O2 sensor issues?
#166
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Joined: Jan 2017
Posts: 3,297
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From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Yes I know. This would be the workaround you were looking for. Heater power would be provided by Yellow, which should be hot only when Key On, and the Oxygen Heater Relay itself would be powered by Orange. Although your issue is Orange is hot all the time (as opposed to hot only when Key On), since ECU decides when to provide power this should work.
However, the best plan is to figure out how the fuel pump gets power without a relay. Sooner or later, one of these repairs or workarounds might end up smoking the whole harness.
BTW, what are the Part#s of the relays for the Oxygen Heater and the Fuel Pump?
Also, I believe you have 4 fusible links in and around the starter relay. Are they all good?
However, the best plan is to figure out how the fuel pump gets power without a relay. Sooner or later, one of these repairs or workarounds might end up smoking the whole harness.
BTW, what are the Part#s of the relays for the Oxygen Heater and the Fuel Pump?
Also, I believe you have 4 fusible links in and around the starter relay. Are they all good?
#167
CF Veteran
Joined: Jan 2017
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From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
#169
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From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Time to start ripping the harness apart.
That wire (F22 14OR) goes to a ton of stuff. With relay out and key off, check it at the EGR solenoid, the fuel injectors, power steering pump, and the fuel pump. We already know it's hot at the Oxygen Sensor Heater. You checked it at the AC and noted that it's not, so something is askew.
That wire (F22 14OR) goes to a ton of stuff. With relay out and key off, check it at the EGR solenoid, the fuel injectors, power steering pump, and the fuel pump. We already know it's hot at the Oxygen Sensor Heater. You checked it at the AC and noted that it's not, so something is askew.
#170
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From: arizona
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
#171
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From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Renix Fuel Injection Manual PDF.
https://drive.google.com/file/d/0B7L...lQYl9vR2c/view
https://drive.google.com/file/d/0B7L...lQYl9vR2c/view
Page 59.
The one with all the secrets.
#172
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From: arizona
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
All the fuse links going to starter relay were are good.
Going to try and check ohms between pin 85 on FP and pin A5 on the ECU plug and pin 85 on O2 and pin A7 on ECU today. Those are the relay pins the jumper wire has been squatting in.
Forgot to mention. The large orange wire that had the coating missing up close to the O2 relay holder (post #67), the junkyard relay holder had the exact same missing orange wire coating.
Also was lucky enough to nab the junkyard ECU. Strange it was still on it being that someone took half the dash harness and the steering column.
#173
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From: arizona
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
#175
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From: arizona
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
#176
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From: arizona
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
#177
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From: Connecticut
Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
#178
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From: arizona
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
#179
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From: Lost in the wilds of Virginia
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0