92 YJ 4.0 Missfire
 

I have a problem with my Jeep. When driving yesterday it started to
miss. It was much more harsh then a single cylinder missfire, when it
would miss, the passenger could hit his head on the dash. I had to stop
several times to on the way home.

This has happened on tow occasion beore. The first tiem it went away
after cleaning the battery teminals (a coincidence I'm sure)

The second time, I replaced the distributor cab and rotor (it was pretty
bad), the plugs and the wires. I check the coil and it measure fine
(don;t have the number on hand).

I checked and cleaned the connections on most of the sensors and injectoirs.

When it happend yesterday it was after 6 hours of 4x4ing and a 70Km
drive down the highway at 105 Kph.

I am not sure what to check next. Has any one else ran in to this?

-Dan

Re: 92 YJ 4.0 Missfire
 

Is your "Check Engine" light on? Did you get water in your gas/gas
filler cap
on tight?
Tom T

Re: 92 YJ 4.0 Missfire
 

Is your "Check Engine" light on? Did you get water in your gas/gas
filler cap
on tight?
Tom T

Re: 92 YJ 4.0 Missfire
 

Is your "Check Engine" light on? Did you get water in your gas/gas
filler cap
on tight?
Tom T

Re: 92 YJ 4.0 Missfire
 

Tom T wrote:
> Is your "Check Engine" light on? Did you get water in your gas/gas
> filler cap
> on tight?
> Tom T
>

No Check engine light.

No water in the gas. Gas cap is tight.

Re: 92 YJ 4.0 Missfire
 

Tom T wrote:
> Is your "Check Engine" light on? Did you get water in your gas/gas
> filler cap
> on tight?
> Tom T
>

No Check engine light.

No water in the gas. Gas cap is tight.

Re: 92 YJ 4.0 Missfire
 

Tom T wrote:
> Is your "Check Engine" light on? Did you get water in your gas/gas
> filler cap
> on tight?
> Tom T
>

No Check engine light.

No water in the gas. Gas cap is tight.

Re: 92 YJ 4.0 Missfire
 

Dan did pass the time by typing:
> I have a problem with my Jeep. When driving yesterday it started to
> miss. It was much more harsh then a single cylinder missfire, when it
> would miss, the passenger could hit his head on the dash. I had to stop
> several times to on the way home.
>
> This has happened on tow occasion beore. The first tiem it went away
> after cleaning the battery teminals (a coincidence I'm sure)
>
> The second time, I replaced the distributor cab and rotor (it was pretty
> bad), the plugs and the wires. I check the coil and it measure fine
> (don;t have the number on hand).
>
> I checked and cleaned the connections on most of the sensors and injectoirs.
>
> When it happend yesterday it was after 6 hours of 4x4ing and a 70Km
> drive down the highway at 105 Kph.
>
> I am not sure what to check next. Has any one else ran in to this?


FWIW, coils can check out just fine but be shot. I've ran into this twice
before. Once on a GM HEI coil and again on my 93ZJ coil.

When the ZJ coil went it would miss on warmup and then just simply
wouldn't start. Even flatly dead the coil still tested in range.
That happens when the insulation breaks down but the widings are still
otherwise good.

I'd replace the coil and go from there. Worst off you will now have
a spare coil.

--
DougW

Re: 92 YJ 4.0 Missfire
 

Dan did pass the time by typing:
> I have a problem with my Jeep. When driving yesterday it started to
> miss. It was much more harsh then a single cylinder missfire, when it
> would miss, the passenger could hit his head on the dash. I had to stop
> several times to on the way home.
>
> This has happened on tow occasion beore. The first tiem it went away
> after cleaning the battery teminals (a coincidence I'm sure)
>
> The second time, I replaced the distributor cab and rotor (it was pretty
> bad), the plugs and the wires. I check the coil and it measure fine
> (don;t have the number on hand).
>
> I checked and cleaned the connections on most of the sensors and injectoirs.
>
> When it happend yesterday it was after 6 hours of 4x4ing and a 70Km
> drive down the highway at 105 Kph.
>
> I am not sure what to check next. Has any one else ran in to this?


FWIW, coils can check out just fine but be shot. I've ran into this twice
before. Once on a GM HEI coil and again on my 93ZJ coil.

When the ZJ coil went it would miss on warmup and then just simply
wouldn't start. Even flatly dead the coil still tested in range.
That happens when the insulation breaks down but the widings are still
otherwise good.

I'd replace the coil and go from there. Worst off you will now have
a spare coil.

--
DougW

Re: 92 YJ 4.0 Missfire
 

Dan did pass the time by typing:
> I have a problem with my Jeep. When driving yesterday it started to
> miss. It was much more harsh then a single cylinder missfire, when it
> would miss, the passenger could hit his head on the dash. I had to stop
> several times to on the way home.
>
> This has happened on tow occasion beore. The first tiem it went away
> after cleaning the battery teminals (a coincidence I'm sure)
>
> The second time, I replaced the distributor cab and rotor (it was pretty
> bad), the plugs and the wires. I check the coil and it measure fine
> (don;t have the number on hand).
>
> I checked and cleaned the connections on most of the sensors and injectoirs.
>
> When it happend yesterday it was after 6 hours of 4x4ing and a 70Km
> drive down the highway at 105 Kph.
>
> I am not sure what to check next. Has any one else ran in to this?


FWIW, coils can check out just fine but be shot. I've ran into this twice
before. Once on a GM HEI coil and again on my 93ZJ coil.

When the ZJ coil went it would miss on warmup and then just simply
wouldn't start. Even flatly dead the coil still tested in range.
That happens when the insulation breaks down but the widings are still
otherwise good.

I'd replace the coil and go from there. Worst off you will now have
a spare coil.

--
DougW