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When I pull my trailer/s (from 5k +) and the truck goes from 3rd to od, there is a constant hissing sound from the engine and it will get louder if I accellerate and won't go away unless I get completely off the throttle. If I push the od button on the shift stalk I won't hear the hiss. If I really get on it the hiss will go to what I think is turbo stall. at 65 mph I will run around 5 psi boost and around 800 + on egt. With no load I don't hear the same hiss sound. Any ideas or is this normal?
The hiss when loaded is your open element filter. Is the 5 lbs of boost when empty? If it's when loaded, then a lot of the hiss is probably a boost leak. If it's while empty, then it seems about ok.
As far as the pulling in OD, I vote for it's ok as long as it's not "hunting" for a lower gear and your Trans temps are good.
The hiss when loaded if your open element filter. Is the 5 lbs of boost when empty. If it's when loaded, then a lot of the hiss is probably a boost leak.
As far as the pulling in OD, I vote for it's ok as long as it's not "hunting" for a lower gear and your Trans temps are good.
5 lbs when pulling. I agree that pulling is ok in od. temp and shifting is flawless.
5 lbs when pulling. I agree that pulling is ok in od. temp and shifting is flawless.
Then Sir I'd say you have a boost leak somewhere. Check all you CAC tube boots. They can come off and or split. That'd be a good start anyway. Someone smarter than I will come around soon and have you straightend out in no time I'm sure.
Sounds like the AFE filter doing its work,to be on the safe-side do yourself a favor and double check all 6 of your intercooler boots for tightness ans cleanliness. Towing in OD is fine unless your tranny consistanly hunts for 3rd. Towing constantly in 3rd will raise tranny temps, unless you have an auxilery tranny cooler to keep them in check.
Exhaust backpressure valve isn't sticking closed is it? 800* at 5psi seems kinda high
Don't think so, I can push it open with my finger. I am getting code 1249 regurlarly and haven't yet found the cause. I was watching my AE today and the duty cycle seemed to be working, but not sure what it is supposed to read. Manifold backpressure was reading about 12-15 psi at a steady 65 mph. I have checked and rechecked the boot clamps, but after reading other posts today, I think i need to start with replacing them all.
WhiteBuffalo the other day gave a NAPA part # for Marine Grade tubing that he says works great for what we need. I can't remember the thread. But search his name and send him a PM. I think he said he got the idea from that big name performance shop where he lives.
EDIT: Here is a picture from his Gallery of the stuff. Looks like it is Marine Exhaust Boot material.
2. DTC P1249 indicates that the PCM detected the turbo was overboosting which is not possible if you are seeing 12 psi max
3. 12-15 psi backpressure at 65 seems kinda low
Just pulled up my AE log. The backpressure was running 21-22 psi at 70 mph and 70 deg outside temp. wastegate duty cycle was around 80 %. #2-That's what I don't understand. 1249 being an overboost condition when I nver see high boost numbers. Bad MAP sensor?