Porsche Enthusiasts Club Forum

hi all broke downs sat and aa man said ( i had a porsche with the one crank sensor its prob that yours has two ) any way went through the motions before towing me back home spark coil did i have petrol in car ect said sensor gone anyway sunday i had a look at the normal clarks garage google youtube tipec ect and check my sensors via youtube had sort of same readings, anyway the out come of still not starting was cheapest first dme relay which i picked up cheep new today .
Put battery back on as i charged it while car was down put wires back on ecu and cranked her over and she fired up ,
however not one to leave it at that i put my old relay back in and she fired up again i did saw this open as it was completely sealed and put it in sunday with the cover off and got wife to crank her over and pushed the little electro magnet arm but she dident fire up ??
or have i got an intermittent problem elsewhere ?
i am going to run her when i get time at weekend with old one in hoping it gets warm ? or fails ? and doing a relay swop or just breaking down as i want her back as an every other day driver.
thanks for any advise or pointers

Have you removed, cleaned and replaced all the fuses ?

When I had a 944S it had an intermittent fault of just cutting out, usually at the most inconvenient time or place, replaced the relay and all was well afterwards, so for £25 or so its worth keeping a spare in the glove box

Recently the battery was low on my turbo so I charged it, when I reconnected it the car wouldn't fire, jumped the DME relay contacts in the fuse box and it fired straight up then fitted the original relay and it runs. When the jumper wire is fitted the fuel pump sounds louder than with the relay in, not sure if that's normal ?

My Turbo had a non starting issue. At the same time the boost gauge (which would normally sit at 1 Bar with the ignition on and not running) was flickering between 0 and 1 as was a clicking in sync with this. On quite a few occasions I had to tap the DME relay to get it to work. Upon replacing it last summer the issue has yet to return.

I have a spare DME in my glove box and a replacement is only about £20 (I think I read on here).

Porsche prices are often mentioned as being high but one of my other cars is a Quantum 2+2 which is our track day car and its fitted with an Escort RS turbo engine which also suffers from DME failure, however the Ford one is a whopping £50 and I have a spare in the glove box for that one too. It come in a lovely shade of pink though, none of this beastly black

The MkIV Escort relays are known for failing due the amount of current the fuel pump draws on them. And people use those pumps in Triumph PI conversions! Capri 2.8is also used the same relay.

From the dealers a DME relay is £52 although from a specialist a genuine relay can be had for £25.

thanks for the reply guys i will see what happens when i run here over weekend
the dme relay was £ 19.20 from eurocarparts but i got it a bit cheaper, which will stay in glove box till something happens

Yes indeed they are well known for fails. I had the pleasure of owning a TR5 PI which uses the original Lucas pump, which when hot suddenly fails, I got over it by using a copper coil round the pump for the returning fuel to tank and had no more fails.

What specialist can supply DME for £25 for the Ford please? cos its still our track car.

hi all took her out today got as far as five miles before breaking down no difference with relay no spark at plug at mo
while waiting for aa man popped over to asda done some shopping when i came back it fired up but then just stopped,
when he arrived i told him what had happened the week before, i told him other aa man said sensor and he check coil when he got me home last week.
This aa man said prob sensor so i said i assume they either work or don't work then checked for spark at coil and said prob coil ? and had another tow home

I've had this in the past, my DME was only 6 weeks old so went straight to the sensor for the fault.

If you have a multimeter see if you can run on the drive tll it cuts out and then check the readings on the sensor http://www.clarks-garage.com/shop-manual/ign-02.htm

I had a similar experience in a Mk1 2.5 PI after it had a fully rebuilt fuel system. Admittedly it may have later that the refurbishment was nothing more than a lick of paint and that the con merchant does not even warrant being named (his car was fine after he had the same parts refurbished again via a known company, who could not believe he was sold 'refurbished' goods). That is a lovely car though.

Regarding the DME I was referring to the Porsche. AFAIK the Ford item is simply a fuel pump relay. I cannot suggest any cheap sources I am afraid. I went to the iffy way of using a heavy duty switch for the fuel pump in addition to hunting out spare relays from scrap cars (I was not exactly flush at the time and the cars back then were worth almost nothing.

yesterday i had a look at the tdc and speed sensor they seem ok checked 12 volt to coil so just took earth lead off battery as it started after taking off batt last week .
built me a little led tester from bits from maplins using guide from here [url][http://forums.pelicanparts.com/porsche-924-944-968-technical-forum/343212-hiow-test-crank-sensor.html/url]
car started after connecting battery so drove it to front of house and it died with in ten mins so put my little tester in pins 8 27
then 25-26 little tester pulsed while cranking
http://s573.photobucket.com/user/camper ... e.mp4.html
http://s573.photobucket.com/user/camper ... e.mp4.html
but while it was running earlier diesel sprang to mind as it sounds so rough i was actually shocked at the sound of it
http://s573.photobucket.com/user/camper ... e.mp4.html
sorry it was getting dark so i have took earth lead off and will see if it starts for a bit tomorrow.
i have a brand new coil in my garage that says on box not suitable for engines with points ? for use with electronic ignition that has a £2 sticker on it suitable for fords providing the connections are same would it be ok to put on to test when it dies or would i be pushing my luck
thanks

Thanks Alpine Turbo
I thought the relay did more than just a pump, but electrics are not my favourite car parts.

started her up today as got home while it was light but the rattle from engine sounds really rough i was expecting her to die after 5 mins as per breakdowns but never happened.
Just left her running out side house and pulled at wiring loom under dash, left in old dme relay and fan kicked in twice to cool her down any one got any ideas on noise as in little video i posted
thanks