boost leak? boost issues? DV? I have no idea

**willowtreexx** · 11-15-2008 08:59 PM

so here is my issue. I searched under boost leaks, and vaccum stuff but didnt find anything that i thought helped

my issue is that when i get on the gas i get 8psi and then it drops REALLY fast and the car just feels sooo slow. Sometime when i go WOT i get a spike to 25psi and again goes to like 1psi.

my mechanic said to replace the O2 sensors so i did and it didnt help at all. i had trouble codes about my o2 sensors and they went away once i replaced them but the boost spikes and massive declines are still there.

any ideas?! thanks guys

EDIT: i didnt have this issue before i replaced the motor, i just started driving it a few days ago once the new motor was in and i noticed this boost issue. dont know if that helped. but all the parts and accessories are the same. i did replace ALL the vaccum lines before the new motor.

**Seerlah** · 11-15-2008 09:10 PM

If you feel you may have a boost leak, do a test. But that does not seem the case if you are able to................................you hit 25 psi? Hopefully that is a k04-15 (I remember you told, but I forget). Even still if you hit 25 psi then it more than likely is no boost leak as you would not even be able to get those numbers. Maybe an ECU issue?

What does your boost gauge read up to?
What are your mods?

I would still do a boost leak anyways. It is always good to do random tests anyways. I did mine maybe again 3 days ago.

**willowtreexx** · 11-15-2008 09:15 PM

Originally Posted by Seerlah

If you feel you may have a boost leak, do a test. But that does not seem the case if you are able to................................you hit 25 psi? Hopefully that is a k04-15 (I remember you told, but I forget). Even still if you hit 25 psi then it more than likely is no boost leak as you would not even be able to get those numbers. Maybe an ECU issue?

What does your boost gauge read up to?
What are your mods?

I would still do a boost leak anyways. It is always good to do random tests anyways. I did mine maybe again 3 days ago.

it wasnt quite pinned at 25, but was near 24 and close to 25 and i got kinda scared since im used to 8 haha
its still a K03 with NO mods. its a stock car with the same ECU and only has coilovers on it. no performance mods

**Seerlah** · 11-15-2008 09:21 PM

So, you hit 24psi on a stock mapped ECU? That is the main concern as the 8psi is normal (11psi being optimum@WOT).

Edit: I remember a thread of an issue of insane boost and found it. In his case, the n75 was hooked up wrong. Maybe that is happening to you then the MAP throws your car into limp mode. Just a guess.

**Spykce** · 11-15-2008 10:39 PM

Isn't the vacuum low? Shouldn't it be like 20-22? Could also be a symptom, or another issue.

**Seerlah** · 11-15-2008 11:02 PM

It would seem about correct for where his idle is at (maybe). Which is rather high in itself. Unless he just happened to take the pic during the idle dropped after warm up. But willowtreexx, Spykce is correct about your hg. You should be ~850RPM and -20 In Hg.

**a87** · 11-15-2008 11:11 PM

Check your MAF sensor. I had the longest time trying to figure out my boost problem after I got chipped. I was only able to boost 10 psi w/ speedtuning chip. The problem turns out was the maf, i disconnected it and now I am boosting 20psi. Need to get a new one, but they're expensive.

**willowtreexx** · 11-16-2008 09:32 AM

Originally Posted by a87

Check your MAF sensor. I had the longest time trying to figure out my boost problem after I got chipped. I was only able to boost 10 psi w/ speedtuning chip. The problem turns out was the maf, i disconnected it and now I am boosting 20psi. Need to get a new one, but they're expensive.

alright just to clear some things up, I will try disconnecting the MAF this morning and see what happends. However it is brand new so i really hope its not bad cause like you said, its expensive.

This pic was taken on the old engine and was just random, my rpm are solid at a little under a 1,000 and my vac is at 20 now with the new motor. Iam going to check EVERY line there is and i probably just forgot to clamp something down tight enough when i put the engine in.

I wanted to make sure that it might be something else that i wouldnt check like the MAF so thank you for reccomending that.