Installed BOVs, now horrible misfire?!?

[Voodoo_ChildR32]

I installed my HKS BOVs and now when I hit WOT, it stumbles and misfires to oblivion at roughly 3000-3500 rpm and 5psi boost. I have my anti stall map running on my emanage so venting to atmosphere does not cause an idle issue. The cross over pipe is capped where the factory BOVs used to be.
Do I need to remove the whole cross over right from the turbos out?
The car was running fine before, and if I slowly creep on the boost I get no misfire.


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[Voodoo_ChildR32]

Anyone?


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[gtrkrauss]

are the blow off valves leaking where they are bolted up to the stock location? Also could be leaking where your cap is? Im assuming your running HKS ssqv's? Are they running the correct spring tension for your vacuum?

[ChezoGTR]

If i remember correctly the gtr's vacuum is around 12 to 13. You spring has to be rated for the vacuum or the bov won't close under boost.


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[Skym]

HKS BOV is a pull type BOV, so spring doesn't matter too much. Could have bought fake HKS BOV's???

Do you have clamp on type of podfilters (check intake hose clamps)??? It could be hitting boost cut on ECU (AFM's or AFM maxing out and happens around 3000-3500rpm when there's a intake airleak before AFM's).

But the low boost level indicates a boost leak somewhere (BOV's themselves, intake piping where BOV's are located, return hose / piping to intake piping infront of turbo's, etc).

[Voodoo_ChildR32]

So I did some googling and found out that my BOVs require 2 vac signals. They are HKS Super Blow Off Valves, kinda old. I found some pictures of them installed and that's where I noticed the nipples were missing off the rear of the BOVs. I repaired them, just waiting for rtv to cure then ill give them a try.

Missing nipple, after repair:

I kinda figured it was a leak, my AFRs were 17+ at idle. I can see them open and close with throttle response, so they appear to be working.


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[Voodoo_ChildR32]

Ok so supplied vacuum to the rear nipples, now AFRs at idle are reasonable. Still misfires over 5psi and while cruising at 60kph. AFRs seem to bounce occasionally while cruising, will go from 14.7 to 17-18, then back to 14.7.


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[h4X6]

reset ECU

[ChezoGTR]

Sounds like a pouched maf


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[Voodoo_ChildR32]

Sounds like a pouched maf


Sent from Mars.

Lol, which one?


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[h4X6]

try reseting ECU, if that doesnt work, try replacing MAFs. try one at a time