924Board.org

[badenkb]

HI

My 924 na project trundles on ... but still won't start. Before I start checking every component attached to the engin that may in some way affect the starting - I am hoping that someone will have experienced similar problems and be abel to say - there's your problem mate!!!

Symptoms:

Car tries to fire after first few seconds of cranking - but does not catch. Sounds and behaves like the timing is out.

What's been done so far:

All new fuel lines / hoses
New fuel filter (this helped - but stil wouldn't start). New condenser (I have points in this 77 model) - and I have spark.
Checked injection boots for leaks and enured a tight fit. New injector rubber grommets.

Anyone experienced similar?

I suspect the fuel pump (insuffient delivery ) and its an old pump! but welcome any / ALL advice.

Thanks

Ian
77 924 NA

[AznDrgn]

Check your injector output and your fuel pump output. Sounds like it may be starting up and then starving for fuel and dying.

[numbers]

Pull your cold start valve and see if it is spraying while cranking.

[badenkb]

Hi

Checked fuel pump - plenty of output (over the 750ccs in Haynes in 30 s- near a litre), but little/no output at the injectors...?

I know my cold start valve is non functional, but that wouldn't affect the main injector operations . Any other specific problem areas ? Warm up reg ? Blocked injectors ?


Help please!


Thanks

Ian
77 924 NA

[numbers]

Your cold start valve, is just that, a fuel injector valve necessary for starting the valve when it is cold. If it's not working, the car will try to start and die. To further diagnose, got to your local auto parts and get some cold starting fluid (either). Follow the directions on the can. Just spray it at the air intake horn, while cranking. If car starts, and you can keep it running with the throttle, everything else is OK. Just fix your cold start circuit.

[larso]

Warm up regulator, or fuel pressure. All my CIS cars from europe I have worked on in my life have all started cold without the cold start injector, it just helps your car fire up faster. So it's definately something to do with fuel pressure I think.

[ricomartinez]

This is just a WAG, but here goes...
How long was the car out of commission? I ask because the one I bought had been sitting for about a year or more. About the time I got it someone posted advice on what to do to the fuel system for such a car. I remember one of the tasks was to clean the fuel plate and cycle it through its travel. Good advice for my car. When first moving it, there was a definite resistance until I had cycled it a few times. If the plate is not moving with the airflow, the injectors ain't gonna squirt. Good luck.

[ This Message was edited by: ricomartinez on 2001-12-28 04:03 ]

[badenkb]

HI

Thanks for the comments.
I am thinking now it is something problematic with the fuel distributor/ air flow meter, as I get NO output of fuel from the unit to any of the injectors. If I squirt fuel injection cleaner in the inlet manifold, the engine will kick over, but not hold as there is no fuel coming out of the injectors!
I'll have a look at the sensor arm movement that was mentioned above.

CHeers

Ian
P.S. car out of commission for at least 3 years

[dpw928]

If the gas has sat that long without a stabilizer if may have separated and formed a shellac type coating on the fuel components. The metering slits in the fuel distributor are only about .002" wide, so these would be the most likely problem area. Since this is an area of the fuel system where fuel doesn't circulate, it is doubtful that cleaners would help get you started. You may need to clean or replace the fuel distributor. Cleaning would be fairly simple but you must be careful to note the postion of the head, plunger etc when you are removing them. Let me know at dpw928@prodigy.net if you want detailed instructions. Good luck.

Dennis

[badenkb]

HI All

Update - I striped the fuel sensor unit and cleaned it as best as I could, but this did not help. I still get no fuel out of the unit to any of the injectors.
I managed to pick up a cheap used fuel unit replacement on ebay that I'll swop to see if this improves matters.
As a matter of interest, how much resistance should there be to the sensor arm in the airflow ? Mine moves but is hardly what I would call without resistance. Would it help to strip the movement down and clean all pivots etc ?

Thanks

Ian

[dpw928]

Ian,

If you aren't getting resistance when you move the plate, your control fuel pressure is low. Have you checked for fuel pressure going from the WUR to the top center of the fuel distributor? Have you checked it at the inlet to the fuel distributor (from the filter)? If you are getting fuel to the distributor but not to your WUR your relief valve is stuck and letting all the fuel return to the tank. BTW you did replace your fuel filter didn't you? 8^)

Dennis

[badenkb]

HI

Thanks for the info...but what's a WUR? (sorry if its an obvious question).
Ian

[Zuffen]

Warm Up Regulator

_________________
Bob Dodd - 924turbo@cox.net
931 1982, 944 1982 euro, 924S 1988SE, 93 968 tip 06 Silver Cayenne S, 06 Black Cayenne S

I have Way too many cars, parts for the 931,944 and 951

[badenkb]

HI

Aah! Yes I have fuel to the WUR, but upon checking the pressure relief piston set up, I noticed that mine did NOT have the 0.5 and 0.1 mm shims described in Haynes, but instead had a single shim of about 1mm thickness. Does this suggest that previously an owner has already upped the pressure in the fuel distributor?

Thanks

Ian

[Roger Hall]

Sounds like you are way past this point, but I had a similar problem with my 81 924 and the fuel pump relay was going out.