Is there a simple answer.........
#1
Drifting
Thread Starter
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to my 'no spark' problem?
Car always ran a bit rough and sluggish. I unplugged the oxygen sensor and it ran better, although a bit rich.
I plugged the sensor back in and the problem remained until on one trip I lost all power. It didn't stall but there was no throttle response off idle. I unplugged the oxygen sensor and the car could rev again.
I limped home and parked it up and ordered a new oxygen sensor.
Fast forward to today and it won't start. Battery very strong and it cranks fine but no fire.
I pulled a plug and found no spark while cranking. So,
Is this related to the oxygen sensor?
Is there another problem that stops it from powering the spark plugs?
I have wired in the new sensor but have not yet screwed it into the exhaust pipe.
Any ideas?
Car always ran a bit rough and sluggish. I unplugged the oxygen sensor and it ran better, although a bit rich.
I plugged the sensor back in and the problem remained until on one trip I lost all power. It didn't stall but there was no throttle response off idle. I unplugged the oxygen sensor and the car could rev again.
I limped home and parked it up and ordered a new oxygen sensor.
Fast forward to today and it won't start. Battery very strong and it cranks fine but no fire.
I pulled a plug and found no spark while cranking. So,
Is this related to the oxygen sensor?
Is there another problem that stops it from powering the spark plugs?
I have wired in the new sensor but have not yet screwed it into the exhaust pipe.
Any ideas?
#3
Drifting
Thread Starter
#4
Drifting
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Speed/ref sensor is the first suspect. Second is the coil or power to it. Third is plugs, cap, rotor (spinning due to backed out screw), plug wires that may be arcing out. But most likely the shielding on one of your sensors has seperated and is not sending signal to the DME. I've had this problem this last May on the highway. Car started to hesitate then just died while driving down the HWY. I replaced the speed/ref sensors and it was fine.
#5
Rennlist Member
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Surprised nobody has mentioned the ignition switch yet, it supplies +12v right to the coil. But if your DME is getting power, and consequently the injectors, it's not the issue.
#6
Rennlist Member
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Always worth checking the DME relay as well.
How did you check for spark? Be sure to use a know good wire from the coil output to a solid ground. Otherwise, what seems to be no spark could be a bad wire (or if you try at the end of a spark plug lead, then a bad cap/rotor, etc.)
Does your tach bounce when you crank it? If not, that points to speed/ref sensors.
When was the last time you changed your cap, rotor and plug wires? DME relays and (to a slightly lesser extent) speed and ref sensors tend to be yes/no parts, so if the car started running worse and worse until it stopped altogether, then that would make me lean toward things that wear out or otherwise get worse over time, like arcing rotors, bad wires, etc.
Does not sound related to the O2 sensor per se. By pulling the sensor you were changing the air fuel ratio and probably helping mask whatever was going on.
Sounds like a little more digging is in order...
How did you check for spark? Be sure to use a know good wire from the coil output to a solid ground. Otherwise, what seems to be no spark could be a bad wire (or if you try at the end of a spark plug lead, then a bad cap/rotor, etc.)
Does your tach bounce when you crank it? If not, that points to speed/ref sensors.
When was the last time you changed your cap, rotor and plug wires? DME relays and (to a slightly lesser extent) speed and ref sensors tend to be yes/no parts, so if the car started running worse and worse until it stopped altogether, then that would make me lean toward things that wear out or otherwise get worse over time, like arcing rotors, bad wires, etc.
Does not sound related to the O2 sensor per se. By pulling the sensor you were changing the air fuel ratio and probably helping mask whatever was going on.
Sounds like a little more digging is in order...
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#9
Drifting
Thread Starter
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Ok Guys!
First off I'd like to thanks you for all the suggestions.
I haven't driven the car much but when I got it I changed pretty much all the serviceable items except for the timing belts.
As it turns out when I was playing with the oxygen sensor I've unplugged the lower of the two plugs near it. Either the speed or reference.
The plug is very brittle and most of it is long gone. But I did plug the two ends back together and she fired right up.
Once again thanks for the help and remember if any of you get down here to NE Victoria you can come stay with us.
First off I'd like to thanks you for all the suggestions.
I haven't driven the car much but when I got it I changed pretty much all the serviceable items except for the timing belts.
As it turns out when I was playing with the oxygen sensor I've unplugged the lower of the two plugs near it. Either the speed or reference.
The plug is very brittle and most of it is long gone. But I did plug the two ends back together and she fired right up.
Once again thanks for the help and remember if any of you get down here to NE Victoria you can come stay with us.
![Cheers](https://rennlist.com/forums/images/smilies/beerchug.gif)
#10
Rennlist Member
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Ok Guys!
First off I'd like to thanks you for all the suggestions.
I haven't driven the car much but when I got it I changed pretty much all the serviceable items except for the timing belts.
As it turns out when I was playing with the oxygen sensor I've unplugged the lower of the two plugs near it. Either the speed or reference.
The plug is very brittle and most of it is long gone. But I did plug the two ends back together and she fired right up.
Once again thanks for the help and remember if any of you get down here to NE Victoria you can come stay with us.![Cheers](https://rennlist.com/forums/images/smilies/beerchug.gif)
First off I'd like to thanks you for all the suggestions.
I haven't driven the car much but when I got it I changed pretty much all the serviceable items except for the timing belts.
As it turns out when I was playing with the oxygen sensor I've unplugged the lower of the two plugs near it. Either the speed or reference.
The plug is very brittle and most of it is long gone. But I did plug the two ends back together and she fired right up.
Once again thanks for the help and remember if any of you get down here to NE Victoria you can come stay with us.
![Cheers](https://rennlist.com/forums/images/smilies/beerchug.gif)