idle problem mfi car

[JA51ON W]

Hi, my car, a 69 2.0e (mfi) will when warm idle high at around 1600 rpm then sometimes will after 30 secs drop down to a low idle of around 700 rpm. Any ideas please, Jason.

[inaglasshouse]

Sticky linkages in throttle bodies
Worn throttle bodies hence air leaks
Sticky idle speed adjust cable (or other issues leading to this being sometimes engaged, eg bad routing, weak return spring etc)
Can't remember whether a 69 E had the two-solenoid MFI pump (one of which being cold start enrichment)? Or the later scheme being a pipe of hot air to MFI pump for the temperature compensation mech?

[JA51ON W]

Thanks for your reply, most of what’s on your list has either been reconditioned/ rebuild or deleted . It’s been doing this for years and I’m pretty much at the end of ideas. Tomorrow I will check the throttle linkage, especially around the gearbox area, you could be onto something there. Also the weights inside distributor seam loose, has anybody changed distributor for a 123 ignition unit?

[inaglasshouse]

Dizzy advance sticking is a very good suspect for your symptoms.
If it remains advanced after you close the throttle, then the weights free up at some point so the advance returns to the correct idle setting, I think you'd see almost exactly the RPM change you mention....

[inaglasshouse]

Have used a 123 in a 356, not in a 911. Opinions differ on whether it's a good idea in conjunction with the CDI, so worth doing some research on that.

[JA51ON W]

I don’t need to go down the route of a different distributor, I’d be happy having my weights replaced if that was possible but couldn’t find anyone to do that kind of service

[inaglasshouse]

Not had it done separately from engine builds, but I would have thought that dizzy refurb would be a readily available service?
Those Bosch units are basically the same in loads of cars (inc vws etc).
I’m sure someone will be along with a recommendation.

[911hillclimber]

Neil Bainbridge?

[jb]

Put some oil on the felt under the rotor arm

[Nine One One]

There are not that many people in the UK that rebuild some of the old distributors, I had this problem when trying to get a Bosch 006 rebuilt.
There are plenty of firms that supply a rebuild kit, but what tension the springs are seem to be hit and miss. In the end I went down the 123 route.
What you really need to find is someone with one of the old SUN distributor machines that can actually measure the advance curve on it, so you know whether it is that, before you start going down a rabbit hole?

If you are handy with some picks and a few basic tools, you could always try dismantling it, and giving it a good clean, as they can get fairly dunked up inside. Also look to see if there is excessive wear at the gear end.

https://forums.pelicanparts.com/porsche ... -lube.html

[neilbardsley]

If the distributor is your issue then you will not be disappointed with the 123. More stable timing and no need to ever adjust the points. Will work well with cdi

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[BILLY BEAN]

Try H and H ignition solutions in Birmingham. They rebuild and service distributors.

[neilbardsley]

Don't they screwed up mine

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[RobFrost]

Put some oil on the felt under the rotor arm

Second that. Maybe even take it out, clean out thoroughly with solvent and re-lubricate.

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[Jonny Hart]

Before you spring for a distributor rebuild, check the timing. If it's 'hung up' on the way down from higher revs that would show on the timing light.