black944 turbo

Mustang dynos read lower than others not the opposite way round.

Porschefile

That's what I said

Driftomagnifico

I just drove his car, the thing has absolutely ZERO torque at low RPM. Taking off from a stop is difficult compared to just about every other car I've driven. Blipping the throttle makes the engine slowly rev up as if the engine had a 90 lb. flywheel.

How can I check the ignition advance on the engine, and where should it be at when idling / 2000 RPM no-load.

When the car is moving it has a typical turbo lag, and accelerates fine, but the off-idle throttle response is non-existant. It's not just a big motor problem, there is something that is preventing the car from having tip in response at low RPM. Perhaps the tip in enrichment is exagerating a retarded timing issue?

How well known are the distributors for developing timing walk? Is the conductive pick-up for the ignition and fuel timing sourced from the distributor or off the flywheel?

toddk911

Check for vacume leaks?

As it could be aleak that once the air flow has some velocity it is ok, but at off idle or low loads there is a noticable leak.

I know I have popped one of the IC pipes before and at normal driving it was ok till I got home, but at idle/off idle I had to really work the throttle to get any response.

Porschefile

I'm not sure if the TB is leaking, but I have all new vacuum lines, intake couplers/hoses, intake manifold gaskets, etc. Everything under the intake manifold is new as well.

dand86951

How hot has it been when you are testing the car. The stock 951, or at least mine, was very sluggish from a stop particularly in warm weather. Also your comment about a 90 pound flywheel is not too far off the mark, considering the weight of the crank assembly and flywheel, lots of built in inertia. If you have checked the compression, checked the plugs/wires/rotor and cleaned the injectors and checked the cat not being clogged, then if it is running smoothly my guess is it is normal.

To check the timing requires marking the crank pulley or trying to use the mark on the flywheel at the back of the engine. The distributors are solid unless the rotor is badly worn or lots of carbon build up is there, but in that case I would suspect you would see some uneven firing.

Driftomagnifico

Thanks Dan, but I know for a fact it's a little beyond the norm.

jimbo1111

With that type of mileage a compression and leak down should be done to check the efficiency of the motor.

Driftomagnifico

I think the leakdown will be a little low.

We just performed the missing timing belt mod whilst driving back to my house.

RIP 951 Engine ... nearly 223ooo miles made a believer outta me.

Porschefile

Yep, the timing belt just let go. Oh well, I got good use out of this motor so now it's time for a rebuild. Thanks for the help and ideas guys.

Driftomagnifico

Hhehe... one way or another

facboy

oh, so that was the problem? the timing belt was on the way out (or gone?)

Driftomagnifico

Doubt it.

The engine picked up a intermittant stalling while driving problem, he picked me up to investigate it and on the way back to my house the engine did it once and dropped power. The engine then cut out later down the road while driving and wouldn't start. The first time it cranked over after the belt broke the engine turned over a little bit then it stopped, popped the hood, gave it one last try and I heard the valve kickback.

Oh well, the motor put in it's duty.

toddk911

Speed/reference sensors???

Porschefile

I've already replaced these twice this year. Nope, it's definitely the timing belt as we could hear the interference from valves slamming into pistons. Oh well, I beat the hell out of this car and put tons of miles on it in the last 2 yrs so I really couldn't ask for more from this motor. I planned on rebuilding the motor this year anyways, so I guess I get to do it a littler earlier than expected.