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  #1  
Old November 17th, 2019, 19:41
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blu3fan blu3fan is offline
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changed oil. car dies now.

hey guys. 92 xj 4.0
I changed my oil. now the car is backfiring and misfiring. feels like shes running on 3 cylinders.
Im thinking crank position sensor failed... again...

Timeline---
Changed oil.
Car would not start. just cranked forever.
Fuel pump is on a manual circuit. so its not fuel related.

Car throwing CEL 27.

Just to be sure this was not my distributor wiring at the plug not connecting again. I just soldered the distributor to the harness.

can anyone confirm if the cps when it starts to fail could cause nonstart/misfire ?
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  #2  
Old November 17th, 2019, 19:54
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Re: changed oil. car dies now.

I might add.
After the oil change and the initial no start.
I fiddled some wires; Unplugged and replugged distributor and cps also wiggled wires around intake since I might have touched those during oil change.
I drove her up the street.
Ran awesome.
Got about a mile up the street. and she died.
Started her up again.
Ran 20 ft.
Died.
Thats why im thinking cps. Bought another one that'll arrive Tuesday.
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  #3  
Old November 17th, 2019, 20:21
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Re: changed oil. car dies now.

Sorry - its been a long day of screwing with this thing.
After she died about a mile up the street.
I got her running. Unplugged and replugged the cps.
The last 3 times the cps has died Its been a week of random stalls then wont start.
never had a misfire..
got me home Ran fine. Just Tried to die 2x.. now she runs-- just backfires... not drive-able.
*** of course the day before I take my puppers in for surgery this happens..... ****
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Old November 17th, 2019, 20:39
lawsoncl lawsoncl is offline
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Re: changed oil. car dies now.

27 is an injector fault. Check the fuel injector wiring harnesses really well for damage, particularly where it runs along the firewall behind the intake manifold. If it looks pinched, open the wiring loom up and make sure the wires aren't chaffed and shorting together. Check that the CPS wiring isn't touching the exhaust manifold. Check all the grounds, in particular where it grounds to the engine block. You might have knock something loose there. Cap/rotor and spark plug wires all in good shape?
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Old November 18th, 2019, 07:29
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Re: changed oil. car dies now.

Quote:
Originally Posted by lawsoncl View Post
27 is an injector fault. Check the fuel injector wiring harnesses really well for damage, particularly where it runs along the firewall behind the intake manifold. If it looks pinched, open the wiring loom up and make sure the wires aren't chaffed and shorting together. Check that the CPS wiring isn't touching the exhaust manifold. Check all the grounds, in particular where it grounds to the engine block. You might have knock something loose there. Cap/rotor and spark plug wires all in good shape?
That was the first thing I did.
Unplugged each injector and replugged.
honestly I dont think I hit anything and this is just an odd coincidence.


Starting to think this is either O2 sensor circuit or cps failing somewhere.
Started her up this morning.
started.
Ran fine.
Got about 10ft.
Died.
would not start again.
I mean considering fuel pump is on a switch. this narrows t/s to injector harness.
Distributor failure.
CPS.
or o2 sensor.
I doubt this is tps or iacv.
Its running rich which indicates spark/timing related.


New Cps arrives tomorrow.
after that im gonna check the harness.
Meh....
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  #6  
Old November 18th, 2019, 08:13
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Re: changed oil. car dies now.

I know you said it is not fuel related, but I would slap a F/P gauge on it just to make sure there isn't something plugging the filter or some such issue.

I think it is also worth reiterating the wiring touching the exhaust. If an O2 sensor wire can brush the exhaust manifold it will short out and give you these symptoms. Takes a few minutes to get hot enough to melt the insulation. Upon cool down it may cease to touch and you get to repeat the joy next time you start it up. On mine it was the wiring behind the power steering pump touching the header. I know others have had issues with the wiring further downstream.
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  #7  
Old November 18th, 2019, 09:08
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Re: changed oil. car dies now.

I have a gauge mounted to the rail 60psi.
Yeah I saw my 02 sensor wiring is a little burned.
I am gonna check that out also.
but its been a little burned for years now..
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Old November 18th, 2019, 09:09
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Re: changed oil. car dies now.

Before I dig into other stuff.
CPS first. since I happen to change that pos every 2-5 years..
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Old November 19th, 2019, 09:03
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Re: changed oil. car dies now.

cps arrives today- I will get back with results.
Not hoping for much. but Im sorta thinking the CEL 27 is a separate issue.
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  #10  
Old November 19th, 2019, 15:32
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Re: changed oil. car dies now.

pulled the cps in the pouring ran.
Wiring to cps is melted.
this might explain the odd misfire and why it worked after I unplugged and replugged the cps.
soaking wet from removing it- but gonna do the "cut slits" mod so that I dont have to remove these bolts again
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  #11  
Old November 19th, 2019, 16:35
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Re: changed oil. car dies now.

so I did some research and found this gem.


https://www.flickr.com/photos/298348...08469/sizes/l/

when I rebuilt the xfer case about a month ago the speedo sensor was so ground down. I could not get the teeth to re-mesh and left it unplugged.
This would explain the code 27.
due to it being in line with the fuel injection.
or at least I suspect it is.
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  #12  
Old November 19th, 2019, 17:35
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Re: changed oil. car dies now.

Cps replaced.
Car start up really clean now.
However the stutter still exists.
it feels like the car is out of timing.
new symptom. when the car stutters the rpms on the dash drop like a short.
I think we have a short somewhere. I messed with the o2 wiring.
saw a slight change.
not 100% yet. but thinking bad connection to o2 sensor...
...
Never had an issue like this before so hopefully its not the main harness or something..
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  #13  
Old November 21st, 2019, 09:03
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Re: changed oil. car dies now.

I think my cps connection is bad. Can't seem to find a replacment harness side plug. Probly gonna junkyard run and pull a harness this weekend
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  #14  
Old November 21st, 2019, 18:53
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Re: changed oil. car dies now.

Update.
cps wiring is sketching me out. there is a slit the harness by the connector.
since every time car has died recently ive messed with cps.
cutting that part out and making a new "ghetto connector" out of rtv.
will post an update.
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  #15  
Old November 22nd, 2019, 10:46
Skwerly Skwerly is offline
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Re: changed oil. car dies now.

I can't wait.
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