Thread: Vacuume miss s14

So i have a s14 with a black top sr20det in it.
My problem is it sometimes miss and spluters almost cuts out under vaccume. It boost fine. It seems to do it after it has been warmed up fully and is then turned off for a short period does it randomly other times. On start up it will then spluter and miss under vacuum but as soon as it hits 1psi boost runs no problems. Might also be helpfull i had a big boost leak that i fixed but it didnt do it while i had the leaak. the car is stock apart from front mount and external waste gate
I have so far replaced
-spark plugs
- coils
-fuel pump
-fuel filter
-Fixed all boost leaks and vacuum leaks

I am thinking it may be my blow off valve sucking in un metered air but am not sure how to test/fix this???

If your maf is draw through and the bov is not recirculated it will have this issue.

you can test the bov with a vacuum tester. pictures of the engine bay will be helpful. Also running a open bov with a draw through maf will cause these types of issues.

If you have the stock BOV this will happen. They are kind of weak.

its not a stock blow off valve its a sqeqential blow off valve and the maf is before the turbo so i presume this is a draw through maf. Is there a simple way of fixing this??? or recirculating the blow off valve the only way?

You can try to go to a blow through (maf after bov) setup but thats hit or miss.. id just recirc the bov.. you can probably get all the shit at lowes in the racing isle.

Whats your afr at during the problem?

DIY BOV fix, isle 13 is the racing isle at Lowes also known as plumbing isle.

I run all my maf cars blow through and have never had an issue. What maf are you running? You would want a n62 maf for best performance.

Lol ya I tried 2-3 mafs all had issues with blow through so learned my lesson.

its a suck through maf so i tryed recirculating the blow off valve and it doesn't do it as bad but still sometimes does it. now it has begun to ocasionaly miss and about 4500rpm it sounds like a very loud bang not just the usual miss what would my next step be? compresion test? or put it on computure and see if it throws any codes?

Maybe your FPR is going bad? Do you have an inline gauge to check fuel pressure?