I have just bought a Golf 2 G60 and I changed the engine as the old one was making pretty much noise from the valves and 2 of the exhaust screws were broken in the block.
Got another engine which had recently done the head and head gasket and installed it in the car.
The new engine has a "slight" problem.
When I first start the car when cold it would run pretty rough, like running on 3 pistons and it idles badly like almost stalling.
If I accelerate and release the RPM will fall hard and it would almost stop ... almost.
I can also smell unburned fuel on the exhaust and the spark plugs are getting black.
What I have changed and done in order to try to fix the problem:
- Checked compression it is 8.4-8.5 BAR (123psi) on all pistons.
- Cleaned all the ground points.
- Re grounded engine, battery, body with 6 Awg wire.
- Re grounded head with 6 Awg wire.
- Re grounded bolt on the back of the engine beside water hose directly from battery with 6 Awg wire.
Changed parts :
- O2 sensor with brand new NGK sensor. Tried also with another Bosch.
- Idle stabiliser valve from my old engine that was running fine but with noisy head.
- ALL vacum hoses. (the car has the charcoal canister removed)
- Spark Plugs with new Bosch Platinum.
- Ignition wires for all 4 spark plugs.
- Distributor cap and pipe.
- Blue and Black temp sensor changed twice with original VW sensors.
- Knok sensor changed.
- Tried with 2 other different throtle bodies.
- Tried with 3 different ECU's, 1 standard and 2 tunned.
- Adjusted the MAF to 500 ohm.
- Ignition timing adjusted to TDC (don't have an ignition check light to test it while running but will have it checked monday).
- Re made the injectors wiring with brand new wires and connectors as it was old and started to crack.
I am now in the process of overhauling the G-Lader and see if the problem maybe lies there but at idle ??
The only thing I have not done yet is to take off the head and check the head gasket but the head gasket was done recently
As soon as the engine gets hot no idle problems anymore. Car pulls nice and no hesitations.(as far as I noticed).
Any idea what can cause the problem ? Anything that I forgot or overseen ?
I am pulling my hair now and don't know what I have missed.