Strange boost leak issue

Ho0ked · 05-16-2006, 06:27 PM

Ok, so I made my boost leak tester from a coupler and a pvc endcap+ tire valve, as per this site.

I stick it directly on my turbo intake and use a bicycle pump.
I canot get ANY pressure to show on my boost gauge in car, no matter how fast I pump this thing.

2nd idea, I use a small cigargette lighter powered air pump.
In car boost gauge barely hits 5psi and drops soon as I shut off the pump

The car hits 24psi atm and holds about 21 to redline. SOMETIMES the car won't boost past 9psi unless I get off the gas and remash the pedal

Also the car is slugish to about 20 psi then comes on roaring and then stutters slighty at about 6k RPM.

Could really use some advice.
Thanks

SBR 2g Race core IC full 3" hard pipes.
SBR G50 Internally gated.
More in my profile.

vintagemuscle · 05-16-2006, 06:38 PM

to do a boost leak test right you should really use an air compressor. a bike pump will not work at all.

Ho0ked · 05-17-2006, 03:40 PM

So any other ideas ?
Am I missing something ?

dnhieu · 05-17-2006, 04:55 PM

1. find a friend with a air compressor
2. if you dont have friends as listed in #1 then hook up your tiny pump again and leave it on. fill up a spray bottle with soapy water and spay all aournd your intercooler piping. throttle body, and injectors.
3. enjoy being boost leak free

Ho0ked · 05-17-2006, 07:01 PM

Quote:

Originally Posted by dnhieu

1. find a friend with a air compressor
2. if you dont have friends as listed in #1 then hook up your tiny pump again and leave it on. fill up a spray bottle with soapy water and spay all aournd your intercooler piping. throttle body, and injectors.
3. enjoy being boost leak free

Thanks, This is what I did tonight lol. Minus the air compressor part.

BISS leaking some, Top of my POS Type S BoV is leaking from under the locknut.
AND the weld for my POS BoV flange is leaking

can HEAR the weld leak, not the BISS or the top of the BoV leak

My little roadside air pump even left running will not go past 3 lbs and my boost gauge in-car agrees

but could those 3 leaks be that significant ? or probly more likely my little air pump can't pump fast enough to overload the 3 leaks.

I sprayed EVERYTHING ELSE, every coupler, the TB, the injectors, the vac lines the intercooler lol all else seems fine.

And it seems my front O2 is shot not oscilating at idle acording to my pocketlogger =/ dead at 0.0 rear reading correct.

The top of the BoV leaking probly means I need a new BoV and im not in the position to buy the HKS SSQ that I want so , guess i'll live with that.

Going to try to JB weld the BoV flange since im poor atm, might hold for a while im hoping. Any recomendation on the BISS leak ? ruber stoper long gone.

Thanks for any help guys

GVR4592 · 05-18-2006, 04:13 AM

Jb weld should hold fine, just make sure to let it cure before you start boosting. The biss has an o-ring, it's probably damaged or missing.

dnhieu · 05-18-2006, 08:10 AM

i dont agree with the JB weld but you gotta do what you gotta do and i do understand that. it seems like your not in that bad of shape.

EDIT: just find a way to take out the biss screw and go to your local hardware store and get a o-ring that matches the biss screw. put some oil or greese on it and screw it back in. i know its just an o-ring but the way i see it is that its a 2 cent part and if it goes bad in a year its worth the time and money you spent swaping it out.

daren_p · 05-18-2006, 08:28 AM

On your bov you said its leaking from under the locking nut, you mean the locking nut thats on the adjusting bolt? If so just put some thread sealent on this. As for the biss, ya probably damaged oring, replace it with a new one. For the ic pipe get it welded or use the JB weld if you have to. As for only getting 3 psi on the little pump, ya it probably can't produce enough volume to keep up. You need a real compressor and check at 20 psi to find all the other leaks. If your able to test at that pressure I'm sure you'll find a couple more.

Ho0ked · 05-18-2006, 08:46 AM

Thanks guys the o-ring idea sounds good im going to do that, and I put some j-b weld around the base of the locknut /shrug theres enough space that it should not be glued on.

The j-b weld round the flange looks good actually, never used it, but im familar with epoxy and this is stronger

We'll see tomorrow when I put it together and fire it up

Now how to come up with a real air compressor.....looked at some at the store this mourning and little more $ then I got to spare this week lol

The search for good boost continues...

FORMONTOYA · 05-18-2006, 08:52 AM

More than likely the throttle body seals are leaking so bad that you can not overcome this with the tiny cigarette lighter compressor you have. If you haven't changed the TB seals in a while...do it now, Then try it again. It's pointless to do a boost leak test and then not fix the problem you're trying to solve in the first place.

And if you can't afford a compressor, go down to Walmart or Harbor Freight and pick up a 10-15 gallon tank and take it to the gas station for fill up. Just find one you can regulate down to 15psi-20psi for test purposes.

talonTSIDriver · 05-18-2006, 09:36 AM

Another way to do a boost/vacuum leak test is to start the car and spray carb cleaner next to some of the spots where a boost/vacuum leak may be present. If your car starts to idle higher, then that’s where the problem is at. I've done this before and it works really well. I've heard of people even taking a small propane canister and letting out propane next to a few places where a boost leak could occur and that will also cause the engine to idle higher.

dnhieu · 05-18-2006, 01:21 PM

Quote:

Originally Posted by talonTSIDriver

Another way to do a boost/vacuum leak test is to start the car and spray carb cleaner next to some of the spots where a boost/vacuum leak may be present. If your car starts to idle higher, then that’s where the problem is at. I've done this before and it works really well. I've heard of people even taking a small propane canister and letting out propane next to a few places where a boost leak could occur and that will also cause the engine to idle higher.

thats a very good idea if you dont have a air compressor.

talonTSIDriver · 05-18-2006, 01:34 PM

Quote:

Originally Posted by dnhieu

thats a very good idea if you dont have a air compressor.

Yes works very well. Its much easier than getting out the air compressor, taking off your intake and messing around with all that. just start your car and go around your engine with carb cleaner or propane. Propane would be cleaner because you wont have to wipe up and stuff. Its really easy to tell when there is a vacuum leak too. Car will go from idleing at 1k to about 3k or so.

Ho0ked · 05-18-2006, 05:08 PM

Thanks guys

The J-B weld is holding and I broke my piggy bank and bought a 2Hp 115psi air compressor

Found some leaking at my IC pipe as it joins the IC on the hotside. and top of my BoV still leaking but not the flange anymore.
The BISS is plastic and yes has a worn out o-ring i'll get to it later, since its plastic and seems like its gonna require a delicate touch and im not in the mood for all that lol.

The most interesting thing is soapy water+ 25psi reveals slight leak from BoV to flange gasket, AND the throttle plate assembly is leaking ALOT, hiss's at 25 psi, the area where the coil spring is and u can manualy turn the throttle. Is that nornmal, or is something there worn out

Thanks again for the help gang, and next time i'll try the carb cleaner

FORMONTOYA · 05-19-2006, 06:08 AM

Yes, there are shaft seals in the throttle body. BOV flange leak is pretty normal also. TB seals are generally going to be one of the biggest leaks in the system if they haven't been done in a while, or you don't even know when/if they've been done.

A quick search for "throttle body shaft seals" should come up with some quick answers on the parts and the VFAQ in order to get the job done. It's a pretty straight forward job if you take your time and follow the instructions.

Ho0ked · 05-19-2006, 03:33 PM

Quote:

Originally Posted by FORMONTOYA

Yes, there are shaft seals in the throttle body. BOV flange leak is pretty normal also. TB seals are generally going to be one of the biggest leaks in the system if they haven't been done in a while, or you don't even know when/if they've been done.

A quick search for "throttle body shaft seals" should come up with some quick answers on the parts and the VFAQ in order to get the job done. It's a pretty straight forward job if you take your time and follow the instructions.

Cool im going to search it out on Vfaq thanks for the info

dnhieu · 05-19-2006, 03:47 PM

Quote:

Originally Posted by FORMONTOYA

Yes, there are shaft seals in the throttle body. BOV flange leak is pretty normal also. TB seals are generally going to be one of the biggest leaks in the system if they haven't been done in a while, or you don't even know when/if they've been done.

A quick search for "throttle body shaft seals" should come up with some quick answers on the parts and the VFAQ in order to get the job done. It's a pretty straight forward job if you take your time and follow the instructions.

not saying your wrong but i have owned 3 dsm's and none of them leaked at the bov flange/gasket. now the bov itself leaking it a whole diffrent story...

here is the how-to on how to replace the tb shaft seals

http://www.plymouthlaser.com/tbor.htm