Spoke too soon!

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norseman

norseman

Well-Known Member
Posts
3,160
Location
Essex - UK
Peeps will recall I recently posted how a new set of plugs appeared to cure a sudden episode of poor running/severe misfiring of my 3.5efi RRC following 14 years of total reliability.
Well it appears not quite :(

That same day the car drove for 30 miles without missing a beat, but this morning I only drove 4 miles before the problem re-occurred .. not quite as bad as prior to the plug renewals. Stopped the car three times on the return journey home, each halt revving the engine a few times cleared the fault only for it to return after about a mile's driving.

Today's symptoms .. very erratic running/total lack of power, but none of the back-firing that was experienced prior to the the plugs being renewed.
Coil, dissy cap & leads were on the car when I bought it (rotor arm replaced a while ago) but if any of these items are at fault why does it 'clear' for a while?
Ideas anyone?
 
Remove the dizzy cap and put the coil to dizzy wire close to the rotor arm center. It shouldn't spark. Had this recently on a 3.5 carb model. The rotor arm was arching through its self. Are the leads in good condition?
Try a nighttime test with the engine running. In the dark you can see if there are any stray sparks around the engine bay. 😉
 
Many thanks for the replies guys.

Been thinking & in consideration at the probable age of the components I listed, renewal of them all would be a smart move?
Back in my day a 12V coil was just that, but today ..?

Obviously the cap & rotor arm need to be quality items, any thoughts on leads (I'll like to stick with black or blue)
 
I went with the big fat Magnecore ones (the ones that don't fit in the LR lead holder comb https://www.magnecor.co.uk/wp-content/uploads/2022/05/Magnecor-Retail-Catalogue-Web-1.pdf ), but they have had no issues in about 4 years of use and are still flexible and good. Genuine for the cap. I went with a lucas coil and have no problems, but everyone has their favourite. As before get Mr DD to look and service your distributor and replace what's needed including arms. Vast fuel efficiency improvement on mine after he waved his wand.
 
Standard set of leads (from DLS IIRC when I did the cam & followers etc a few years back).

NGK plugs.

Rotor arm from simonbbc. The one with the metal strip moulded in NOT the ones that have the strip riveted on.

Lucas cap - at least that's what it says on the box!
Has the lead pickups well shrouded with just the side that faces the rotor arm exposed & some plastic ridges inside the cap.
I had to use a pattern cap a few years ago when I found the carbon brush in the cap was looking a bit knackered.
Pattern had a misfire when at speed & also in damp conditions.
This cap didn't have this shrouding & ridges.
Put a new carbon brush & spring in the old cap & instant cure of the misfire.

And if it's a flapper with 4CU ecu that ecu has a reputation. I'm on either my 3rd or 4th since getting the car in 1994.
One suddenly started running very rich with lots of black smoke, one ran like a bag of spanners, popping & farting & I can't remember what the other(s) did.
I'm also on LPG (manually switched) & that's been handy when I've had running issues - so far if it runs badly on petrol but fine on gas it's been the ECU & if it's bad on both it's been ignition issues, to date one lead & one dead plug.
That said, when the ecu had gone it stayed gone & didn't cure itself.
 
Last edited:
Ratae said:
Standard set of leads (from DLS IIRC when I did the cam & followers etc a few years back).

NGK plugs.

Rotor arm from simonbbc. The one with the metal strip moulded in NOT the ones that have the strip riveted on.

Lucas cap - at least that's what it says on the box!
Has the lead pickups well shrouded with just the side that faces the rotor arm exposed & some plastic ridges inside the cap.
I had to use a pattern cap a few years ago when I found the carbon brush in the cap was looking a bit knackered.
Pattern had a misfire when at speed & also in damp conditions.
This cap didn't have this shrouding & ridges.
Put a new carbon brush & spring in the old cap & instant cure of the misfire.

And if it's a flapper with 4CU ecu that ecu has a reputation. I'm on either my 3rd or 4th since getting the car in 1994.
One suddenly started running very rich with lots of black smoke, one ran like a bag of spanners, popping & farting & I can't remember what the other(s) did.
I'm also on LPG (manually switched) & that's been handy when I've had running issues - so far if it runs badly on petrol but fine on gas it's been the ECU & if it's bad on both it's been ignition issues, to date one lead & one dead plug.
That said, when the ecu had gone it stayed gone & didn't cure itself.
Click to expand...
I'm considering a Lucas branded cap, coil & of course a moulded rotor. I have a problem equating the word 'genuine' with any component manuf. for a vehicle that ceased production 28 years ago :rolleyes:
After a tedious trawl across the 'net Famous Four would appear to offer a decent selection of ign. components, so I will give them a call tomorrow.

nb: My RR is a flapper & is still on what I assume to be it's original ECU, although I do have a spare that was rebuilt for a previously owned Classic. On the subject of fuel, I've only used premium (so called protection grade) petrol since the intro. of E10.
nb2: As the car has only done 62k from new I'm hoping the dizzy itself is still working within parameters, but thanks 'R' for the Distributor Doctor heads up.
 
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