Hot idle on road rally xflow

[mexicotait]

Hi folks


Have a strange problem with my mk2


When im doing Road rallies tests etc after a fast section the idle drops right down.


The temperature stays level and tye fan cuts in and out fine never had it over heat.


Did a 10 mile fast section last night good blast came into control and the idle is struggling around 500 rpm

If I drive it on the road it stays around 1000 900 and idle smoothly


The car has had three different xflows and used to run on a twin choke and now a single 40 and its always done it



The worrying thing is as the idle drops so low the oil pressure drops down under 20psi


Any ideas

[Graham]

The worrying thing is as the idle drops so low the oil pressure drops down under 20psi

nothing unusual a hot x/flow wont generate 20psi at a slowish idle, but that in itself isnt a problem, at idle the engine only needs a few pounds of oil pressure

[mexicotait]

Thats good to know

But the low idle is more annoying than anything else

[daniele]

valve lash?
distributor is ok?

[onecamohv]

when i used my xflow for the same thing even though the coolant temperature was ok, i was experiencing terrible heat soak and tried many things to get rid of it. it was so bad it used to missfire and cut out. id have to let it cool for 10/15mins it would run perfect and then the same thing would happen again and again.
after all that a few people told me electronic ignition module i was using have trouble if the block and therfore the dizzy got too hot. i never looked into it much further as it only inspired me to crack on with the XE conversion.

[mexicotait]

Distributor is fine and ive used different ones anf its still done it



Valve lash?

[mexicotait]

when i used my xflow for the same thing even though the coolant temperature was ok, i was experiencing terrible heat soak and tried many things to get rid of it. it was so bad it used to missfire and cut out. id have to let it cool for 10/15mins it would run perfect and then the same thing would happen again and again.
after all that a few people told me electronic ignition module i was using have trouble if the block and therfore the dizzy got too hot. i never looked into it much further as it only inspired me to crack on with the XE conversion.

Mines never done that it stays idling all day long just drops
If I turn the Idle up when its warm at the end of a section after driving gently for a while the idle will be sitting at about 1500

[daniele]

is the carb frozen?

[mexicotait]

No I dont think so I used to get that on my old pug 205

Never had it happen on my mk2


Was thinking due to heat build up in the bay could fuel be vaporising in the carb

[Miniliteman]

Do you have a fuel-return-line to tank? (from carb)

[mexicotait]

No
Its a single dhla dellorto

Never seen one with a return

[waverunner]

Is your exhaust manifold wrapped?

If no, try that, you'll be surprised the difference it can make plus you will get a few more bhp