Hey there everyone,

Having a little bit of trouble with my 1985 944, which I think ultimately will be related to timing, but here's the issue. I always fill up with 98 Octane fuel, highest available in Australia. I get a fair bit of pinging, especially when under load driving uphill. When this starts the engine temp normally starts to rise. As we come into summer now I'm noticing it more. In winter it would only begin pinging when the engine reached operating temps.

I've also started getting an odd whistle which gets louder as the RPM increases when moving from the engine bay since the last time I fueled up without adding any octane booster to the tank. When I do add octane booster, the issues disappear. As a precaution I've fueled up with 98 Octane fuel from 3 different service stations and it's always the same result with pinging, unless I add the octane booster in which case the car starts to run better.

Do you reckon this is an issue with my timing being out? Or could it be injectors need cleaning/replacing? The MAF adjusted? Any insight into this would be greatly appreciated!

Thanks,
Garth

 

You're either running lean and / or timing is too advanced. You'll do engine damage continuing to drive it pinging because the noise is caused by the fuel igniting before the piston is at the top of the compression stroke, so mechanically it's still trying to come up, but the fuel air mixtotee explosion is trying to push it down.

 

Timing can not be adjusted except if the timing belt is not installed with #1 piston at TDC and the camshaft gear aligned with mark on front housing. Consult Clark's Garage website for procedures.

The mechanical adjustment to timing is an offset camshaft key.

 

It would be ignition timing rather than cam timing.

I'd start with fuel. Change your fuel filter, check fuel pressure at the rail. If fuel is in spec, check all things ignition; firing order, ignition wires, cap, rotor, flywheel pickup. You'll find the problem.