Boost problem

[dsmulla]

Ok guys, I have been trying to fix this problem for the past week but I haven't gotten anywhere.

My car would only boost to about 10 psi and it would take a lot of effort to get there. I checked the wastegate arm and reconnected it to the turbo with some tension so it keeps the wastegate closed. I thought that would fix the problem but it didn't however, I do get boost around 3000rpm which is what my turbo is rated at and responds faster now. It still goes to about 10 psi though. Now I have tried doing a boost leak test but my boost gauge only reaches up -10 vaccum and it doesn't go higher.

What do you guys think could be causing the boost leak test to fail like that? Is it the wastegate flapper still open slightly?

P.S When I get on it, I can hear the leaks. I also tightned up all the couplers and I can still hear the leaks.

Thanks in advance,
Osman

 

[98eclipsekidd08]

did you check the TB, BOV, IM all that junk??

 

[SwitchSkier]

So, when you do a boost leak test your gauge says -10psi? Huh?

 

[bluetlr2001]

did you check the TB, BOV, IM all that junk??

Like he said test all that and spray soapy water on it dont jsut listen for the leaks. Spray the water on then do the boost leak test and look for the water to bubble up. do it to all your intercooler couplers and your bov and all vacuum lines.

 

[dsmulla]

Actually, when I do the test, the boost gauge only climbs up to -10 VACCUM and thats it. It does not go past that. I thought that maybe the tester is bad but I have tried multiple testers.

 

[weldtuner]

you should be pressurizing your piping, not trying to pull vacuum. That is why its called a BOOST leak test.

 

[dsmulla]

Well as I always did it, I put the boost leak tester on the turbo inlet. Before and I have performed a boost leak test on many cars, the boost gauge (obviously) starts reading boost. It goes from vaccum into boost.

What I wanted to also ask is that, when a person does a boost leak test, and you pressurize from the turbo inlet, does the air go into the wastegate area at all. Keep in my I do have an internal wastegate. If the wastegate is leaking would that make a difference when performing a boost leak test?

 

[SwitchSkier]

Well as I always did it, I put the boost leak tester on the turbo inlet. Before and I have performed a boost leak test on many cars, the boost gauge (obviously) starts reading boost. It goes from vaccum into boost.

What I wanted to also ask is that, when a person does a boost leak test, and you pressurize from the turbo inlet, does the air go into the wastegate area at all. Keep in my I do have an internal wastegate. If the wastegate is leaking would that make a difference when performing a boost leak test?

I still don't really get it. Something seems fishy about the boost leak test you're doing. So you clamp it on, then attach your pressure source. Are you using an air compressor? A handheld bike pump? I don't see how the pipes could ever see a vaccuum. Could you explain your bost leak test process a little more?

Also, a tester is quite a simple thing. Just a valve on a coupler. It won't really "go bad" and certainly not lead to a vaccuum. Are you using a homemade one?

 

[dsmulla]

Yes I am using a homemade one. I am also using a big shop compressor at local shop here. What I really mean is that the system is not being pressurized at all. The boost gauge does not even move.

I clamp the boost leak tester to the turbo inlet and pressuize the system.

 

[cbrue122]

No, pressurizing your system at the turbo inlet is not affected by an internal wastegate. You may hear the sound of oil bubbling due to air leaking past seals in the turbo, which is a common result.

Try clamping the tester on your throttle body elbow and testing just the throttle body and intake manifold area first. Then move the tester down to the inlet of your intercooler and test again from there. I have heard this method recommended by wisemen all over these forums.

I am also confused by your test results showing vacuum. The boost gauge should be at zero gauge pressure whenever the car is not running, and should only rise into positive pressure when doing a boost leak test.

 

[dsmulla]

Thats exactly what I am saying, it doesn't be at zero when that car is not running. Its a -10 vaccum. What could be causing that? All the vaccum hoses are in place and the car is timmed right.

 

[ikillsuckers]

try checking the lines to and from te turbo and wastegate.

 

[c4uldr0n]

You could have a bad gauge... hook up the gauge directly to a metered pressure source and see if it works on its own.

 

[dsmulla]

Ok guys, just wanted to update and ask for help.
I swapped my turbo with a 14b and the car still does not boost. When I am driving it would get to 0psi and start to stutter and bogg out. I did a boost leak test again with soapy water almost every where but no bubbles and no sound. In fact, the boost gauge doesn't even move from zero psi. I know the gauge is working fine because when I am driving it shows me -20 vaccum and then it builds up to 0psi and starts to stutter.

Where is the air going? I mean it has to go somewhere when I do a boost leak test. Couplers, intercooler pipes, TB, BISS screw, injectors, intercooler itself, turbo housing, BOV and all around the throttle body............where esle can it escape from?

 

[oldman]

What were the results of your boost leak test? ie maximum pressure achieved and bleed down time.

 

[dsmulla]

I was pressurising the system but my boost gauge displayed no boost at all. So honestly, there was no maximum pressure that I achieved at all.

 

[oldman]

I was pressurising the system but my boost gauge displayed no boost at all.

That means either you have huge leaks or you're not doing the test correctly, I'm guessing you're using a bike pump instead of a compressor. Here is something I posted in the past, make sure you're doing the test properly.

1. Disable your mbc.

2. Turn your motor to 30* ATDC to avoid valve overlap.

3. Start your test at the TB elbow and focus on area behind the TB first.

4. Spray soapy water at TB gasket, BISS, TB shaft on both sides, IM gasket, injector insulators, brake booster, afpr and all vacuum lines/connections.

5. Open your oil cap and listen for leaks. (PCV, valve seals/guide, rings)

5. Listen to your tailpipe for leaks. (EGR, valve overlap, jumped timing, bent/unseated valves)

6. Once all leaks are fixed, move the tester back to the turbo inlet.

7. Spray down the compressor cover (known leak), BOV return/flange (DO NOT TAP YOUR BOV LINE FOR YOUR MBC!!!), IC end tank/fins and all connections. Re- test.

8. Note that you will leak air into the crankcase through the turbo seal but do not panic, this is normal during a static pressure test as long as there are no shaft play.

The desired test result from the begining of the LICP (bypassing turbo) is around 20psi (on boost gauge) with the compressor set at 30psi, while taking no less than 30 seconds to bleed down to 0.

As a reference, my last test on my 500 mile new engine, I was able to pressurize the system to 25psi, bled down to about 16psi (my 1G bov) in about 30seconds, then took about 3 mins to 6psi and just kinda lingered there for a while. It's not easy to do but the point is it's possible. My next goal is 30psi After motor break in and Dodge modding my BOV. A boost leak test is one of most pita but important regular maintenace task, the key is patience and endurance, have fun.

 

[dsmulla]

Ok I will try all that, mind you most of things I have already done but there are somethings that I will perform. Also I wanted to ask, do you think it could be a tunning issue the way it is stuttering. My wideband reads about 10.00-11.50 at idle and I know it should be at 14.00 or so. However, when I am cruising, it seems to hover around 13.9-14.9 which I know is correct. What do you think?

 

[oldman]

Ok I will try all that, mind you most of things I have already done but there are somethings that I will perform. Also I wanted to ask, do you think it could be a tunning issue the way it is stuttering. My wideband reads about 10.00-11.50 at idle and I know it should be at 14.00 or so. However, when I am cruising, it seems to hover around 13.9-14.9 which I know is correct. What do you think?

1. If you did the test some what correctly, you have huge leaks because your boost gauge doesn't lie, that issue/result has to be addressed or verified.

2. Idling at 10 - 11.5 is another issue, either your WB is off or your system isn't getting into close loop, what is your logger telling you about O2 sensor cycling, fuel trim, coolant temperature...etc.

 

[dsmulla]

I can answer number 2 by tommorrow. Ill hook the laptop and check on link.

 

[dsmulla]

Here is a link for a log I posted on dsmlink forums:


http://www.dsmlink.com/forums/showthread.php?t=19469

Thanks Osman

 

[oldman]

Well, like Jeff said on link, your log doesn't make sense.

1. Your TPS is off.

2. Is your maf hacked? Looks like it is, you're flowing way too much air at idle.

3. Tell me more about your boost gauge (prosport), something is not right there either

 

[dsmulla]

No my MAF is not hacked and by TPS you mean throttle postion sensor right? I was told maybe that could be a loose throttle cable. I have the prosport electronic boost gauge. I have it wired directly from the battery as are my other 4 gauges and I have a swtich to turn them on/off. I followed vfaq to install the boost gauge.

Here is where I bought the gauges from:

http://www.machv.com/prelboga.html

 

[dsmulla]

Oh also, I forgot to mention, my CEL light came on a week ago. It give P01108 IAT sensor malfunction, I cleared it and it never came back on again. Well I haven't really driven the car so.....
Now as I understand, the IAT sensor is within the MAF itself right?

 

[oldman]

No my MAF is not hacked

How do you know this? There are two ways to hack a 2G mas, removing honeycombs and adjusting the screw on the underside of the MAF. In any case, your maf is not reading correctly, probably the reason why you're running rich even though your global is set to -52 instead of -47, on top of the fact that you have also subtracted airflow from the maf table and your LTFT low is at -7%. Your entire log doesn't make sense unless,

1. Your maf is not reading correctly.

2. Your injectors are larger than 850s.

3. Your fuel pressure gauge is way off.

and by TPS you mean throttle postion sensor right? I was told maybe that could be a loose throttle cable.

If anything, it would be a cable that is too tight. What ever it is, you need to fix it, your TPSvolts needs to be at .63v at idle and you're at .71v. This is probably also one the reason why you're idling at 1100 rpm+. Log your idle switch to verified.

You need to go back to the basics and eliminate one thing at a time.

I have the prosport electronic boost gauge. I have it wired directly from the battery as are my other 4 gauges and I have a swtich to turn them on/off. I followed vfaq to install the boost gauge.

Here is where I bought the gauges from:

http://www.machv.com/prelboga.html

Why not a simple and reliable mechanical boost gauge? Why make a already complicated equation even more complicated? Did you turn your key to on position during the boost leak test?