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LRH40258 Scots Pine Green Silver Wraith II (1.08.80) Dark Green Everflex and Green leather
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Discussion Starter · #1 ·
Hi guys, I am a new to the forum and RR ownership so I really value the expertise that is evident through all these threads. I purchased a Wraith II recently, completely unseen and without any interaction with the previous owner. The car was sold at Auction out of a deceased estate after a number of years in storage, possible 4 years. The car starts and runs at idle absolutely fine but under load seems to misfire, on cold short runs it wafts along quite adequately but as it warms, the oil pressure begins to drop and the running gets increasingly rough. On one occasion it FTP after 30 mile but once it cooled down it fired up straight away. The cars history suggest fuel lines, tank and pumps have been overhauled as has the ignition coil, HT leads, rotor arm, distributor cap all prior to it being stored. So I am just wondering where I should start investigations? It is heading in for a compression test and some investigation next week at a local specialist but I would appreciate some advice as to where they should be focusing there investigations rather than randomly changing components at my expense. Any thoughts would be very much appreciated.

Cheers

Mike
 

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Welcome to the forum Mike and hopefully you'll soon have the gremlins fixed. The Wraith 11 has a low compression engine and it is normal for the oil pressure needle to drop a little as the oil thins with engine warming. The fact that it runs well until fully warmed and then starts to misfire or even FTP but drive again once cooled down might indicate a problem with the electronic ignition module in the distributor or a faulty ballast resistor or coil as these 3 components, if defective, are known to adversely react to heat. Check also that the rotor arm is of good quality as there are known dodgy aftermarket ones that usually have a cheap rivet holding down the brass section. I would check also if the correct coil to compliment electronic ignition has been fitted. Another possibility is that your choke cam is sticking and causing the spark plugs to foul up. An inspection of a couple of spark plugs will reveal whether your fuel/air ratio is correct, golden brown is good, sooty black indicates too much fuel to air and possible choke problem, white means vacuum air leak at inlet manifold which will cause a misfire and possible rise in engine temperature but is unlikely to cause a FTP when the engine is warmed up and oily plugs may indicate piston ring wear and loss of compression. Given that your engine misbehaves when fully warmed up but drives well up to that stage I'm inclined to think that the worst case scenario is that the electronic ignition module in the distributor is the culprit but given that it's a relatively expensive part I would try to rule out the less expensive fixes first.
 

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LRH40258 Scots Pine Green Silver Wraith II (1.08.80) Dark Green Everflex and Green leather
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Discussion Starter · #3 ·
Welcome to the forum Mike and hopefully you'll soon have the gremlins fixed. The Wraith 11 has a low compression engine and it is normal for the oil pressure needle to drop a little as the oil thins with engine warming. The fact that it runs well until fully warmed and then starts to misfire or even FTP but drive again once cooled down might indicate a problem with the electronic ignition module in the distributor or a faulty ballast resistor or coil as these 3 components, if defective, are known to adversely react to heat. Check also that the rotor arm is of good quality as there are known dodgy aftermarket ones that usually have a cheap rivet holding down the brass section. I would check also if the correct coil to compliment electronic ignition has been fitted. Another possibility is that your choke cam is sticking and causing the spark plugs to foul up. An inspection of a couple of spark plugs will reveal whether your fuel/air ratio is correct, golden brown is good, sooty black indicates too much fuel to air and possible choke problem, white means vacuum air leak at inlet manifold which will cause a misfire and possible rise in engine temperature but is unlikely to cause a FTP when the engine is warmed up and oily plugs may indicate piston ring wear and loss of compression. Given that your engine misbehaves when fully warmed up but drives well up to that stage I'm inclined to think that the worst case scenario is that the electronic ignition module in the distributor is the culprit but given that it's a relatively expensive part I would try to rule out the less expensive fixes first.
Thank you shadow II, I must admit when I saw that the rotor had been changed I assumed that I could dismiss that as an issue but I will certainly take that further and also the ignition module. I think taking out plugs to check condition will be a really useful suggestion, in my limited experience people often change the easy to reach plugs so it may well be I have a few ancient plugs at the front of the two banks which seem a tad tricky to extricate. I had a ballast resistor fail on a Rover P6 3500 V8S years ago and that took ages to fathom, so again that is a good area to check.

On the oil pressure issue, none of the gauges in that cluster seem to function normally, the fuel needle is off the full end of the scale which I think might be an earth short, the ammeter never moves so I think may be I should not get too hung up on the pressure drop. As you say the engine warms, the old oil thins and the pressure goes down, the fact that its at the bottom of the gauge markings may not be totally representative of the working pressure. Still lots to follow up on and I hope I can reports some positive progress. Thanks for your suggestions, greatly appreciated.
 

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If it starts easily and idles well when cold the chances are that the plugs are good, besides if someone has gone to the trouble of changing the distributor cap and plug leads the likelihood is that they wouldn't have omitted to change the plugs but you never know. A misfire and an actual FTP when the engine is warm points more towards defective electronic ignition module, ballast resistor or coil especially if the car starts and idles normally again once it has cooled down. Good luck narrowing down the fault. The fuel level sender unit connections are under the boot carpet and could possibly be corroded. If you have to remove the sender unit from the fuel tank you will need a new gasket when reinstalling.
 

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Discussion Starter · #5 ·
Thanks for the feedback, I have just checked over the car and it appears the points have been replaced with a Pertronix Ignitor system, which all looks sound and relatively new, the rotor is actually genuine Lucas item, not a dodgy aftermarket item, again looks very sound. I whipped outa couple of easily accessible plugs and they look newish and remarkably they are golden brown! So every obvious item is looking fine. I did however just notice the fast idle/choke seemed a bit stuck open so maybe it is getting over choke when warm hence the rough running. I think I shall do a bit of a test run making sure the choke is full off and see how that goes. Fingers crossed!
 

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Yes, sticky choke staying on and/or sticky pistons in the dash pots.
Undue the oil caps in the damper tubes and pull up on them to check the easy rise and fall of the pistons _ easy enough to do before assuming another more serious problem.

These things are notorious for acting up when sitting for a long time.
Needle valves and floats would appear to be working as it's not flooding and runs well and starts well when cold.

Could also be the Pertronix unit, but intermittent operation of that has to be eliminated by substitution.
Same with a faulty coil, start with the simplest as above.
 

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Discussion Starter · #8 ·
Thanks for the suggestions and not wishing to appear totally ignorant of auto-electrics but there are no ignitions light for oil or generator when starting up, I just assumed blown bulbs but they are fine could it be this is more likely indicative of the problem? The multi-warning panel illuminates and then goes off but not the generator/oil light?
 

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To test for blown warning light bulbs move the shift lever to R and turn the key to start. The engine will not start due to the neutral interlock but this should illuminate all the warning light bulbs.
From your description the fault is most likely the coil. Here is a copy of a testing procedure I have posted previously on this forum to quickly and easily pinpoint an FTP fault. Do this when it quits running when warmed up.


First thing to do is to check for spark at a plug lead, then spark at coil lead. If no spark at plug but spark at coil lead - rotor is faulty. If no spark at plug and no spark at coil lead - coil or module faulty. To determine which, attach a 12 volt test light to negative low tension terminal of coil. Have someone crank over the engine, if light flashes quickly the module is working trying to fire the coil - coil is faulty. If light doesn't flash the ignition module is faulty. These tests are assuming you have confirmed there is power at the positive low tension terminal of the coil. If no power at the terminal with ignition on check the ballast resistor, bypass it to test if power at ballast but not at coil.
Also to confirm a rotor is faulty, remove cap, remove coil lead from cap, hold end of coil lead to within an eighth inch of the centre of the rotor with gloves or insulated pliers. Have someone crank over the engine. If the sparks jump to the centre of the rotor the rotor is faulty. A spark SHOULD NOT jump to the rotor if it is good. Rotors can function fine when cold, short out when hot, and have intermittent symptoms. We see faulty rotors fairly often, especially aftermarket ones.
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Discussion Starter · #10 ·
Thanks Jim,

That is really helpful and comprehensive diagnosis list, I looking forward to giving it a good test and will let you know what I find out.

Cheers
 

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Also regarding Pertronix ignition modules, the Ignitor is susceptible to damage caused by leaving the ignition turned on but without the engine running. The Ignitor II is less liable to fail if the key is left on without the engine running. Don't assume it is OK just because it looks new. Check that it is switching the coil by a rapid flashing of a test light on the coil negative low tension terminal.
 

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Discussion Starter · #12 ·
Quick situation update, the car had new plugs, a new coil fitted and compression test, 180 psi plus or mins 5% across all eight cylinders, which seems remarkably strong? Drove home well, circa 30 miles, set off again to pick up my Grandson from nursery and after a little popping sound we gently coasted to a stop, fortunately right outside a favorite pub. No amount of cranking showed any sign of attempting to fire. I topped fuel wondering if I had made that school boy error but to no avail. Car was finally recovered to Bowling and Ryan our local RR&B Independent specialists. John diagnosed the problem in minutes, the nearly new looking rotor arm, which I proudly mentioned as being nearly new Lucas items was to blame. I am advised the stuff being branded Lucas now is very poor replica and this one was shorting out all over the place, once changed it was back running smooth as silk. I know a number of you guys suggested that could be the cause, particularly you Jim so hats off to you. I have learnt that just because a component looks sound that proves nothing, test everything and ideally have a substitute item available to confirm diagnosis. Just looking forward to getting back out on the road once the fuel sender, service brakes and park brake overhaul are complete.

Thanks again
 

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Yep, had the same issue with my '68 Land Rover a few years ago. Brand new rotor not worth the cost of the plastic it was made out of....
 

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Quick situation update, the car had new plugs, a new coil fitted and compression test, 180 psi plus or mins 5% across all eight cylinders, which seems remarkably strong? Drove home well, circa 30 miles, set off again to pick up my Grandson from nursery and after a little popping sound we gently coasted to a stop, fortunately right outside a favorite pub. No amount of cranking showed any sign of attempting to fire. I topped fuel wondering if I had made that school boy error but to no avail. Car was finally recovered to Bowling and Ryan our local RR&B Independent specialists. John diagnosed the problem in minutes, the nearly new looking rotor arm, which I proudly mentioned as being nearly new Lucas items was to blame. I am advised the stuff being branded Lucas now is very poor replica and this one was shorting out all over the place, once changed it was back running smooth as silk. I know a number of you guys suggested that could be the cause, particularly you Jim so hats off to you. I have learnt that just because a component looks sound that proves nothing, test everything and ideally have a substitute item available to confirm diagnosis. Just looking forward to getting back out on the road once the fuel sender, service brakes and park brake overhaul are complete.

Thanks again
Glad you found the issue. "Distributor Doctor" supply very good rotor arms, the one for the Silver Wraith/Shadow is the same as the one for a Triumph Stag. If you're thinking of carrying a spare rotor arm for emergencies I would recommend Distributor Doctor. They don't do online sales, orders by phone only.
 

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Discussion Starter · #15 ·
Cheers guys, I am just glad that is one issue off the list, plenty more things to play with yet though, it keeps things interesting
 
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