Airflow issues

Ok, this started just a few days ago. First off the car is stock, not even any gauges. My problem is that all of a sudden I am getting no boost, or feeling no boost kick in. However, my factory boost gauge is telling me otherwise. I am pretty confident that the stock boost gauge works too. On top of that I started getting a real bad idle. I have not done a boost leak test but I have briefly from the top checked to make sure that all the connections after the turbo are tight. My thoughts are maybe it could be a post-turbo boost leak, that would account for the crap idle, but if I had a leak that big I think I would hear it or notice it more when I checked the pipes. Or maybe my waste gate is stuck open, how would I know if it's open or closed?

Any ideas?

Thanks guys.

 

[grocery_getter]

The factory boost gauge is not actual. It is a figure derived from calculation from the ecu by measuring airflow thru the MAS. If your boost gauge is still showing stock boost then it means the same amount of air is still being flowed/sucked thru the MAS. That means your turbo should still work as it should. If you have no power then it means that you have a boost leak between the turbo and the cylinder head.

 

[RayH]

If you've got stock pipes, check the inside bend of the rubber pipe coming off the turbo compressor, the one that runs over the exhaust manifold. They tend tp split there as they get old. You may have to take it off to check but it's a simple job.

 

Will do, i will make me a boost leak tester tomorow. So with the stock boost gauge workin does that tell me the turbo is working and not dead?

Thanks guys

 

[curtis]

Check the manifold to head and manifold to turbo gasket

 

it is a good possibility. as your making a boost leak tester. may as well check the turbine shaft for free spin and play also. i was having a similar problem and it turned out to be my injector seal at the intake manifold were split and leaking. after fixing them my idle came back and my car pulled just like before. however. i do have a boost gauge. see if you can borrow one from a friend or jsut hit up your local parts store and buy a cheap sunpro boost gauge for 30 bucks. even if you dont mount it. hook it up and see if your getting boost.

 

WOW, I am surprised and upset at the same time. I bought this car 2 months ago I really don't drive it hard but when I did I thought it pulled much harder than my previous stock GVR4. The reason was the PO removed the wastegate actuator hose so it ran at full boost, that explains why it was quicker. Also the stock blow off valve appears to be crushed, I think. I have never done it but it has been crushed down to where the nipple sticking out is burried into the lower section, you can't actually fit the hose on it all the way. Will the 22 or so psi running through the bov cause the spring to weaken to the point where it can hardly hold anything?

 

A pic of the bov would be helpful to see if it is crushed too much. The boost leak tester is a great tool especially for stock couplers/pipes. It can be difficult to see splits because of the weave over the rubber.

 

I will get a picture of it tomorrow, I'm tired.

 

[Barnes]

Quoting Red_Bird:
WOW, I am surprised and upset at the same time. I bought this car 2 months ago I really don't drive it hard but when I did I thought it pulled much harder than my previous stock GVR4. The reason was the PO removed the wastegate actuator hose so it ran at full boost, that explains why it was quicker. Also the stock blow off valve appears to be crushed, I think. I have never done it but it has been crushed down to where the nipple sticking out is burried into the lower section, you can't actually fit the hose on it all the way. Will the 22 or so psi running through the bov cause the spring to weaken to the point where it can hardly hold anything?



This is not good. Sounds like your BOV is over crushed. It sounds like this car is intended to be stock, so I suggest hooking the wastegate back up properly, and getting a stock BOV. Also inspect everything else carefully to see what other crap the previous owner might have done.

I hope you just have a boost leak and didn't melt anything. /ubbthreads/images/graemlins/frown.gif

 

[steve]

At this point I'd pull the cluster and make sure they didn't remove the bulb for the CEL. /ubbthreads/images/graemlins/uhh.gif

 

^what is the cel?

 

Ok i took everything apart and all the pipes look good. The bov spring is still stiff. I did notice my intake pipes were full of oil and a little on the turbo inlet. The turbo had no shaft play but would the bad seals cause this?

 

[steve]

Check engine light. In other words, the PO sounds like the type of person who would say "hm how do I fix that check engine light thats on? Oh I know, I'll remove the bulb!"

 

[Barnes]

Quoting Red_Bird:
Ok i took everything apart and all the pipes look good. The bov spring is still stiff. I did notice my intake pipes were full of oil and a little on the turbo inlet. The turbo had no shaft play but would the bad seals cause this?




The BOV spring still being stiff isn't the problem. The problem is that an over crushed valve can essentially cause the valve to stop doing it's job. You'll notice if you look in the BOV outlet as you fully compress the valve, the open is very small. Also, as you crush the valve, you effectively raise the spring pressure making the valve open at higher boots. If it is crushed too far it will hardly ever open, and even if it does, have such a small opening that flow rate is negligible essentially making the BOV do nothing. If you intend to run the car essentially stock, I *highly* recommend you buy an uncrushed stock BOV to replace the one you currently have. People will disagree whether this actually affects turbo life, but why chance it.

Also, did you actually build a boost leak tester and do a boost leak?

 

^ i will get a picture of it here soon. If the bov is over crushed then it would keep the valve closed and i would not lose air through it. I will get a new one but i dont think that is where i am losing air. This weekend sometime i will make a boost leak tester and get a gauge to see what is actually goin on.

 

[Barnes]

I didn't say you are losing air through the BOV. But you brought up the BOV being seriously crushed, so I'm addressing that. I also addressed the question of the air leak by asking if you have performed a boost leak yet. Have you performed a boost leak test yet???

 

I did a boost leak test and i could not get it to hold any pressure. The only area i saw leaking was at the turbo outlet.

 

check your front mount. those pipes love to come off. another thing. if you can. test it from beyond the turbo to see if the turbo is the problem. also soak the pipes in soapy water so if your missing a leak. bubbles will help you spot something your missing.

 

^Well I first did the test at the turbo but it kept sounding like the air was leaving through the turbo some how. I heard a low hissing sortta sound at the turbo. Then I did it after the turbo and did not here that sound anymore, so could it be the turbo?