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98 disco 4.0 rough idle will not run

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  #21  
Old 02-07-2009, 06:08 PM
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Default RE: 98 disco 4.0 rough idle will not run

The stepper motor is on the front, closest to the t-body opening.
Two bolts hold it on, the throttle position sesnor has two star head bolts holding it on.
If you find something let me know.
I will be working on mine again tommorrow after it gets light.
 
  #22  
Old 02-08-2009, 10:22 AM
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Default RE: 98 disco 4.0 rough idle will not run

FIXED!!

Being a idiot...$0.
Being a frustrated idiot...$0
Owning a stupid as you are easy as pie to fix if you think about it Land Rover...PRICELESS!!

oljohnboy-start your truck, let it run until the temp gauge reaches normal and the upper radiator hose is hot.
Make sure A/C is off.
With the engine still running loosen, do not remove the two screws that hold your TPS, watch out for the fan and pullies, it is really hard to type one handed.
Adjust the TPS just a smidge, your idle will either increase or decrease, adjust the TPS until the idle is down to the 600 rpm range, 500-700 rpm is the base idle for a fully warmed DI V8.
Tighten the screws back up, rev the engine a few time to make sure the idle goes back to normal.
Job is done!
 
  #23  
Old 02-09-2009, 06:54 AM
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Default RE: 98 disco 4.0 rough idle will not run

I did the same thing, as far as I took the whole think loose. I do not see how to adjust it. it seems to be a solid piece to me. I took it off when it was running, and turned by hand and the idle dropped. is there an adjustment screw? Also, i cleaned the stepper motor, is there a way to test that also?

Thanks
 
  #24  
Old 02-09-2009, 07:11 AM
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Default RE: 98 disco 4.0 rough idle will not run

No do NOT remove the TPS from the truck, just loosen it and then move the TPS unit, the whole thing, just move THAT.
There is no adjustment scew, just the TPS.
(there is a idle speed adjustment screw but you never need to mess with it)

There is no way to test the stepper motor.
Either it works or it does not.
A stepper motor from a 1997 Jeep Cherokee 4x4 with the 4.0 engine is the same as a LR 4.0 stepper motor.
It is $40 from AutoZone.
 
  #25  
Old 02-09-2009, 07:41 AM
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Default RE: 98 disco 4.0 rough idle will not run

Well that is not my issue apparently, I think I am going to replace the stepper motor anyway. It was pretty gunked up, and they are relatively inexpensive. I will let you know if that helps this afternoon!
 
  #26  
Old 02-09-2009, 08:45 AM
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Default RE: 98 disco 4.0 rough idle will not run

Also John, make sure that your plug wires are seated properly onto the coil posts.
Mine were not, I had to stand on a ladder to get enough power to seat them properly, now it idles smooth as silk.
 
  #27  
Old 02-09-2009, 12:43 PM
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Default RE: 98 disco 4.0 rough idle will not run

Cool. I will check that. I called auto zone, they had the cherokee one in stock for $44, the "land rover" motor would have to be ordered for $244. what a croc [sm=jawdrop.gif]
 
  #28  
Old 02-09-2009, 09:38 PM
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Default RE: 98 disco 4.0 rough idle will not run

Hi
Great thread,,thanks for all the info Spike.

Ed
 
  #29  
Old 02-10-2009, 11:31 AM
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Default RE: 98 disco 4.0 rough idle will not run

You guys may hate me, and I may hate myself a little, i took it to a mechanic, it is the stepper motor, which i already bought, they want to install it so they can calibrate it to the ecu or something like that. is this bulls#*t, or can i just plug and play. I feel the need to get her out of there. They do a good job, I just dont need to drop 85/hr for no reason.
 
  #30  
Old 02-10-2009, 12:36 PM
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Default RE: 98 disco 4.0 rough idle will not run

The TPS has to be calibrated "sometimes", but the stepper should be plug and play.
 


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