help with a 944 no start: Grassroots Motorsports forum: Grassroots Motorsports Magazine

Subscribe get a full year for only $23.95 Sample Free Test Drive—no strings attached

March 4, 2011 4:22 p.m. Rustspecs13 Reader

So a while back my dads 944 died on me.

I was driving home from FL to OH, and getting on a highway. Ran though first (up too 6K or so) shifted to second and then nothing happened, it just sputtered. Thinking back I may have hit the rev limter, or started to mess up then.

Since then my dad ordered a fuel pump relay, and that wasn't the problem. It also leaks fuel at the #3 injector even now so it has fuel pressure.

It does not have spark. Im going to go test the ignition coil resistance and if it has power now.

Ive been searching for the past 2-3 hours on porsche forums to maybe get an idea of what could cause it, but I just get a list of tonns of relays and the like that could be bad or should have 12V going to them. Or the crank sensors and all that.

I'm used to mid 90's Japanese cars and their relative simplicity lol. Is there any specific direction to point me in that causes ignition failure more often then anything else?

I'm going to also try bypassing the security system, I doubt it could be a problem but maybe.

~Alex
March 4, 2011 4:25 p.m. Javelin SuperDork

Not to be that guy, but did the timing belt break? You won't have spark if the cam isn't spinning.

I'm assuming you would have figured that out though, so check for power to the coil with a multi-meter, coil might have gone out.

Then check the DME Relay (most common failure I'm told). Then the alarm doo-dad.
March 4, 2011 5:21 p.m. Rustspecs13 Reader

yeah the timing belt is fine, it still spins the distributor. It was replaced a few months ago and has ran fine ever since.

~Alex
March 7, 2011 3:43 p.m. racerdave600 HalfDork

Yeah, I'd check the DME Relay for sure if you haven't already. Mine had exactly the same problem, and DME relay was the answer. After than, I never left home without a spare. Fortunately they're cheap, even from the dealer.
March 7, 2011 4:23 p.m. Rustspecs13 Reader

For some reason my dad hasn't bought one yet, he wants to find it first. Any idea where it is? Got a pic? I haven't been able to find one.

~Alex
March 7, 2011 4:28 p.m. Woody SuperDork

On 911's, they're under the driver's seat.
March 7, 2011 4:40 p.m. 16vCorey SuperDork

I would guess crank sensor. There are two of them, and they're interchangeable. Unplug them and switch them and see what happens.
March 8, 2011 8:07 a.m. racerdave600 HalfDork

In my '89 the DME relay was in the fuse box under the hood. They fail on a somewhat regular basis, and almost all Porsches from the era use the same one, so they are cheap and easy to find. i think I paid $12 for it at the local Porsche dealer.
March 8, 2011 8:30 a.m. Otto Maddox HalfDork

In reply to racerdave600:

Man, I think I paid over $100 for mine a few years ago. My dealer must suck.
March 8, 2011 9:25 a.m. johnp2 New Reader

Yea try the DME, failed on mine as well. Luckily the previous owner included an extra.

Pelicanparts.com has them for 25 bucks.
March 8, 2011 12:07 p.m. racerdave600 HalfDork

I probably should add that we have a good dealer in town, and they do give PCA discounts. All of them that I priced were well under $100 though, way under.
March 9, 2011 10:45 a.m. Rustspecs13 Reader

Ok I'll get him to order one just for a spare,

BUT where is it? I haven't been able to find where this relay is....

~Alex
March 9, 2011 11:04 a.m. Otto Maddox HalfDork

On the driver side of the engine compartment, almost all the way back to the windshield. There is a box full of relays. You'll find it there.
March 9, 2011 11:28 a.m. Rustspecs13 Reader

Ah thanks a lot for the info! I'll go check it out

~Alex
March 20, 2011 2:47 p.m. Rustspecs13 Reader

Jumped the DME relay. Didn't change anything.

We did find one of the speed sensor bolts wasn't there holding in place. I think its the speed and not reference sensor. Any way there's no bolt in place because its off a little and you cant thread a bolt into place because its clocked wrong.

Its in the shadow you can barely see it. But I think its been like this forever, and we cant get a bolt in it.

However, it failed after driving for 14hours on a road trip. So if the speed sensor is the problem, it would have had to rotate while it was hot or move away from the crank and weaken the signal in some way. Its NOT moving now with out taking off that sub bracket that its mounted too.

I still need to measure the resistance on both sensors but I don't have an oscilloscope any way.

So any more suggestions? I'll keep going down the list of possibles i found on clarks garage.

~Alex