need some dme relay diag experts
#1
Racer
Thread Starter
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i seem to have a starting issue today.I will give you guys some back ground that lead up to this post.I"ve been driving this car as my daily driver and had some electrical gremlins pop up along the way since the beginning of may when i got the car most have been sorted out.
It's been raining here in edmonton on and off for a week with some heavy and some drizzle but car has always started up.Last night drove it to a nephews bday party and it sat outside in some heavy rain.when i left it took 2-3 attempts at cranking but it sdtarted and drove fine.i got home parked it and left it.today i go to leave and my battery is completely dead.look over and saw my fog light switch had been left on.so i through the charger on it and it turned over nicely but would not fire.so i left it on the charger and proceeded to read some posts and checked the distributor for moisture. so well i'm there pull each spark plug lead off and put dielectric grease on each coonector to create a water barrier for the rain.tried to start it again no luck drained the battery again.So i hooked up my truck to boost it and eventually it started.took it for a spin after letting it idle for 20 min came back pasrked shut it off and tried to start it again and a repeat of previous problem turns over but no fire .Back to reading and tried jumpering the dme relay pin 30,87,87b.here the fuel pump come on go turn it over and bang she starts.
Now before you guys say it"s obvious dme has seen better days let me say i tried swappimg with some new ones i got from rock auto which were uro relays and it didn't help so did i buy 2 piece of crap relaysd which were $10 a piece or could there be another explanation for it?
if the dme are garbage where can i get better and more reliable ones to try and have as spares?
I apologize for the long winded story but thought it might help.
It's been raining here in edmonton on and off for a week with some heavy and some drizzle but car has always started up.Last night drove it to a nephews bday party and it sat outside in some heavy rain.when i left it took 2-3 attempts at cranking but it sdtarted and drove fine.i got home parked it and left it.today i go to leave and my battery is completely dead.look over and saw my fog light switch had been left on.so i through the charger on it and it turned over nicely but would not fire.so i left it on the charger and proceeded to read some posts and checked the distributor for moisture. so well i'm there pull each spark plug lead off and put dielectric grease on each coonector to create a water barrier for the rain.tried to start it again no luck drained the battery again.So i hooked up my truck to boost it and eventually it started.took it for a spin after letting it idle for 20 min came back pasrked shut it off and tried to start it again and a repeat of previous problem turns over but no fire .Back to reading and tried jumpering the dme relay pin 30,87,87b.here the fuel pump come on go turn it over and bang she starts.
Now before you guys say it"s obvious dme has seen better days let me say i tried swappimg with some new ones i got from rock auto which were uro relays and it didn't help so did i buy 2 piece of crap relaysd which were $10 a piece or could there be another explanation for it?
if the dme are garbage where can i get better and more reliable ones to try and have as spares?
I apologize for the long winded story but thought it might help.
#2
Racer
Thread Starter
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thought i would add to this a little more .took out the bentley manual and read where it says for no start first check for power at the dme relay pin 86 with key on position cause alarm control unit will interupt power to dme.Well i pulled mout the relay and stuck a circuit friendly test light in pin 87 got power stick it in pin 86 resting at ground go turn key over to power on and no 12v at pin 86.
tried it again if a jumper pin 30,87,87b car starts upand i can hear fuel pump running with relay in turning the key over i don't hear the pump start up.
what do i try next replace the relay tried the original and the 2 new uro i bought a month and a half ago relays what are the chances all 3 are pooched.
also read to check speed reference sensor connectors try wiggling it where do i find it and if it is speed reference sensor is it one of those it either works or doesn't?
tried it again if a jumper pin 30,87,87b car starts upand i can hear fuel pump running with relay in turning the key over i don't hear the pump start up.
what do i try next replace the relay tried the original and the 2 new uro i bought a month and a half ago relays what are the chances all 3 are pooched.
also read to check speed reference sensor connectors try wiggling it where do i find it and if it is speed reference sensor is it one of those it either works or doesn't?
#3
Nordschleife Master
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I would start with the battery . Pull it out and replace it with a known good battery .
That deep drain might have made the battery , not so good .
20 minutes of charging at idle is not a real charging .
The fact that your car started up connected to a known good , truck , battery ...
That deep drain might have made the battery , not so good .
20 minutes of charging at idle is not a real charging .
The fact that your car started up connected to a known good , truck , battery ...
#4
Racer
Thread Starter
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what about the fact that there is no switched power at pin 86 of dme relay socket when key turned?
I will get a new battery for it but in the mean time what can i try cause i jumper the dme relay 30,87,87b and it fires right up on first turn.Indy i agree with you i should start with the basics but wouldn't a bad battery cause a no start with or without dme jumper? I have read a few posts about alarm module keeping pin 86 from energizing and not powering up the dme relay is this correct?
I will get a new battery for it but in the mean time what can i try cause i jumper the dme relay 30,87,87b and it fires right up on first turn.Indy i agree with you i should start with the basics but wouldn't a bad battery cause a no start with or without dme jumper? I have read a few posts about alarm module keeping pin 86 from energizing and not powering up the dme relay is this correct?
#5
Nordschleife Master
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I don't think you should get a new battery , I suggested you use a known good battery as a test .
If you take the battery from the truck and temporarily use it as the battery for the car , does the engine start ? The space in the front trunk is large when you remove the little toy tire .
If the engine starts , put a real good full charge on the old battery that came out of the 964 and try that battery again .
I have seen a low battery crank the motor over but not start the engine .
Lets start with the battery , the worst that happens is nothing improves .
If you take the battery from the truck and temporarily use it as the battery for the car , does the engine start ? The space in the front trunk is large when you remove the little toy tire .
If the engine starts , put a real good full charge on the old battery that came out of the 964 and try that battery again .
I have seen a low battery crank the motor over but not start the engine .
Lets start with the battery , the worst that happens is nothing improves .
#6
Racer
Thread Starter
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don't know what id id but i got home took battery off charger and measured voltage was sitting at 13 v so i decided to disconnect ground from battery and proceededt mo work on removing my passenger seat to try and fix motors not working which will be another post. 20 min later connect battery ground again and go turn over and wham she's up and running again.
I did make one observation with the carpet out i noticed the top of fuel tank was sort of collapsed in and when i opened the gas filler neck lid it was like a vacum had been released and she inflated back to normal.Is this normal or result of cranking over without firing so many times? Do i need to be concerned with this causing a vapor lock?
well looks like my issue is solved for the time being checked pin 86 and it has switched 12v now again i have no idera whart happened or if i should expect it to happen again.....
I did make one observation with the carpet out i noticed the top of fuel tank was sort of collapsed in and when i opened the gas filler neck lid it was like a vacum had been released and she inflated back to normal.Is this normal or result of cranking over without firing so many times? Do i need to be concerned with this causing a vapor lock?
well looks like my issue is solved for the time being checked pin 86 and it has switched 12v now again i have no idera whart happened or if i should expect it to happen again.....
#7
Racer
Thread Starter
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hate to say this but it was a short lived triumph.I got in the car this morning started it up and she fired up like a champ drove to work and got out locked the doors,i came out after work unlocked the doors with key and go to start it and again just cranks but no start. tried swapping dme relay with good one no change pulled out dme jumper and she started right up so i drove home.when i got home i checked pin 86 and again no power there so i really suspect my immobilizer to be at fault since the only variable from last night to today is the locking of the doors and battery voltage is good just under 12.8v.
how do i bypass immobilzer and how do i get to it under passenger trunk hinge.Once i am there which pins do i jump to power up dme relay and supply 12v switched power to dme and relay?
how do i bypass immobilzer and how do i get to it under passenger trunk hinge.Once i am there which pins do i jump to power up dme relay and supply 12v switched power to dme and relay?
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#8
Nordschleife Master
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Just post charging the battery ran the car , let the battery sit and it fails to run the car ?
Have you tried replacing the battery for a known good one ?
Have you tried replacing the battery for a known good one ?
#9
Racer
Thread Starter
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no i haven't indy i know you suggested that instead i took out my battery and put it on charger for almost 18 hrs and installed it and again it just cranked over wasn't til after i unplugged the battery and let it sit for 30 min did it star up again and i drove it most of the night came home parked overnight started first thing in the morning on first attempt got to work locked the doors and the saga starts all over that is why i suspect immobilizer cause the only variable that changged was i locked the doors today where as last night i did not or overnight cause it was in the garage.I am having a hard time believing a battery with full voltage and cranking the motor over really strong would cause this.
How ever i am no pcar expert and rely on you guys who have been around the block a few times with these cars for guidance so please forgive me if i am coming across as a doubter in you logic....
How ever i am no pcar expert and rely on you guys who have been around the block a few times with these cars for guidance so please forgive me if i am coming across as a doubter in you logic....
#11
Racer
Thread Starter
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i think my car is trying to play with my emotions.Iwent out to the garage after supper to cut some plywood and wouldn't start had to jumper the dme relay and then moved car out of garage and locked the doors.3 hours later go unlock the doors hop in try turning it over and vroom she fires up .I pulled out the dme relay tested pin 86 and again have 12v.
So here is what i know obviously intermitent problem of pin 86 not getting 12v. The variables appear to be locking and unlocking doors and anytime i have had electrical gremlin pop out it has had to do with rain also as today it did rain while car was parked at work and later having the no start issue again.
I honestly don't believe battery is at issue here as voltage is at 12.8 v and it cranks over strong....
so let me ask this what happens if i leave the immobilzer alone and just run another wire with switched 12v to pin 86 under the fuse box will i fry something down the road?
So here is what i know obviously intermitent problem of pin 86 not getting 12v. The variables appear to be locking and unlocking doors and anytime i have had electrical gremlin pop out it has had to do with rain also as today it did rain while car was parked at work and later having the no start issue again.
I honestly don't believe battery is at issue here as voltage is at 12.8 v and it cranks over strong....
so let me ask this what happens if i leave the immobilzer alone and just run another wire with switched 12v to pin 86 under the fuse box will i fry something down the road?
#13
Three Wheelin'
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A 20 year old immobiliser!
Is it a factory alarm?
If so loose it, its likely to be faulty. And an old immobiliser will only stop you from starting it.
Any half right thief will have learnt how to bypass it 15 years ago!
First thing i did when i got my flash was have a good immobiliser fitted, threw the oe alarm in the bin.
The auto elec fella said he could bypass the old imm in 3 mins, old old tech.
Is it a factory alarm?
If so loose it, its likely to be faulty. And an old immobiliser will only stop you from starting it.
Any half right thief will have learnt how to bypass it 15 years ago!
First thing i did when i got my flash was have a good immobiliser fitted, threw the oe alarm in the bin.
The auto elec fella said he could bypass the old imm in 3 mins, old old tech.
#14
Racer
Thread Starter
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ok guys i pulled out my alarm control unit and i hate to say it but nasty in there water was in there at some point.and i think it is what is causing my issues at least i think .
Could someone please chime in how to elininate the control unit and what pins i jumper and can i drive the car with just the jumpers in place on the harness and what is best way to water proof it so no shorts.Part # on control unit is 928.637.104.05. i took some pics of what i found let me know what you guys think.
Hey indy i don't doubt your knowledge nor do i toss your advise away i appreciate you taking the time to helping me find a solution to my troubles like i said before you and others on this forum are alot smarter than me when it comes to these machines that dreams are made of.
![](http://i587.photobucket.com/albums/ss318/po36/DSC01762.jpg)
![](http://i587.photobucket.com/albums/ss318/po36/DSC01765.jpg)
![](http://i587.photobucket.com/albums/ss318/po36/DSC01766.jpg)
can this be salvaged or no?
Could someone please chime in how to elininate the control unit and what pins i jumper and can i drive the car with just the jumpers in place on the harness and what is best way to water proof it so no shorts.Part # on control unit is 928.637.104.05. i took some pics of what i found let me know what you guys think.
Hey indy i don't doubt your knowledge nor do i toss your advise away i appreciate you taking the time to helping me find a solution to my troubles like i said before you and others on this forum are alot smarter than me when it comes to these machines that dreams are made of.
![](http://i587.photobucket.com/albums/ss318/po36/DSC01762.jpg)
![](http://i587.photobucket.com/albums/ss318/po36/DSC01765.jpg)
![](http://i587.photobucket.com/albums/ss318/po36/DSC01766.jpg)
can this be salvaged or no?