Intermittent Starting issue... 3.2 Carrera
Discussion
Hi chaps, sorry, this is a long drawn out tale of woe...
...another of those annoying and potentially endless problems...
I had an alarm and immobiliser fitted on my 3.2 a couple of weeks ago... and on top of that Ive been out of the UK for a couple of months, so the car has sat in the garage with very little attention.
First problem occured when my mate attempted to start the car after having not done so for a couple of weeks prior to the alarm fitting, with a 24 hour charge the car started fine and the alarm fitters collected the car and it obviously started without issue.
Once the alarm was fitted they tried to start the car and it wouldnt, they replaced the fuse to the fuel pump (corroded) and it started no problem. So the car was placed back in my garage and left for a week til I arrived back in blighty to collect.
When I arrived to collect the car it was really struggling to turn over, and only on the last throws of the battery did she kick into life... I didnt have chance to go for a blast as it was already 2.00am and I needed my bed. Next morning same problem but this time battery didnt have enough left. I got a jump start off a mates car and again she fired up fine...
So, I assume this is a battery issue and replace with a new one - It starts fine after fitting and I fill up with hi-octane and start at the garage fine too... Then to my parents and turn car off set alarm and leave for an hour..... This time when I go to start it just turns over and over and doesnt fire... I leave it again for ten minutes and lock it up again, when I return again she starts... So this time I go for a good blast round the local bypass and make sure that everything seems normal, which it does...
I park up in town and leave for a while, come back and same starting problem, this time I phone for recovery and he fiddles under the bonnet (engine) and it starts instantly...
Having left the car with Matt and Autowerke in Norwich for the whole of Monday he cant get it to show any issues, starts on the button every time (the alarm fitter even came down to the workshop and explained his work etc)! When I turn up to collect it she doesnt start typically, although now he has all the guages removed that he was checking the fuel pressure with...Sods law!!! Anyway, he also sticks his hands under the bonnet and it starts again...
So, I am in the hideous situation of having to travel back out of the UK in my daewoo, and the Porsche is sat in the Uk with an unidentified intermittent problem.
Has anyone come across this before, can you point me in the direction of a likely fault (without jumping to the conclusion that its the alarm which I still havent ruled out obviously).
Somebody please help, the shame is almost unbearable and I need to show some of these belgians how to drive...
Cheers
Dom
...another of those annoying and potentially endless problems...
I had an alarm and immobiliser fitted on my 3.2 a couple of weeks ago... and on top of that Ive been out of the UK for a couple of months, so the car has sat in the garage with very little attention.
First problem occured when my mate attempted to start the car after having not done so for a couple of weeks prior to the alarm fitting, with a 24 hour charge the car started fine and the alarm fitters collected the car and it obviously started without issue.
Once the alarm was fitted they tried to start the car and it wouldnt, they replaced the fuse to the fuel pump (corroded) and it started no problem. So the car was placed back in my garage and left for a week til I arrived back in blighty to collect.
When I arrived to collect the car it was really struggling to turn over, and only on the last throws of the battery did she kick into life... I didnt have chance to go for a blast as it was already 2.00am and I needed my bed. Next morning same problem but this time battery didnt have enough left. I got a jump start off a mates car and again she fired up fine...
So, I assume this is a battery issue and replace with a new one - It starts fine after fitting and I fill up with hi-octane and start at the garage fine too... Then to my parents and turn car off set alarm and leave for an hour..... This time when I go to start it just turns over and over and doesnt fire... I leave it again for ten minutes and lock it up again, when I return again she starts... So this time I go for a good blast round the local bypass and make sure that everything seems normal, which it does...
I park up in town and leave for a while, come back and same starting problem, this time I phone for recovery and he fiddles under the bonnet (engine) and it starts instantly...
Having left the car with Matt and Autowerke in Norwich for the whole of Monday he cant get it to show any issues, starts on the button every time (the alarm fitter even came down to the workshop and explained his work etc)! When I turn up to collect it she doesnt start typically, although now he has all the guages removed that he was checking the fuel pressure with...Sods law!!! Anyway, he also sticks his hands under the bonnet and it starts again...
So, I am in the hideous situation of having to travel back out of the UK in my daewoo, and the Porsche is sat in the Uk with an unidentified intermittent problem.
Has anyone come across this before, can you point me in the direction of a likely fault (without jumping to the conclusion that its the alarm which I still havent ruled out obviously).
Somebody please help, the shame is almost unbearable and I need to show some of these belgians how to drive...
Cheers
Dom
Well it may be totally un-related. I would bypass the immobiliser and disconnect the alarm and run it for a few days to check.
It could be a fuel pump relay and sometimes when this happens it messes upo the fueling and then you have a flooded engine, which then magically cures itself.
In IT when a change breaks a system we back it out and investigate bringing in the new systems little bit by little bit so you can back out as above, then bring in the alarm, leave for a few days then bring in the immobiliser.
Good Luck
It could be a fuel pump relay and sometimes when this happens it messes upo the fueling and then you have a flooded engine, which then magically cures itself.
In IT when a change breaks a system we back it out and investigate bringing in the new systems little bit by little bit so you can back out as above, then bring in the alarm, leave for a few days then bring in the immobiliser.
Good Luck
graeme73s said:
I gaurantee its the DME relay. Go and buy a couple so you have a spare. One of the guys that works for me bought an 86 3.2 carrera a few years back and for some strange reason the car seems to burn them out regularly.
So, for the layman - what is a DME relay...?
Its worth bearing in mind that Matt at Autowerk will have checked the 'obvious' points of fault, he had some guages on the car and attempted to recreate the problem to see if there was a fuel pressure issue - sods law, it wouldnt play up whilst he had the guages attached
!!! I am still really concerned that this is going to turn into a hideous wiring issue following the alarm fitting and continue to have this glitch until some major surgery is performed... I really hope this isnt the case because reliability wise this car has been an absolute dream, I did have an engine rebuild which turned into a bit of a monster job, but this was by choice as I wanted to prolong the life of my P&J for as long as possible...
Dom
graeme73s said:
I gaurantee its the DME relay. Go and buy a couple so you have a spare.
Ditto! Mine had an intermittent start problem when i bought it, though not quite the same as yours and it was the relay. The DME relay is under the pasenger seat and apparently very easy to swap, so i always have the spare in the glovebox just in case. They are not too expensive.
However, as has been suggested... disconnect the alarm and run it for a while without and see if that is the problem.
graeme73s said:
I think from memory the relays about a tenner from Porsche and you'll need a 10mm spanner to unbolt it,
cheers Graeme
cheers Graeme
You chaps could have just hit upon the very thing - I asked the company who fitted the alarm to check my passenger side seat electrics as the forward/backward motion was not functioning. I will phone Matt in the morning and ask him to test this theory and I have my fingers well and truly crossed for a swift and inexpensive fix to a very frustrating problem!!!
Heres hoping!!!
Cheers chaps!
Dom
A911DOM said:
graeme73s said:
I think from memory the relays about a tenner from Porsche and you'll need a 10mm spanner to unbolt it,
cheers Graeme
cheers Graeme
You chaps could have just hit upon the very thing - I asked the company who fitted the alarm to check my passenger side seat electrics as the forward/backward motion was not functioning. I will phone Matt in the morning and ask him to test this theory and I have my fingers well and truly crossed for a swift and inexpensive fix to a very frustrating problem!!!
Heres hoping!!!
Cheers chaps!
Dom
Update: Sadly, and as I kind of suspected, Matt at Autowerke already swapped the relay, so this is not the quick fix I was hoping for... I really hope this doesnt drag on, without a proper problem there consistently its really difficult to sort it...
Any more suggestions welcomed...
burriana said:
graeme73s said:
I gaurantee its the DME relay. Go and buy a couple so you have a spare.
Ditto! Mine had an intermittent start problem when i bought it, though not quite the same as yours and it was the relay. The DME relay is under the pasenger seat and apparently very easy to swap, so i always have the spare in the glovebox just in case. They are not too expensive.
However, as has been suggested... disconnect the alarm and run it for a while without and see if that is the problem.
Are you positive the DME relay has been changed ?
They are about £25 from
www.type911.co.uk
in Beckenham
My 3.2 presented in exactly this manner. I think it probably scared the last guy off, because it wouldn't start sometimes.
Did it on me, and I felt absolutely lost, didn't know where to start [pun not intended]
DME just plugs in, no bolt as I recall. Under the passenger seat for RHD cars.
Double check mate, it sounds as if your chasing your tail !
Okay, I will try that again - problem being location at the moment as Im in Belgium and my beloved car is in the UK. I will speak to my usual mechanic and ask him to look at the three possible minor issues as highlighted by the good folk of Pistonheads and then I'll begin to panic again... I want to be chasing the beemers down the motorways here not my bl00dy tail
Thanks again for the responses.
Dom
Thanks again for the responses.
Dom
My 911SC is experiencing exactly the same problem at the moment. It always seems to not start at damn petrol stations. The embarrassment of having to be pushed out of the way is hurting beyond belief.
I think my prob is immobiliser related as the LED seems to flash inconsistently during the non starting phase. However, I will be changing the DME and fuel pump relays just to eliminate them from the equation.
Damn annoying.
I think my prob is immobiliser related as the LED seems to flash inconsistently during the non starting phase. However, I will be changing the DME and fuel pump relays just to eliminate them from the equation.
Damn annoying.
993SC said:
My 911SC is experiencing exactly the same problem at the moment. It always seems to not start at damn petrol stations. The embarrassment of having to be pushed out of the way is hurting beyond belief.
I think my prob is immobiliser related as the LED seems to flash inconsistently during the non starting phase. However, I will be changing the DME and fuel pump relays just to eliminate them from the equation.
Damn annoying.
I think my prob is immobiliser related as the LED seems to flash inconsistently during the non starting phase. However, I will be changing the DME and fuel pump relays just to eliminate them from the equation.
Damn annoying.
I know how you feel, I thought my problem had decided to go away whilst I was back in the UK so I parked outside a restaurant I had only eaten in about an hour before to pop into town...Oh how they loved watching as my car refused to start and I had to wait for the recovery guy to come and rescue me.... awful...
Its not the actual buying of a 911 thats hard. What's a really good Carrera worth, £15k ?
They are not that dear. Plenty of cars cost more new.
You've got to really hold your nuts in your hand when you buy one.
It's the dealing with them when they fail.
I've had the same experience with intermittent start.
People love seeing it not start. Cringingly bad.
DME failure on these year 911's is well covered on the net.
Hope this helps.
They are not that dear. Plenty of cars cost more new.
You've got to really hold your nuts in your hand when you buy one.
It's the dealing with them when they fail.
I've had the same experience with intermittent start.
People love seeing it not start. Cringingly bad.
DME failure on these year 911's is well covered on the net.
Hope this helps.
Edited by stuttgartmetal on Tuesday 10th October 11:46
stuttgartmetal said:
I "wished" mine started once.
You know the deal.
It wouldn't start trying every 15-20 mins.
"Okay, if you start I promise I'll...etc etc."
It started. Was spooky though.
Amazing when its fixed.
You know the deal.
It wouldn't start trying every 15-20 mins.
"Okay, if you start I promise I'll...etc etc."
It started. Was spooky though.
Amazing when its fixed.
Stutt',
Thanks for that really helpful illustrated DME article, I feel better armed to go and question the diagnosis on my car thus far. I'll phone my mechanic in the morning and actually talk through some of this to ensure he has COMPLETELY ruled out these popular issues.
I got the the 'praying' stage with mine, sadly the recovery guy must have had stronger faith than me cos it just wouldnt answer to my pleas....
I'm sorry I couldn't be more forthcoming before. It would have taken more words than I had the time to generate. Now that someone has posted the circuit, it's easier.
You can see that Pin 20 drives the DME fuel pump half of the relay pair and when. Mine was intermittent like this, and it was down to more than just the relay, which I replaced more than once.
I think the source of the problem is that pin 20 is not protected against the EMC and spikes that are seen due to it driving a relay coil. The output eventually dies, but intermittently, as is common in this failure mode for transistors.
What I did, isnt necassarily the best because it takes away any protection you may get with regard to a stall fuel cutoff, but it does work. The problem never returned, and it was much cheaper than a new DME box.
Remove completely the black and white wire between pin 20 and 85b. Connect a new wire between 85b and Chassis Ground.
The proper solution for me would have been to replace the DME main box, and fit a beefy 25V zener and series resistor down to ground from pin 20. A sligtly different way of doing the same is to put a beefy diode across pin 85b and pin 87.
It seems crazy to me that for a pair of relays in one box, that one has proper protection and the other not!
Edited to remove glaring error!
You can see that Pin 20 drives the DME fuel pump half of the relay pair and when. Mine was intermittent like this, and it was down to more than just the relay, which I replaced more than once.
I think the source of the problem is that pin 20 is not protected against the EMC and spikes that are seen due to it driving a relay coil. The output eventually dies, but intermittently, as is common in this failure mode for transistors.
What I did, isnt necassarily the best because it takes away any protection you may get with regard to a stall fuel cutoff, but it does work. The problem never returned, and it was much cheaper than a new DME box.
Remove completely the black and white wire between pin 20 and 85b. Connect a new wire between 85b and Chassis Ground.
The proper solution for me would have been to replace the DME main box, and fit a beefy 25V zener and series resistor down to ground from pin 20. A sligtly different way of doing the same is to put a beefy diode across pin 85b and pin 87.
It seems crazy to me that for a pair of relays in one box, that one has proper protection and the other not!
Edited to remove glaring error!
Edited by dilbert on Tuesday 10th October 20:05
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