Boost acting weird, 15-16-15-16-15psi???

[Sbeing1]

I took out my car today and stepped on it. In 2nd gear at like 5krpm the boost gauge kept going 15-16-15-16-15-16psi over and over till it finally shifted at 7rpm. Is this normal? i dont usually step on the gas so i dont know. Also the engine comparment makes a weird brabrobrabrobrabro (when its goiing up and donw 15-16-15-16psietc) anyone know what this could be from? normal? i have a exhaust leak in my downpipe, think that could be the problem? thanks guys

 

[Sbeing1]

btw, i have it set at 16psi and its fluctating to 15 and back to 16

 

[jaredgsx]

have you done a boost leak test?
sounds like your car can not hold 16psi which is why it falls back to 15 because of a boost leak. just my 2 cents

 

[dsmsucks]

Plugs and wires

My car was doing the same thing. 14-15-14-15-14. Pulled over to the side and was like WTF
It only happened when I was high in boost. 10-13psi was fine
Good luck

 

[jaredgsx]

well i had the same problem i had mine set to 15 and it went down to 14 under WOT and then back to 15 and then down to 14, it turns out i had a boost leak, it was a small one that held up untill 15psi when it would start to seep out, then when it got back down to 14 it would start to build up again since it was under WOT. a boost leak test does not take that long and it very well might be your problem

 

[oldman]

Both of you are right, plugs and wire then leak test.

 

[dsm_illicious]

Definately a boost leak. Check all the clamps and tighten. I had the same issue when I installed my upper IC pipe, needed a silicone "hump" coupler to fix the issue.

 

[jaredgsx]

not to go against oldman, because he is about as smart as they come, but i would do the leak test first. If it does turn out to be just a leak no need in buying new wires and plugs when the ones you have might be good

 

[oldman]

not to go against oldman

How dare you??!!!

If it does turn out to be just a leak no need in buying new wires and plugs when the ones you have might be good

Obviously, inspection before replacement goes without saying.

 

[jaredgsx]

How dare you??!!! .

sorry, i hold my head in shame, but there is a lot that is assumed to be unspoken that needs to be said.

*cough* daily mantiance

You never really know who you are talking to, no offense Sbeing1, just a general statment

 

[PieEyedPiper]

My vote is for mbc installation. Try a different more accurate port. i.e. not the bov line.

 

[Sbeing1]

Sounds great guys. Im going to buy new plugs and wires today, it has some aftermarket ones that were supposidly new when i bought it but they look a little worn out, maybe thats the problem, i dunno better safe than sorry, and a boost leak testor. Do you guys think pepboys, napa, or advanced auto sells boost leak testors? Thanks so much guys for your help

 

[Sbeing1]

Also, about the MBC installation. I installed it via the insructions in the tech forum. It says its the best way to install it, but thats just what i read. If you know a better way please tell me, ill try whatever. thanks

 

[oldman]

Also, about the MBC installation. I installed it via the insructions in the tech forum. It says its the best way to install it, but thats just what i read. If you know a better way please tell me, ill try whatever. thanks

My vote is for mbc installation. Try a different more accurate port. i.e. not the bov line.

Try tapping the pressure source from the compressor housing, especially if you have the Turbo XS or any bleeder type mbc.

 

[mitsuclipsegsx]

not tring to hack this thread but what do you think is my problem i have my greddy e -01(just the ebc) set at 15psi i hit 10psi at 3200 then at 5k it goes to 19psi

 

[oldman]

not tring to hack this thread but what do you think is my problem i have my greddy e -01(just the ebc) set at 15psi i hit 10psi at 3200 then at 5k it goes to 19psi

Sounds like the typically EVO3 16G boost creep. Bypass the EBC and just run pressure source directly to the actuator and tell us what happen.