conflicting service info? 1995 range rover lwb

[bargecapt]

i have a 1995 rr county, lwb 4.2. it has 98,000 miles. i bought it in april with 95,000 miles.

vehicle started to fluctuating idle, and according to the fault readout, code 48, stepper motor.

not knowing how long it has been since last tune up, i repaced the plugs with patinum, plug wires, cap. rotor, fuel and air filter, and both temp sensors that are located in the manifold.

i also replaced the vacuum line to the distributor, and the aux air line that runs from trottle body to the air plenum.

truck ran fine for about 200 miles, then like crap.

cat's were hot, truck barely moved.

got code 48 again. cleaned the trottle body and mas sensor, still ran like crap.

pulled plugs, running rich.

adjusted idle according to rave cd, blocked off air pipes on throttle body and stepper motor, to 750 rpms, replaced aux hose, truck would hardly idle now.

every thing i did came from information that is on the rave cd or the land rover pay site, and i noticed several things that conflict.

1. according to the site and the cd, you can clear fault codes 1 at a time by turning the ignition on, then dissconnecting the serial data link connector for 5 seconds. this connector seems to be a mystery, as no one knows what it looks like or where it's located. a top land rover mechanic say that to clear a fault, disconnect the battery, but this will clear all faults.

2. there are 3 temp sensors. 2 in the manifold, and 1 in the thermostat housing. i have read that the one in the thermostat controls the fans, but i also read that it sends a signal to the ecu.

3. anyone have a chart that shows how to test the mass airflow sensor and the throttle position sensor? also, how about resistance on the various temp sensors?

i am about to sell this thing for parts, as i have spent many hours with it, and after being a mercedes tech, i hate to say it, but this is getting the best of me.

[sven]

I understand your frustration. I worked primarily on German cars all my life. Then I bought my 95 LWB 3 years ago....It was quite a learning experience!

That serial mating plug is located behind the passsenger side kick panel on a 95 RRC. If I remember correctly, I think either the connector is orange or the wires were orange.

Sounds like you need a RAVE CD, its the factory repair manual on CD. It has all the diagrams you'll ever need.

You said the truck ran fine for a little bit after the tune up....These rovers HATE platinum plugs, they foul too easily. I think thats your problem. Goto NAPA and buy some Champion "Truck" plugs part #4404. These plugs are great in my 4.2.

Give that a try, good luck!

[bargecapt]

thanks for your support. i pulled the platinum plugs and replaced them with the champions that were in it before.

now to try and clear the codes and get the idle back again.

i have the rave cd, and i also downloaded items from the range rover data pay site, and they show a data connector under the glove box. funny this is, there isn't one there on my truck, nor under the passengers seat, as someone else mentioned. i will look inside the kick panel tomorrow, as i need to dissconnect the cable to the ecu to do volt and ohm checks on the engine management sensors ect.

i know it's just a minor problem causing my truck to run like crap, just got to find it.

thanks again, barge capt.

[Disco Mike]

Have you cleaned out the throttle body, if not get a good can of car cleaner a tooth brush and some paper towel. Soak it goddd infront and behind the butterfly, scrub with the tooth brush, spray again and then wipe out as much of the carbon build up.
You might want to consider decarboning the engine do a induction cleaning, might also want to check the air trumets in the intake to make sure one hasn't popped loose, also clean them all with carb cleaner.
Don't worry about clearing the codes until after you have resolved the problem, and don't clean the MAF, half the time you will land up killing it. As for the Bosh plugs, Rovers do well with them if you have good wires and a hot coil, I have alot of friends who have switched to them with great results.
Bt the way, what sort of wires, and size mm did you install.
Mike

[bargecapt]

[quote=Disco Mike]Have you cleaned out the throttle body, if not get a good can of car cleaner a tooth brush and some paper towel. Soak it goddd infront and behind the butterfly, scrub with the tooth brush, spray again and then wipe out as much of the carbon build up.
You might want to consider decarboning the engine do a induction cleaning, might also want to check the air trumets in the intake to make sure one hasn't popped loose, also clean them all with carb cleaner.
Don't worry about clearing the codes until after you have resolved the problem, and don't clean the MAF, half the time you will land up killing it. As for the Bosh plugs, Rovers do well with them if you have good wires and a hot coil, I have alot of friends who have switched to them with great results.
Bt the way, what sort of wires, and size mm did you install.
Mike[/QUOTE

i repaced ther wires with oem borg warner 8mm, cleaned the front of the throttle body, will see what it looks like behind the butterfly this afternoon.
cleaned plugs to all sensors, replaced several vacuum lines, to fuel pressure regulator, vacuum advance, aux air.

truck started right up this morning, idled at 900 rpm, and when got to operating temp it started to flucuate. turned on the air and it wanted to die out, seems like the stepper motor is not working.

is there some way to adjust or calibrate the stepper motor, or are they automaticlly self adjusting?

[deadboy1977]

I have been having the SAME EXACT problems!
For over a year now...
PLEASE let me know what you found!
Mike