Author Topic: odd lack of boost? (Read 4607 times)

1slowvw · « **on:** November 11, 2007, 03:20:48 pm »

Hey guys, well two weekends ago I was out testing my jetta, which I recently put a AZZ in, I had a T-3 on it, however after several minutes of driving I lost all boost, then it I slowed down, and it cam back, then it disapeared again. I was only running 10psi, and when it cut off i assumed that it was just the turbo that had failed. So this week I purchased a junk yard K-24, with very minimal shaft play, and swaped the T-3 out. After putting the K-24 on I still am not seeing any boost. The turbo spins freely at idle, and it sounds like it wants to spool up, but its like it keeps venting its boost or something, it sounds almost like a siren, where it will spool, then drop, then spool, then drop.... I don't have any exhaust leaks pre turbo, and am not running an intercooler yet. I am not running any exhaust at the moment, and I am wondering if that could be affecting things ,although i can't see how it would.
I am simply wondering if anyone could suggest any areas to look for problems.
Thanks
1SlowVW

jtanguay · « **Reply #1 on:** November 11, 2007, 03:40:48 pm »

it sounds as if you have the 1.6TD manifold with the blow off valve, and it has become 'stuck'.

if you do not have the blow off valve, then there is a problem between the compressor & the intake. i highly doubt it is the wastegate since you've had the same problem with two different turbo's, but it is definitely a possibility (especially since it is a junkyard K24). i think the only way of testing that out is to pull the turbo and run an air line to the wastegate to pressurize it and see if it opens, or maybe the sealing surface on the valve is letting exhaust gas flow past?

by not running any exhaust what do you mean? do you at least have a downpipe???

does the engine smoke a lot? does it feel underpowered? have you tried 2nd gear max pedal all the way through the rpm's??? when i had my wastegate disabled i could peg 20 psi no problem on my pump. even now with conservative fueling i was still able to hit it, but i hooked it back up because of excessive oil consumption :cry:

hopefully it is just a simple fix! good luck

1slowvw · « **Reply #2 on:** November 11, 2007, 04:17:41 pm »

I have swapped the manifolds, so I do not have a wast gate, and when I say no exhaust I mean, no downpipe. There is some black smoke under load, and I have tried pulls in all gears in an attempt to et boost, the only effect of running hard is EGTs go up fast! The car is slow, not as slow as a 1.6na but slow none the less.
I just tried a run without the wast gate line hooked up, and it still did not build any boost. I am going to try and put compressed air to the line and see if the wastgate opens.

1SlowVW

jtanguay · « **Reply #3 on:** November 11, 2007, 04:56:10 pm »

Quote from: "1slowvw"

I have swapped the manifolds, so I do not have a wast gate, and when I say no exhaust I mean, no downpipe. There is some black smoke under load, and I have tried pulls in all gears in an attempt to et boost, the only effect of running hard is EGTs go up fast! The car is slow, not as slow as a 1.6na but slow none the less.
I just tried a run without the wast gate line hooked up, and it still did not build any boost. I am going to try and put compressed air to the line and see if the wastgate opens.

1SlowVW

so you have the 1.6TD manifold with the blow off valve??? you will need to block it somehow.

1slowvw · « **Reply #4 on:** November 11, 2007, 05:01:22 pm »

Sorry, I guess that wasn't very clear, I do not have a BOV, I am using a manifold off an AZZ with a turbo from a 1.6TD.

1SlowVW

jtanguay · « **Reply #5 on:** November 12, 2007, 01:44:19 am »

Quote from: "1slowvw"

Sorry, I guess that wasn't very clear, I do not have a BOV, I am using a manifold off an AZZ with a turbo from a 1.6TD.

1SlowVW

oh ok.. does the AAZ manifold have EGR on it? your best bet is to check the boost hoses then. since you're not running intercooled yet, how is the compressor hooked up to the manifold? using the elbow? is it the standard hose hookup?

1slowvw · « **Reply #6 on:** November 12, 2007, 10:21:32 am »

There is no EGR port on the manifold, and I am using the standard elbow to get the boost from the turbo to the intake manifold.
That being said I pulled the turbo again last night, and checked the bov. It seems to work fine. I am begining to believe the turbo i purshased, although is has less shaft play, is shot.

1SlowVW

jimfoo · « **Reply #7 on:** November 12, 2007, 10:37:10 am »

Did you check all the pre-turbo air lines and air filter for obstructions?

1slowvw · « **Reply #8 on:** November 12, 2007, 11:38:38 am »

Yeah, I even commited the original sin, and tried running it without an air cleaner(only because we have snow here now so dust is a not an issue) and still wouldn't build boost.

1SlowVW

burn_your_money · « **Reply #9 on:** November 12, 2007, 04:56:35 pm »

Is the oil drain line flowing oil properly?

Seeing as you seem to have covered almost everything else, maybe the turbo is being starved for oil or has no where to drain it.

1slowvw · « **Reply #10 on:** November 12, 2007, 05:29:54 pm »

The drain is free and clear, and i took off the oil line to check if it was getting oil, and it spit all over my engine bay(had a bit of a stupid moment).
At this point i have pretty much written the k-24 off as junk too, my father will be taking both of them to a local turbo rebuilding shop tomorrow to see which one would be cheaper to rebuild. That being said is there one that is a better turbo. My set up is a AZZ with TD boost pin, will be intercooled, crank fix, and I am looking to run around 15-20psi. I think either will do fine, but its always good to here a second opinion.

1SlowVW