jimsbruv
Rover Rookie
1963 3 litre coupe auto
Posts: 65
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Post by jimsbruv on May 12, 2008 16:57:57 GMT
here is a problem for you that i can not seem to solve hopfully you guys can help. I have a 1963 3 litre auto which since i bought 2 years ago has had a occasional misfire . Now every thing i have done has made it better but it started again today this is what i have changed points plugs condensser dissy cap rotor arm ht leads added an in line filter changed carb float changed the needle valve in the float chamber Today when it misfired and started to cut out i started to susspect fuel evaporation but it was cold and i had no problem comming back from the p4 rally yesterday when it was really hot any ideas? ?
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Post by Phil Nottingham on May 12, 2008 18:16:50 GMT
Faulty distributor earth or frayed insulation allowing shorting on the earthing lead on te baseplate? Sticking valve? Sticking fuel pump contacts - change to Reserve (do you remember to do this onec every tank flull?)
The quality of modern rotor arms is suspect so it could be this. Even the Coupe rev counter could be causing it - eg broken wire. How does this behave when it missfires? If it drops straght to Zero then sits electrical if just drops a bit then fuel/mechanical
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Deleted
Deleted Member
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Post by Deleted on May 12, 2008 19:30:45 GMT
Hi
I think it could be carbon deposits. I have had that problem on both my 3 litre. I sorted the ignitions and fuel systems but the misfire was still there, then I burned two exhaust valve on my Mk III. When I lifted the top I found out it was excessive carbon deposits. Try to use some modern "total system cleaner" in your petrol. If it helps then it is carbon deposits.
Regards
Lars
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Post by dorsetflyer on May 13, 2008 15:18:54 GMT
The interesting bit is when you say that it 'started to cut out' which gives a clue as though it might be fuel pump problems. I have had the same problem since last October when I broke down on the way home from a run and had to call the RAC out. I found if I hit the pump with the handle of a screw driver it started to 'tick' and of course started on the button. Eventually it wouldn't start at all. The lad from the RAC stripped the pump cleaned the points and re-assembled everything. Hey presto no more trouble until a couple of weeks ago. Traveling at idle in slow moving traffic and only 3/4mile from home the engine suddenly died on me. Luckily this time it wasn't the pump but suspected the coil. Again the RAC came out and true enough he confirmed the coil had virtually no output. So I was towed home this time as it was only just over 1/2mile.I had a new coil and fitted this and everything was fine. Last week I had to take my elderly neighbour down to B&Q to get a new lawn mower so I took the Rover which was the nearest car with a large boot. All went well until I turned a corner and put my foot down on the accelerator pedal and there was a moments hesitation before accelerating away, and rest of the journey was fine. The same evening I had to go out in it to get details of a wedding I'm doing. No problems getting there, or coming away from them, but about a mile up the road it again hesitated, and flooring the pedal made it judder and then come to a halt. A few bangs on the pump got me another hundred yards or so before stopping. I knew I couldn't keep doing this as I had a very steep and narrow hill to go down and with no power assistance in any direction decided to call my favourite people out. This time I asked for recovery straight away as the problem couldn't be fixed at the roadside. A small world though, as the recovery truck that came out to me, I drove it when it was new in 2003, and he was a Jowett Javelin fan and had four of them, further to that the chap back at his base recovered another local P5B which broke down a couple of days earlier. I won't mention his name as he might be embarrassed, as he does contribute to this site. Anyway a quick call to Burlen next morning resulted in a new pump being dispatched that day and by 1200 the next day it was fitted. So far fingers crossed, no problems. The one difference I have noticed is that I can tell when the pump is working by the flicker of the ammeter, something I cannot remember seeing before.
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Post by enigmas on May 17, 2008 10:29:52 GMT
Start the vehicle in as dark a place as you can find (inside your garage with the lights out at night), lift the bonnet and take a look, you just might be surprised at what you see.
PS. If you can see the spark plug leads glowing they're marginal at best. If they are sheaved within a tube or bound together they are possibly cross firing.
A misfire is generally due to an electrical fault and may be enhanced if you put the engine under load.
Also ensure that all you earths are good...that means scratch/remove the paint from beneath any earthing point. If you have a bad earth to the engine (it's rubber mounted) you'll find the earth may track through choke cables and the like causing wierd electrical faults.
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Post by Phil Nottingham on May 17, 2008 11:48:41 GMT
He does seem to have tried and changed all the obvious like leads - of course even new one can be faulty. One thing though what about plug caps - are you using the suppressed type or have you replaced with suppressed leads. If you are still using the separate suppressors which screw into the Bakelite plug gaps remove them and also check tye pulg caps themselves are not corroded inside. These but not the suppressors are available new Also remove any radio suppressors on the LT feed If that does not do anything try hot wiring coli direct as there may be a break or high resistance in the LT coil feed (white braiding if you can still see any)
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Deleted
Deleted Member
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Post by Deleted on May 18, 2008 10:40:49 GMT
Don't want to hijack the thread, but here's my experience. My 3 litre manual/od coupe ran like a dream until a short time ago I had electronic ignition fitted. It returned from the garage with a judder between 2500 and 3500 revs (as if it was misfiring), the formerly working clock now going intermittently, the main beam blue indicator light no longer working and the rev counter playing up. Outside that rev band it still goes well and would happily cruise along at 90 if I was so inclined. The garage have had it back and report they found a short, but actually nothing changed and you know how you run out of energy for the battle.... I'm about to start investigating it, so I'll hopefully be able to let you know how I get on in a week or two.
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Post by enigmas on May 18, 2008 10:59:56 GMT
Try the midnight test and also clean (scuff with abrasive) all the fuses and the saddles within which they fit. Ensure good earth contacts exist. If the car ran well before the experts fitted the the electronic ignition (did they power it through the existing loom? What voltage does the electronic ignition require?) see if you can fit a points distributor (beg or borrow?) and hot wire it. If it runs well after this you know where the problem exists.
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Post by Phil Nottingham on May 18, 2008 11:24:52 GMT
The wiring any any P5 and P5B with the fabric covered looms is suspect and on borrowed time - house wiring is condemned after 25 years. The fabric coovered stuff especially when oil soaked is a burnt out car waiting to happen. Fitting electronic ignition may well have disturbed craking insulation - its better to renew the feeds anyway. Cars before Mk3's are very poor as regards fusing as well.
Even later P5B's with all PVC wiring need checking as heat hardens the insulation especially in the engine compartment of behind overeharting ignition and light switches
One members concours Mk2 wiring shorted in the boot (it was the unfused petrol pump feeds). The whole car was burnt out and the driver was lucky to get out before the tank might have exploded.
So do not ignore shorts/intermittent electrical faults and fit extra fuses even though they are not"original" they can be hidden from prying eyes if that sort of mod bothers you
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Deleted
Deleted Member
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Post by Deleted on May 18, 2008 20:25:41 GMT
Thanks for the advice, guys.
I forgot to mention that the car was re-wired about 5 years ago (before I got it), although in a non-standard way. Very little seems to match the wiring diagram in the workshop manual.
I'll try the tests suggested and also get an auto-electrician to check it all out, including the safety checks and extra fuses you advise.
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Post by Phil Nottingham on May 18, 2008 20:54:34 GMT
The wiring certainly needs looking at if its none-standard even using the wrong terminals on the ignition switch, which may also be faulty, can cause some strange symptoms
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