QuestionQUESTION: Erratic (cyclic surging)idle on 1300 OHC 8V motor. I'm actually in South Africa, where it is know as an Opel Kadett 1300 5 door, but pictures of Astra mk2- mk4 1985 -1990 or thereabouts looks like the same model. Carb does not seem to have good old idle mixture etc. Distributor is on the end of the cam.
The car is a mk2, however I do not know the year as the VIN is not logical to me. We think it may be 1990. If one increases revs to 1500 then the hunting is gone. Hi / lo period of hunting is about 1 second.
ANSWER: Lambda sensor kaput. (at a guess)
Is it injection or carburettor?
If its injection give me the numbers off the ECU
If its carburettor give me the model/maker of the distributor.
---------- FOLLOW-UP ----------
QUESTION: It is carb, distributor is Deico Remy made in USA.
AnswerAhh.. pretty much mk1/2 astra OHV engine.
This surging, There's a lot of causes - could be more than one thing too.
Check the water level in the radiator is brimmed, and the expansion tank is at the FULL mark.
Best to get the carb cleaned up before doing anything else, clean out the jets and use some carb cleaner, get it working smoothly and generally pretty clean.
And also verify the valve timing is correct. - there are marks on the flywheel and engine block, and marks on the cam pulley and timing cover, verify they line up together.
If possible verify the ignition timing too with strobe -
1: Check battery condition and charge - a partially discharged/worn out battery can do some strange things.
2: Vacuum line from manifold to distributor - check for leaks.
3: Airbox, airfilter and airbox/carb seal, check for leaks and security, wobbling boxes WILL be leaking, also oil-cap and engine breather hoses, check those for blockage/security/leaks as applicable.
4: Inlet manifold, check for leaks.
5: Automatic choke (if applicable), check the auto-choke does fully open eventually.
6: Engine grounding straps/body ground/battery ground/engine ground... all your grounds, check for security, clean and reifit any that look a bit iffy.
7: Distributor contacts.
8: Lambda sensor (early), you can get pattern lambda sensors for 80's +early 90's stuff from ebay, maybe even used parts.. the opriginals would be hard to get hold of and I'm not too trusting of "old stock", often dusty/rusty/bashed about... so the pattern parts are the ones to go for.
Go Astra! ;-)
