PINKING

[dukeenfield]

Hi,Well my car past MOT OK,except for one headlight being to high,but the the kind MOT tester ajusted it for me. So I thought I would go for blast in it and I noticed it was pinking a bit,and it had never done this before.The only thing I could put it down to was I hadn't been putting any lead replacement and octane booster stuff in for a little while.Could this be the cause,do most people use lead replacement and octane booster,in there cars.The ignition is set to about 4 degree's before top dead centre.

[dickymint]

Aye that will do it. You need about 8 degrees TDC to run unleaded or use additives.

[350zwelgje]

Unleaded is fine, but with correct octane rating.
Use 98RON unleaded myself for a standard 350i, with the ignition set at 8 degrees as mentioned before.

Picking with correct octane petrol is also possible with a low fuel level. Happens to me when I am not careful and the petrol level is low (less than 1/4) and require a full acceleration run. This is due to not enough fuel that can be pumped to maintain the fuel pressure at the injectors. Backing of and filling up is the solution.

Rob

[350matt]

Also helps to move the air filter /intake to the space occupied by the header tank as its much cooler there.

Matt

[dukeenfield]

I will try and get some better petrol and perhaps try move air flow meter,thanks for all your help.

[wedg1e]

Try to find a post-'85 XR4i in the breakers and pinch the heads off it. They were modified for unleaded petrol. Clue is that the engine type plate is stamped PR-D or PR-E instead of just PR.