any experience with any of the Denver area dealer service departments?

Pete

 

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Pete :
Read all the post and can't belive anybody said check the fuel shutoff solenoid. The power will be cut to the point of no pull. Not enough to hardly move the truck. This has been gone over many times on the site, so it should be many threads on the issue. It cured my trouble.
Good luck.
Preston

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96 3500 Black 5 speed turbo diesel, SLT, with US Gear overdrive, Rhino liner, Reese 15,000 lb. fifth wheel hitch, US Gear de-celarator exhaust brake, muffler elimination kit, Amsoil lub. , with other goodys on the way.

 

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The truck went into the dealer Friday morning. Picked it up Saturday morning. They replaced the overflow valve, and set the timing as well. It started hard the first couple times, been fine since. I think there was a bit of air left in the lines. The power is back, the truck is much smoother, and is more driveable. One added benefit, the truck does not smoke at all now. It used to let out a thick black cloud under hard throttle, I can now stand on it from idle to redline with no smoke. All was covered under warranty. I didn't get a chance to talk to the tech (the service dept was closed on Sat. ), so I don't know if & how far the timing was off. I guess you could say I'm happy. Thanks to all who helped diagnose the problem.

Pete