turbo problem??

[thomasinnv]

truck and mods in my sig...yesterday i was towing my 5er (somewhere between 11-12K) and noticed that when under moderate acceleration, such as pulling a hill, boost would build to about 12psi and stop and would start sounding like the turbo fart, such as when you get on it really good and it shifts gears. but it is in overdrive and running around 1900 rpm and just hangs at 12 psi boost and farting. if i back off a little it stops, if i step in more it gets worse. also when it does this i notice that the boost guage needle bounces slightly. if i kick it out of overdrive it will stop farting and will boost up to about 24psi if i floor it. this is something new, it didn't used to do this, and i have not done any mods or anything since the last time i towed. is it possible the wastegate could be opening and causing this? any ideas?

[HVAC SuperTech]

sounds like you are losing boost somewhere. check all your clamps and boots on your intercooler pipes and intakes(under the Y pipe off the turbo) you an take em off and clean them with carb cleaner, and then spray the inside with hairspray before you put em abck on and that will help seal them

[thomasinnv]

but the only time it does it is in overdrive pulling my 5er. any other gear it doesn't happen, and not pulling a load it doesn't do it at all in any gear no matter how hard i get on it. it will hit 23-24 psi no prob, unless in overdrive pulling my 5er, then it farts. would a boost leak sound like turbo farts?

[HVAC SuperTech]

I think they could. Are your revs comming up any when it does it? Maybe its you TC?

Hope someone else chimes in....

[eab]

possibly surge?

[thomasinnv]

i'm pretty sure it's not the tc, the tach stays pretty steady. the boost gauge flutters just slightly. It sounds exactly like the turbo fart, but it is not shifting gears when this happens. if i apply more fuel, it farts more without building any more boost, and if i decrease fuel it stops farting. is the amount of boost the turbo is capable of producing dependant on engine rpm? meaning, under heavy acceleration when boost goes way up, does the engine rpm need to be high enough to absorb all the boost being created to prevent excess pressure from "farting" back through the intake? come to think of it, this is the first time i have pulled a steep grade since putting on the open air intake. is it possible it has always done this and i just never noticed it with the stock air intake? or am i just talking outta my arse?

[HVAC SuperTech]

I think its surge. Surge is bad. Surge is when the turbo is taking in all the air possible under a load and it backs up and actually tries making the turbo spin the opposite direction. If it gets worse, the only option to cure it is the ATS housing.

[eab]

Open intake will help you hear what's been happening the whole time...surge!

[Tyler]

Your sig says you have a WG disconnect, so shouldn't it not open anymore and just give you boost all the time no matter what? The only time I've seen Turbo farts are right before I turbo blows. But, I have never had this problem so I don't know what the problem could be. I dont think RPM means anytihng to boost. You are only going to get a certain amount of boost at a certain RPM because of exhaust speed, thats what turns the Turbo. I don't want to be a negative Nancy, but your turbo might be getting ready to take a dump. I could be wrong?

[cchase]

do you have a tranny gauge?

Edit, I read your sig. Whats the temps on your trans when this is happening, and is this different the them temps you useally run?