fn_42

Hi all, new 944 owner here looking for some help getting it running. A little background - I just picked this car up for free from a guy looking to clear out his yard, was told it had clutch issues (the pedal is stuck down) but ran when parked 10+ years ago. I've been trying to get it started and so far have not been successful.

I don't get fuel, spark, or a tach bounce when cranking. I'm not really sure how to tell if the DME is actually alive, I've tried bypassing the relay for it with no change in behavior. But I checked the resistance of the crank sensors and am getting 3.5-4 megaohms on both and infinite resistance on the outer two pins. From what I saw online the resistance should be ~1k ohms but I'm a little skeptical that they're broken because both sensors are reading the same. What are the chances they are both dead? Any other leads I should be chasing here?

thanks

Mr. Toasty

Free? Congrats! Lots to love at that price

I hate to say it, but it could be any number of things after sitting for over 10 years. I'll let those with more experience answer your specific questions, but I'll throw this out there in case you haven't read it somewhere already: before you get it cranking and started, replace the timing and balance belts. Better to do that now than to get it started only to possibly wreak havoc on the valves/head/pistons within minutes.

The fuel pump might also be gunked up and not working, although you'd probably get spark and some tach action if that were the only issue. There could also be bad grounds or wires somewhere. Do any of the gauges seem to function? What about the other electrical systems and accessories?

fn_42

Thanks, I do not hear the fuel pump prime but I couldn't figure out if it primes koeo or just when cranking so not sure if that's an issue

With the alarm box plugged in it will trigger the alarm when I put the key in the ignition. With the box bypassed from the back of the connector (still plugged in) the tach will sweep up to the max rpm on cranking and then settle at 4k. With the alarm box unplugged and bypassed I get no tach activity at all besides a small jump when I turn the key to position 2. I think you may be right about electrical gremlins sadly

Mr. Toasty

The pump will run only after receiving a signal that the engine is cranking, so the only way I know of to check it would be to hook it up to a power source directly and force it to run.

Yikes. Well, I'm unfortunately not experienced enough to help there, and I don't want to give you bad info. Most cars have already had the alarm disabled so it doesn't cause any issues, and it sounds like the alarm isn't the problem here anyway. If I were in your shoes, I'd leave the alarm disabled and go from large to small checking the wires, then go after the DME and speed/reference sensors if everything else checks out. Hopefully it's just a simple and obvious connection or shorting issue that clears everything up.

Spring44

Did you just add gas and try to start it? If so, since the car sat for 10 years, you have probably plugged the fuel pump and fuel filter with the rust, gasoline varnish and even asphaltines that form when the fuel evaporates. You need to drain the fuel tank, unscrew the large filter screen located in the fuel tank sump and see what all is in the sump. If it is filled with bad stuff it will be drawn into the fuel pump and lock it up and/or plug the filter downstream of the pump. Anything that gets past the filter will go to the engine and plug injectors and pressure regulators. Fuel injection systems demand clean fuel to run reliably and yours will not be clean after ten years of storage.

I had this problem last year after seven years of storage and it gave me fits. My sump was full of rust, varnish and a thick, tar-like substance and the filter screen inside of the tank was completely plugged by it. I put off removing the tank for cleaning and tried cleaning it with solvent flushing because tank removal requires removal of the transmission. But I finally dropped the trans and had the tank professionally cleaned and coated, inside and out, and have had no further problems; and the car runs great.

I now wish that I had cleaned the tank to start with because not doing it set me back by weeks, cost me a new fuel pump, two $30 filters and $75 to clean and flow test the injectors and I still ended up having to do it anyway. A really good tank restoration and coating, inside and out, by a tank and radiator shop using the RENU process will do a good job on it and give you a lifetime warranty for just north of $400. Not doing it right away probably cost me nearly that much plus a lot of time and frustration. You can still get new tanks but they cost $1800 so this restoration seems to be a relative bargain.

After you remove the tank filter screen, be careful, as it is made from a very delicate nylon mesh and will tear open if you scrape on it. You can remove varnish and tar from it with spray carb cleaner. It also costs $75-100 to replace, so handle with care!

Clean all of the ground connectors in the engine compartment and make sure that the small cables on the positive battery cable are tight. I discovered that mine were slightly loose and once tightened my car started. I also replaced both speed and position sensors, timing belts water pump distributor cap, rotor.
Good Luck

fn_42

I guess they were both bad! I had to remove the bracket and break the sensors to get them out because they were frozen in there so badly. But it starts right up now! Thanks for all the advice everyone, looking forward to fixing what's next =)

Kopenhagen944

Sorry to make you relive the past, but how did you remove the sensors after breaking them? Any issues re-gapping the new sensors?

Asking for a friend...

fn_42

if I remember right they were frozen in the aluminum bracket pretty badly but I was able to
drill a hole through them for relief, pull out the guts, and then use a flat head and hammer to chip away at the plastic bits stuck in the bore of the bracket. I don’t remember the gapping process much unfortunately! Think I just happened to get lucky there