Pyzik

I noticed today that the L- shaped hose from icv ( the shorter one ) has a crack along it, could that couse the problem ?

JHowell37

The crack won't help. BTW, the 3 -pin plug at the front by the diagnostic connector is for the throttle position switch. Your mechanic is incompetent (no surprise there.)

Pyzik

Actually I am surprised since its a Porsche only place since the 70s! I should have went to my regular mechanic that did my tb/wp job .( a diagnosis at that porsche shop cost ms as. Much as tb/wp Job. At my regular mechanic )

Mike Frye

You're right, you have no knock sensor and that plus the fact that they were going to charge you $1000 to replace the ISV (ICV) are two major indicators that they nothing about your car but are willing to learn if you pay them... alot.

I'm with Stan (mrmerlin) on his comments about cutting corners.

There is a test plan for the '85-86 that you can go through to isolate the problem and fix it. here is the one for the '85. The one for the '86.5 is slightly different but this will get you 90% there. If you have or can get the Jim Morehouse CDs I would HIGHLY recommend it.

Rule #1 for the Porken chip upgrade (or any upgrade) is to have your car running 100% in stock configuration. If this was the case and it ran OK with the chip/FPR swap initially then the problem is probably something small but you'll have to work through everything methodically to find it.

IMO, the #1 cause of idle problems in the S3s is unmetered air. It's not easy to isolate and remove them all. It takes time and patience and unfortunately a little money.

Pyzik

Is it possible I would have to adjust timing ?

Pyzik

alright, after re doing the intake plenums (really tight) and charging the battery for 2 days , the car started and idled normally at 700 rpm!i i let it idle for about 2 min and took it for a 3 mile ride . its ran pretty good and it wasn't warmed up yet ,i stopped and put some gas in it too, after the car started nice, so i kept driving . after about 2 miles when coming to a red light i pushed in the clutch pedal so the rpm dropped all the way to zero, it didn't stop at normal idle rpm. would that be the idle control vavle? im going right now to find that 90 degree hose . after that first it died it did it again and again and the it wouldn't even run unless i held my foot on the pedal ( also it was jerking like a misfiring or something) so i got home the car revved and it would run at any rpm as long as i would have my foot on gas pedal.so i took the 90 degree hose off and going fix that .

SteveG

Anything is possible, but if you hadn't done anything to the timing, it's not likely. Try to be systematic; you are going in muliple directions, rule out one issue at a time and move to the next. You've started Merlin's list, I would follow that. Certainly a cracked hose should be replaced. Get the isv which includes any vacuum issue solved. You can apply 12V to the isv and you can see the valve open or close; if in doubt get a new one. If you are in doubt about the vacuum hoses, get a smoker, there's a thread here about making your own attachment and where to attach.

[edit] https://rennlist.com/forums/928-foru...ml#post6188035

This is a thread by Dwayne. I'm not sure it uses smoke, but it shows how to trouble shoot vacuum issues with an adaptor on the MAF on an '87. Dwayne's stuff is the best.

Pyzik

Problem solved !!!!! The robber piece connecting the plenums the big pipe to the T, the rubber is kind short plus the shark vent plumbing is right underneath the plenum making it even harder o align, anyway I got lucky once and car ran fine but after mile engine got warm and rubber would slice little and unmeasured air got in and couse the problem. So I got new clamps (wider ) and seemed to work but it would be nice to get those plenum rubbers much wider and not to worry about it sitting properly.

The car runs really good , but after reaching higher rpm the car engine feels shaky and seems not to pull as much as it used to. Have any of you guys Messed around with the co screw after you got your maf rebuild ? Or should I just leave it at 382 ohm? Also. Exhaust seems to smell like gas .

SteveG

Well, a sniffer test would be good, so you would know exactly what is going on. Gas/sweet smell = rich = probably a vacuum leak. A top end refresh of all rubber is a good idea on 30 yr old rubber. I'm betting you'll find a leak somewhere. If you have been following the GTS cutting out at higt rpm thread, you know that vacuum is second only to grounds that cause problems on these cars. Both of these can be difficult to find, but cheap to fix.