Low rev popping

[alfiembra]

I'm hoping someone can give me a few pointers with tickover/low rev rough running. My car is a bog standard 85 mk1a with 68k on the clock. At just over 1000 revs the engine seems to miss the occasional beat and "pops" slightly but is running fine above this level. When its fully warmed up it ticks over at around 600 rpm and the revs bounce about a bit. I've recently changed the plugs, (NGK's) air filter, distributer cap and rotor. Which didn't have any effect. Its been an ongoing niggle as long as I've had the car but apart from that it runs fine.

Cheers

Alfiembra

[crazylegs]

the bouncy idle points to air in the coolant .when warm it should tick over at around 850 rpm so this needs adjusting a bit.check/adjust the ignition timing and see what happens.the pop may be a small air leak in one of the vacuum hoses but sort the others first

[alfiembra]

Thanks Crazylegs

I'll try bleeding the coolant system, not too confident to tinker with the timing myself but got a friend that can help me with that.

Cheers

alfiembra

[Mk1 Turbo Powered Steve]

As i say on here all the time i am no expert but when i had a coolant change and new thermostat fitted to my sc,the problems of revs and temp have been sorted.
My revs used to be all over the place at idle,the temp rarely got out of cold.
As far as i know the cooling systems between an na and sc are are about the same.

[crazylegs]

timing is easy get a strobe,set the idle when hot, bridge out the terminals t and e1 in the diagnostics box and shine your light on the crank pulley.with the terminals bridged your timing should be on the middle mark,10 degrees, if not adjust the distributor. clamp it up and remove the bridging wire.the timing should now read 12 degrees or higher.job done.there is a handy tool for the bridging being sold on ebay.you could always use a bent paper clip but this tends to fall out.