Classic LSE cutting out at idle...

Above are the displays from the ECU, with the ignition on but the engine not running as it still won't start.

The ecumate isn't registering any faults.

I've just taken one of the plugs out, and it smells of fuel so it would appear that I am getting fuel, but no spark.

The coil is a new Bosch one, and the ignition amp has been replaced in the past, but I'm wondering if the amp could have failed again. The connector is currently off of it but I've got two spade connectors directly on the pins so that shouldn't be causing the issue.

VogueLSE4.2 said:

Above are the displays from the ECU, with the ignition on but the engine not running as it still won't start.

The ecumate isn't registering any faults.

Click to expand...

Yes it is!

Your throttle pot is a mile out. 57% and 2.80v no good if that is the idle position, should be more like 0.28v and 5%. The non-starting is probably due to flooding because throttle pot at 2.80v, ecu thinks the throttle is open so no idle stabilisation and will be wanting to dump more fuel in.

Suggest set throttle pot to read between 0.28v and 0.3v (no more). Re-set ecu. Charge the battery, you'll need plenty voltage - read on.

Once you've done that spin it over and see if it will start, if it doesn't fire after a couple of tries STOP. Pull the plugs and see if they look wet, if they are, dry and clean them. Pull the leads off the negative side of the coil and with the plugs still out crank the engine over a couple of times to clear the cylinders. Reconnect coil.

If you can get somebody to help out, check you have a good spark. First, crank the engine with the king lead held just above the rocker cover, there should be a nice strong spark, next put a plug in one of the leads and earth the plug electrode on the rocker cover and check for a good spark on the plug (make sure the rocker cover is clean, if it doesn't give a good earth you won't see a spark). If you are happy you have sparks, put the plugs back in.If you have a good spark from the king lead and nothing from a plug lead pop the dizzy cap off and check the rotor arm then clean it. Check the contacts inside the cap, if they have deposits on them clean them off with either a needle file or some medium wet and dry paper. Look carefully for any track marks or cracks in the cap. If you replace the arm and/or cap use genuine Lucas - DO NOT USE PATTERN IGNITION PARTS. Re-fit arm and cap.

Now mark the position of the distributor (this is important), then loosen the dizzy clamp so you can rotate the dizzy with moderate pressure (you don't want it too loose). Advance the timing by turning the distributor (anti-clockwise), don't go too mad with it though. Then try firing it up. If you have an assistant, get them to crank the engine while you rotate the dizzy to advance the timing, hopefully it will fire. If it does, let it run for a couple of minutes to get some heat in to the engine, then rotate the dizzy back to its original position. Switch off and try a re-start, hopefully all will be well.

Further to kev's advice above:

The voltage the ECU recognises as idle position is 0.33v

Make sure you check the spark with insulated pliers to avoid a shocks

Personally, I would be reluctant to adjust the timing at this stage, if it hasn't been moved since it last ran, just in case you create a second reason not to run.

Before you start any of this, pull your dipstick and sniff the oil. If it is contaminated with petrol, dump it, it could ruin your engine

Also before you start reset the ecu (clear the exclamation warning light) by disconnecting your battery for a couple of minutes. Your ECU mate is telling you it is currently running the limp home fuel map.

cooltide said:

Also before you start reset the ecu (clear the exclamation warning light) by disconnecting your battery for a couple of minutes. Your ECU mate is telling you it is currently running the limp home fuel map.

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For reference, the Ecumate will always show "limp" if engine is not running, and 4.99v at afm, it also says no cats which is not true for this engine, I nearly said the very same but checked it against my own with engine off and had the same so just a peculiarity of the thing. If it shows limp with engine running then there will (should) be fault codes.

About advancing the ignition timing, this is only to help the engine to start. I have used this method a number of times and it works well.

Thanks a lot for the help.

I've been out to look at the car today, and I can't get the potentiometer below 58% with the engine switched off, even though the holes have been filed to allow some adjustment. Does this mean the potentiometer is completely knackered?

Also, I took the King lead off and held it above the inlet plenum, but I'm getting no spark. I've used a basic voltage checker to see if there's power going to the coil when I turn the ignition, but it's not showing live on any of the wires attached to the coil.

Finally, I took the distributor cap off and found that there's some movement in the rotor arm - this doesn't seem right to me, what do you think? A pal also remarked that when turning the car over, the dizzy cap appears to move up and down slightly.

VogueLSE4.2 said:

Thanks a lot for the help.

I've been out to look at the car today, and I can't get the potentiometer below 58% with the engine switched off, even though the holes have been filed to allow some adjustment. Does this mean the potentiometer is completely knackered?

Also, I took the King lead off and held it above the inlet plenum, but I'm getting no spark. I've used a basic voltage checker to see if there's power going to the coil when I turn the ignition, but it's not showing live on any of the wires attached to the coil.

Finally, I took the distributor cap off and found that there's some movement in the rotor arm - this doesn't seem right to me, what do you think? A pal also remarked that when turning the car over, the dizzy cap appears to move up and down slightly.

Click to expand...

Throttle pot sounds like it is dead but I would first say take it out, put a meter on it to measure resistance then turn fully one way then the other, the resistance should scale smoothly. Obviously check what the resistance reading is where it is, measure across the same wires you used to check voltage. I'm a bit rusty but the resistance should increase to produce lower voltage.

No spark at king lead - Possibilities are faulty ignition switch, faulty ignition amplifier or faulty coil. AFAIK and according to the big book, if you measure voltage (IGNITION ON) between battery -ve and coil +ve you should see battery volts (-1v max. is permissable). Next measure battery -ve to coil -ve you should see the same as test 1. If you don't get these results suspect the ignition switch and/or wiring. If test 1 is O.K. but test 2 shows something else suspect coil or ignition amplifier.

If you measure voltage (ign on) from one of the ignition amplifier securing screws (on the side of the dizzy) to ground you should see 0v - 0.1v, anything else indicates ignition amplifier ground fault.

To check amplifier switching you'll need an assistant to crank the engine. Ignition on, check volts between battery +ve and coil -ve, should be 0v, then probes still in place crank the engine, volts should rise.

If the amp is dead you won't get a pulse through the coil so no ignition, this also means no injector pulse so no fuel either. Trouble is if the coil is dead, you have exactly the same problem. Unfortunately, I couldn't see anything in the workshop manual to check the primary and secondary winding resistances for the coil, if I find that info I'll let you know.

Dizzy, slight movement in the arm is normal, you should be able to gently rock it back and fore and hear the mechanical advance mechanism moving, with the cap off, disconnect the vac pipe from the plenum and suck - you should be able to see the base plate in the dizzy move, if it doesn't something is wrong or if you can suck air through the vac pipe with no resistance the vac advance is dead or the pipe is split. As for dizzy cap moving then there is definitely a problem. Check the centre electrode moves freely and that the spring is correctly seated, avoid pulling the centre electrode you could loose the spring! You also need to be careful when putting the cap on, there are a couple of locating lugs on the cap, these have to be properly seated. If the clips for the cap are difficult to put on it normally means the cap isn't seated right. HTH

Sorry for taking so long to update this...

I replaced the throttle potentiometer, but the car would still not start due to a lack of spark. It turned out that the distributor had failed.

I replaced the distributor and it finally fired into life.

However...on part throttle the car felt a bit sluggish, like it wasn't firing on all cylinders. On full throttle the exclamation mark warning light would come back on.

Having read the faults using the ECUmate, I got the following error messages:

"25 Engine misfire on full load"

"50 Engine misfire on right OS bank"

As all other ignition components were new, other than the HT Leads, I replaced them with new Silicone ones, but the issue remained, although the car generally drove ok, and the warning light would stay off until full throttle was applied again.

After a few runs, I checked the ECU codes again using the ECUMate, and an additional error code had appeared...

"45 right OS lambda O2 Sensor faulty"

I was sitting in the car with it idling, when it stalled, and now will not restart. It appears I have lost spark again. There is power going to the coil, but no power coming out. I have tried a new coil, to no avail, and also replaced the ignition amplifier.

Still no joy - any ideas?

VogueLSE4.2 said:

Sorry for taking so long to update this...

I replaced the throttle potentiometer, but the car would still not start due to a lack of spark. It turned out that the distributor had failed.

I replaced the distributor and it finally fired into life.

However...on part throttle the car felt a bit sluggish, like it wasn't firing on all cylinders. On full throttle the exclamation mark warning light would come back on.

Having read the faults using the ECUmate, I got the following error messages:

"25 Engine misfire on full load"

"50 Engine misfire on right OS bank"

As all other ignition components were new, other than the HT Leads, I replaced them with new Silicone ones, but the issue remained, although the car generally drove ok, and the warning light would stay off until full throttle was applied again.

After a few runs, I checked the ECU codes again using the ECUMate, and an additional error code had appeared...

"45 right OS lambda O2 Sensor faulty"

I was sitting in the car with it idling, when it stalled, and now will not restart. It appears I have lost spark again. There is power going to the coil, but no power coming out. I have tried a new coil, to no avail, and also replaced the ignition amplifier.

Still no joy - any ideas?

Click to expand...

Replace lambda probes.
Check all ignition wires and their connectors.

ECU gets the engine running signal from the coil....if the coil isnt firing the ECU wont inject.

Check all connections to the dizzy, coil and ecu....

Fixed at last...

The ignition components were stripped and refitted, timing re-set and away it went. Runs great until warm then the ignition system warning light comes on and it goes into limp mode. This ties in with the ECUMate reading I got about the misfire and right lambda failing as the lambda is ignored when cold which explains why it runs fine until up to temperature. I've ordered two new lambdas so will be fitting them on Wednesday and hopefully that will be the end of my woes.

It's been an expensive one this....since the problem began I've bought a new stepper motor, throttle potentiometer, ECUMate, Ignition Coil, Silicone HT Leads, distributor, dizzy arm and cap, and two lambda sensors....not to mention a couple of garage labour bills and an RAC uplift.


Thanks for all your help and input!

I'd be tempted to ditch the cat and lambda sensors altogether and swap to non cat tune resistor.

I think fuel economy would suffer?

I've been wanting to de-cat the car for a while, but I can't find anywhere that does such a thing for the LSE.

Any ideas?

West Slope Rover said:

You're going to have to systematically start looking at it. A simple start would be just giving a listen to your pump's activity. Is it making noise? .

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I wouldn't worry unduly if it is. My '87 Vouge has had a slightly noisey pump (sounds like the exhaust is loose somewhere) ever since I bought the car seven years/13k miles ago & it's never missed a beat, even on long motorway journeys at sustained legal limit speeds. Having said that I doubt it's an aftermarket (BP etc.) unit as the car had only done 40k when I bought it.

VogueLSE4.2 said:

I think fuel economy would suffer?

I've been wanting to de-cat the car for a while, but I can't find anywhere that does such a thing for the LSE.

Any ideas?

Click to expand...

Not sure of setup as in where flanges are, but any exhaust shop could sort it. You could go all the way and fit tubular headers with a complete stainless system, not sure on options on lse length from janspeed or Rimmers. A bespoke one off system could set you back a grand.

If fuel economy did suffer, reckon it'd be by less than 1mpg.

My 1993 brooklands didn't have a cat. Was queried once on an mot but no bother. 1993 was year they became mandatory but many cars registered 93 were manufactured 92

I apparently spoke too soon...

The new lambda sensors were fitted yesterday, and the car ran perfectly from cold, felt nice and crisp, and the orange (!) symbol on the dash didn't illuminate, even under full throttle.

As soon as the car was up to temperature however, the light appeared and it went into limp mode again.

Using the ECUmate with the car running and fault codes cleared, when revving the engine in neutral it tells me that lambda A is "ok" throughout the rev range, however at a little above idle lambda B tells me that it is "lean". I assume that lambda B is the one reading from the right, o/s bank, and that the lean conditions are what's causing the misfire putting the car into limp mode?

So...what would be the possible cause and where do I start fixing it?

In addition to all of this, on the way home from having the new lambdas fitted, I lost forward drive, leaving me stranded until the RAC could pick me up and take me back to the garage. I've still got reverse, but none of the forward gears do anything. Am I looking at worn out forward clutch packs and therefore a replacement gearbox or a rebuild?

I'm not having much luck at the moment...

Check Fluid Level first....

saying that, I think forward drive engagement is mechanical and the changes hydraulic....if you get no forward drive, it may be a sprag clutch thingy (just recalling from previous similar threads) has gone......James Martin or Wammers will know more.

As for the Engine issue, Something is telling the fuel system to lean out....that comes from MAF and Lambda readings...

VogueLSE4.2 said:

I apparently spoke too soon...

The new lambda sensors were fitted yesterday, and the car ran perfectly from cold, felt nice and crisp, and the orange (!) symbol on the dash didn't illuminate, even under full throttle.

As soon as the car was up to temperature however, the light appeared and it went into limp mode again.

Using the ECUmate with the car running and fault codes cleared, when revving the engine in neutral it tells me that lambda A is "ok" throughout the rev range, however at a little above idle lambda B tells me that it is "lean". I assume that lambda B is the one reading from the right, o/s bank, and that the lean conditions are what's causing the misfire putting the car into limp mode?

So...what would be the possible cause and where do I start fixing it?

In addition to all of this, on the way home from having the new lambdas fitted, I lost forward drive, leaving me stranded until the RAC could pick me up and take me back to the garage. I've still got reverse, but none of the forward gears do anything. Am I looking at worn out forward clutch packs and therefore a replacement gearbox or a rebuild?

I'm not having much luck at the moment...

Click to expand...

I feel your pain! Range Rovers can be fickle and cruel. I'm afraid I can't help with gearbox issues, gear boxes scare me! Now, the engine issue - so you have ignition sorted, throttle pot is now doing its thing and the engine runs fine when cold. IIRC the ecu relies on the MAF when cold then switches to lambda once warm to control the fuel trim. It sounds like the ecu is working O.K. and switches to lambda control so the issue is something else.

The indication of a lean condition suggests the efi system itself is probably O.K. because failures in the efi sensors normally result in a rich condition so what are the possible culprits?

I think the first thing I would look for is a possible inlet air leak. Tracking down an inlet leak can be a bit hit and miss, you could try having the engine at idle and then cupping a hand over the main air inlet (the big pipe on the air box that holds the air filter), in theory the engine should stop but as the air is restricted, you might be able to hear air being drawn in somewhere else. The other method is to spray water around the various hoses and joints in the inlet system and where there is a leak you should hear a change in the engine idle.

To save too much heartache it might be more sensible to bite the bullet and remove the plenum, ram housing and inlet manifold. This has a couple of potential advantages - first you can clean all of the inlet system, second you can check the various hoses associated with the inlet side so any split or perished hoses can be identified, third you can check and set the throttle butterfly and lastly, you can seal the ram housing and plenum when you put it all back together. It should take a morning to remove, clean and reassemble the plenum and ram housing.

If you go the route of removing the plenum etc, it isn't much more work to pop the inlet manifold off, if the manifold isn't properly sealed the effect is essentially an induction air leak, it will also give you the chance to check for the common coolant leaks associated with the valley gasket that you can't always see with everything in place. Luckily, if the valley gasket is in need of replacement the cylinder heads don't need to come off so it is a simple case of undoing the bolts and putting in a new valley gasket but be sure to use hylomar or similar gasket sealant as appropriate.

If there isn't an air leak, I might be tempted to say it could be a worn camshaft, if the inlet valves aren't able to open fully then arguably it might show as a lean condition.

A compression test might also be a useful thing to do.

So perhaps the best way to proceed would be first do a compression test (do dry and wet). Then remove plenum and ram housing and thoroughly clean, by the way, if you find a loose trumpet or two on the ram housing don't panick, you can re-seat them and hold them in place with rtv silicon. With the plenum and ram housing off, have a careful look at the inlet manifold, check there are no loose bolts and look for any evidence of coolant leaks where the inlet manifold meets the valley gasket, replacement of the valley gasket might be a good choice.

With all that done, put it all back together and fire it up!

Hope that helps, good luck.