Thanks Tiger, there's really nothing nearby.

 

Good suggestion Paul, I'd use it but I have all those other parts on the way now. If they don't work I'll try the rubber hose solution. I'm sort of afraid of gas, my Grandfather nearly burned off his right arm cleaning his tractor with gas and a nylon brush. Not something I ever want to see again, certainly nothing I want to experience. I hate gas.

 

Keep a good fire extinguisher (or two) close by anytime you are working on vehicle.
You never know.

 

If you pull the DME relay and jumper terminals 30 and 87b you will hear the fuel pump start to run even without a fuel pressure gauge attached. Obviously checking pressure is better but for ruling out a bad pump you would at least know that.

 

Yeah, that's the next step. I have a DME/Fuel pump relay that should be here today but I'll need to use a jumper test anyway since it's a URO relay and I've been told they're sometimes DOA, so a swap might not be conclusive. Even with that, until I can rig up a gauge that works I won't know if the pump is really working to spec.

What I was really asking though was whether or not having spark and also having injector signals was enough to rule out the Reference Sensor?

 

Oh, this was a quote I found while looking for methods to disable the alarm system. I still don't know exactly what the alarm does to disable the car, but this confirms that turning the key to "start" won't run the fuel pump long enough to hear. It's from a thread at:

http://www.tipec.net/_forums/viewtopic.php?f=25&t=9313


Don't bother listening for the fuel pump ,the pump doesn't run on these cars with the ignition on.

When you first switch the ignition on the DME relay is momentarily energised and the pump runs for less than 1x second. then is switched off by the DME relay de-energising .(This is a safety feature which prevents your car catching fire in the event of a crash etc)

This allows the fuel pump to pressurize the fuel system to 2.5 Bar ready for starting.

The Motronic fuel injection and ignition system is very complicated and it would be pointless trying to explain how it works here.

I also discovered that the instructions for disabling the alarm system written up at Clark's doesn't apply to the S2 and if you follow it blindly you'll burn up the wiring in your car. Just a slightly off topic FYI.

 

MJ; I just wanted to follow up on the jumper results-- the fuel pump didn't come on when jumpered. I raised the car and went to disconnect the fuel pump at the connector just above the fuel filter and found it loose. When I reseated the connector the pump came on.

The car still doesn't start though, so I'm waiting for plumbing parts that will let me attach my pressure gauge to the S2 fuel rail. They might be here today but probably not until next week.

Thanks for the suggestions,

 

Sometimes progress comes in tiny steps...

 

Scott, while cranking the engine, do you have spark at the plugs? Spray at the injectors?

You do not need a gauge to verify fuel pump/pressure...simply pull the rail and check for spray at the injectors while cranking.

Highly doubtful your non-start is due to reduced flow from the fuel pump...as the root cause for a pump-related non-start is usually a non-operational pump. Suspect your issue is either a faulty pump, faulty pump wiring, faulty DME relay part II [switched 12v to fuel pump], or faulty speed sensor/wiring/connector [not closing part II of an operational DME relay].

Keep us in the loop.

 

Mel, certainly will do.

I verified fuel pressure just a few hours ago using the traditional fuel pump gauge method (see attached photo). Most of my uncertainty came from not being able to connect my gauge to the 944 S2 fuel rail. Today I finally received the correct parts and hooked it up.

The summary of my investigation so far is:

- I have spark, demonstrated by one of those "test" plugs.

- I have injector signal, demonstrated by a noid light.

- I have fuel pressure, demonstrated by a 52 psi reading at the rail.

- I have air, demonstrated by injecting ether into the intake and starting the engine.

So where are we now? I've tested everything but the DME, which apparently isn't testable? I'm open to suggestions. I haven't actually tried to start the motor today, so it's possible, after removing and re-installing the fuel filter, I've cleared a problem that was preventing correct pressure at the rail. I'm waiting this evening for the gas I spilled installing and removing the pressure gauge to evaporate before I try starting the engine again.

I should have an update tomorrow, in the meantime all suggestions and guesses are welcome.

Regards,

 

Update: After removing the filter this morning, checking rail pressure this afternoon, I tried starting the car this evening with frightening results.

Nothing caught fire

After letting all the fuel evaporate from removing the gauge on the rial I went out to try starting it. It started right up and ran to about 8000 rpm before I could turn it off; like a rocket. My foot was nowhere near the throttle.

Not really believing what had just happened, I waited a few seconds and turned the key again. Same result.

I checked to see if the carpet or something else was pushing down the gas peddle, nothing. The peddle seems a little low, but I haven't driven the car in two years so it's hard to tell. The throttle cable has some play in it so it isn't stuck or anything.

It just went from "nothing" to "way to much". No idea where to go with this. Too tired to think about it tonight.

At least I know it runs, even though it seems stuck on 11.

'Night all and thanks for listening,

 

Strange...faulty throttle switch/air flow meter, or connector/wiring?

Have you gone anywhere near them over the past few weeks?

 

It turned out to be the throttle cable. When I raised the engine to put in the new mounts the cable got stretched and it pulled the guide sleeve out of the grommet in the firewall. when I dropped it back down the sleeve got stuck outside the grommet and that shortened the cable by about an inch.

I re-seated the sleeve in the grommet and the problem went away.