Very fast revs from DG 1.9

Post by **AdamW** » 20 May 2012, 16:41

Hi,
I replaced an overheated dg engine with a secondhand one. This is now installed but revs very high when I start it up. I am not sure why.
The old engine had a solex carb & the new one has pierburg carb. Also the distributor is slightly different. The old one had 2 vacuum connections and the new one has one connector.
Do I need to change the idle stabilising unit to the one that goes with the new distributor? or are they standard?
What other reasons could it be reving so high? I think all the vacuum hoses are connected correctly?
Also I wondered if all of the choke, the idle cut off solenoid and the throttle body heater connect to positive supply from the thermoswitch.
I can't find any air leaks which may cause the high revs. I have sprayed around with WD40 and get no change in engine noise when spaying around the carb and inlet manifold.
Any advice would be appreciated.
Thanks Adam

Post by **Ian Hulley** » 20 May 2012, 16:57

There isn't an 'Idle stabilising unit' on a DG ... there's an ignition amplifier and an automatic choke though.

Ian

Post by **ermie571** » 20 May 2012, 17:34

Adam,

just to let you know when they first start up kevtherev says his will idle at 2000 revs, then reduce in steps as the engine warms. Mine has never revved that high, but sometimes it will start at 1200, then after a short while when I next idle it will be down to the 900-1000 revs (or whatever it feels like that day)

so, do your revs drop as it warms?

sometimes, a quick blip on the throttle is all it needs to bring it down.

Em
xx

Post by **AdamW** » 20 May 2012, 18:41

Hi - thanks for your replies.

Em - The revs are very high and don't drop when I blip the throttle.

Ian - The black box between the control unit and the coil. Haynes call 'Idle stabilising unit'. Its on the first picture in the Ignition system chapter. I just thought that something they call 'Idle stabilising unit' may the cause of the high revs or else a carburetor adjustment.

I have tinkered with the automatic choke but it hasn't made a difference.

Adam

Post by **kevtherev** » 20 May 2012, 19:40

the pierburg 2e3 has a fast idle mechanism which is operated by the auto choke.
this mechanism is is a stepped cam that moves anti clock wise as the choke flap opens.

if it constantly on fast idle even when the engine is warm then it needs to be checked for correct operation

Post by **toomanytoys** » 20 May 2012, 19:50

Throttle cable is returning all the way isnt it?? it may be that the solex has a different position there ofre the cable is too short and actually keeping the throttle open.. disconnect the cable and see if it idles properly then...

Post by **AdamW** » 20 May 2012, 21:35

Thanks for the responses

Kevtherev - As you say I may need to check the stepped mechanism on the automatic choke. I think the carb has to come off for this, so I just wanted to rule out other things such as wrongly connected wires, first.
I was looking at one of your previous posts and wondered if you can confirm that all 3 wires coming off the carb all connect to positive supply from the thermoswitch. These are:
autochoke wire
idle cut off solenoid
throttle body heater

Also some post mention the air bypass - Is this the same thing as the idle cut off solenoid.

Toomanytoys - You are correct that the throttle cable to the solex was shorter. It also had a different attachment. I have already swapped the cable over and this problem is not caused by throttle being too tight.

Post by **kevtherev** » 20 May 2012, 21:41

the thermo switch does not connect to the idle speed cut off
the thermo switch connects to the manifold heater the carb heater and the choke heater

Post by **dazzzer1** » 21 May 2012, 17:45

youve not just got the cable too tight have you. the cable has a clip that fits in about 5 positions where it leaves the linkage and disappears under the van.

i have a idle stabiliser that im selling if you need one

daz 07969774085

Post by **waltraud** » 21 May 2012, 21:27

How about you take the two connections from the idle stabilisation and join them together. I swapped from DF to DG and it helped a lot to reduce the revs.

Post by **AdamW** » 22 May 2012, 18:31

Hi
Waltraud
- I'm not sure I understand this. Which wires would you join together?

waltraud wrote:How about you take the two connections from the idle stabilisation and join them together. I swapped from DF to DG and it helped a lot to reduce the revs.

Dazzzer1 - It's not the cable. I'm not sure if I need the stabiliser or not.

I tried to change the distributor for the one that was on the old engine, which went with the solex carb. The distributor on the new engine is jammed on. The rotor turns ok, but the body will not pull off the engine. I have taken off the nut which clamps it down and the one which stops it twisting. Any ideas?
Adam

Post by **ermie571** » 22 May 2012, 18:36

Yep. take the fuel pump off....then it will come out!

Found that out the hard way when I needed to turn mydizzy through 180 degrees....we tried for ages and ages....then gave up, garage had it out in 2 mins once the fuel pump was removed.

And nor does it go back in straight...it twists...not sure which way, but I think that was why mine was 180 degrees out....

Hope that helps

Em
xx

(I hope that info is correct - sure someone will correct me if wrong!)

Post by **waltraud** » 24 May 2012, 18:55

There are two round, black plugs about 10mm width which enter the bottom of the unit, if you gently twist each one to loosen and pull it out these two 'plugs' should fit together. W

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