kwikt

Trying to track down an on going hesitation problem. Repaced vac lines, intake gaskets etc. The only thing left are fuel injectors or idle control valve. What are the symptons of a bad idle control valve? Thanks!!

Kevin

Mike O

When mine failed the car was stalling because the valve was not open enough. Since they are expensive, look everywhere else first.

968workaholic

When is the hesitation occuring?

FRporscheman

Could it be that the ISV just needs to be cleaned?

RajDatta

Usually cleaning the ISV does not give a permanent solution. It will gunk up again.
You hesitation could be an arcing spark plug wire. Did you try checking the car in the dark to see if any wires have arcing issues?
I would also check the distributor cap and rotor to be on the safe side. I think this is ignition related.
Raj

kwikt

I replaced wires, plugs, cap, rotor, altrnator, battery, hal sensor,02 sensor, crank sensor, throttle position sensor, timing belt, chain tension pads all within the last year. The hesitation is when idling and gassing it, quite a lag before rpms rise. The car seems to have lost some low end power. The spark plugs appear to be on the "white" color side. Compression #'s run 185psi to 195psi between cylinders. Checked codes and nothing pops up. Ideas?????

Kevin

RajDatta

It might help checking the fuel pressure and see if its getting proper fuel.
Raj

FRporscheman

Kevin, my '93 does the same thing! It's so annoying!!! From a stop, when I hit the throttle, the revs dip about 200rpm then it starts to rev up... I keep stalling it!

I also have new plugs/wires/cap/rotor, O2 sensor. I cleaned out the whole intake manifold which was very gunky, and replaced all vacuum hoses but I forgot to at least clean the ISV.

So I hope you can figure out what it is!

ryan@usaimage.com

Did this start after the cams were r & r ? I was thinking cam timing.

Madridcab

If it is fuel starvation related, what about fuel filter, fuel pressure, and injectors? Try cleaning the injectors, it cured some slight hesitation on acceleration for me..

kwikt

Oh... also replaced fuel filter and check valve. I also ran numerous injector cleaners through the system but can't really feel any difference. Cam timing is exactly what was before pad change. Another idea

kwikt

......I thought that maybe the variocam solenoid wasn't working. Would that retard or advance timing. Maybe I'll unplug it and see if there is any difference using the g-tech 0-60mph.BTW I also replaced the fuel regulator so it's not that. To me it appears to run lean according to the "white" plugs. Maf sensor also was cleaned using CRC stuff(no difference). Any other ideas

Kevin

FRporscheman

I had my injectors sent out for cleaning/testing and that didn't help.

How did you preserve your cam timing? If you changed the chain, the new chain is shorter (unstretched) than the old one so if you used marks on the intake cam, it's off now. If you used marks on the exhaust cam then you're fine.

kwikt

Arash... it did cross my mind on the timing. What do you mean by intake cam marks? I scribed the timing gear to the backing plate and also used the 3 bolt method to secure alignment marks. Of course at tdc using a dial indicator. Also marked cam gear teeth in relation to the chain links on both intake and exhaust, also paying attention to the cam stamp markings by the cam gear. I'm 99.99999% sure it's right.

Kevin

FRporscheman

Oh yeah, sorry. You're right on. I have a weird way of doing it that no one else does and I was referring to that, my bad!

What is your car's idle?