Going thru spark plugs

[Jeepmedic46]

I have a 2000 Cherokee with a junkyard motor. Jeep seems to be going thru spark plugs and misfiring. I bought the Jeep with the motor in it. It has 90,000 miles on it. What Could be causing the misfires?

 

[8Mud]

Regular coil or coil pack?

The only other reason I can think off besides to hot of a spark is the motor is running way lean which is likely to damage a piston eventually.

Regular coils are designed to start hot then reduce spark while running. If the coil is aftermarket it may be designed to use with a ballast resistor (lower input voltage while running, bypass the ballast resistor while cranking).

 

[RCP Phx]

The 2000-01 is a coil pack, but the better question would be what plugs are you running? And at what gap?

 

[Unclewolverine]

My 01 was cooking plugs then started misfiring, coil pack was the culprit. Unfortunately the coil pack system is horrible and causes lots of problems. My 01 was easily the worst xj I have ever owned out of 7 or 8.

 

[Tim_MN]

Define and explain "going thru spark plugs" ?

Obviously the 2000-01 are distributor-less coil on plug ignition so there is no ballast resistor.

Is, or was, the Check Engine Light ON ? What trouble codes were previously downloaded, or are currently stored or pending ? Have you performed any diagnostic testing on the coil pack ?

As already asked, what brand/type/part number spark plugs and plug gap ?

 

[RCP Phx]

I never had a problem with my coil rail(s) other than it was a PITA to check plugs and anything else it got in the way of. Easy fix!

 

[Jeepmedic46]

The code was 0300 and I put NGK plugs gapped at .035. Engine light is on again. Drove the Jeep one day and the check engine light came on. The Jeep sits for a while between being used and it’s only driven local.

 

[Scrubber3]

Still have the 0331 head?

 

[RCP Phx]

The code was 0300

That's how mine started...... https://naxja.org/forum/showthread.php?t=1145993

 

[old_man]

Post up a pix of the spark plugs.

 

[Jeepmedic46]

Still have the 0331 head?

Where do I find out what head I have?

 

[Unclewolverine]

I don't remember how to tell that, but I think if it was replaced with an earlier non 0331 head, (not a tupy) then you have to use the earlier exhaust manifold and would lose the precats which would cause a host of issues.

 

[Jeepmedic46]

I looked and couldn’t find numbers for the head. My wife isn’t feeling well so wasn’t able to pull plugs. The Jeep sits for days at a time. Could this cause a issue with my plugs or could this be why my check engine light keeps going on?

 

[Tim_MN]

If the Check engine Light is ON, there is malfunction. Download the the Check Engine Light trouble codes and use your Factory Service Manual to perform the recommended diagnostics.

0331 and TUPY are cast into the heads near cylinder 3/4, all you have to do is look. If you don't know where to look, use the Google.

Did we ever come to a conclusion on define and explain "going thru spark plugs" ?

 

[Jeepmedic46]

If the Check engine Light is ON, there is malfunction. Download the the Check Engine Light trouble codes and use your Factory Service Manual to perform the recommended diagnostics.

0331 and TUPY are cast into the heads near cylinder 3/4, all you have to do is look. If you don't know where to look, use the Google.

Did we ever come to a conclusion on define and explain "going thru spark plugs" ?

Thank you for that information. I’ll find what the head is. When I put going thru Spark plugs it was because I am getting misfires on cylinders 3 and 4. I’m learning this as I go along. This is all new to me.