RallyCross Breaks the Porsche 944 Again

[@raywach2571]

I've owned about a dozen old 944s, none of them in very good condition, but I don't think I've ever had exactly the problem you describe. I've had engine fires, warped heads, broken cam belts, scored cylinders, and many many electrical problems; these 944s are generally very reliable but they are old and most have been neglected and abused for many years. As I understand it, yours runs fine when cold or warm, but runs very poorly when hot. I agree, a sensor is the first thing I would think of but this car only has a few sensors -- MAF, coolant temp, crank position, throttle idle position switch, O2 sensor, off the top of my head. You can try unplugging them one by one to see if you can duplicate the symptoms, but the coolant temp is the only one that might cause this problem; it won't run with the others disconnected. The coolant temp sensor is on top of the head by the intake runners and you can reach the connector easily. The fuel pressure is controlled by a vacuum line from the throttle body; it will run poorly if that line is disconnected but the temperature shouldn't affect it. The MAF often is worn out or bad, but generally it will run poorly all the time usually hesitating on acceleration, but perhaps one could be bad in a way that is affected by heat. There is an intake air temp sensor in the MAF; one possible problem might be that a couple things are wrong in a way that they compensate for each other so when it is cold it runs alright but when it gets hot the system is out of whack. Putting your cold air intake tube back on couldn't hurt; I have a couple spares here if you're ever in southern Ohio. Of course, there are other parts on the car that could be affected by temperature such as the fuel pump or ignition coil, so you might check them if you haven't already. Or, electrical problems are common on these old cars and often connections that look good are corroded inside -- perhaps you have a connection that becomes intermittent or poor when it gets hot. You might join one of the 944 groups on Facebook; you can probably find another owner in your area who will let you swap parts until you've isolated the problem. Thanks for sharing the great videos -- we've thought about rallycrossing a 944 and your videos make it look like a lot of fun.

[@stephenricketts7764]

I don't know much about the 944 engines but here's one suggestion that may or may not help. Flushing the block might clear any gunk in the waterways thus improving cooling. Just a suggestion Steve. It would be nice to get this car running well. I think the water on the track did help a little but the first few cars were much slower so it is a difficult balance between huge dust clouds and cars sliding. All looked like fun anyway and people seemed to be enjoying themselves. I am sure you will sort this car out soon Steve but I do understand your testing dilemma. 👍👍

[@CMKshadow]

Cool Car 😁the mirror falling at 4:37 was a nice touch.

[@adamgrosskreutz7546]

I am enjoying the updates on my old car

[@bobmanzi7712]

great stuff thanks

[@thmmotorsports2940]

Nice car, and I like your driving style. I'm not familiar with the early model 944's but it looks like every long right hander your oil pressure warning light comes on. I think the pans from the later models are transferable and have a rudimentary baffle built in. Its a lot of work but will save your motor in the long run!

[@TomMcCanna]

I used to have an e-type that had a similar issue for a while. Turned out to be an ignition coil. As things got hot, its electrical output decreased.

[@mundanestuff]

I have a bugeye Sprite that i think would be fun for this. Fear it would get wrecked.

[@davidnelson6893]

Those cars out my nerer had one Peace out

[@brackishcycles]

Is this not a vapor lock condition? Is the fuel pump getting hot and boiling the gas before it gets to the engine, then not atomizing correctly? Is the fuel rail getting too hot?