dme relay ?
11-08-2008, 07:18 PM
#1
dme relay ?
i posted a few days ago about my car issue...my question is..my car would not start,my tech said it sounded like a relay..i have not received the relay yet..the cranks,but doesnt fire up...well i took the relay out..cleaned it a bit and it started...and today it would not start..so i figured i would give it a jump..and it started..my ? is this...if i need a dme relay, and the car wont start cause of it...why does it start with a jump...thanks..j
11-08-2008, 08:15 PM
#2
Rennlist Member
When relays go bad they tend to be intermittent, so the results you are getting are not suprising, the dme relay controls the ignition and the fuel pump, so generally the motor will crank but not start with a bad one. You can bypass the relay by jumpering the contacts if you want to confirm it's bad, just do a search on DME relay.
11-11-2008, 08:12 PM
#5
Three Wheelin'
I had the same experience with you where I went to the mall and when I cam out, the car wouldn't start. I towed it to my mechanic and it started and worked fine. Then it started intermittently dying on me. Now I keep a spare of all relay types in my glove box.
11-15-2008, 09:45 AM
#7
Rennlist Member
Trending Topics
11-15-2008, 08:38 PM
#8
Instructor
Joey C,
Glad to see that the DME was your issue. As an 'additional info' item, know that this Relay is actually two Relays in one package and that both of these Relay's coils are always 'hot/engaged' when the car is running. This explains why the DME is usually suspect #1 - in short, it NEVER sleeps while the car is running. Only when the car is off & parked does this Relay get a chance to snooze.
Other Relays usually live a life of an 'on/off' sort. Lights? A/C? Coils only powered when the system is on. DME? Coils ALWAYS powered when the engine is running and, over time, that can take it's toll.
It's not that the DME Relay is badly designed or a cheap part, it's just that it's probably the hardest working Relay in your Porsche's electrical system - hence the general advice of always having a spare in the car.
Cheers!
Barry
Glad to see that the DME was your issue. As an 'additional info' item, know that this Relay is actually two Relays in one package and that both of these Relay's coils are always 'hot/engaged' when the car is running. This explains why the DME is usually suspect #1 - in short, it NEVER sleeps while the car is running. Only when the car is off & parked does this Relay get a chance to snooze.
Other Relays usually live a life of an 'on/off' sort. Lights? A/C? Coils only powered when the system is on. DME? Coils ALWAYS powered when the engine is running and, over time, that can take it's toll.
It's not that the DME Relay is badly designed or a cheap part, it's just that it's probably the hardest working Relay in your Porsche's electrical system - hence the general advice of always having a spare in the car.
Cheers!
Barry
11-17-2008, 08:41 PM
#10
Instructor
Joey C,
How long do they last? If you have a spare the installed one will last forever! No spare? Look for about 3 days... ;-)
Actually they do last for many years (10+ ? at least). The one that came in my car has been fine since the car's purchase in 2002 and my car's a daily-driver so it definitely sees a high level of usage. It's definitely NOT a replace every n-Years/Miles kind of thing as far as I know.
Just keep that spare in the glove (along with various fuses and bulbs), research how to change it so you know how and you'll be ready if one of the two coils in the DME shorts out or succumbs to a bad/loose solder joint.
If you're electrically inclined, I'd also suggest adding an inexpensive Digital Volt/Ohms Meter (DVOM) and a battery powered soldering iron w/some electrical quality flux-core solder to the tool kit. Good things to have when you're on a long trip!
Cheers!
Barry
How long do they last? If you have a spare the installed one will last forever! No spare? Look for about 3 days... ;-)
Actually they do last for many years (10+ ? at least). The one that came in my car has been fine since the car's purchase in 2002 and my car's a daily-driver so it definitely sees a high level of usage. It's definitely NOT a replace every n-Years/Miles kind of thing as far as I know.
Just keep that spare in the glove (along with various fuses and bulbs), research how to change it so you know how and you'll be ready if one of the two coils in the DME shorts out or succumbs to a bad/loose solder joint.
If you're electrically inclined, I'd also suggest adding an inexpensive Digital Volt/Ohms Meter (DVOM) and a battery powered soldering iron w/some electrical quality flux-core solder to the tool kit. Good things to have when you're on a long trip!
Cheers!
Barry
