gremlin found!
08-19-2013, 02:29 AM
#1
Drifting
Thread Starter
gremlin found!
I pm'd Greg in california to get some Ideas where to look and he led me in the right direction...
My car was cruisding in 3rd when the car spit and sputtered 4 times in about 6 sec. with the tach going from 0 to 7 k 4 times with no comparible engine rev then died. started right up and quickly drove home 10 miles with no further problem until start up the next am. same thing happened!
He told me to check grounds , then computer etc.....I had just changed the plugs and looked around there first after checking all the grounds. turns out the switch for the hood light was intermittantly shorting out and causing the engine to stumble and die, very reproducible! fixed that and no further problems.
sooooooo, with the switch shorting out , I figured this would blow a fuse but you could hear a click click then dead in the computer area LINK g 4. what is the explaination????
thanks for all your ideas...
My car was cruisding in 3rd when the car spit and sputtered 4 times in about 6 sec. with the tach going from 0 to 7 k 4 times with no comparible engine rev then died. started right up and quickly drove home 10 miles with no further problem until start up the next am. same thing happened!
He told me to check grounds , then computer etc.....I had just changed the plugs and looked around there first after checking all the grounds. turns out the switch for the hood light was intermittantly shorting out and causing the engine to stumble and die, very reproducible! fixed that and no further problems.
sooooooo, with the switch shorting out , I figured this would blow a fuse but you could hear a click click then dead in the computer area LINK g 4. what is the explaination????
thanks for all your ideas...
08-19-2013, 03:22 AM
#2
Rennlist Member
My wild guess - antitheft circuit causing 'no start' condition as is meant to happen when hood opened with car locked IIRC.
Glad you faound it so easily and that it is an easy fix.
Myles
Glad you faound it so easily and that it is an easy fix.
Myles
08-19-2013, 03:35 AM
#3
Rennlist Member
Andy,
Recent experience tells me that area around the hot post/14 pin connector is very vulnerable to heat degradation. On many of my cables there the insulation has literally crumbled away so I am hanging on by a wing and a prayer until I can get that front harness replaced. Whether something similar is going on in your switch area causing a problem may be another matter altogether but once these problems start to manifest a clean sweep of the deck is probably the best solution to give the motor another 20 year lease of life.
I thought our hot climate was the culprit but it seems the 928 wiring insulation does not do a whole lot better in your areas with hotter climes. My insulation around the 14 point connector has literally fallen apart. If you have not done so already, take a general poke around in that area and see if the wire insulation is still flexible or whether it seems fragile when the wire is flexxed. Might give you a clue as to overall condition.
How such might explain your symptoms remains to be seen but never rule anything out until you know for sure the source of the problem. Once you have a stray current amazing where it can end up sometimes.
Regards
Fred
Recent experience tells me that area around the hot post/14 pin connector is very vulnerable to heat degradation. On many of my cables there the insulation has literally crumbled away so I am hanging on by a wing and a prayer until I can get that front harness replaced. Whether something similar is going on in your switch area causing a problem may be another matter altogether but once these problems start to manifest a clean sweep of the deck is probably the best solution to give the motor another 20 year lease of life.
I thought our hot climate was the culprit but it seems the 928 wiring insulation does not do a whole lot better in your areas with hotter climes. My insulation around the 14 point connector has literally fallen apart. If you have not done so already, take a general poke around in that area and see if the wire insulation is still flexible or whether it seems fragile when the wire is flexxed. Might give you a clue as to overall condition.
How such might explain your symptoms remains to be seen but never rule anything out until you know for sure the source of the problem. Once you have a stray current amazing where it can end up sometimes.
Regards
Fred
08-19-2013, 11:14 PM
#4
Drifting
Thread Starter
thanks for the ideas. the insulation on the switch was cracked and exposing wires with magnifying glass. took it for 120 ;mile cruise and was without problems,. seems funny . maybe real cause will pop up later.....
08-19-2013, 11:18 PM
#5
Watch carefully men - this is a car run by the aftermarket ecu LINK - so issues are always about grounding and ground paths. Well, usually.
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08-20-2013, 02:21 PM
#9
Rennlist Member
If it was very reproducible, I would think that one could identify the circuit that was being "shorted" and surmise what engine control system may have also been affected.
08-20-2013, 02:30 PM
#10
It does make sense. After all the reading I have done on the ECU forums, from Link, to Vipec (link box), Megasquirt, adaptronic, AEM, Efi101, etc - if one wire is somehow not grounded the way it should be, (and there are ECU grounds and sensor grounds - MUST NOT CREATE GROUND LOOP - say it in your sleep) - then you can have BIG changes in the ECU operation.
08-20-2013, 11:56 PM
#12
Electron Wrangler
Lifetime Rennlist
Member
Lifetime Rennlist
Member
To the original question - unless the aftermarket engine controller is designed to shutdown with the hood open I have no idea.
In stock config on a GTS the hood switch connects to ground only when the hood is open, the other pin connects to the hoodlight and the alarm.
If you short one side of the switch to ground - nothing happens (it was already ground) if you short the other side - the hood light comes on (and the alarm can detect that the hood is open). Basically nothing bad happens.
If you shorted either side to the jump post with the hood open you'd get lots of sparks (maybe melted wires) - but no fuse blown - but how would that happen...
So I think it was something else...
Alan
thanks for the explaination....I am learning all the time...
08-21-2013, 02:48 PM
#15
Former Sponsor
I pm'd Greg in california to get some Ideas where to look and he led me in the right direction...
My car was cruisding in 3rd when the car spit and sputtered 4 times in about 6 sec. with the tach going from 0 to 7 k 4 times with no comparible engine rev then died. started right up and quickly drove home 10 miles with no further problem until start up the next am. same thing happened!
He told me to check grounds , then computer etc.....I had just changed the plugs and looked around there first after checking all the grounds. turns out the switch for the hood light was intermittantly shorting out and causing the engine to stumble and die, very reproducible! fixed that and no further problems.
sooooooo, with the switch shorting out , I figured this would blow a fuse but you could hear a click click then dead in the computer area LINK g 4. what is the explaination????
thanks for all your ideas...
My car was cruisding in 3rd when the car spit and sputtered 4 times in about 6 sec. with the tach going from 0 to 7 k 4 times with no comparible engine rev then died. started right up and quickly drove home 10 miles with no further problem until start up the next am. same thing happened!
He told me to check grounds , then computer etc.....I had just changed the plugs and looked around there first after checking all the grounds. turns out the switch for the hood light was intermittantly shorting out and causing the engine to stumble and die, very reproducible! fixed that and no further problems.
sooooooo, with the switch shorting out , I figured this would blow a fuse but you could hear a click click then dead in the computer area LINK g 4. what is the explaination????
thanks for all your ideas...
Great find. Something like that could have haunted you for a long time, as it seems like the two things should not be related.
I'll have to look in a wiring diagram and see how these two systems interface.
gb