akatech

Hi people

I am having trouble with idle speed especially when i hit the pedal to the bottom. when i first changed the ignition control module after change the idle rpm on hot engine was between 1200 an 1300 rpm wich it is not normal. using a audi 80 b3 1986-1991 managed to finde how to stabilize the idle speed to 950-1000 rpm, and that through Overrun Shut-off Valve. 3 days ago my car stoped starting and i changed again the ignition contol module and it started without problems.

the problem with my car is when i set th idle rpm to 1000 it stays there, when cold it goes 1100-1200 depends on temperature and it stabilizie to 1000. but when i hit the pedal to 7000 rpm the bolt of Overrun Shut-off Valve pops out, and the idle speed jumps to 1800 rpm and do not get normalized even after a restart. i have to set up again the Overrun Shut-off Valve to lower the idle speed rpm.

Did any body had that problem and how you fixed it.

Rusty Spokes

might need a little more information to be able to help. what year and model audi..and I dont know what the shut-off valve is exactly..got pictures?

dgcantrelljr@verizon.net

Check and make sure the butterfly valve shafts on the throttle body are closing all the way when you let off the accelerator pedal. The linkage for the pedal operates separately from the cruise control linkage. Sometimes the cruise portion will not return to the closed position when opened up by the accelerator linkage. I had that happening on my 5000 a while back and it took me a while to spot it. I sprayed penetrating lube on the top and bottom portions of shafts to free things up.

IdahoDoug

What engine? What transmission? What year?

akatech

thanks for Your reply

it is a audi 80 1988 b3 1.9e 83 kw FWD, 5 + R manual. the shut off valve on the picture below

dgcantrelljr@verizon.net

That's the idle speed adjuster screw (circled). If you have it bottomed out and it still idles fast, either the butterfly (throttle) valves are not closing all the way or the shaft seals that the valves mount to are leaking. It really only takes just a tiny amount of air to make it idle faster than it should.

akatech

the problem with the idle shows up when i hit the gas to max and the screw (circled, exact) starts spining outside. then the idle stay at about 1800. after that i need to set it again. and the idle stays at 1000 while normal driving till about 4000 rpm. over that spins out.

dgcantrelljr@verizon.net

There's an o-ring on the screw that should prevent it from backing out under vibration. It may be missing or needs replacing. Easy fix. Or you can just set it and dab some RTV into it to prevent it from moving. Removing the RTV at a later date if it needs to be readjusted should not pose a problem.

Rusty Spokes

Check around for a suitable "O" ring..the part number for the screw is 049133432 which is NLA..but available from the bone yards for most 4 cylinder VW/Audi cars with CIS injection..the "O" ring can be had from the local parts store

Looks like your intake rubber boot needs replacing too...look for a part number on the boot and check ebay or google the part number..should be 026133357G

akatech

thank you Rusty

i was afraid to take the screw out not nowing wat it is inside, i am an electrical engineer but love cars. i drive that audi for 7 years and the most services i do it by my self. but never played with air and fuel systems. the intake rubber had one crack when i bought it it was a 1.5 cm crack between two ribs so i wrapped it with silicone rubber sealant a pair of ribs just for safety.