Engine won't start, new fuel pump not working
CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
theres a ballast resistor bypass relay located out side of pdc box also need to check o2 sensor wiring for shorts that fuse also powers o2 good luckhttp://www.google.com/search?hl=en&s...1c.V2nggyXnfdk
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Bypassing the ballast resistor won't really change anything. (unless it's bad/"open"/(not passing current))
Renix Jeeps have an "Electronic Control Unit", to 90, then it's Power Control Module after that. (ECU>PCM)
No, a relay is not like a fuse or breaker. Current passing from the "right hand" to the "left hand" energizes a coil that closes points to then pass current from the toes to the head. The "SPDT" "single pole , double throw" we have even passes current from the toes, out the belly button (middle), while it's not energized. (then cuts that with current passing through it's coil)(hence, "double throw")
Circuits can get pretty clever there, grounding, or energizing different terminals.
Renix Jeeps have an "Electronic Control Unit", to 90, then it's Power Control Module after that. (ECU>PCM)
No, a relay is not like a fuse or breaker. Current passing from the "right hand" to the "left hand" energizes a coil that closes points to then pass current from the toes to the head. The "SPDT" "single pole , double throw" we have even passes current from the toes, out the belly button (middle), while it's not energized. (then cuts that with current passing through it's coil)(hence, "double throw")
Circuits can get pretty clever there, grounding, or energizing different terminals.
Last edited by DFlintstone; Aug 25, 2012 at 06:01 PM.
CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
Thread Starter
Junior Member
Joined: Jul 2012
Posts: 37
Likes: 0
From: Santa Cruz, CA
Year: 93
Model: Cherokee
Engine: 4.0L I6 HO
Yep relays were in, so is the pump itself shorted somehow? how could that be?
I checked the o2 sensor, and everything visibly looked alright. though now that I see the location of the o2 sensor, this would probably be a good time to mention I recently found a crack in my exhaust manifold...its right above the connection to the pipe section with the o2 sensor. is there more than 1 o2 sensor? Looks like the manual shows only 1...
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I checked the o2 sensor, and everything visibly looked alright. though now that I see the location of the o2 sensor, this would probably be a good time to mention I recently found a crack in my exhaust manifold...its right above the connection to the pipe section with the o2 sensor. is there more than 1 o2 sensor? Looks like the manual shows only 1...
Uploaded with ImageShack.us
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Last edited by Sir Jeep-a-Lot; Aug 25, 2012 at 07:33 PM.
Thread Starter
Junior Member
Joined: Jul 2012
Posts: 37
Likes: 0
From: Santa Cruz, CA
Year: 93
Model: Cherokee
Engine: 4.0L I6 HO
Thread Starter
Junior Member
Joined: Jul 2012
Posts: 37
Likes: 0
From: Santa Cruz, CA
Year: 93
Model: Cherokee
Engine: 4.0L I6 HO
Cool, there's a local store here that carries Bosch pumps....knew I should have stayed away from O'Riely's for any important parts haha.