05 TJ LS swap

77GreenMachine said:
Digital angle finder is invaluable for many reasons. One very big one is for reference. You don’t always need to find a true angle, but you can zero it out on something (like a cage) and find the difference, or needed angle.
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cuz OMG math and using a tool that doesn't require batteries is hard.

JK, I have multiple of both styles, they all have their place.

:p
 
this TJ has a 1 wire oil sending unit. that wire shows ground with key off, hot when key on/running? but no gauge, nothing. driving me crazy with this stupid sensor.
anyone know should the wire be hot when running and ground when off? Does the computer control polarity on it or is there a wire crossed somewhere. thanks in advance
 
braxton357 said:
Jump that wire to ground and the gauge should swing to max pressure. The gauge is just an ohmmeter sensing resistance to 12v neg through the sender that changes resistance based on pressure.
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So it's not supposed to turn positive when key on/running but remain a ground circuit that just changes the resistance of that ground based on pressure? Am I understanding that correctly...thank you
 
Jumped it to ground, it didn't budge... guess I'll pull it out and see what the resistance is
 
marty79 said:
Jumped it to ground, it didn't budge... guess I'll pull it out and see what the resistance is
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If you grounded the gauge and it did not move the gauge is bad or the wire to it is bad. Check continuity in the wire. Then ground the gauge with a short wire. That how I would test that.
 
ghost said:
If you grounded the gauge and it did not move the gauge is bad or the wire to it is bad. Check continuity in the wire. Then ground the gauge with a short wire. That how I would test that.
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Oh no I ground the wire coming off the sensor itself and nothing.
Sensor reads 2.0 ohms with multimeter set to 200
 
Dont believe it's a gauge issue cause all other 3 work, just not oil and they share a ground behind the dash
 
99-02 GM trucks with a single wire sending unit do not feed oil pressure information through the ECM(diesel) or PCM(gas). It feeds directly to the dash. Then if it drops below the threshold, it'll throw a dash light.

That's probably where your issue lies. If you're using any part of the Jeep wiring or dash, you'll probably need to put the Jeep sending unit in it.
 
Stupid dam Haynes manual about worthless..I knew this but was again just now confirmed cause well, its wrong again.
Wire from ECU to sensor is good!
Sensor has 2.0 ohms but apparently should read infinite since it's a switch?? So since I have 2.0 that confirms it's bad correct?

Croatan_Kid said:
you'll probably need to put the Jeep sending unit in it.
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Gauges are factory
 
Factory, as in the Jeep gauge cluster is still in place? If so, that's why I was saying you'll likely need to use the Jeep sending unit and it'll probably need a threaded adapter. I THINK the LS ones are metric, but I can't remember.

GM changed a lot of wiring from 02 to 03 in the trucks as well as that hideous front end they went to :D

I believe 03+ got a 3 wire sending unit and it does, in fact, read through the ECM/PCM.

Whether the GM oil pressure sending unit is bad or not, it likely won't communicate with the ohm range of the Jeep oil pressure gauge on the dash. Hell, the Jeep gauge may have originally been fed through the PCM, I'm not sure, but that's definitely something you'd want to figure out. Most Jeep LS swaps (that I've seen) piggyback the Jeep PCM with the GM one to control the dash and some other things....or they swap out the dash panel and do an insert with a handful of aftermarket gauges.

I'm sure someone has figured this out and has put it on the interwebz though. Off to Google you go!
 
I'm assuming fuller screwed the jeep sending unit into the 5.3 block. If its a pressure sending unit for a gauge it should not read infinite, if it's a discrete on/off switch for a dummy light then it also shouldnt read inf with the engine off.
 
Correct. You'll need to put the Jeep pressure sending unit in the engine. It'll probably play nicer that way.

EDIT: Add some Interwebs halp.
 
Croatan_Kid said:
Factory, as in the Jeep gauge cluster is still in place? If so, that's why I was saying you'll likely need to use the Jeep sending unit and it'll probably need a threaded adapter. I THINK the LS ones are metric, but I can't remember.

GM changed a lot of wiring from 02 to 03 in the trucks as well as that hideous front end they went to :D

I believe 03+ got a 3 wire sending unit and it does, in fact, read through the ECM/PCM.

Whether the GM oil pressure sending unit is bad or not, it likely won't communicate with the ohm range of the Jeep oil pressure gauge on the dash. Hell, the Jeep gauge may have originally been fed through the PCM, I'm not sure, but that's definitely something you'd want to figure out. Most Jeep LS swaps (that I've seen) piggyback the Jeep PCM with the GM one to control the dash and some other things....or they swap out the dash panel and do an insert with a handful of aftermarket gauges.

I'm sure someone has figured this out and has put it on the interwebz though. Off to Google you go!
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Nono I'm using everything jeep factory stuff put into LS block.
 
braxton357 said:
I'm assuming fuller screwed the jeep sending unit into the 5.3 block. If its a pressure sending unit for a gauge it should not read infinite, if it's a discrete on/off switch for a dummy light then it also shouldnt read inf with the engine off.
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His is a gauge so either way your confirming from my tests it's a bad sensor?
Thanks yall
 
Scooter402 said:
Correct. You'll need to put the Jeep pressure sending unit in the engine. It'll probably play nicer that way.

EDIT: Add some Interwebs halp.
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I done that without ever finding it on the web..I just figured that's how others did.
 
braxton357 said:
If you used a bunch of teflon tape on the threads, it might not be able to ground out through the engine like it needs to. You can run a wire from the body of it to the neg battery terminal and see what happens
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Ok will try this, I read about that too. Thanks
 
braxton357 said:
If you used a bunch of teflon tape on the threads, it might not be able to ground out through the engine like it needs to. You can run a wire from the body of it to the neg battery terminal and see what happens
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That's a negative. Gonna pick up new sensor later on
 
it's all done, tried test driving past 30 now and trans jumping out of gear, revving up then back into gear..couldn't go much faster. No codes except maf sensor low circuit...
So the np241 has a different vss on tailshaft so what do I need. I'm kinda lost on this speed sensor talk and different pulse rings etc etc. Help in right direction would be appreciated much. Thank you
 
marty79 said:
it's all done, tried test driving past 30 now and trans jumping out of gear, revving up then back into gear..couldn't go much faster. No codes except maf sensor low circuit...
So the np241 has a different vss on tailshaft so what do I need. I'm kinda lost on this speed sensor talk and different pulse rings etc etc. Help in right direction would be appreciated much. Thank you
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I thought that’s one of the things that get turned off in the tuning?
 
77GreenMachine said:
I thought that’s one of the things that get turned off in the tuning?
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uhh forgive my ignorance but if that got turned off how can the trans shift? I've been reading so much on it, according to research the vss in the NP241 "should" work without any other things besides just splicing in the wires...but at this point it seems I'm missing a main harness that goes from ECU down to the T-case that has the original 3 speed sensor plugs with the electric shift harness on it...idk, I'm all confused with this now. I'm a keep on researching to see what I'm missing. thanks bud
 
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