mdarney

Can someone post the trick with pictures or direct me to the site that has the information on cleaning/lubricating the ISV idle valve with WD40. I can't figure out whitch hose to add the WD40, and I can't find it on the search I did. Thanks.

Rob Edwards

Yer in luck, this was just reviewed mid-week:

https://rennlist.com/forums/928-forum/376389-new-start-stall-issue-ideas.html

perrys4

I just did it. I think it seems better now but need to give it a few days to see if it worked. Thats my thread btw.

Imo000

Did this today on an S4 and it worked.

SeanR

I still call bull**** on it. There is too much hose and angles to go through for the WD-40 to get anywhere near the ISV. I just reinstalled one or I'd have taken a picture showing all the angles and elevation changes you have to get through to get any liquid to the ISV.

All you've done is shot WD-40 in to your maf boot.

Hilton

Considering the swept volume of air the 5L engine consumes at 675rpm, and that its all passing through that 1cm dia. hole in the MAF boot side, I'd have thought that the velocity of air passing into that small hose with the ISV on it would provide a fair amount of suction off the hose people spray the WD40 through?

I haven't done the "trick" or needed to - and will happily bow to evidence to the contrary, but common sense tells me that if you stuck a loop of clear tube in front of the ISV, you'd see WD-40 along it.

You could probably set up a test rig with a vacuum pump, a plastic bottle, MAF boot and some rubber hose to see whether any of it leaks into the boot against a flow of air thats comparable to what would happen in there at idle? (the platic bottle is to catch the WD40 so it doesn't go straight into your expensive vacuum pump )

Imo000

I sprayed a $hitload of WD40 in there while the engine was idling (15sec each time and did it twice in 5 min). The idle changed halfway throught the first burst. I was waiting for smoke to start coming out of the tailpipe but I didn't see any. Then took the car out for a quick run (20 min) and was fully expecting the problem to come back but it didn't.
I'm telling you, it fixed the idle. Why would I make $hit up?

GlenL

I've tried this on a couple of cars and was left wondering how it could possibly work.

All the WD-40 might be going somewhere else.

If you're serious about it, pull the ISV and use a battery to actuate it while you shoot in brief shots of the lubricant.

James Bailey

If you go to all the effort to pul the intake to access the ISV on any 87> 928.....best to just replace it !
Even Wally has said that a few shots did the job on his GT years ago but there are different causes of a "sticky" ISV and one is the brushes wear out and no amount of lube/cleaner/magic juice is going to fix that.

GlenL

You're probably right, Jim.

My supply of parts is less than my supply of determination, frugality and orneriness.

Connecting up 12V does give a feel for its performance.

hallowzeve

Howdy,

Not to completely disagree with Sean, but I've done this for both my GT and S4, and it works like a charm.

For the s4 it was an issue of surging at idle. Once a month or so, I'd have to give it a spray and it'd be fine for another month or so.

For the GT, it had sat for a while and the actuator was stuck. For this I had to hit it with wd40, and then jumper the isv, until it finally broke loose, been running like a scalded dog since, with no idle issues. I say this is no replacement for rehabbing it, but it'll keep you running until you decide to get in to the manifold.

just my experience and 9.28