Loss of power - 05 LLY

[cptxguys]

Hi,
I am new to the fourm, but was wondering if anyone has some thoughts/comments on the following loss of power from my 2005 D/A.

I have a 2005 Chevy 3500 dooley with the LLY engine and Allison Transmission. The truck has 18,000 miles on it.

While towing our 5'er this weekend (12,000 lbs), on the way home, I was crusing along at 60mph. All of a sudden, the engine reved as if it was downshifting and the I had a major loss in power. My maximum speed was 30 mph.

I can hear the 'whistle' of the turbo when starting from as stop and when shifting from 1st/2nd. At that point, engine sounds 'normal'. Once the truck shifts into 3rd, the engine chugs/bucks and will only speed up to 30 mph. No apparant problems while stopped. It seems to idle just fine.

I limped into a local diesel repair shop (that happend to be only 2 miles away)to have it diagnosed tomorrow. In the meantime, I was wondering if anyone else had a similar issue.

I've read quite a bit about fuel filters on the forum (thanks!), so I'm thinking this may be the problem.

Any ideas?

Thanks,
Robert

[DmaxMaverick]

Welcome to the Forums!

Sounds like it went into "Limp Mode". I wouldn't call it a "loss of power", although you did lose power, because the PCM forces the condition. If you are on your original fuel filter, that would be the place to start, and will very likely be the end-all of your problem. Before you spend a bunch of $$ on diagnostics, change it (or have them do it), and try to repeat the incident. If you found a good shop, this should be their advice, as well. A check of DTC's (the SES light should be on) will indicate the problem. If you have a fuel delivery trouble code, my bet would be the filter.

[cptxguys]

Hey, Thanks for the response. That's kinda what I was thinking. I did speak with the owner of the diesel shop (his home is behind his shop and he came out to see what was going on). His mechanics will hook it up to see if there are any codes and will replace the filter (as I requested, since it has never been done before). If it's anything more than that, he advised us to have it towed to a dealer since we'll just be 'waisting our money' with him, as it will be covered under warranty.

The SES light didn't come on, and all guages were in the normal operating range. Was interesting to drive in 'limp mode.

[Kennedy]

GM recommends 15k service intervals for the fuel filter. There was a bulletin/campaign letter that you should have received offering a no charge filetr change and instruction on service intervals.

That said, my best suggestion is to:

1) Always carry a spare fuel filter (or 2) and the tools to change it (WIF wrench etc) on board as well as familiarizing yourself with the procedure to change filters.

2) Always carry my filter restriction gauge so that you can verify any potential problems rather than just changing the part.

3) Always change moderate mileage filters before a trip. It just makes life easier knowing that you started out with a fresh filter, and makes sense just like changing oil before a trip.


I've gone to writing the mileage or hrs on the filter can itself with a marker so that I will know when serviced if I cannot find notes etc...

P.S. I'm pretty sure you'll be wasting your money on something that should have been done as general maintenance as it's likely just the fuel filter...