My misfire " A warning to you all"
Discussion
As per my other thread I had a misfire on No3 cylinder due to the injector not delivering fuel.
After many hours head scratching and testing I worked out that there was no power to the injector and that the injectors must share a common feed. I suspected it has to be where 1 wire becomes 6.
I removed the 2 plugs which enter the bulkhaed under the air box and I could feel about 8inches down there was a connector inside the loom so I sliced the loom open this is what I found.
It was all green inside which is what happens when copper wires meet water. It looks like water can enter the loom at the top and where it branches off for the smaller plug. When I removed the small heatshrink covering the connector the feed for inj 3 was clearly broken off from the rest.
Now to me this is a brakedown waiting to happen on all Speed Six powered cars. I have cut out the crimped connector and replaced it with a soldered joint.
I have also filled the loom where water can get in with silicone sealent to prevent future water imgress.
I would get yours checked and sealed as this can happen anytime.
After many hours head scratching and testing I worked out that there was no power to the injector and that the injectors must share a common feed. I suspected it has to be where 1 wire becomes 6.
I removed the 2 plugs which enter the bulkhaed under the air box and I could feel about 8inches down there was a connector inside the loom so I sliced the loom open this is what I found.
It was all green inside which is what happens when copper wires meet water. It looks like water can enter the loom at the top and where it branches off for the smaller plug. When I removed the small heatshrink covering the connector the feed for inj 3 was clearly broken off from the rest.
Now to me this is a brakedown waiting to happen on all Speed Six powered cars. I have cut out the crimped connector and replaced it with a soldered joint.
I have also filled the loom where water can get in with silicone sealent to prevent future water imgress.
I would get yours checked and sealed as this can happen anytime.
Edited by Barry Ashcroft on Saturday 29th May 17:09
I have an engine missfire problem that could have been similar to yours. Intermittently my engine dies while driving; it feels like it's dropped 3 cylinders. There's no popping and banging, it's like you've taken your foot off the throttle. If you slow to a stop it is extremely hard to keep the engine running, you have to blip the throttle all the time. Pulling away is hard as the engine is not running smoothly.
So, having seen your post, I stripped back the loom that you indicated but all seems fine in there, no sign of anny water ingress at all.
This is what my wiring loks like.
So, if it's not the same problem - what is it? I suspect an electrical problem somewhere. It has a replacement ECU in at the moment and that hasn't cured it.
Anyone got any ideas?
Regards
Phil.
So, having seen your post, I stripped back the loom that you indicated but all seems fine in there, no sign of anny water ingress at all.
This is what my wiring loks like.
So, if it's not the same problem - what is it? I suspect an electrical problem somewhere. It has a replacement ECU in at the moment and that hasn't cured it.
Anyone got any ideas?
Regards
Phil.
Barry,
I actually decided not to do that as it was all pristine in the loom and there was no sign of any corrosion. As you say, I've got more than one cylinder that cuts out for sure and less than all 6!
My skill level is moderate I think. I don't have any diagnostic or tuning gear specific to this car - apart from a multimeter! I've got a strobe etc and a reasonable tool kit.
I've been relying on a garage to try and sort this problem for quite some time, but they've been as much in the dark as I have. If it crapped out completely they'd be able to fix it because then they'd be able to find what isn't working. But with an intermittent fault the problem is that when you're looking at it in the garage it's all working. You've only got the described symptoms to go on, you can't actually measure anything wrong.
Does the coil pack exhibit intermittent problems? It is one of the things the garage suggested but they were hoping the ECU swap would cure it. I'd rather not replace everything bit by bit until I strike the real problem.
Location is near Woking, Surrey.
Regards
Phil.
I actually decided not to do that as it was all pristine in the loom and there was no sign of any corrosion. As you say, I've got more than one cylinder that cuts out for sure and less than all 6!
My skill level is moderate I think. I don't have any diagnostic or tuning gear specific to this car - apart from a multimeter! I've got a strobe etc and a reasonable tool kit.
I've been relying on a garage to try and sort this problem for quite some time, but they've been as much in the dark as I have. If it crapped out completely they'd be able to fix it because then they'd be able to find what isn't working. But with an intermittent fault the problem is that when you're looking at it in the garage it's all working. You've only got the described symptoms to go on, you can't actually measure anything wrong.
Does the coil pack exhibit intermittent problems? It is one of the things the garage suggested but they were hoping the ECU swap would cure it. I'd rather not replace everything bit by bit until I strike the real problem.
Location is near Woking, Surrey.
Regards
Phil.
Edited by Phil Tudhope on Friday 4th June 21:51
Well it sounds like there is not much left to change apart from the coil pack.
Where did you have it serviced?
It might be worth tomorrow removing all the plugs from the injectors completley and checking with your meter that you have a stable 12volts to them all with the ignition on.
They bank fire 1,2,3 & ,4,5,6
There is 2 earth pulses from the ecu 1 to each bank of 3.
The wires are split under the dash to 6 seperate wires going to the injectors so pull the rubber caps of the injectors to get to the wires and view the colours and check you have continuity to the plug in the bulkhead.
You can then check the same from the bulkead plug back to the ecu but I don't know the colours when the enter the ecu.
From looking at the crap type of crimp connector it is quite possible that you could have a beake down on one of the crimps.
Good luck
Where did you have it serviced?
It might be worth tomorrow removing all the plugs from the injectors completley and checking with your meter that you have a stable 12volts to them all with the ignition on.
They bank fire 1,2,3 & ,4,5,6
There is 2 earth pulses from the ecu 1 to each bank of 3.
The wires are split under the dash to 6 seperate wires going to the injectors so pull the rubber caps of the injectors to get to the wires and view the colours and check you have continuity to the plug in the bulkhead.
You can then check the same from the bulkead plug back to the ecu but I don't know the colours when the enter the ecu.
From looking at the crap type of crimp connector it is quite possible that you could have a beake down on one of the crimps.
Good luck
Another thing you can also do is when the engine is runnng and missing get under the bonnet keep the revs high so the engine does not stop and remove the plug from each injector in turn and work out which clyinder is missing you can tell easy as the engine note will change.
That will tell you valuble info if it happens to be a whole bank of 3 missing
That will tell you valuble info if it happens to be a whole bank of 3 missing
Barry,
Thanks for the suggestions on the injector wiring. The chance of getting under the bonnet when it's missfiring isn't too high I'm afraid. My car's a Tuuscan S so you have to unbolt the bonnet and then it's a 2-man lift to get it off. Most often switching the car off and restarting cures the problem so when you've got the bonnet off the chances are that the problem will have gone away!
I'll have a check on the voltages on the injectors next time I have a problem and the bonnet off though. This time i cleaned all the conenctors with switch cleaner.
Phil.
Thanks for the suggestions on the injector wiring. The chance of getting under the bonnet when it's missfiring isn't too high I'm afraid. My car's a Tuuscan S so you have to unbolt the bonnet and then it's a 2-man lift to get it off. Most often switching the car off and restarting cures the problem so when you've got the bonnet off the chances are that the problem will have gone away!
I'll have a check on the voltages on the injectors next time I have a problem and the bonnet off though. This time i cleaned all the conenctors with switch cleaner.
Phil.
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