THe hole in the blower housing can cause problems, but should be temporary. It will blow hot air onto your ignition control units (the flat computer chip looking things just below the coils). When these get hot, they mess with your spark. When you reinstall your fan, plug the holes and make sure your rubber boot is tight.

 

Loren

I have kind of pinned my hopes on the coils now, I know it is £92.00 for 2 , but it is still cheaper than the 100 mile round trip to my nearest Porsche dealer on a flatbed.
At least i have eliminated a few items when the Coils are fitted , Fingers crossed.

Before i had this non start problem i went on a 800 mile round trip on the return journey i stopped for fuel, then when i went to start the car it would not start, It finally started after an hour, when i got a couple of miles away from back home at the end of my journey i hit the slower roads and the car started to play up, hesitation, kangarooing etc . and that was the last time it drove.

Prior to all that i had some really difficult starts and none starts usually with it attempting to fire , this time is the only time there is no attempt whatsoever to fire.

We will know in a day or 2 one way or another

Colo

Thanks for the tips on tightening all the seals, I noticed also this evening that the wide tube connecting to the housing is a bit squashed and bent and must not have provided a very good seal where it fits into blower housing, I will attempt to even it out with an hot air gun.

I dont know what has happened in there before i owned the car, some people just dont take too much care.
I cant grumble too much i only paid £10k for the car over 3 years ago and have had no real problems or bills up to now , so it has been very cheap motoring up to now.

Dave

 

The ignition output switches will by design get much hotter than the air moving through the rear blower assembly. They are mounted to a heat sink and for proper installation require a heat-conducting paste.

 

Maybe, but that heat sink is pretty small and if the surrounding air is already way hotter than normal, it doesn't really cool the chips.

The day mine cut out on me, the weather was 110+. Couldn't restart it at all. A buddy's Bronco (yeah I know.....Ford P.O.S.) had a recall for its ICUs overheating. So I tried icing the ICUs down, right away I could get it to start. There was zero heat paste on the backs. I also noticed a crimped connector pipe (kinda like what Dave has) blowing a lot of hot air onto the coils so I reclamped the rubber boot, I was back on the road. The combo of colling the uncooled ICUs and keeping the heat off of them seems to work.

When I got back home I did repaste the backs of the ICUs. Dave should do the same - go to Radio Shack or similar for transistor heat paste. And use some hot water or heat gun to reshape the connector pipe.

 

"I have kind of pinned my hopes on the coils now, I know it is £92.00 for 2 , but it is still cheaper than the 100 mile round trip to my nearest Porsche dealer on a flatbed."

A better first approach would've been to use a test light to check for pulsing on the
coils. Then use a LED test light to check the output of the DME ECM for a signal
to the ignition modules from pin 1. The next step would be to check for power
at pins 18 & 37 on the ECM.

"The ignition output switches will by design get much hotter than the air moving through the rear blower assembly."

Jason is correct, i.e. the additional small amount of hot air will have little effect in reducing
the reliability.

 

I have just fitted my new coils and it still wont start, its turning over OK but just wont even attempt to fire.

I wish i would of listened to Lauren, I certainly will from now on, i am just going out to buy a new electrical tester and a test light.

So far i have jumpered the dme relay , changed the dme relay, tested pins 47 and 48 on the dme , and changed the coils.

Does anyone want to buy a pair of coils , maybe i can sell them on ebay,

Can some one tell me what an led test light looks like

Dave

 

How do you feel about going back to the scope ?

 

Indy

Yes i think it is back to the scope,

I have just completed further tests

1 , There is power going to both terminals on both coils

2 , pins 18 & 37 reading 12 .5 Volts

3 , There is power going to 2 of the 5 pins at the ignition module ( i did not record the pin numbers)

 

have you got any leads for the scope ?

 

No leads yet , i will have a look on E-bay , There is nothing local to me i am miles from civilisation or it seems it.

Does anyone know if i can adapt my electrical tester leads or are they special leads for oscilicopes , i know the fittings are different.

Dave

 

I have just completed further tests

1 , There is power going to both terminals on both coils

2 , pins 18 & 37 reading 12 .5 Volts

3 , There is power going to 2 of the 5 pins at the ignition module ( i did not record the pin numbers)

Next, you need to check that the fuel pump relay is energized, i.e. pin 3 of DME.
The key, though, is a signal at pin 1 (spark output).
Just get a LED (light emitting diode) test light. It great for electronic circuits as it won't damage them.

*

 

Loren

I am a bit confused as how to test just one pin ie pin 1 on its own

if it is the signal coming from the DME then the connector would have to be connected, would it not , so how do i test it with the connector connected.

As for the fuel pump test yet again one pin on its own i dont understand how to test it,

I think the fuel pump is pumping as i can smell unburnt fuel when i crank it over, so do i still need to test pin 3

Thanks

Dave

 

"if it is the signal coming from the DME then the connector would have to be connected, would it not , so how do i test it with the connector connected."

Just check at the input to the ignition modules.

 

Lauren

Do you know what colour wire at the ignition module i am looking for.

and i presume its a pulse i look for ?

Dave

I have got an oscilloscope lead coming will one be enough or do i need 2

 

The spark signal from the DME pin 1 is on the white wire.
If you disconnect the DME unit and connect a test light to +12, you can test
the coils & ignition modules by touching the test light end (ice pick) to
pin 1. Each time the test light is touched to pin 1 (NO DME CONNECTED),
the coils will spark (pull the coil wire & place about 10mm from metal engine
pieces).