Joel Lester

I've had my '86 3.2 Carrera for a few months and am getting used to it. One thing I've noticed, soon after buying it, is that it tends to idle erratically - meaning it "oscillates" between 1200rpm and about 900rpm. At the stop lights the guy next to me probably thinks I want to race him - like I'm revving up my engine! The car runs just fine otherwise. It is a beautiful car that looks like new.

After doing a little reading I found that the idle is controlled by a "switch" on the throttle body. What do you guys think? Do I need a new one? I see they go for $80 (Pelican)

Also, I was also wondering if I was getting full throttle - the guy who test drove it for me said it wasn't as peppy as his (he's got an '85 Carrera). So, I had the wife push down the gas peddle all the way to the floor (car not running of course!) and I reached in a found that I could move the linkage 1/8inch or so farther. Hmmm. Is this also controlled electronically? Is this a common issue with these cars? Input would be much appreciated.

Joel

84_Carrera

Joel -
My 84 does the same thing. I replaced the idle valve/switch you mention (FYI, Autozone carries Wells brand, which when I opened the pkg was identically marked Bosch like the original one on mine), and it made no difference.

My supercharged SHO did the same thing, and it was traced back to an over-rich condition caused by the aftermarket chip mapping. I have a Weltmeister DME chip in my 84 as well, so I'm feeling she may be running rich. I believe I asked about this on the list here about a year ago or so. From memory, I also believe Steve Wong mentioned moving up to the later 80's 8k memory DME / his chip should eliminate this condition, but check with him on it directly. I'm hoping the fiscal year end bonus situation hands me $1k, so I can go with an M&K muffler & a Steve W / 8k conversion myself. With the cat gone, you can get more accurate air/fuel readings with a local dyno shop's tailpipe sniffer - local dyno time here in New England's around $65, air/fuel is typically another $10 or so.

As for the stoplight revving, try it with a Fabspeed Cat bypass / Muffler bypass setup like mine - it definitely gets the looks.

Joel Lester

Thanks Fred. Nice to know that a new idle valve/switch didn't fix it for you. I will most likely be getting a Steve Wong chip as well.

Brian_77_3.6

I had this problem on my 86 a few years ago and the shop who does the maintainence adjusted something in the fuel injection, don't remember what , and the up and down idle disappeared. Took them about 10 minutes to make the adjustment.

Corrales911

I have the same sympton that has developed over time. I've noticed that it seems to be worse as the operating temp increases. I suspect a temp sensor...

Joel Lester

Brain, "adjusted something in the fuel injection, don't remember what , and the up and down idle disappeared." Should would love to know what they did..... we're getting close. Any ideas anyone?

Brian_77_3.6

I looked back on the service records and here is what the shop did to fix the problem. They referred to it as Idle Hunting. First they checked and adjusted the CO level using a tail pipe probe. I think there is an adjustment for CO at the bottom of the Air Flow Sensor. Then they disabled the Idle stabilization valve (also reffered to as Idle Control Valve) by placing a Jumper on the rear diagnostic socket. They set the idle to 850 and then disconnected the jumper. Problem was gone.

84_Carrera

Nice, thanks for the info - I think I'll do that AFTER the new chip goes in though so I don't potentially have to do it twice.

mcuozzo

I have the same problem on my 993. After doing some research, it seems that the ISV valve may need cleaning (I'm going to tackle it soon!). Maybe it's the same problemo on the 3.2 cars?

Anyway here's a link to the cleaning diy on a 993: ISV cleaning

Matt

84_Carrera

Matt, similar component to the one I mentioned being replaced in my post. Since there was no change, I kept the original one as a spare anyway. Thanks for the input!

Brian_77_3.6

There are several DIY descriptions of this adjustment on Pelican Board. I would certainly try this before replacing any more parts. If this doesn,t work then you can get into chasing the gremlin.

KC911

Do a search on Pelican about 'cleaning your ICV' with alcohol. Sometimes the internal 'plunger' isn't moving freely, and cleaning out the ICV may help your problem.

Keith
'88 CE coupe

edited: Here's a thread...see Jeff's response to my post....
http://forums.pelicanparts.com/showt...hreadid=247990