DG Auto Revving high hot

[andy_l]

Hi forum,
I have a curious problem and would welcome your wisdom...

Basically, hot idle rises.. the longer the van is running the higher the idle.

I'm on a Pierburg 2E3, with 1.9 water cooled, DG automatic, 1985
At cold start RPM about 880, then warm it comes up to about 1000, then at hot its around 1900

As it's an auto the idle was always a bit high, to hold in Drive at lights etc; but it is now so high that the van is hard to hold on the brakes, if I take it out of Drive into Neutral to stop it edging forward, the revs are too high to put it back into Drive, it really slams in and bolts forward.

Vacum lines are tight, but recently replaced the ends, as they were perished, it was around the same sort of time as this problem started, but I would have expected the reverse effect!

The only other 'quirk' which I wonder if it is related and worth mentioning, is the van takes a good time to get hot, it takes more than half an hour of driving to get the needle up to the middle, and probably an hour to get it just over middle..

Thanks in advance for all your thoughts

[kevtherev]

There's a fast idle cam on the carb make sure it's free to move and the springs are in place
Use the search for "fast idle" and you'll get some pictures.

[andy_l]

Thanks Kev, will take a look

[andy_l]

For anyone else who found this topic, this is a great post with pics from Kev:

https://club8090.co.uk/forum/viewtopic.p ... t+idle+cam" onclick="window.open(this.href);return false;

I'm hopeful this is my issue, will post back with news!

[pionte]

If it is taking that long to come up to temperature, then it could be that your thermostat is stuck in the open position. ( better than being stuck closed!) the job of said thermostat is to promote fast warm up of the engine, cutting down fuel and reducing wear caused by rich running. Worth a check, cheap to replace but if yours is an early set up ( probably by the year) then they can be a pain to change due to seized bolts...

[kevtherev]

The choke comes off after six to eight mins from fully closed. it has it's own heater.

[pionte]

The only other 'quirk' which I wonder if it is related and worth mentioning, is the van takes a good time to get hot, it takes more than half an hour of driving to get the needle up to the middle, and probably an hour to get it just over middle..

Thanks in advance for all your thoughts

hence why I suggested looking into the thermostat as well.