2.1 Idling problems

Post by **Womboy** » 16 Sep 2007, 19:28

Just wondered if anybody had any suggestions? My 1989 2.1 DJ is idling too high.

I tried to set the ignition timing the other day. I checked the revs and found it was idling at about 1400rpm instead of the 800 it's supposed to be at. I tried to back it off with the idle speed adjuster, but when it got below 1000 it started to stall. Also when I disconnect the vaccum hoses from the dizzy, the revs shoot up to 2000rpm.

There does seem to be a slight misfire at idle and the exhaust is blowing a bit. It's had new leads, cap, rotor arm and plugs. The idle stabilising unit is missing, although someone said this isn't a problem when I asked about it in another post. The engine is a VW recon unit with less than 30k on the clock.

Post by **syncrodoug** » 16 Sep 2007, 20:07

Make sure the pipe to the idle stabilisation valve hasn't worked loose.

Website · Post by **syncrosimon** » 17 Sep 2007, 13:53

hi. my 2.1 dj used to idle very high, this was to do with the temp sender not working. The computer unit was being told that the engine was cold all the time, which was fine on first start up, but as the engine warmed up the revs went up and up. the sender is the one on the thermostat pointing towards the n/s rear wheel, the one pointing to the front with only one terminal is the dash board one.
when you set the timing and the idle, you are supposed to unplug the advance, and then block the vacum pipe off with a small bolt or similar.
the revs shouldnt roar up like that though.
simon.

Website · Post by **syncrosimon** » 17 Sep 2007, 14:00

The other things that can raise the idle speed include the power steering pump sensor, and the microswitch on the throttle valve. When you open the throttle just a tincy tiny bit you should hear a little click, thats the microswitch operating. this tells the computer that the engine is supposed to be idling and activates all the idle stabilisation gubbins. You can check these with a multi meter. the bentley manual takes you through each bit of the injection process.
air leaks will also raise the idle, and are worth checking.
good luck.
simon.

Post by **Womboy** » 17 Sep 2007, 14:10

Cheers guys, I'll give all those suggestions a go.

I thought it was strange that the revs shoot up so high when I unplugged the vacuum pipes... Any ideas on why that might happen? I made sure that I plugged the ends of the hoses when I took them off.