PDA

View Full Version : M30 3.5 engine pings


Denis
09-07-2004, 10:58 PM
I have got 3.5 engine in my e34 535i which pings on regular (87 octane) gas. Pinging is really bad when Shell gas used, Sunoco gas is better but it still pings under load. This engine compression is 9.0:1, so it _have_ to run on regular. Am I wrong? Does anybody runs 1988-93 M30 engines on regular? Thanks.

Quack
09-07-2004, 11:46 PM
Shell has the worst gas for european cars, please stay away from Shell they have high sulphur content, Esso gas is dirty, try to use the highest octane gas possible it can't hurt except for your wallet :D

MarkD
09-09-2004, 07:36 AM
Have you checked for intake air leaks caused by cracked rubber parts (bellows) after the AFM, and other vacuum leaks? Maybe someone has "adjusted" the spring tension on the AFM? Or maybe the car has carbon in the motor? Those are some of the causes of pinging. Or has a previous owner installed a performance chip? That could cause pinging also on 89 octane.

MarkD

Denis
09-09-2004, 06:43 PM
Engine is airtight, tested it by closing intake outlet, exaust pipes and pumping it with air. It holds pressure.
Well, then I will adjust spring tension (engine really runs lean).
Did hot soak once, no changes noted.
Not sure about chip, will open motronic some day. On 89 octane it does not pings.

MarkD
09-09-2004, 07:59 PM
Originally posted by Denis
Engine is airtight, tested it by closing intake outlet, exaust pipes and pumping it with air. It holds pressure.
Well, then I will adjust spring tension (engine really runs lean).
Did hot soak once, no changes noted.
Not sure about chip, will open motronic some day. On 89 octane it does not pings.

Isn't that car supposed to use 89 octane? I didn't think it was tuned for 87.

MarkD

everlast
09-20-2004, 05:52 PM
I think Mark's right.