No spark on #1 cyl - very weird

[dkfrizzell]

Out of the blue, my 98 Disco had a power loss. After some checking I found that my #1 plug was not getting any spark. Tested the plug wire (by swapping it with another wire) and it was fine, but no spark is getting to the plug itself.

I tested the 2 leads that are hooked to the coil and both read about 12v with the ignition on and since this only happening on #1 I assumed the coil pack.

Just put on a new coil and I am still having the same problem... no spark getting to the #1 cyl. I can't get anywhere to check codes so I dont know if I have any.

Suggestions? Thanks!

 

[FIVESPDDISCO]

sounds like a coil pack. i think there are 4 of them. is there another plug not working?now can we trade for the rack??

 

[dkfrizzell]

i replaced the coil that controls the #1 cyl with a new one, same problem. Odd part is the other side of the same coil is getting spark just fine.

dont have the rack any more, i cut it up to make the kids a jungle gym. ;-)

 

[FIVESPDDISCO]

funny rover uses my spare ecu as a chew toy

 

[FIVESPDDISCO]

ill briing 1 if you need it

 

[dkfrizzell]

anyone? Is ECU the right direction on this or am I barking up the wrong tree?

 

[Chris-St Louis]

Cylinder 6 is firing ok?

 

[dkfrizzell]

ya... #6 is fine.

 

[Chris-St Louis]

Then your computer is fine. GEMS uses a Waste spark which means the computer commands the coil to light 1 and 6.

Since 6 works, the computer is likely ok. I think your hunt is elseware.

 

[dkfrizzell]

so 1 and 6 get one signal to fire at the same time then? now this is getting VERY weird.

I checked 3 times that 6 was firing, but I think a 4th check is needed.

 

[Chris-St Louis]

Yes, See, when 1 is firing, 6 is firing also to reduce emissions, and vice virsa....Many manufacture do it like this, its called "Waste Spark".

http://www.findarticles.com/p/articles/mi_qa3828/is_199907/ai_n8876015

This may be helpful.

 

[dkfrizzell]

interesting read... by that logic, I think it would be impossible for 6 to fire with 1 firing.

So perhaps in haste, I was checking the wrong plug wire (I traced it down to the plug but now Im not sure if I was looking at 8 or 6 when I checked). Now I know I need to recheck #6 spark.

Now on the assumption that both 1 and 6 are without spark, back to the ECU?

 

[Chris-St Louis]

interesting read... by that logic, I think it would be impossible for 6 to fire with 1 firing.

More detail please. I dont quite follow you.

Now on the assumption that both 1 and 6 are without spark, back to the ECU?

Where/how are you checking spark?

If 1 and 6 are not working, I would confirm conduction from the blue wire at the coil pack to the White and black wire at the ECU. You could have a open connection.

 

[dkfrizzell]

More detail please. I dont quite follow you..

Well, it sounds as though it would be pretty much impossible for #6 to fire and #1 not fire.

Where/how are you checking spark?

pulled the plug wire, let it arc on the exhaust manifold. But I wasnt sure exactly which cyl shared the coil so i just traced the wire from the coil around to the plug. could have gotten it mixed up because now Im not sure if I was checking #8 or #6.

If 1 and 6 are not working, I would confirm conduction from the blue wire at the coil pack to the White and black wire at the ECU. You could have a open connection.

I will take a look at the tonight when I get home. Thanks so much for your help.

 

[Chris-St Louis]

Well, it sounds as though it would be pretty much impossible for #6 to fire and #1 not fire.

That is correct if the coil is working correctly.

pulled the plug wire, let it arc on the exhaust manifold. But I wasnt sure exactly which cyl shared the coil so i just traced the wire from the coil around to the plug. could have gotten it mixed up because now Im not sure if I was checking #8 or #6.

Do you have a Misfire code or something?

http://www.jcwhitney.com/webapp/wcs...162&TID=101&productId=2008162&catalogId=10101

ON SALE! THis is a great tool, and more accurate of a test.

I will take a look at the tonight when I get home. Thanks so much for your help.

I am a river to my people.