Porsche Enthusiasts Club Forum :: View topic - 944 s2 1989 ..... runs for 20 min .dies .won't start til coo

Temperature sensor maybe?

No it would not cut the ignition but it would run horrid, it's the little blue sensor just below the top hose,

Ok guys thank you so far .....
Changed coil today and checked fuel pressure ...fuel pressure fine...
Coil made no difference ..25 min out like a light ...

What did notice was this !
Once cut out , when turning over the car there is no movement from the Rev counter on cranking !!!
Would this suggest no signal pic up from either of the crank / cam speed sensors ????

solomk1 wrote:

A coconut to Solomk1. Yup knackered sensor or DME. Make sure you can access the connectors & know the connections. Next time it happens meter the sensor itself from memory they should be around 800-900 Ohms each. I bet one will be open circuit. Hot air gun on the sensor may make it kick in earlier.

It won't be the cam sensor, the engine will still run but go into a different injection mode and retard the timing

Has to be the crank sensor that gives the ignition pulse to the ECU

I know this as my cam (hall sender) was broken not just open circuit but smashed and I drove the car 300 miles

ChrisM wrote:

Temperature sensor maybe?

Pls expand on this ...... would this cut ignition / fuel ?

Author:	solomk1 [ Wed Nov 18, 2015 3:47 pm ]
Post subject:	944 s2 1989 ..... runs for 20 min .dies .won't start til coo
Just bought a 1989 s2 ...starts great from cold .. Drives crisp ... Then after say 20 min ..fans cut in ..ticks over etc fine ... Then just cuts out ... Coil fine.. New rotor arm.. New dizzy cap.. Fuel pump 12.8v and quiet. . DME - relay new ..and tested old unit . Once cooled down say 45 min...starts !! Thinking crank timing sensors ...? Can't find pin out for ecu plug to check with multi meter.. Any help please guY's. ..Thank you

Author:	tr7v8 [ Wed Nov 18, 2015 4:47 pm ]
Post subject:	Re: 944 s2 1989 ..... runs for 20 min .dies .won't start til
When it dies you want find out using a neon plug on lead whether you have a spark. I suspect not, in which case crank sensor or wiring to it could be the case. But you need to find out what drops.

Author:	solomk1 [ Wed Nov 18, 2015 4:58 pm ]
Post subject:	Re: 944 s2 1989 ..... runs for 20 min .dies .won't start til
Yeah ..gonna pull a lead and check for spark next ... Have been told potential crank sensor by the previous owner !! Tried to do pin out check on ecu plug to sensors but info I had was incorrect to my ecu plug .. I only have info for 2 row plug ..mine is 3 row ..... !

Author:	ChrisM [ Wed Nov 18, 2015 5:37 pm ]
Post subject:	Re: 944 s2 1989 ..... runs for 20 min .dies .won't start til
Temperature sensor maybe?

Author:	solomk1 [ Wed Nov 18, 2015 5:47 pm ]
Post subject:	Re: 944 s2 1989 ..... runs for 20 min .dies .won't start til
ChrisM wrote: Temperature sensor maybe? Pls expand on this ...... would this cut ignition / fuel ?

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944 s2 1989 ..... runs for 20 min .dies .won't start til coo https://forums.tipec.net/viewtopic.php?f=25&t=20617	Page 1 of 2

Author:	Waylander [ Wed Nov 18, 2015 7:39 pm ]
Post subject:	Re: 944 s2 1989 ..... runs for 20 min .dies .won't start til
No it would not cut the ignition but it would run horrid, it's the little blue sensor just below the top hose,

Author:	solomk1 [ Wed Nov 18, 2015 9:04 pm ]
Post subject:	Re: 944 s2 1989 ..... runs for 20 min .dies .won't start til
Waylander wrote: No it would not cut the ignition but it would run horrid, it's the little blue sensor just below the top hose, The car runs fine as in smooth clean... no excessive fuel or hunting .... coil next ... then speed sensors ...

Author:	solomk1 [ Thu Nov 19, 2015 5:13 pm ]
Post subject:	Re: 944 s2 1989 ..... runs for 20 min .dies .won't start til
Ok guys thank you so far ..... Changed coil today and checked fuel pressure ...fuel pressure fine... Coil made no difference ..25 min out like a light ... What did notice was this ! Once cut out , when turning over the car there is no movement from the Rev counter on cranking !!! Would this suggest no signal pic up from either of the crank / cam speed sensors ????

Author:	tr7v8 [ Thu Nov 19, 2015 7:25 pm ]
Post subject:	Re: 944 s2 1989 ..... runs for 20 min .dies .won't start til
solomk1 wrote: Ok guys thank you so far ..... Changed coil today and checked fuel pressure ...fuel pressure fine... Coil made no difference ..25 min out like a light ... What did notice was this ! Once cut out , when turning over the car there is no movement from the Rev counter on cranking !!! Would this suggest no signal pic up from either of the crank / cam speed sensors ???? A coconut to Solomk1. Yup knackered sensor or DME. Make sure you can access the connectors & know the connections. Next time it happens meter the sensor itself from memory they should be around 800-900 Ohms each. I bet one will be open circuit. Hot air gun on the sensor may make it kick in earlier.

Author:	solomk1 [ Thu Nov 19, 2015 7:56 pm ]
Post subject:	Re: 944 s2 1989 ..... runs for 20 min .dies .won't start til
tr7v8 wrote: solomk1 wrote: Ok guys thank you so far ..... Changed coil today and checked fuel pressure ...fuel pressure fine... Coil made no difference ..25 min out like a light ... What did notice was this ! Once cut out , when turning over the car there is no movement from the Rev counter on cranking !!! Would this suggest no signal pic up from either of the crank / cam speed sensors ???? A coconut to Solomk1. Yup knackered sensor or DME. Make sure you can access the connectors & know the connections. Next time it happens meter the sensor itself from memory they should be around 800-900 Ohms each. I bet one will be open circuit. Hot air gun on the sensor may make it kick in earlier. Lol..A coconut thank you .... Can you clarify which sensor does what pls .. Flywheel ....crank timing ... spark issue..? Cam sensor ...tdc....? I'm really concerned about it being ecu !! $$$$$.. ££££ I can take a couple more sensors lol.. Cheers ..... Jim ( coconut dispenser )

Author:	Waylander [ Thu Nov 19, 2015 8:22 pm ]
Post subject:	Re: 944 s2 1989 ..... runs for 20 min .dies .won't start til
It won't be the cam sensor, the engine will still run but go into a different injection mode and retard the timing Has to be the crank sensor that gives the ignition pulse to the ECU I know this as my cam (hall sender) was broken not just open circuit but smashed and I drove the car 300 miles

Author:	solomk1 [ Thu Nov 19, 2015 8:43 pm ]
Post subject:	Re: 944 s2 1989 ..... runs for 20 min .dies .won't start til
Waylander wrote: It won't be the cam sensor, the engine will still run but go into a different injection mode and retard the timing Has to be the crank sensor that gives the ignition pulse to the ECU I know this as my cam (hall sender) was broken not just open circuit but smashed and I drove the car 300 miles That my good man is where my head was at too... Wish it was the other way for ease of fix / less fragile ..but hay Ho ...nothing good comes easy .... Thank you

Author:	Waylander [ Fri Nov 20, 2015 9:13 am ]
Post subject:	Re: 944 s2 1989 ..... runs for 20 min .dies .won't start til
The crank sensor is also used in old volvos 740,760 you might find one of those a bit cheaper

Author:	RH944 [ Fri Nov 20, 2015 12:49 pm ]
Post subject:	Re: 944 s2 1989 ..... runs for 20 min .dies .won't start til
solomk1 wrote: ChrisM wrote: Temperature sensor maybe? Pls expand on this ...... would this cut ignition / fuel ? I can drive mine for 20 minutes and occasionally it will then cut out. Porsche Mid Sussex didn't belief me and left the car running on a ramp for 40 minutes before it suddenly died without notice. They advised there was a sensor at the front of the block underneath the inlet manifold. Only a £30.00 part but seems to have cured the problem. That is on a 1982 model. Don't know if differnet on an S2

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Author:	tr7v8 [ Fri Nov 20, 2015 1:05 pm ]
Post subject:	Re: 944 s2 1989 ..... runs for 20 min .dies .won't start til
Yes S2 & the S are completely different, they changed the management totally with the 16V lumps.