DoubleTrouble

iTrader: (1)

I'm looking for some suggestions of where a vacuum leak could be coming from on my turbo truck. It surges when i let off the accelerator but it's not real bad and I know it's getting worse MPG. The wastegate had a broken seal and was bleeding off boost through the top port on the wastegate. It was throwing a MAP code but I sent the wastegate off to tial to be rebuilt and it no longer throws that code. Now it throws a IAT code and surges just like a vacuum leak. It also doesn't feel like it has as much power as it should and doesn't spool as fast. I sprayed starter fluid around the intake manifold just to see if it would idle up and I had no luck. Also checked the line going to wastegate and the one from the back of the intake manifold to the brake booster. It usually surges worst when the a/c is on.

Could a cracked intercooler cause this? I had it pressure checked at the shop up town and they said it held 20psi.. but you never know.

Should I be looking for places on the turbo system or mainly the motor?

The brakes have been a little jolty lately but I havn't thought much about it. Could it maybe a leak in the brake booster?

Daryn

iTrader: (19)

get some brake cleaner and spray all the cold side while the truck is running,

TURBHOE

iTrader: (4)

can you log the iat's? if they are way cold or way hot it will pull timing add too much fuel and do all kinds of stuff. the computer needs that info to compensate for heat. its there for a reason.

DoubleTrouble

iTrader: (1)

I took the starter fluid and sprayed all on the cold side and through the intercooler when I checked the intake manifold but it had no result either.

I don't have hp tuners available right now but I understand what you mean about pulling timing and compensating for heat. However that still doesn't explain the delay in building boost. A vacuum leak would make sense because it would allow boost to bleed off but I'm not sure where it is coming from... I'm about to head out to my shop now and check over everything again.

TURBHOE

iTrader: (4)

Bad iat= bad tune. Bad tune can cause lag. Just like a purpose made tune to spool turbo on the line can increase spool time.

Either way what I did on my tahoe to check for leaks is: take a small cup. Like a child cup. Drill a hole in it for a air fitting. Scuff the side of the cup to make it grippy. Connect that n where the turbo connects to the cold pipping (hints the small cup). Then install a airhose with about 10psi to it. That will charge your entire intake system. You don't HAVE to open the throtle. It wil makes it way inthere. But you can if you wanna. If you have a meth system make sure to pull it's fuse. Or else it will engage it. Then you can find any leaks you have. I found my injectors were leaking on mine. So underboost some fuel mist was coming out. Which is why I smelled fuel n boost.

DoubleTrouble

iTrader: (1)

Oh okay well that makes sense about the IAT now. My buddy has a truck like mine so I'll see if I can swap the MAF to see if that fixes the problem. I hope it fixes it because if it was a vacuum leak then the map sensor code should be popping up like before.

DoubleTrouble

iTrader: (1)

Well I took my buddy's maf sensor and put it in my truck but it didn't help at all. It still threw the iat code. I'm still not sure what's going on at this point.

DoubleTrouble

iTrader: (1)

Turns out my vacuum leak was really an exhuast leak. I put my truck up on the lift while running and found a crack on the flange that connects the waste gate to the crossover pipe. This explains why my truck has been running so crappy and throwing the IAT code. I'm gonna weld it up in the morning and hope for the best. And maybe even make it to the track tomorrow night for some new times

TURBHOE

iTrader: (4)

that don't make much since. but hope it works out for ya.