83 944 - Engine turns over but doesn't catch

[AwesomeIsLuke]

Hello all, I just sold my car and am looking for a new one. Being a former BMW owner, I've always been fascinated with Porsche as well so I've been keeping my eyes open for older models.

I just went to look at a 944 that I'm interested in buying. The engine turns over and tries to fire, and will sometimes keep running for a few seconds if the gas is held down, but it won't idle without help. The seller is a mechanic and builds racecars, so he knows his way around cars but has another 944 and is trying to get rid of this one.

He has already replaced the fuel pump, fuel pump relay, distributor cap and rotor, the starter, and the fuel filter. All cylinders have good compression (185-190 psi). He thought the plug wires might be bad, so I took a multimeter with me and two of the wires checked out normal (9k-10k ohms) and the other two read pretty low (3k-4k ohms). I assumed this was the problem, but when we swapped wires from his working 944 and they seemed to help the cylinders fire but it still wouldn't really hold an idle. When I checked those wires afterwards, they read about the same resistance as the originals so I'm pretty much assuming that 3k-4k ohms for those shorter wires is about normal. On top of all that, it appears that the engine has under 70k miles because some of the old receipts show similar mileage.

He said that the car had been sitting for about 2 years and he never put new gas in (just a can of Seafoam) so I'm thinking that probably has to do with it. Are there any sensors or anything else that might give me the issue I'm having? Injectors and the plugs themselves also come to mind, but I'm thinking at this point that the gas is just completely stale but I figured you guys would know better than me.

Besides that, the car is in pretty good shape as far as I can tell. It isn't immaculate by any means but it's a neat car for sure. The guy wants $1200 for it which is a steal if all I have to do is get new gas and/or plugs, but I don't want to buy the car and realize that something much larger is at play.

Anyway, thanks in advance for any advice you can offer me,

Luke

[Rdward]

Hello all, I just sold my car and am looking for a new one. Being a former BMW owner, I've always been fascinated with Porsche as well so I've been keeping my eyes open for older models.

I just went to look at a 944 that I'm interested in buying. The engine turns over and tries to fire, and will sometimes keep running for a few seconds if the gas is held down, but it won't idle without help. The seller is a mechanic and builds racecars, so he knows his way around cars but has another 944 and is trying to get rid of this one.

He has already replaced the fuel pump, fuel pump relay, distributor cap and rotor, the starter, and the fuel filter. All cylinders have good compression (185-190 psi). He thought the plug wires might be bad, so I took a multimeter with me and two of the wires checked out normal (9k-10k ohms) and the other two read pretty low (3k-4k ohms). I assumed this was the problem, but when we swapped wires from his working 944 and they seemed to help the cylinders fire but it still wouldn't really hold an idle. When I checked those wires afterwards, they read about the same resistance as the originals so I'm pretty much assuming that 3k-4k ohms for those shorter wires is about normal. On top of all that, it appears that the engine has under 70k miles because some of the old receipts show similar mileage.

He said that the car had been sitting for about 2 years and he never put new gas in (just a can of Seafoam) so I'm thinking that probably has to do with it. Are there any sensors or anything else that might give me the issue I'm having? Injectors and the plugs themselves also come to mind, but I'm thinking at this point that the gas is just completely stale but I figured you guys would know better than me.

Besides that, the car is in pretty good shape as far as I can tell. It isn't immaculate by any means but it's a neat car for sure. The guy wants $1200 for it which is a steal if all I have to do is get new gas and/or plugs, but I don't want to buy the car and realize that something much larger is at play.

Anyway, thanks in advance for any advice you can offer me,

Luke

I had an 83 944 that had sort of the same problem. It took me a while to find the problem, but after throwing parts at it I finally found the problem. The return fuel pressure regulator was stuck open. I'm not saying this is your problem, but it could be. The easy way to check is by clamping off the return fuel line while you are cranking the car, then release it after it starts. The 2 year old gas doesn't help much either. You can do this regulator check with just a clamp.

I've owned several 944's and I would suggest you look at 85 1/2 and newer cars. These newer models are much more reliable as far as the electrics go and the interior is much nicer. The $1,200 sounds good but I've seen newer ones for $1,500 that might need the same work that you'll end up doing to this car. That is if your looking for a project car. I actually paid $2000 for my current 88 944s. It needed work but it wasn't a POS.

Just my opinion,

Robert

[lupdiesel]

I did some checking on iATN and from what your describing sounds like stuck injectors or a failed fuel pressure regulator. You really need to get a fuel pressure gauge on it. When the fuel pressure regulator fails, it usally has too much fuel pressure. I'm talking over 100 PSI. For some reason, I've seen several posts that were a no start untill one injector was unplugged and then it fired up. Replacing the fuel regulator was the fix for all these. I'm not for sure what the relationship between unplugging one injector and the fuel pressure regulator being bad.

As far as the possible stuck injectors, you could try and tap on them ro see if they free up. Anything further than that, I would think they would need to ben removed and cleaned on a flow bench.

Hope this helps,

Kyle

[bukzin]

Good tips.

 

what is iATN, by the way?

[Loren]

43 minutes ago, bukzin said:

Good tips.

 

what is iATN, by the way?

 

iATN = International Automotive Technicians Network