Clem

Hi all, I'm new here and hoping someone can steer me in the right direction on troubleshooting an idle problem that just popped up. My car is an '85 2.3 190e automatic with around 180k on it. I had the car parked for about a year and just recently started driving it again. When I took it off the blocks I put a new battery in it and filled it with fresh gas. It ran perfect for a couple of weeks. I dropped it off at a detail shop and they pressure washed the engine compartment, it ran a little rough when I picked it up (#2 plug cap jumping fire to ground because it was still wet). After the motor dried out it ran OK for a few days then it developed a low, lopeing idle of around 500 rpm. I can press the accelerator pedal down and raise the idle to around 650 and it smoothes out. Take my foot off the pedal and it drops back down to a lightly surging/rough 500 rpm idle.
I don't know if this might be related but I'll mention it anyway, when this first started (been going on a few weeks now) I had the exhaust system replaced from the headpipe back (no cat now). It made no difference.
So before I start throwing parts and money at this little feller does anybody here have any tips for a starting point ?
Thanks, I appreciate y'alls help.

Clem

Here's a couple more symptoms. It starts very well but it won't idle at all when it's cold. After it warms up it has a rough/surging idle of about 500 rpm.
After driving for awhile it smells very rich.
???????????

DePIB

I would first check if the iddle regulator is activated -the small electrically motor that makes air bypass at iddle time.

If there is no power, it can be the overvoltage protection relay (the one that has fuses on it). That happened to me.

If there is power, it can be stuck.

I think that they made it for safety reasons: a very small amount of air goes through it even when "closed" that causes very low iddle RPM.

190Newbee

The electrical system would be the first place that I would look after a motor wash (even after a couple of weeks).
How do the rotor-cap /rotor look? Cables? – dry? – firmly connected (can you measure the resistance?)?
Check all other electrical cords/connectors? Vacuum hoses?

Let us know what you find.

Good luck.

Clem

Well, I put new plugs in it and swapped out the cap/rotor/wires with known good ones and it didn't make a difference. The IAC is being energized so OVP is good. I did find that the lower hose on the IAC was split and hard so I have a new one on order. When I pulled the IAC to clean it I noticed that the flow arrow was pointing up, shouldn't it point down ? Also there is a manually adjustable bypass valve on the IAC. Is that to fine tune the idle ?????