BeerBurner

For the first time in my 19 years, 11 months of 944 ownership, the old girl didn't make it home under her own power today.




It was a struggle to get the car started and would sputter and quickly die at idle. If I could get the engine going, I could hold the throttle at 3k rpm and it did it just fine but as soon as I let off the gas, it would sputter and die.

I recently replaced the vacuum lines but I didn't realize the kit didn't have the parts to do the other air hoses until I was already in there. I got two of them replaced but the rest are still 33 years old. The car was driving strongly until I tried to leave work today when I had to get towed.

I couldn't find any lines falling off in the parking lot but I still think that's my biggest issue. My plan is to take things apart tomorrow and order new hoses for anything else that wasn't replaced. Whether or not they are causing this, they are 33 years old so I should do them anyway.

In the meantime, can you think of anything else I should look at?

(On the plus side, kudos to the tow truck driver for putting the 944 directly in my garage!)

Thanks,
BB.

MAGK944

How old is your ICV and the hoses to it and the AOS?

BeerBurner

As far as I know, original, save for the hoses to the ICV which I was able to replace.

BB.

BeerBurner

Also, my wife (who works just down the road from me) snapped this picture. Both the tow truck driver and I laughed!



BB.

curtisr

A smoke test can help isolate leaks in vacuum lines and other hoses. Best part of this is you can both enjoy the cigar.

BeerBurner

Indeed! I plan on doing that! Although I have to get it running first.

Anyway, I dug into it this morning and couldn't find any hoses that popped off although several of the old hoses do kind of spin around on their nipples and they have those funky clamps that I don't know how to adjust. The J-boot is in good shape and still very pliable.

I started by popping off the distributor cap to check it and the rotor. Everything looked good but I wanted to give it a second look because I didn't feel like I inspected the rotor well enough. This time, one of the cap mounts shattered. So, while I can't say it was the problem before, it definitely is now. Kind of disappointing for a part that's only a few years old.

No fuel came out of the damper and regulator when I disconnected the vacuum lines from them.

I'm going to go ahead and replace all of the other hoses while I've got it apart, as well as the AOS seals, DME temperature sender, and the ICV (I've read that they tend to leak over time and, as best as I can tell, it's original). Hopefully, that will solve any air leak problems. I don't mind throwing a little more money at it now since I plan on keeping this car for a few more decades.

If it still doesn't run, I'll start looking in to the fuel system. But, for now, one piece at a time.

BB.

mahoney944

Could be the ignition coil.

T&T Racing

In my 944 race car, the engine had periodic no start issues, idle and stall, running OK above 2000 rpm.
If the engine starts but stalls, then the first system to test and evaluate is the fuel system.

Your testing indicated that the FRP and FD on the fuel rail are probably OK. So hold off on fuel pressure test

Next are the fuel injectors firing. Remove the fuel rail from the intake manifold and place each injector in a equal volume container. Crank the engine for several seconds and measure the volume of fuel in each container

If no fuel in all containers, then there is low voltage or no voltage to injectors. Could be a failure in DME injector firing, short in fuel injector harness either on the fuel rail or the 12v supply to fuel injector harness. Or, the DME ground is poor.
To check ground, place jumper on negative terminal of battery to the brown lead grounds on the bell housing. Repeat test, If not grounds, then install temporary jumper to 12V supply to fuel harness. Retest test.

I discovered that the 12V supply from DME to fuel injector harness was randoming shortening or grounding, dropping the voltage below pulsing voltage.

If initial test indicates some injectors do fire and others do not fire, then switch good and bad ones. If the good ones do fire and bad ones do not fire, then the fuel injectors should be cleaned and test. SouthBay Fuel Injector Service is very reputable vendor.

BeerBurner

Thanks for the advice. I'll check that next if this doesn't work. I have access to some graduated cylinders that I can use for this test.

Unfortunately, I won't know until next weekend.

BB.

curtisr

Actually, you don't. You just need one of each of these...





And thanks to the friend of every 924s/944 edredas, here's a

how-to video.

BeerBurner

She's back on the road now.

As mentioned earlier, I replaced all of the other air hoses that I could get replacements for and tightened down the ones I couldn't (they were a little stiffer than they should be but no cracks), AOS seals, DME temperature sensor, cap/rotor, ICV (I didn't test it for function but it was definitely leaking when I blew into it) and maybe one or two other little things I'm forgetting about.

I'm a little nervous that I didn't find a smoking gun so, as long as this isn't an intermittent thing, I should be good to go!

Thanks everyone for the help and I hope to not have to make an update!

BB.

Charlie

I had the same thing years ago and the metal fitting where the ISV hose fits to the intake had pulled out of the intake.

Dan Martinic

Hey keep your ICV! Shortly after throwing old one out, I learned about the rebuilding method. As you know, they are pricey

BeerBurner

Indeed. I still have mine and plan on rebuilding it. That ought to guarantee I'll never need it!

BB.

Jfrahm

What do the plugs look like? Maybe it has a blown FPR or damper diaphram.