Not firing on cylinder 4 and 5 -
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Go Back > Models > Jeep Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > Not firing on cylinder 4 and 5

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Unread 07-16-2014, 08:25 PM   #1
Registered User
1995 ZJ 
Join Date: Dec 2006
Location: Cincinnati, OH
Posts: 60
Not firing on cylinder 4 and 5

3 days ago I parked my ZJ and it was running fine. The next morning I decided that I was going to treat it to some exhaust work at the local shop. It had developed a misfire overnight. I drove it a couple of miles and it got worse.

Started by pulling the spark plug wires to determine which cylinders weren't firing...4 and 5 were the issue so I pulled the plugs and they looked worn out (brownish color and very large gap). I replace all of them and it didn't fix the issue.

I then checked for trouble codes and got code 27(Injector #3, and/or 4, and/or 5, and/or 6 output driver does not respond properly to the control signal. )

Next I looked at the injectors. All voltage and ohm measurements checked out but I still pulled the injectors and threw in 2 that I got from the local junk yard just in case. Still has the same issue.

I'm not sure where to look next. Any suggestions?

95gc is offline   Reply With Quote Quick reply to this message
Unread 07-17-2014, 08:13 AM   #2
Registered User
1993 ZJ 
Join Date: Aug 2010
Location: Austin
Posts: 1,886
The first time my coil went bad it had a misfire. I checked for spark and it had spark it just was too weak to fire sometimes. Might be worth checking.

Wasn't there also a post recently about not having spark on 1 and 6 that was caused by a bad CPS? Might check that out too.
zjosh93 is offline   Reply With Quote Quick reply to this message

injector , misfire

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