Jump to content
SAU Community

Recommended Posts

I have just realised that the BOV on my car is not working at all. I'm pretty sure it's a HKS Sequential. I had thought (since i've had this car straight from Japan) that it was working, as the car emits a loud whistle when the accelerator is lifted - this turned out not to be the BOV though, as the car still makes this noise with the BOV completely removed from the engine bay and a straight piece of pipe put in it's place.

I have read literaly about 50 threads to try and find out what's wrong. Have already tried the adjusting screw on the back of it and even wound completely out it does not seem to work at all.

All i can think is that vacuum hose that runs in the top is not connected to the correct place.

In the pic it's where it was when the car arrived - is this correct? it currently joins the top (thicker) hose of the 2 that run to the front of the engine bay. Should i try another location ?

My intercooler piping does not have the little piece on it that lets the hose connect to it directly.

post-23664-1137409330.jpg

Link to comment
https://www.sau.com.au/forums/topic/102084-bov-not-blowing-off/
Share on other sites

So i guess that this (in red) is the stock blowwoff valve?

Why the heck would they leave it in if they install an aftermarket one too!!??

Is this easy to remove and block off the pipework where it's attached? Really want it off as it emits a LOUD whistle noise when the accelerator is lifted which is damn annoying.

Some of the things done with this car (straight from Japan) absolutely mystify me ( the JIC coilovers being the first - which were so friggin hard it's not funny and are now replaced with a set of Bilsteins:) and the set of actual large box stereo speakers sitting on the rear seat hooked up to the radio ( i have photo's as proof of this one) - what were they thinking?!

post-23664-1137463028.jpg

Yes you have two blowoff valves which is totally unnecessary. The standard one is all you need. The only reason I canthink of why the aftermarket BOV isnt opening is that is may be siezed, or the vacuum line has a leak or there isnt enough vacuum to reach it because of the first BOV? The reason why thay have left the standard BOV in place is so it remains plumbed back to avoid running rich I think??

Thanks for they reply LANFOH. I can't believe they wanted to avoid running this thing rich as according to the Apexi RSM the air fuel ratio's don't actually ever get above 10:1 and most of the time sit at about 8:1 - i am getting this tuned with the next two weeks (i'm they guy from a thread a couple of months back that gets only about 200kms to a tank).

Still would rather remove the original one if it's at all possible due to the high pitched whistle it makes. Does anyone have any info on how to do this and block it up easily?

as an experiment could i place a block in the vacuum hose for the stock BOV - this should then stop the stock BOV working altogether and the HKS one will work instead?

Then if i decide i do not like the HKS one or the car does not run well, just remove the block to the stock BOV and the HKS BOV completley and be back to normal.

For anyone curious - i did as per above with the vacuum hose to stop the stock BOV opening and let the HKS one take over.

It worked.

Car makes a flutter noise when released at low revs and a loud whoosh at high revs.

I have now decided that this is all too loud for me so the HKS BOV will be removed completely.

Thanks to everyone who help me figure this out. And i have a 2nd hand HKS BOV for sale if anyone''s interested:)

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
    • Hi,  Just joined the forum so I could share my "fix" of this problem. Might be of use to someone. Had the same hunting at idle issue on my V36 with VQ35HR engine after swapping the engine because the original one got overheated.  While changing the engine I made the mistake of cleaning the throttle bodies and tried all the tricks i could find to do a throttle relearn with no luck. Gave in and took it to a shop and they couldn't sort it. Then took it to my local Nissan dealership and they couldn't get it to idle properly. They said I'd need to replace the throttle bodies and the ecu probably costing more than the car is worth. So I had the idea of replacing the carbon I cleaned out with a thin layer of super glue and it's back to normal idle now. Bit rough but saved the car from the wreckers 🤣
    • After my last update, I went ahead with cleaning and restoring the entire fuel system. This included removing the tank and cleaning it with the Beyond Balistics solution, power washing it multiple times, drying it thoroughly, rinsing with IPA, drying again with heat gun and compressed air. Also, cleaning out the lines, fuel rail, and replacing the fuel pump with an OEM-style one. During the cleaning process, I replaced several hoses - including the breather hose on the fuel tank, which turned out to be the cause of the earlier fuel leak. This is what the old fuel filter looked like: Fuel tank before cleaning: Dirty Fuel Tank.mp4   Fuel tank after cleaning (some staining remains): Clean Fuel Tank.mp4 Both the OEM 270cc and new DeatschWerks 550cc injectors were cleaned professionally by a shop. Before reassembling everything, I tested the fuel flow by running the pump output into a container at the fuel filter location - flow looked good. I then fitted the new fuel filter and reassembled the rest of the system. Fuel Flow Test.mp4 Test 1 - 550cc injectors Ran the new fuel pump with its supplied diagonal strainer (different from OEM’s flat strainer) and my 550cc injectors using the same resized-injector map I had successfully used before. At first, it idled roughly and stalled when I applied throttle. Checked the spark plugs and found that they were fouled with carbon (likely from the earlier overly rich running when the injectors were clogged). After cleaning the plugs, the car started fine. However, it would only idle for 30–60 seconds before stalling, and while driving it would feel like a “fuel cut” after a few seconds - though it wouldn’t fully stall. Test 2 – Strainer swap Suspecting the diagonal strainer might not be reaching the tank bottom, I swapped it for the original flat strainer and filled the tank with ~45L of fuel. The issue persisted exactly the same. Test 3 – OEM injectors To eliminate tuning variables, I reinstalled the OEM 270cc injectors and reverted to the original map. Cleaned the spark plugs again just in-case. The stalling and “fuel cut” still remained.   At this stage, I suspect an intermittent power or connection fault at the fuel pump hanger, caused during the cleaning process. This has led me to look into getting Frenchy’s fuel hanger and replacing the unit entirely. TL;DR: Cleaned and restored the fuel system (tank, lines, rail, pump). Tested 550cc injectors with the same resized-injector map as before, but the car stalls at idle and experiences what feels like “fuel cut” after a few seconds of driving. Swapped back to OEM injectors with original map to rule out tuning, but the issue persists. Now suspecting an intermittent power or connection fault at the fuel pump hanger, possibly cause by the cleaning process.  
×
×
  • Create New...