Porsche Enthusiasts Club Forum

Hi there,
I have been hoping to get an opertunaty to get my bum in a Porsche for longer than I can remember and have always liked 944's but didn't see it happening.
Tonight after work though I went to look at a 1986 944 that has been standing for about 4 years and is a non runner, it's fairly cheap but not cheap enough to just dive in at the deep end.
I'm a mechanic with a lot of years experience and spent a bit of time trying to get it to start but with no luck.
The current owner thought it was something to do with the immobiliser but having traced all of the wiring it would seem that it has been bypassed but there is no spark. There is power to the coil but no pulse on the neg side of the coil.
Not knowing too much about the ignition system on a 944 am I right in thinking it has two crank sensors?
What if anything is the most common thing that could cause no spark?
I really want a944 now I have sat in it and spent some time trying to save it from being broke for spares.
Any help would be great fully received!
Thanks in advance Kris.

I've been rebuilding my 83 944 which was sat for 10 years before I got it. It's been...emotional. It's also worth noting that a lot of parts are quite reasonable but when you venture into engine components prices go up rather significantly due to them being specifically made just for the 944 and not usable on anything else.

First thing to check would be the speed and reference sensor (or crank position sensor). When cranking the engine the tacho needle should bounce, this shows that the ECU is getting a signal from the two sensors and should then provide power to the fuel pump, ignition and injectors. If no tacho bounce try checking the pins on the sensors for resistance as this is a quick easy way to tell if they are dead or not, not conclusive but a good start.

Have a read of this guide and it will tell you where to test the connectors for resistance. http://www.clarks-garage.com/shop-manual/ign-02.htm

If the tacho bounces then change or bypass the DME relay (instructions on Clarkes above), if it doesn't bounce, the crank sensors are likely culprits.

Are you getting fuelat a decent pressure?

Thanks guys that info should come in handy. When I viewed the car the other night I do seem to remember the tachometer did bounce and the crank position sensors had been looked at by someone before me as they where not fitted into the bracket that holds them. I tried swapping them round but still no spark.
Also there was a new looking relay(possibly dme relay) on the passenger seat suggesting that someone has already tried that.
Is it likely that the dme (is that Porsche for ecu?)has failed causing it to not switch the coil?
The coil has ignition feed but does not switch when cranking.
Another question is does the fuel pump prime whilst switching the ignition on or cranking as I didn't hear it at all?
Something is telling me to walk away but something else is desperate to breath some life back into an old car!

Get someone to crank over the engine while you listen to the bottom of the tank (opposite side rear to where the exhaust is) you should hear it running while the engine is cranked.

If you do not hear it, give the bottom of the fuel tank a thump with the side of your fist a few times, if it has been sat, it may well be stuck, thumping it often free's it up and gets it pumping.

If you can hear it, crack off the fuel pressure test point, looks like a big hex nut on the front of the fuel rail, and see if fuel leaks out under pressure, if so, ignore the fuel system, it should at least try to start if it has fuel pressure, even if its not the right fuel pressure (it may well want a fuel pressure reg, especially if it has been stood.)

Listen to the fuel injectors with a screwdriver tip on the body of them, and the handle against your ear, if they are ticking, the ecu is ok (usually)

Check to see if it has a spark at the leads by putting a screwdriver in the plug lead end and laying it across the intake or cam cover... if it sparks, all is well

Take a peek past the timing belt cover and make sure the belt and pulleys are spinning.

Basicly the old rule is true, if it has a spark, fuel and compression, it should run.

Last resort, take the black top off the airflow meter, and while someone is cranking it over, turn the metalic wiper you see that is sweeping across the circuit board track.. try turning it to several positions.

If all this fails, report what you try and what results you get here.

Thanks again for the adivise!
I have decided to take the plunge and bought the car, it is being delivered to my house tomorrow evening.I couldn't let it get broken for spares after spending some time last week trying to breath some life back into it.
Hopefully I won't regret it and it will be a reasonably cheap entry into Porsche ownership.
At least when it is at my house I can remove all the poor aftermarket wiring and put things back to how they should be and hopefully get it running soon.

Good news that another 944 looks like it will be saved. Good luck with the electrickery bits

Right car is now at my house but have had little time to try much else.
Recharged the battery yesterday at work and refitted last night and it does run the fuel pump whilst cranking but no spark. Forgot to check for tacho bounce tough.
I then had the dme out of its bracket and it seems that at some point fairly recently it was probably looked at/repaired by frazerparts. Had the cover off anyway to look for water damage but it looked ok.
After googling last night I found a case of someone with no spark finding that one of the pins on the flywheel had been broken off so guess I need to check things like that as well.
Another issue I found was that where I had been laying over the centre console I had knocked it into gear and then been cranking it over but the car hadn't tried to move.?
Is it common to loose drive somehow? Maybe clutch damper broken or clutch stuck? Or maybe I didn't quite have it in gears even though it felt that way?

Maybe it had not gone all the way into gear?

Could be that at some point someone has pushed down on the clutch peddle while it has been stood and the clutch slave (possibly foobared) has stuck out and the master has drawn in more fluid trying to adjust for it. So in fact your clutch is disengaged, even if the peddle is up! If this is the case, you will not hardly be able to move the peddle down.

Don't think frazerpart rebuild ecu's, but they do sell lots of used bits, so I guess it could be a used ecu that someone has bought. probably to fix this problem.

No spark, how quickly is the engine cranking?

What voltage do you have on the coil?

Have you checked to see if you have a spark at the coil/king lead? Remembering of course that the king lead might have broken down, so make sure you try another lead in there.

Check to see if the rev counter bounces

Thanks Jon,
Tonight when I got in from work I removed all of the non o.e wiring that had been put in for the poor alarm and poor immobiliser so as to eliminate those, still no spark.
I have over 12 volts at the ignition side of the coil and I am checking for a spark at the king lead which is in good order also.
The engine is cranking over at a normal kind of speed.
The tacho flicks up to about 1000rpm when you first start to crank but then does not look like it moves at all, no bounce at all.
The fuel pump can be heard running as I stop cranking.
So far it would seem that someone before me has replaced pretty much everything to do with the ignition apart from the two crank sensors, one of which I can get out of the bracket.
I need to check the sensors next I suppose!

The clutch issue I will have to sort when I get it running but I'm hoping it isn't anything to serious.

Little update!
After worrying that I may not be able to get this car running and that I would never get the time to diagnose the problem, tonight after working late I came home a fitted a new crank sensor and it fired straight up
Well chuffed!
It wouldn't idle as the idle speed control valve pipe work is all perished and split but the engine has good oil pressure and sounds ok.

The DME relay we talk about is not the ECU, it is a seperate relay which controls the ability for fuel and ignition to occur, i believe it looks for a certain speed from the crank sensor, switches and allows fue and ignition, nice to know that you got it going.
A good service and belts would see it happy.
Jim.

Right I have it running now, all be it a bit rough, now I am keen to work out why I have no drive??
It seems that it is selecting gears and the hydraulic side of things feels to have the right amount of travel and resistance but you can let the clutch pedal up in any gear and have no forward/reverse movement.
I had it jacked up this morning before word and the torque tube seems to be connected to the input shaft on the transaxle fine.
The clutch fork and slave cylinder seem to be all the way back away from the clutch, I was hoping to find it stuck forward holding clutch disengaged
Now I'm pretty sure it can only be the clutch fiction plate has no lining material left on it or the rubber centre drive has let go completely??
Someone please tell me It is something else simple and that I don't have to pull the engine or transaxle out!??

You can see from underneath inside the clutch housing via an inspection port (albeit very small) but with a good torch you should be able to see the gap on the clutch plate and possibly if the housing is full of rubber. Might be oil contamination on the clutch plate from the back of the crankshaft seal you should be able to see this if its a big leak. If the car has been standing for so long it might be worthwhile dropping the gearbox and torque tube to change the clutch anyway and while it's off you could do the fuel and brake lines as they will probably be shot.

Cheers for that David I will have another look tonight if I can get under it properly(and safely).
Would be a lot easier if I can get it into the workshop where I work and do it on a ramp though!
The thing that puts me off a bit is the prices I have seen for clutch kits.The car was fairly cheap at £500 but not sure I can justify the same again for a clutch kit.
Is it possible to pull the engine out without too much hassle?