My '05 3500 Cummins suddenly started acting as if it is starving for fuel under hard acceleration at 22-2400 rpm. Does fine under "normal" acceleration, but who wants that? Changed filter and put new fuel to no avail. Is there another filter? Possible lift pump failure?

 

What is your lift pump fuel pressure?

You do have a gauge, don't you?

Sounds like fuel starvation...

 

Not yet. Heavy on the yet.

 

Stupid comment.....but I've "fixed" no fewer than five trucks this year for this very issue that were towing. How's your air filter??

 

Air filter is fine. When I say load I mean just hard acceleration. Not even when towing. Also I noticed HEAVY black smoke if I stay on the pedal. As soon as I let off and ease back into it everthing is fine. If I accelerate slowly it does fine up to 2600 rpm. Haven't had it any higher since this started. I will be getting a fuel pressure gauge tomorrow. What is normal for this truck? '05 3500, 6 spd, quad cab, single rear wheel.

 

Hows boost pressure - no chance you blew off a turbo hose is there?

I have second gen so don't know if its the same but I blow mine of every month or so -- even when real tight.

 

Well, if you have black smoke it's starving for AIR... check your boost psi!

 

Yup!^^^ Check all the charge air hoses, and double check that air filter!

 

Make that 6 that you've "fixed". I checked the 5,000 mile old air filter. It didn't look dirty but it was deformed. I replaced it and now truck runs perfect. I am curious now what would cause the filter to be clogged even though banging it on bumper only produced very little dirt. Most (75%) of filter was still white. I tried to get a K&N but the NAPA I stopped at was out. I will pursue the K&N elsewhere. Thanks very much for your advise. You don't always get what you pay for, sometimes you get MORE.

 

....and helped by a dealer tech no less!!! Glad that's all it was. Seems to me the surface area of the filter is a bit under sized for the application. Guess they need to bring back that great big huge round sucker they had on the 1st gen trucks. I've also found that some of the aftermarket filters seem to restrict way earlier than the factory ones. There are some out there with a dense gray foam on them and they will crown the top wire mesh out here in less than 10K.

Any chance you filter was exposed to moisture? I'm assuming that since you said "deformed" that bottom pleats were spread in some areas? (I really need a pict here). It's really amazing at the air requirements of these things.

.....and to the totally somewhat off topic part: I had a guy come in with a 98 12 valve complaining of "oil all over". Went out on the drive and checked it out. Bottom of engine covered. Had him start it up. Sounded weak. Pulled the oil filler cap off and it looked like "the little engine that could"....major blowby. Shut the engine down and gazed over at the filter minder. Pulled the air box cover and filter was dang near folded in half. That poor little Cummins was doing all it could to suck that thing in and spit it out. Lord knows how long it had been that way. Long enough to ruin a perfectly good engine.

 

There was a writeup on air filters some time ago I have it somewhere here that showed how they faired the one you mentioned wasn't that good check into it further before you continue.