Hey guys, newbie here. New to the site and new to XJ’s. I replaced my 1988 motor with a 1997 motor. I kept all the 1988 components except the actual motor. It ran and idled while I was working out the bugs, and then one day it stopped sparking in cylinders 3 and 4. I have replaced everything I can think to replace but still no change. Please can someone help me out. I have a ride this weekend and it looks like I will have to cancel. Please can someone help.
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No spark in 3 and 4
- Thread starter XJ Aaron
- Start date
denverd1
NAXJA Forum User
- Location
- Dallas, TX
woah.....
Black1990jeep
NAXJA Forum User
- Location
- california
So you are running the renix ignition system as in 1988. you got no spark on 2 of 6 plugs.
1. spark wires bad.
2.plugs bad,
3. dizzie cap bad
If those are known ok, then Id suspect the sensor, the crank position sensor (CPS) which tells the ecu when to fire the spark. Cylinders 3 and 4 use the same crank pposition pulse, so Id be inclined to check that the ecu is getting the 3/4 cylinder pulse, as I think if that pulse is missing, the spark will not fire
the CPS sensor picks up pulses from the flywheel. this tells the ecu when top dead center (TDC)happens, which is used by the ecu to time the spark firing. 1 and 6, 2 and 5, 3 and 4 cylinders use the same positions for TDC detection. i.e. in one crank rotation, there are three trigger points 120 degrees apart and each of those three are used for two each cylinders. 3 and 4 use the same crank position for TDC.
good luck
1. spark wires bad.
2.plugs bad,
3. dizzie cap bad
If those are known ok, then Id suspect the sensor, the crank position sensor (CPS) which tells the ecu when to fire the spark. Cylinders 3 and 4 use the same crank pposition pulse, so Id be inclined to check that the ecu is getting the 3/4 cylinder pulse, as I think if that pulse is missing, the spark will not fire
the CPS sensor picks up pulses from the flywheel. this tells the ecu when top dead center (TDC)happens, which is used by the ecu to time the spark firing. 1 and 6, 2 and 5, 3 and 4 cylinders use the same positions for TDC detection. i.e. in one crank rotation, there are three trigger points 120 degrees apart and each of those three are used for two each cylinders. 3 and 4 use the same crank position for TDC.
good luck
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