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TQ: Cutting out

PaulHere

PaulHere

PCGB Member
Member
Member technical question:

I have recently bought a 1981 924turbo (series 2?), which has been stood for a while. The car seemed fine but had an annoying start then cut-out problem. It doesn't start at all now! I have had a specialist diagnose a faulty/knackered pulse sensor/crank angle sensor, but I cannot get a replacement one for love nor money. Is there a similar size one out there used on a different car which might just need spacing with washers or have I just bought a lovely looking (expensive) piece of (s)crap! Someone please help me. This car deserves a better end than this.

Nick Kenealy
 
Unfortunately for Nick the crank angle sensor is made from unobtanium, and I have even been on the 'phone to Siemens who made the sensor and the numders on it don't mean anything to them now either. The are a couple of things to check before condemning the sensor though, as unlike the 944 they don't often fail. Touch wood, the one on mine has done 184,000 miles. Locate the ecu under the heater matrix and check that the plug is not damp, or have any corroded terminals, 924s can leak from a number of places. Also check that it is pushed all the way home.

Next, check that the cluster of earths bolted to the left, or rear (depending on viewpiont) of the throttle body is tight as the car will run erratically and cut out if there is an intermittent earth here.

A number of people break turbos and have parts for offer on ebay. I have never seen a sensor offered so someone may have one sat at the back of their garage/shed. Try traders 'franklinhill porsche' as I know he is breaking a turbo, I have just put the gearbox in mine, 'southcoast porsha', who buys to break and 'porsche-9xx'


Stroke of luck, go here;

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=10408&item=4548667168&rd=1

email the seller, he may have a sensor for sale.
 
If it is any help, the Siemens part number for the ditc unit itself is 5 WK 1664, so if you have to buy a second hand one complete to get the sensor make sure the number is correct because there are four types depending on the country of origin of the vehicle.

 
Response from Nick:

Thanks for that. I had already tried at least 15 breakers and a number of other specialists as well! The sensor has gone. There is no magnetism at all and the resistance ha totally gone to pot. I had already spoken to the chap selling the DITC on ebay as well and he has given me the part number of 931.602.071.00 for his unit, the one on my car finishes with 01 so I am presuming that it is a different module. But, the other siemens number of 5wk1 664 is the same!. Does anyone out there know about this? He also said that he would have a look to see if the sensor is still with the remains of the car, but again, I am presuming that his is a series 1 being a 1980 car, and mine a 1981 car. It has a different number on the DITC but I don't know if the sensor is different.

I am a man in great need of a drive in this car as I bought it in the mot station where it was purring and having a perfect MOT test. Unfortunately it stopped as it was being brought out of the garage and has not run since! So if I cant get the sensor, maybe there is someone out there who knows about possibly changing the whole starting system for a modern one that spare parts are available for!

A greatly appreciate your help in this and any information to do with this car would be really appreciated.

Thanks again,

Nick K
 
Crikey, I feel sorry for this guy. That sounds like a real frustrating purchase with it sat there and he can't go nowhere, but with Nutter on the case we know it'll work out OK.

Phil

(sorry, that's of no help at all in getting his motor to run.....)
 
you might want to invest in this to see if works. Its gonna be trial and error.

go to< http://rswww.com > and tpye in 304-166 in the 'search for' box
 
Update. my electrician is going to havea poke about on the internet. It doesn't have to be a seimens sensor, but we need it capable of sensing at over 1 Mhz. The best we have seen so far is 20Khz
 
5wk 1664 is ditc part code for Europe and the rest of the world except;
US, Canada and Japan 5wk 1665,
Sweeden 5wk1668

Carerra gt 5wk 1666.

If it was my business I would have one sensor and programme the ditc modules differently.
 
You couldn't easily use a conventional system on the turbo as many systems sense the vacuum in the inlet manifold, either before or after the throttle body, but the vacuum disappears in the turbo as it goes on boost.

An option might have been to source a Bosch 009 distributor which is centrifugal advance only and go with contact breakers, but you are faced with another problem of actuating the fuel pump relay. Early c/b ignition 924s had an earth on the airflow sensor which actuated the pump when broken by the lifting of the plate, but later 924s derived a signal from the coil to a terminal on the fuel pump relay.
 
I have found different Siemens site (Siemens automotive) and on behalf of the club, emailed them for any info about the sensor or anything that may be compatible with the 5wk 1600 series of ditc modules, as this is going to become an ever worsening problem for 931 owners, as the supply of even good secondhand sensors dries up. Awaiting a reply
 
Thanks John.

Nick Kenealy rang me a day or so ago and he's desperate to get his car running - an alternative electronic gadget to replace this unobtainable part would be of great benefit to the very survival of the 924 Turbo itself! [&:]
 
If the worse comes to the worse he can revert to contact breaker igntion from an early 924, nothing simpler. He would need to fit an intercepting relay to the coil l.t. feed such that when the overboost switch operated(which is an earth breaking type switch) the relay would drop out cutting the ignition. He would probably have to remotely mount an early fuel pump relay and rig some kind of earth to the sensor plate so that as the plate deflected, breaking the earth, the pump operates. This was a feature of early 924s with breaker ignition. Later models derived a signal from terminal one on the coil to terminal 1 on the relay to enable it, as, I have oft writ, to prevent the pump from running until the engine was turning. A bosch 009 distributor would be preferable as it is centrifugal advance only, remember the turbo has no inlet vacuum when the turbo comes on boost. This would not be ideal but the engine should run. I will give the guy I bought the box from a ring to see if he has a proper sensor.

As yet I have had no reply from Siemens.
 
Update. One is one the way to me for £20 + £5 p&p. Payment confirmed by paypal so the deal is done. I expect it to arrive Tues Weds next week. I am making nothing on this deal.
 
You folks are all fantastic! This means a lot to me, and my turbo! I cannot wait to get out there for a drive.

Thanks again all!

Nick
 
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