KEVWRX95

Can anyone tell me what the nut and screw at the back of the HKS dump valve is for?????

I assume it is to adjust it in some way?

Can anyone tell me if I tighten it what effect that has?
And if I loosen it what will happen?

Cheers Kev.

tath

it'll preload the spring i'd imagine. so if you're running big boost a bit more preload will stop it forcing open, too much preload and the vac won't 'pull' it open. i'll stand by my correcting mark though...

jaytc2003

iTrader: (1)

basically what Tath has said, I have just removed mine and gone back to a recirc type valve. I was having issues where my car was running slightly more than standard boost, and it was being forced open and causing erratic running at revs around the 4 - 4.5k mark. Tightening this bolt up slightly made a heck of a difference.

TonyFlow

I didn't think it was possible for the HKS SSQV to open under positive manifold pressure?

jaytc2003

iTrader: (1)

Dont know if it was opening or if it had a faulty diaphram, but by adjusting the tensioner it sorted my erratic performance (have posted previously) When I split it to look at the internals everything appeared to be okay.. Dont think mine was the SSQV, think it was the older one so I was told (was on the car when I bought it)

KEVWRX95

When you say erratic running what did it feel like ?????????????????
As I also am running more boost now and was wandering if I should tighten it a little as I am having a running problem at the minute, and I am trying to eliminate things as I go along to try to find my gremlin

Cheers for the replys guys

Kev.

tath

if it's leaking, then air that's been metered by the MAF isn't reaching the engine so it'll run pretty bad! As in stalling at idle, hesitating, lack of power and, depending on how much air is escaping, damage to the engine.

Just tighten it and if it stops dumping you know you've gone too far!

KEVWRX95

What about if I don't have a MAF ??????????
I have a GEMS ECU will tightening it still help ?

tath

Well something will still be metering the air - i revel in my ignorance of GEMS but it must have some sort of airflow measuring thingy. Unless it just goes off throttle angle and boost?

KEVWRX95

Tath
Thanks alot mate for the idea,
As mentioned I have a terrible running problem at the minute, and as I don't have the luxury of error codes anymore as I have the GEMS, I have to try to eliminate causes,
On the list :
Dump Valve
Air idle valve
Crank sensor
Spark plugs
Coil packs

My car under boost seems to pull superbly, but on normal driving I get constant stuttering. hesitation, I put my foot on the throttle peddle and it starts to splutter, if I put more pressure on the pedal my car will go but I am now hitting the boost, so my car takes off (which isn't good in traffic !!) So from behind my car splutters then takes off. splutters then takes off,
It is impossible to find the balance for normal 30mph driving.
I think it is an intermittent fault as I only had my car remapped last month to try to eliminate this problem, but its come back

Kev.

KEVWRX95

Anyone out there have any other ideas for me to look at ???????

jaytc2003

iTrader: (1)

It would splutter at around the 4k revs mark. as though I was losing air and overfuelling slightly. Economy was very poor

KEVWRX95

Well I tightened the dump valve and went for a blast this evening and although slightly better I still had a lot of stuttering and some activity on my knocklink...............................back to the list of things to change/clean/buy etc etc,

I think my spark plugs are next, I think they are gapped to 0.7 and I think they might need to be 0.6, as I'm running a bit more BHP than normal.

Cheers Kev.

RB5108

yeah just a little

jaytc2003

iTrader: (1)

Knocklink activity? Could be a dirty fuel filter, dirty injectors, causing your car to under fuel slightly.