When accelerating from a standstill, you can pour the pedal to it and it will accelerate furiously until 3rd gear....then approaching 2800 rpms, it just acts starved for fuel or air and just loses power right when you think it should shift and pin you to the seat again.
All the get up and GO, just stops, and until you back out of it and let it shift soft, it will just stay there at 2800 rpms and not go on no matter how much pedal you give it.
Also, traveling at 65-75 mph, and romping down on it to pass, it will shift down and accelerate like the devil until about 2800 rpms in 4th, and it just acts fuel starved and no power.....until you back out of it and let it shift soft and sort of "catch up".
Once it shifts you can accelerate swiftly, as long as it doesn't downshift, all the way out to 96 mph where it is topped out.
I don't understand what is happening.
Is it fuel starved from filter being clogged, or injector pump not keeping up? If so, how could it run over 90 mph?
Is the turbo kicking out?
Is the Allison tranny screwing up?
Any ideas why I am experiencing this?
It hasn't happened before....until now, I oculd pour the pedal to it and it would run like the wind...shift all the way up...and when it got to those critical 2800 rpms places, hit the next gear and pin you to the seat....now it isn't.
I don't know what the deal is, and would like the advice and help of the forum experts, please?
I've repaired many diesels with those same symptoms with a fuel filter change. If it's a recurring problem, you may have algae growing in your fuel tank. Diesel will suspend enough water in it to actually grow algae, as wierd as that may sound. I would go the fuel filter route first.
Dave
Thx Dave...I was thinking it sure feels more like fuel starved more than anything.
I am guessing that there is also some tank treatments available to kill any growing bugs?
Yes there are, but if the fuel is contaminated, you usually would need to drain or pump the fuel out and start over. If you kill the algae, it is still going to be in there. IMO, the additives work better for prevention, or to control a mild case of contamination. Good luck.
Dave
GM may be trying to help owners who forget regular fuel filter changes by now programing into the DIC an advisory as to how much time is left until a change is recommended. Pretty cool idea and it may help us out.
Almost always , first step , second step , check the air filter . If you have algae the fuel will look slimmy in the filter . Good luck , and let us know the outcome.
David,
If I read you correctly it will accelerate hard in 1-3 gears then die off in 4th? That is not a fuel feed problem that sounds more like a transmission program error. I am not familiar with the Duramax/Allison combo at all. I am an first generation PSD man myself But if it pulls hard in the lower gears it is not fuel or air flow.
Aaron
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I had similar symptoms with my ex-2001 PSD. I had used the truck in the pastures during hay cut/bale/ delivery summer season. The air filter was jammed closed with hay debris...as indicated by the airflow gadget on the filter box...something I did not know about 'till pointed out by the mech who showed me, changed the air filter and solved the problem. The air filter had closed off in about 1200 miles of work and did not make it to the 3000 mile service I usually do. I had changed both fuel filters with no effect. Note...I said both filters. Good luck!
Edit....I noticed the above note on tranny problems. I went through two PSD trannys with very similar symptoms. Am now a Duramax owner.
I have a 2005 Silverado Duramax/Allison and believe the fuel filter should be the first thing to check. However there have been several recent articles about the algae growth for those who have been using bio-diesel. Those fuels made with blends of recycled cooking oils etc.
In the past algae/microbe growth in jet aircraft was a common problem. There is a product called BioBor, usually about $10 for 8oz which will prevent the problem.
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But if it pulls hard in the lower gears it is not fuel or air flow.
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