Not getting enough boost

[szabon]

Ok, so I got an aftermarket boost gauge and hooked it up last night. It read a vacuum of about 16 at idle and when I pushed the car I got it to give me 6 boost, but it would just stop there. I thought these guys were supposed to get 11 or 12 boost? I also thought that if I had a vacuum leak I would not have a good steady vacuum at idle? Am I off on something? What do I do to fix this problem? I tried searching everywhere but I got lost in all of the discussions about the million different things that can go wrong with boost...

[szabon]

nobody has any suggestions?

[Pete R]

Originally Posted by szabon

I got lost in all of the discussions about the million different things that can go wrong with boost...

which is probably why no one has any suggestions You just have to start ruling things out.. I don't know what though.. I haven't had to do this yet

[Techno Duck]

Vacuum leaks and boost leaks are not always one in the same. Alot of times leaks only show up under vacuum or vice versa and under boost. 16"hg is ok at idle, a perfect system i think should be closer to 17-18"hg fully warmed up.

Pressure testing the intake track is a good way to find leaks and is pretty easy to do with just an air compressor and a home made PVC cap from your local hardware store.

In my opinion, if you are seeing low boost, i doubt a boost leak is your problem. Typically you would only really see slow spool up and probably a richer mixture from a boost leak.

I would start with checking the wastegate to make sure its not stuck partially open. Also may want to pull the j-boot and make sure the compressor side of the turbo is still intact.

[szabon]

Ah, well I sat down today with a tube in my ear and listened everywhere while the engine was on (i don't have an air compressor handy...). I cannot find an air leaks. I'm not quite sure where to go next...

[szabon]

I pulled the j-boot as well and the turbo spun nice and easy by hand and I didn't see anything bad, but this is my first turbo. I'll do a search on how to check the wastegate. Any suggestions on this before I search? There is a TON of info on all of this....

[nize]

do a search about clamping the wg control line. and be very careful you don't overboost and destroy your motor.

[rick13]

Is the gauge hooked up correctly?

[szabon]

I believe the gauge is hooked up right. I cut the clear line going to the klr, used a plastic t and hooked it up to the gauge. the gauge is an autometer gauge I got from Lindsey Racing. I also made sure the gauge connections had no leaks.

[szabon]

Ok, is the circular black thing connected to the j-boot with two lines that has another line coming off the top the blow-off valve? If so, why would I not have a line connected to the top? I was looking at lindsey racing's vacuum diagram and noticed that this line is just missing, and the part where it connects via a T is just lined right through without the T. Could this be my issue? Is this a common delete?

[rick13]

How long does it take to make your boost?

[szabon]

not long. starts kicking at 3500 ish and I will get to 5psi if i floor it around 4000-4500 if memory serves me correctly

[rick13]

Yes. You need a vacuum line on top of bov. It sounds like you found something there.

[szabon]

cool. I will run out to the store and do it now. Let you know what happens

[rick13]

Disconnect line to waste gate. Watch boost carefully on test drive.

[rick13]

If it goes over 10 psi STOP!!! Lemme know what happens.

[rick13]

The line to waste gate comes off of hard pipe front and center. It is held by a banjo bolt. You will need to plug it.

[kdjones2000]

Originally Posted by szabon

Ok, is the circular black thing connected to the j-boot with two lines that has another line coming off the top the blow-off valve? If so, why would I not have a line connected to the top? I was looking at lindsey racing's vacuum diagram and noticed that this line is just missing, and the part where it connects via a T is just lined right through without the T. Could this be my issue? Is this a common delete?

Not common, fix it. Be aware that the stock BOV itself is a common failure point. Check to make sure that your diaphragm is not leaking.

[szabon]

ok, so reconnected the line to the bov, and i got a .... wait for it..... 1 more psi! so not as exciting as I hoped. How do I check for the bov going bad, just listen for air? Didn't hear anything... I am about to clamp off the wastegate hose. From what I understand, I take the hose going to the firewall from the cv off the cv, and clamp it shut, right? or am I missing something?

[89-944NA]

When you checked the intake side of the turbo (with the j-boot off) did you just spin the impeller? You need to grasp the nut and see if there is any side to side, up and down play. Excessive play in the impeller equates to lack of boost and time for a turbo overhaul.