1991 Range Rover Classic or My Foray Into Madness
- Thread starter en480c4
- Start date
en480c4
Well-known member
Kinda hoping a tree falls on this thing while I’m out of town for work.
Tried troubleshooting a cold-start issue. It would have a bit of a rough idle and stumble for about 30 seconds after starting to drive. Seemed like it was tied to ignition since it was worst after damp/rainy nights or lots of humidity. Consistent through multiple tanks of gas, so it doesn’t seem like a fuel issue. So I pulled the cap and rotor to check them. Didn’t touch the distributor. Things looked fine-ish. Figured I’d order a replacement and see if that did the trick. Well, after reassembling, it barely runs. Stumbles, misses, even backfires. Timing seems totally jacked. But the rotor and cap are keyed, so I don’t see how it could’ve gotten so much worse from what I did. Tried swapping cap, rotor and plug wires from the parts RRC, which “ran when parked” to see if that helped while waiting for new. No change. Swapped in a new coil. No change. So I now have a new distributor to install, but can’t find the timing mark on the crank pulley. So I need to find someone to have it towed to or pull the #1 plug and see if I can find TDC. My only hope is that it’s the pickups or ignition amplification module on the distributor and it’s an east fix.
The plus is I picked up a gravel bike when I went back to my old Federal job. It’s a 5-7 mile ride each way, depending on the route. So at least I can work on getting back into shape.
Tried troubleshooting a cold-start issue. It would have a bit of a rough idle and stumble for about 30 seconds after starting to drive. Seemed like it was tied to ignition since it was worst after damp/rainy nights or lots of humidity. Consistent through multiple tanks of gas, so it doesn’t seem like a fuel issue. So I pulled the cap and rotor to check them. Didn’t touch the distributor. Things looked fine-ish. Figured I’d order a replacement and see if that did the trick. Well, after reassembling, it barely runs. Stumbles, misses, even backfires. Timing seems totally jacked. But the rotor and cap are keyed, so I don’t see how it could’ve gotten so much worse from what I did. Tried swapping cap, rotor and plug wires from the parts RRC, which “ran when parked” to see if that helped while waiting for new. No change. Swapped in a new coil. No change. So I now have a new distributor to install, but can’t find the timing mark on the crank pulley. So I need to find someone to have it towed to or pull the #1 plug and see if I can find TDC. My only hope is that it’s the pickups or ignition amplification module on the distributor and it’s an east fix.
The plus is I picked up a gravel bike when I went back to my old Federal job. It’s a 5-7 mile ride each way, depending on the route. So at least I can work on getting back into shape.
en480c4
Well-known member
Talked with a guy who has a shop that specializes in Range Rover Classics and Land Rover Discoveries and Defenders, many of which share the 3.9L Buick-based engine. He's pretty convinced it's the distributor since messing with the cap/rotor kind of kicked off the escalation of issues. He's local, about 20 minutes away, but can't look at it until the 25th. So I'll probably swap plugs and wires when I have the chance, and if I can fish around some more and determine TDC, I'll consider stabbing the new distributor into it. Worst-case, it still gets towed in two weeks and he takes care of it.
en480c4
Well-known member
Well, I’m not afraid to admit defeat. This exceeded my diagnostic skills, even following the shop manual. It’s off to get looked at by someone far more knowledgeable than me. Hoping to hear back later this week.
Before it went off, I was able to swap in the new alternator… The regulator was shot and it was overcharging. So at least I won’t have to deal with that when it gets back.
Before it went off, I was able to swap in the new alternator… The regulator was shot and it was overcharging. So at least I won’t have to deal with that when it gets back.
en480c4
Well-known member
Despite the reputation they have, it really has been. The only other thing I've fought is the safety inertia switch for the fuel pump. And that was mostly my struggle to diagnose it.
The driver even let my youngest help him load it! She had so much fun.
I'm really looking forward to getting some color on the replacement panels.
en480c4
Well-known member
I picked up the RRC yesterday. They did plugs, wires and the new distributor, and going down the road, it runs better than ever. The vacuum advance mechanism had essentially grenaded in the distributor, probably when I tried to address the fact that it was falling out, which was why it went to hell when I did so little to the distributor.
However, it has a major issue with the idle. Whatever issue I was trying to troubleshoot before making it worse has itself gotten worse. It uses an old-school EFI setup where idle is handled with an IAC or Idle Air Control bypass valve. It does not appear to be operating, and it hunts for idle and stumbles and nearly stalls. Both the new and original IAC result in the same issue. The shop ran the idle up to make it kind of drivable, but it still needs to get sorted. There are a number of possibilities, from the MAF, TPS, coolant temperature sensor, road speed sensor, engine speed output from the coil or a bad ECU. Any of these could affect the EFI system from correctly setting the idle, but it seems to all go back to the IAC not operating as intended. I have some spares already pulled from the parts RRC, and the manual has some decent troubleshooting guidance. But frustration is pretty high right now. I'm quickly learning LR's bad reputation regarding electrics is well-deserved.
However, it has a major issue with the idle. Whatever issue I was trying to troubleshoot before making it worse has itself gotten worse. It uses an old-school EFI setup where idle is handled with an IAC or Idle Air Control bypass valve. It does not appear to be operating, and it hunts for idle and stumbles and nearly stalls. Both the new and original IAC result in the same issue. The shop ran the idle up to make it kind of drivable, but it still needs to get sorted. There are a number of possibilities, from the MAF, TPS, coolant temperature sensor, road speed sensor, engine speed output from the coil or a bad ECU. Any of these could affect the EFI system from correctly setting the idle, but it seems to all go back to the IAC not operating as intended. I have some spares already pulled from the parts RRC, and the manual has some decent troubleshooting guidance. But frustration is pretty high right now. I'm quickly learning LR's bad reputation regarding electrics is well-deserved.
en480c4
Well-known member
So, thanks to the parts rig, I had a spare EFI ECU, TPS and MAF to swap. After swapping things and clearing codes, it appears I’ve been able to narrow it down to the TPS. The one from the parts rig is bad too, but in a different way. With the original, it stumbles and wants to stall once you put it in gear. With the second one, it idles great, and is fine off the line, but it cuts out at 1500 RPM when driving. New ones aren’t available, but a kit to convert it to a different type is, albeit ridiculous money for what it is. But with no other choice, the new one arrives tomorrow and I should know in about 15 minutes if it’s the cure for what ails the RRC.
en480c4
Well-known member
Well, I’m not giving up on the Rover, but I am admitting defeat using it as a daily driver. Committed to buying a low(ish)-mileage ‘05 VW Touareg with the V8 with the air suspension. Nothing like supplementing British automotive reliability with an 18 year-old example of overly-complicated German automotive engineering. What could possibly go wrong?
I’ve been reaching out to everyone I’ve met in the Rover world for help. The new TPS acts the same as the old one. Still getting a TPS code. So I’m guessing broken wire somewhere or a short. Still pretty frustrated. I probably would move on if I wouldn’t take a bath selling a non-driving project.
I’ve been reaching out to everyone I’ve met in the Rover world for help. The new TPS acts the same as the old one. Still getting a TPS code. So I’m guessing broken wire somewhere or a short. Still pretty frustrated. I probably would move on if I wouldn’t take a bath selling a non-driving project.
en480c4
Well-known member
So, I haven’t updated in a while. It starts great, runs and drives amazing when cold, but it badly wants to stall when up to temp if you have it in gear and are stopped. And the idle is rough in N when warm.
So far I’ve replaced:
Distributor
Coil
Plugs & Wires
Idle Air Controller
Throttle Position Sensor
Lambda Sensors (Oxygen)
Fuel Pump
Fuel Filter
And I’ve tried swapping:
Vehicle Speed Sensor
Mass Air Flow Sensor
EFI ECU
It seems like it’s running rich, so I’m thinking an injector may be stuck open? So I’ve picked up a new set of injectors and a new fuel pressure regulator. When I do that, I’ll be able to clean the intake.
I still need to swap my ignition amplification module. But other than that, I’m not sure what else it could be. I may disconnect the muffler in case the cats deposited some material in it and partially clogged it. And the only other thing I can think to do is pay with the timing in case the crank pulley rotated on the crank and the timing is still off even after being set with a light.
Since it’s a bit of a mess cosmetically, I’d really have to take a bath on it if I were to try to move on. So I finally wrapped up my headliner mod with a little filler to smooth the tradition, as well as relocating the front overhead light.
Now I just need to add the fabric.
I also need to start respraying the sheet metal from the parts RRC, and since I don’t want to spray a metallic, I wanted to try my first choice fora color change before spending a ton on paint. I picked up a spray bomb off single-stage Land Rover Balmoral Green. I sprayed the tailgate, and it turns out I don’t love it, so I’m going to try Eastnor Green before I decide.
Otherwise, a tree landing in this thing won’t hurt my feelings. It feels like expensive yard art at this point. If injectors don’t do it, I’m thinking carb conversion in the spring.
So far I’ve replaced:
Distributor
Coil
Plugs & Wires
Idle Air Controller
Throttle Position Sensor
Lambda Sensors (Oxygen)
Fuel Pump
Fuel Filter
And I’ve tried swapping:
Vehicle Speed Sensor
Mass Air Flow Sensor
EFI ECU
It seems like it’s running rich, so I’m thinking an injector may be stuck open? So I’ve picked up a new set of injectors and a new fuel pressure regulator. When I do that, I’ll be able to clean the intake.
I still need to swap my ignition amplification module. But other than that, I’m not sure what else it could be. I may disconnect the muffler in case the cats deposited some material in it and partially clogged it. And the only other thing I can think to do is pay with the timing in case the crank pulley rotated on the crank and the timing is still off even after being set with a light.
Since it’s a bit of a mess cosmetically, I’d really have to take a bath on it if I were to try to move on. So I finally wrapped up my headliner mod with a little filler to smooth the tradition, as well as relocating the front overhead light.
Now I just need to add the fabric.
I also need to start respraying the sheet metal from the parts RRC, and since I don’t want to spray a metallic, I wanted to try my first choice fora color change before spending a ton on paint. I picked up a spray bomb off single-stage Land Rover Balmoral Green. I sprayed the tailgate, and it turns out I don’t love it, so I’m going to try Eastnor Green before I decide.
Otherwise, a tree landing in this thing won’t hurt my feelings. It feels like expensive yard art at this point. If injectors don’t do it, I’m thinking carb conversion in the spring.
en480c4
Well-known member
Injectors and the fuel pressure regulator didn’t help.
So, time to close out another thread. This got picked up today. 4 1/2 months and no progress with the issues and I could take no more. Cool rig, and I’ll miss it. But I won’t miss the frustration of the past few months. It’s going to a guy who works in a LR shop.
I’ve never owned a YJ before, and the wife and I are thinking of trying to find something for beach and ice cream runs. So the (next) hunt is on.
So, time to close out another thread. This got picked up today. 4 1/2 months and no progress with the issues and I could take no more. Cool rig, and I’ll miss it. But I won’t miss the frustration of the past few months. It’s going to a guy who works in a LR shop.
I’ve never owned a YJ before, and the wife and I are thinking of trying to find something for beach and ice cream runs. So the (next) hunt is on.
en480c4
Well-known member
Not RR related, but spent a couple of hours working on the '62 Willys with my father. After sitting for an unknown period, we want to make sure it'll run before doing anything else. So we cleaned the crank pulley to find the timing marks, pulled the carb for a cleaning and rebuild, and pulled the distributor someone had put on in an effort to convert it to another ignition system. PO couldn't get the ignition system to work correctly, but we have a new OE-style distributor to go back to, and the rest of the ignition parts are new and ready to go in. So once we get the distributor squared away, we'll get ignition-critical stuff wired and a basic fuel source plumbed and see if we can get things thing to light off.
