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1970-1995 Range Rover Classic
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Discussion Starter #1
As I continue forward sorting out this long abandoned RRC that sat in a field for 6 years I find something new pops up for resolution. I am not sure if this is two different issues or one tied to the the ignition switch.

1. While test driving around town the RRC has developed a hiccup in her idle and running. Variations in the idle go from smooth at normal 850 rpm to holding steady at 1100 rpm or at other times varying between 900 to 1500.

2. When driving she starts to hiccup and seem like she wants to shut down. When I come to a stop light, she will stall out at times. She always starts back up after a few trys.

3. During a most recent test drive, she died completely with all electrical on the panel going dead. Jiggling the key and start attempts brought power back and she started up. We got her home.

So I am sure we have an ignition switch issue. My question is do we have a fuel system issue or vacuum issue as well?

Thank you in advance,

Walt
 

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Is sounds like a tps
Or stepper motor issue
The switch is an interesting assembly
If you were too pull of the cover.. the switch wraps around the steering column
And the electric part of the switch just pops on and is held in place with a set screw... just a fyi thing
Have you checked for any codes ??
 

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Idle is raised while air-con is on, so you'll see some variation if used or not. Leaving off will allow that to be taken out of equation for assessment.

Rpm report to ecu only comes from a signal wire on ignition coil (think it's white with black tracer) but worth making sure the low tension wires in those terminals are clean and secure to avoid intermittent contact.

The completely dead if all warning lights etc go out would make the switch on back of ignition barrel a prime suspect and worth inspection, wiggling to ascertain if you're looseing contact there.

If the above are all verified as ok, then idle speed is controlled by the stepper motor at rear of intake plenum. It just bleeds air past the main throttle plate to range idle up or down. This is in response to that signal wire input from coil mentioned above. So above target it closes valve to reduce rpm and opposite for too low. Sounds like the stepper (IACV "idle air control valve") is working as it is ranging the rpm up and down.

Also check first the timing advance, if it's been set too far in advance the ecu will struggle to modulate rpm effectively. In effect it will overshoot and be unstable in it's effectiveness.
If it overshoots by too much going low, then it breaches the ecu floor rpm value which will switch the fuel pump off with the motor quitting.

The overall idle is specifically set mechanically, but the control when running is entirely with the ecu. There's a specific routine to reset it if it's been inappropriately tampered with.

It's a fairy simple system but you've got to go through it in order to diagnose and not react to something spurious. Many of them have been screwed around with that makes them seem poor. Sounds like you're not far away but need to go through it to get it competent.
 

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1970-1995 Range Rover Classic
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Discussion Starter #4
1. The air conditioning is inop right now so that is not a factor.
2. I will check, clean and tighten the wires to the coil
3. How difficult will it be to remove and replace that ignition switch?
 

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1970-1995 Range Rover Classic
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Discussion Starter #5
In response to Mikieman, I have not pulled the codes yet, but the Check Engine light comes on and off at times. So there is definitely something going on there.
 

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The switch block detaches from the mechanical part of steering lock etc. Just a peripheral screw to unsecure it an it'll come off.

Access ok once you remove cowelling around steering column.
 

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I recently experienced pretty much everything you described on my '93. After talking to a mechanic, cleaning out the T piece by the plenum helped. It had some buildup inside for a 27yr old car and it smoothed things out, but only a little. Finally brought it in to an expert and a repair to the mass air flow sensor fixed everything.
 

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1989 Range Rover Classic
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Other things to look into could be the ignition amplifier module (not sure if that was mentioned in a previous thread?), they're notoriously unreliable and can be really finicky before they die completely. When they're on the fritz it can cause random dying at idle/stoplights. For the IAV, there are are identical ones for other cars that cost a tiny fraction of what the land rover ones do, so do a bit of searching rather than waste money one an OEM one. Sometimes just cleaning it can help, they get all gummed up and get stuck, so if there's lots of crap on it when you pull it off, clean it up and try it again, see if the problem goes away.
 

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To remove the screws that hold on the switch assembly... I used a sharp punch and hammer to turn the screws...
Also the 91 has the code reader attached to the side of the passenger seat .. behind panel faceing door
 

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1989 Range Rover Classic
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As mentioned above, a sharp punch (or flathead screwdriver) and a hammer are the needed tools for those breakaway studs. I had to do exactly that on a trail in the desert. Drove for miles down a dirt wash, parked, went on a nice hike, came back, and the ignition barrel was locked up! There was one other car in the wash, guy happened to have a couple of rock hammers in his truck and let me borrow one. That teamed with a screwdriver from my kit meant I could spin out the screws to remove the steering lock, pull the ignition switch off the back of the ignition barrel, and use a pair of pliers to turn the rotary switch. Got me back to town!
 
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