C

Cappo

Member
Hi all, hope someone can help me out here, I'm going mad with this one. Bit of a long story, please bear with me!

I have a Defender 90 fitted with a 3.9i V8 from a Disco 1. Been running like that for a couple of years. About a month ago, I was towing a (large) trailer on the motorway when there was a loud bang (sounded mechanical) which I *thought* came from the trailer. Pulled straight onto the shouldwe whereupon the engine stopped and would not start. Had to get it recovered (mate came out, we put my Defender on the trailer it had been towing :p). When I got to look at it, there was no spark at the plugs but there was from the coil. Swapped out the cap and arm with old ones I had lying around and we were away again.

Last week, it was running but not brilliantly. Felt like it was down on power, a few times on the motorway on long hills I had to chuck it down a gear but when I did that it sailed up the hills happily, just at higher revs. I've had a lot of RV8s over the years and I know they're sensitive to dizzy cap, rotor arm etc so I ordered replacements from simonbbc. Yesterday I went to fit those. First off I got all the leads one position out (duh) but even when I put them right it wouldn't start. Put the old cap and arm back and way she went.

Today, I needed to go to the shops so I used the Landie, thinking that would warm it up and when I got back I'd try the other cap and arm again and reset the ignition timing (hence my other post yesterday). Swapped the cap and arm out again and it wouldn't start :mad: I tried all combos of old and new cap and arm to try and narrow it down, but now it won't run at all. No leads are disconnected, everything is in place. The problem I seem to have is with the spark from the coil. It's not consistent. If I earth the king lead and dab the 12v on and off the coil, it seems to spark fine. If I turn it over with a plug lead earthed, well, there's a spark but not a great one. I even got to the point of taking the dizzy out and spinning it with the ignition on to see if I was getting a spark - yes, kinda, but it wasn't as fat and consistent as I would like.

Coil resistance with my (very) cheap multimeter is coming back at around 9 ohm, which I think is too high? Should be less than 4 I think?

So I'm erring towards the coil breaking down, but could it also be the ignition amplifier? That's what I'm not sure about.

And then, which coil and amp do I need? I was thinking of where I could get one today but Euros only list a Bosch at £92 :eek: whereas all the "usuals" list Lucas coils at £20-30, but I can't find a definitive on which one I actually need. And then, which amp do I need. Mine is the one which sits on a bracket alongside the coil, not on the dizzy itself.

EDIT: just realised, with the usual ECP "amazing sale code" :rolleyes: it's "only" £60....

All thoughts and input welcome. Am I on the right track here with the coil and/or amp? It's driving me mad. I can't actually believe I went out in it this morning and now it won't run at all.....

TIA.
 
Cappo said:
Hi all, hope someone can help me out here, I'm going mad with this one. Bit of a long story, please bear with me!

I have a Defender 90 fitted with a 3.9i V8 from a Disco 1. Been running like that for a couple of years. About a month ago, I was towing a (large) trailer on the motorway when there was a loud bang (sounded mechanical) which I *thought* came from the trailer. Pulled straight onto the shouldwe whereupon the engine stopped and would not start. Had to get it recovered (mate came out, we put my Defender on the trailer it had been towing :p). When I got to look at it, there was no spark at the plugs but there was from the coil. Swapped out the cap and arm with old ones I had lying around and we were away again.

Last week, it was running but not brilliantly. Felt like it was down on power, a few times on the motorway on long hills I had to chuck it down a gear but when I did that it sailed up the hills happily, just at higher revs. I've had a lot of RV8s over the years and I know they're sensitive to dizzy cap, rotor arm etc so I ordered replacements from simonbbc. Yesterday I went to fit those. First off I got all the leads one position out (duh) but even when I put them right it wouldn't start. Put the old cap and arm back and way she went.

Today, I needed to go to the shops so I used the Landie, thinking that would warm it up and when I got back I'd try the other cap and arm again and reset the ignition timing (hence my other post yesterday). Swapped the cap and arm out again and it wouldn't start :mad: I tried all combos of old and new cap and arm to try and narrow it down, but now it won't run at all. No leads are disconnected, everything is in place. The problem I seem to have is with the spark from the coil. It's not consistent. If I earth the king lead and dab the 12v on and off the coil, it seems to spark fine. If I turn it over with a plug lead earthed, well, there's a spark but not a great one. I even got to the point of taking the dizzy out and spinning it with the ignition on to see if I was getting a spark - yes, kinda, but it wasn't as fat and consistent as I would like.

Coil resistance with my (very) cheap multimeter is coming back at around 9 ohm, which I think is too high? Should be less than 4 I think?

So I'm erring towards the coil breaking down, but could it also be the ignition amplifier? That's what I'm not sure about.

And then, which coil and amp do I need? I was thinking of where I could get one today but Euros only list a Bosch at £92 :eek: whereas all the "usuals" list Lucas coils at £20-30, but I can't find a definitive on which one I actually need. And then, which amp do I need. Mine is the one which sits on a bracket alongside the coil, not on the dizzy itself.

EDIT: just realised, with the usual ECP "amazing sale code" :rolleyes: it's "only" £60....

All thoughts and input welcome. Am I on the right track here with the coil and/or amp? It's driving me mad. I can't actually believe I went out in it this morning and now it won't run at all.....

TIA.
Click to expand...

I have a ex Disco 1 3.5 efi V8 in my 90 and formerly had two 3.5s 90s and three 3.9s (90, 110 & RRC) but I'm no expert.:rolleyes:

Coil giving 9 ohms doesn't sound right; SimonBBC says a standard coil (DLB105) should read around 3 Ohms or around 12 volts and a ballast coil should read around 1.5 Ohms or around 6 volts. Is it a standard or a high energy type ~0.8ohms?

Ign amp depends on the dizzy. External, internal, relocated? SimonBBC does a range to suit and I use his ignition parts without issue.

If you've got a spark at the coil to dizzy, it isn't the module as that would give no sparks anywhere. A common ignition failure seems to be the rotor arm tracking down to ground thus no spark at the plugs even though there is one at the coil.

That's all I can suggest; perhaps someone with more knowledge of the V8 ignition system can chip in.

P.S. :eek: @capo and @Cappo, both long term RV8 90 owners, now with ex Disco1 90 conversions. Mine is an auto, an upgrade made desirable after driving the RRC :D
 
Thanks both for the replies.

@capo: I don't know whether it's standard or high energy - any way to tell? I do use SimonBBC for ignition parts but their website isn't great if you don't know the exact part number you need.

The ignition amp on mine (which came from the Disco) is mounted beside the coil on a chunky aluminium bracket, which is how it came from that car. Does that make it "relocated"? Good to know that it's probably not that if I have a spark at all.

I suspect that the original problem when it broke down could have been the arm tracking.

I think I'll try a new coil on it, either the ECP one which I can get quickly or order from Simon. Is that DLB105 the standard coil for the 3.9?

Strange about the names and the cars! Is yours guitar-related? Mine's an old nickname I got in a job years ago.

@Col, funny enough I ordered a new set (and some plugs) a few days ago but they haven't arrived yet!
 
Cappo said:
Thanks both for the replies.

@capo: I don't know whether it's standard or high energy - any way to tell? I do use SimonBBC for ignition parts but their website isn't great if you don't know the exact part number you need.

The ignition amp on mine (which came from the Disco) is mounted beside the coil on a chunky aluminium bracket, which is how it came from that car. Does that make it "relocated"? Good to know that it's probably not that if I have a spark at all.

I suspect that the original problem when it broke down could have been the arm tracking.

I think I'll try a new coil on it, either the ECP one which I can get quickly or order from Simon. Is that DLB105 the standard coil for the 3.9?

Strange about the names and the cars! Is yours guitar-related? Mine's an old nickname I got in a job years ago.

@Col, funny enough I ordered a new set (and some plugs) a few days ago but they haven't arrived yet!
Click to expand...

Do you have any numbers on the coil currently fitted or a brand, we could try narrowing it down from there ?
 
If the donor Disco1 was unmodified it should have a 35D dizzy like this:
Screenshot 2021-03-13 at 18.49.09.png

and a 3ohm DLB105 coil like this:
Screenshot 2021-03-13 at 18.50.14.png

At least that is my set up. Plus Powerspark leads, red rotor and cap.

Some dizzy have the ignition amp near the coil but you can get it kit to move it to avoid heat issues (not that I've had any on my RV8s).
Screenshot 2021-03-13 at 18.59.02.png
Screenshot 2021-03-13 at 19.00.53.png


A high energy (low ohm) coil requires a high energy electronic ignition kit, the coil is Lucas DLB198 and SimonBBC does high energy ign modules to match.

Note I have no vested interest in SimonBBC/PowerSpark, just a satisfied customer. RV8s are notoriously fussy about ignition components especially rotor caps and arms and I find his products work.

Re 'capo', just a lifelong diminutive of my surname, along with 'cappers' :rolleyes:
 

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Thanks again for all the replies!

@Col - I did change the king lead, only for an old spare I had hanging up, but that didn't cure it.

@capo & @Dippypud: the label on the coil has long since departed but on the top it says Bosch (with a 1 by one terminal and a 15 by the other). It also has the following reference numbers stamped on the top: 1 220 522 011

I can't find those anywhere except in an ancient expired eBay listing here: https://www.ebay.com/itm/Ignition-C...=true&nordt=true&rt=nc&_trksid=p2047675.l2557

capo, mine's not like the ones you have pictured above at all. I used to have a RRC and I think it was like that on there, but I don't have the amp module mounted on the distributor like that. Mine, or what I assume is mine, is alongside the coil on a hefty bracket holding both items. I'll try and get a pic tomorrow, or check how similar it is to your second pic.

I agree, simonbbc has always been the "go to" for RV8 ignition parts.
 
One of these then :
Distributor assembly part number ERR5209. This fits the 3.9L V8 Efi engines in the Land Rover Discovery 1 & Range Rover Classic 92-94. Used in the Discovery 1 models with catalyst from vin MA094073. The ign. amp is next to the coil on these.

Screenshot 2021-03-13 at 20.50.27.png

If that is what you've got then it's powered by a standard 3ohm coil, not a high energy job.

The fact that you are getting a good spark from the king lead and poor one from a plug lead suggest to me the ign.amp or the wiring to and from it?

You mentioned random working when changing the different caps and rotors; is the dizzy itself ok ie. the central spindle tight with no play? Getting the old rotors off can be a pain and if yanked too hard can loosen the innards. Not sure if that would give the symptoms you describe?

I had a 110 with a 3.9 transplant; beautiful until one day on the motorway to Wales started misfiring then conked out and wouldn't start. AA couldn't sort it so it was the trailer of shame home. Next morning I started up just to see, and it roared into life! Opened the bonnet, moved a few wires to check for anything amis and the engine died. The moved wire that did it was one of those from the coil to the ign.amp - it had an internal break not obvious with the plastic sleeve. Repaired the wire and AOK.
 
Thanks capo, this is really helpful! Yes, that's the distributor I have.

Those symptoms you describe above with your 110 are very very similar to what I have. I'll have another good go through it, check the cables out, and maybe change the amp if necessary. (Incidentally, the OEM part number comes out at about 10x the cost of a Powerspark one - literally!). I have disconnected the amp connector on the side of the distributor since working through this so I'll check those went back in OK.

I know what you mean about removing the rotor arm, yes it can be stiff to get it off. I have been gently levering it up rather than yanking. The spindle etc seem OK to me. What would I look for to check that the innards are still OK, just in case?

By the way, I didn't mention earlier, this is also an auto like yours.
 
The problem with levering or pulling the rotor arm off on the electronic dizzys is that you can disengage the auto advance/retard mechanism which is under the plate you can see when you have the dizzy cap off.
You must press down on the reluctor (the 8-pointed star shaped thing under the rotor arm) as you pull the rotor arm off to avoid this possibility.
This isn't mentioned in any of the workshop manuals I've seen.
To check turn the rotor arm with your fingers until it stops.
When released it should spring smartly back to its original position.
If it just stays in the new position the engine might pop & fart a bit but it's unlikely to run.
Not an unusual issue.
 
One trick I learnt long ago when trying to trace ignition and erratic running problems was to run the engine at night in the dark to see if there is any arcing from HT leads. You can't always see it in daylight.

Col
 
Thanks @Ratae. Been out and checked that and it's ok. So that's one less thing to worry about (although a small part of me did think that if it was that it would be a quick win!).

I'll have a go through all the low-tension wiring later today and report back.

Thanks also Col, I'll bear that in mind, just got to get the damn thing started first!
 
Cappo said:
Thanks @Ratae. Been out and checked that and it's ok. So that's one less thing to worry about (although a small part of me did think that if it was that it would be a quick win!).

I'll have a go through all the low-tension wiring later today and report back.

Thanks also Col, I'll bear that in mind, just got to get the damn thing started first!
Click to expand...
Get the wife to turn the engine over tonight whilst you look under the bonnet.

Col
 
So tonight's update: This morning I tried to start it just in case it had a fit overnight, but still nothing. I didn't touch it beyond that, just turned it over then walked away. Waited until dark as per Col's suggestion above (plus I had a mountain of other things to do today anyway, plus I was properly hacked off with the Landie after yesterday). Got the missus in the car, pulled the king lead, she turned it over and there's a lovely big fat spark. So then I replaced that and pulled a plug lead to check there was a spark to the plugs, she turns it over again and bam, the *&^@%&^ thing fired straight up. Lucky really, I completely wasn't expecting it to start, I could have had my hands in there or whatever....anyway, no harm done.

So I stuck the plug lead back on, it fired up immediately and revs cleanly. This is on the original cap and arm, not the new simonbbc ones. I'm dreading even thinking about fitting those again, that's what got me into this mess.

So it's kind of good news as I know nothing significant has failed, but it's also really annoying as it's now completely not to be relied on. I think the original failure on the motorway must be connected to this in some way too. It does now make me think there is a low tension wiring problem somewhere, and a slight movement is enough to make or break the connection.
 
Does the simonbbc rotor arm have the metal strip moulded in or is it riveted?
I do recall another website where someone (not me!) reckoned he spent around £600 trying to sort a misfire issue which was resolved by refitting the old rotor arm....
 
It's currently running back on the old arm. I don't know the history of that one, it's one which I just added to the "bits" box somewhere along the way. Possibly from my old RRC. Anyway, I think, without checking, that it's a riveted one. The simonbbc one I have is a red one, moulded and the metal plate is much thicker.

Rather cleverly, after the first breakdown, I binned the old cap and arm, figuring that they were the cause and therefore I never wanted to see them again!
 
Hmm. Usually the riveted ones that let the current earth into the dizzy & the moulded ones that are good.

Are the lead pickups in the new cap well shrouded with just the faces towards the rotor arm exposed - I ask as I had to fit a cheapie some years ago which had the pickups fully exposed & had a misfire at speed which was worse in wet weather.
Putting a new carbon (the old one had started to break up) into my original cap solved the issue
 
That's an interesting thought. The new one is a Simon one so I would have expected it to be a decent one. It's out in the shed at the moment but I'l check and report back!
 
Just a quick note of caution, do not use high power coils on this ignition system, they don't like it and will fail. I have posted on this before.
Make sure you check the wiring very carefully, old corroded wires break inside the insulation where you can't see the breaks. If any of the LT wiring including power feed and grounds feels hard and not very flexible suspect corrosion and consider cutting out the crusty bits. Similar with old spade connectors, swap out ones that are corroded.
I'm not sure if you have the remote amp or not but it is also worth opening up the loom for the coil and amp, follow the wiring and you should fine a splice IIRC on the power feed for the coil, the splice can corrode. Clean it!
I don't know if any of that will help but I feel your frustration trying to run down a phantom ignition problem, I've been there more than once!
 
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