Boost leak?

[SoloWingLunar]

I should know the answer, but I want to make sure. would a boost leak cause the engine not to rev past 3k rpm and feel like it's misfiring when it does under load? Its a gvr4...

 

[Brandon Mau]

It would have to be huge! Have you thought of a bad MAF?

 

[gofast63]

I should know the answer, but I want to make sure. would a boost leak cause the engine not to rev past 3k rpm and feel like it's misfiring when it does under load? Its a gvr4...

I bet its a boost leak. Do a test.

-Gary

 

[Brandon Mau]

Yes there is probably a boost leak but with the car not reving past 3k that sounds like something different to me. I blew the coupler off of my car today and it still went past 3k only once though because I hadn't completely realized it.

 

[SoloWingLunar]

Hmmm... I well be certain to check the vacuum hose and etc. I can sit and rev all the way to the red line no prob, but only under load will it misfire past 3k. I can downshift and let it rev past 3k on deceleration, but the moment I try to accelerate it will give me maybe a couple seconds of good throttle before it acts up again. I have a maf translator that came with the car. Should I plug it in and set it to the stock injectors?

 

[Brandon Mau]

What are your mods? If you aren't running bigger injectors then I would concentrate on finding the problem before you mess with the translator.

 

[SoloWingLunar]

It has a 16g with 850cc's plugged in when I bright it home. I quickly took off the 850s and put the stock 450s back on with the stock ecu (had a dsm link v3.lite attached and was boggy all through the power band). The exhaust is disconnected after the turbo. What I was told was that the o2 hosting has a bent stud and needs bent back to get the exhaust back on. The dp is just hanging there with the rest of the exhaust. I'm taking it out to an exhaust shop tomorrow to fix that issue.

 

[Brandon Mau]

If I were you I would put the ecm link back in the car and use your laptop to log and monitor the car. Then you can tune for that bog which was probably a bad tune. Read up on link you can do a lot with it and will give you a better idea on whats going on with the car once you get familarized.

 

[SoloWingLunar]

I was going to go back to stock... Yeah, it most certainly wasny tuned yet, but I'll try that route.

 

[Brandon Mau]

It will give you a wide variety of logging certain things with the car fuel,spark ect. and you can put everything stock on the car and tune it for more fuel economy and a little performance as well. The stock fuel tables on our cars run really rich when you get into the throttle.

 

[allthrottle]

You could very well have a boost leak. I have one now that had multiple(LICP, UCIP, TB shaft seals) and would bog and sputter right when boost would start to come on but drove fine otherwise; also wouldn't rev passed 3k rpm while sitting still. Did a boost leak test, found and fixed leaks. It revs smooth now and holds boost steady. Try that, and definitely plug your dsmlink back in.

 

[Tiki2777]

bad spark plugs caused me to cut out in boost, and it would stop accelerating, you might want to check those, especially because it is really simple. GL

 

[SoloWingLunar]

I appreciate all the help. I have today off, so I'll be under the hood until I can find the solution.

Its definitely a boost leak of some kind. I can hear is hissing when the its running. I've been looking everywhere I know to look and cant find it. It sounds like it's coming from the intake manifold close to the fuel rail.

 

[Brandon Mau]

You need to make one or buy one off of ebay. Can make one out of $10 worth of materials at a hardware store. The intake manifold gaskets go out after time and if you here the hiss then you need to test for all the rest I'm sure you have more than one.

 

[SoloWingLunar]

Will do. In the mean time, at least I have a way to work...

 

[joew]

my factory BOV was leaking and was doing the same thing. replaced it... just fine! easy to do a boost leak test. soap an water in a squirt bottle and spray your piping

 

[SoloWingLunar]

I've checked the bov and found nothing. When I'm not at work, I'll check again just to make sure.

 

[jlsjr1986]

MAF take it out and clean it with alcohol i had the same thing happen to me

 

[xrdgx]

I should know the answer, but I want to make sure. would a boost leak cause the engine not to rev past 3k rpm and feel like it's misfiring when it does under load? Its a gvr4...

Mine was doing the same thing had boost leaks everywhere

 

[SoloWingLunar]

Looks like I'm taking the intake manifold off. The gasket has a nice gap in it. I'm going to check the rest of the intake system as well just to make sure its all nice and tight.