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starts and runs - but then does not start after

RTFM

RTFM

NAXJA Forum User
Location
Southern I-De-Ho
OK 1989 XJ I6 5SP Manual 205,000miles.

Starts with on issues - but if I drive it for an hour or so all of a sudden it's like I'm running with one cylinder and the other 5 are dead, massive loss of power with no acceleration, followed by complete death and no start.
It cranks and cranks and cranks but no start.
If I let it sit for 5 or more hours it will start and run again.

I notice when I start and run it the voltage gauge is at 14V
When it does not start (when dead) the gauge is less than 9.

I think it's a sensor issue but don't know which sensor(s) to start looking at.

EDIT:
I should add less than 6 Mo ago I replaced the plugs, plug wires, dist cap, rotor (inside dist cap), all vacuum lines, battery, battery cables, clutch, clutch master cyl, clutch slave cyl, fly wheel, radiator.
All were new parts not from the junk yard.

:repair:
 
Last edited:
1) Where do I find the Crank Position Sensor... and is it testable by me?

2) I don't know - but I think no color or odor.... what are you getting at with the exhaust? Also do you mean when it's dead and I'm trying to start it - or when it's running?
 
OK I have a new CPS coming from 4wd.com - my problem is that I have limited skill and just a driveway to change the sensor in.

How do I get at the damn thing? I am not able to reach it from the top (through the open hood) and can not get at it from laying on the ground looking up at it.

So how did you all (that have changed one) do it?
 
Hold off on the CPS for now. When it won't start, have someone crank it while you check the primary HV wire for spark to ground, if it sparks it is not the CPS, if the spark is missing then change the CPS as it might be the real problem.

If you have spark, but no ignition then check for fuel pressure at the fuel rail. IF the fuel pressure is there, then check to see if the spark plugs are getting gas, maybe flooded?

If the plugs are wet, flooded, the IAC on the throttle body may not be working all the time, it may be sticking, or the shutdonwn / reset relay (I forget its name, B+ latch relay IIRC?) for the IAC may not be working to reset the IAC for the next restart.

Search "crankshaft position Sensor installation" and 5-90 as the poster in advanced search for a few good threads on CPS instalation tricks and tools, and warnings about not dropping parts in the housing.

Sorry I did not see your question sooner.

OH, and if it is flooded, you can dry it out quickly, and get it to start by holding the gas peddle to the floor, wide open throttle, WOT, as that shuts off the fuel injectors at the ECU during starting!!!!
 
Ecomike said:
Hold off on the CPS for now. When it won't start, have someone crank it while you check the primary HV wire for spark to ground, if it sparks it is not the CPS, if the spark is missing then change the CPS as it might be the real problem.

If you have spark, but no ignition then check for fuel pressure at the fuel rail. IF the fuel pressure is there, then check to see if the spark plugs are getting gas, maybe flooded?

If the plugs are wet, flooded, the IAC on the throttle body may not be working all the time, it may be sticking, or the shutdonwn / reset relay (I forget its name, B+ latch relay IIRC?) for the IAC may not be working to reset the IAC for the next restart.

Search "crankshaft position Sensor installation" and 5-90 as the poster in advanced search for a few good threads on CPS instalation tricks and tools, and warnings about not dropping parts in the housing.

Sorry I did not see your question sooner.

OH, and if it is flooded, you can dry it out quickly, and get it to start by holding the gas peddle to the floor, wide open throttle, WOT, as that shuts off the fuel injectors at the ECU during starting!!!!
Click to expand...

Mike great trouble shooting steps. I did not step back and remember not to just start thowing parts at it.

On the IAC if it is failing most of the time you can hold the gas peddle down and it will start, as soon as you let off the peddle it will die.

Found the holding down on the gas peddle down all the stops fuel to the injectors interesting. Never knew.
 
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