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I have a 1988 Silver Spur that starts with no problem and runs fine for about 15 minutes and then cuts out like there is a vapor lock. The problem is that this occurs in cool wheather. The fuel pump is 2 years old. The fuel pressure seems to be adequate. After sitting for about 30 minutes the car starts and runs fine for another 10 t0 15 minutes and then cuts out again. Any ideas or suggestions will be appreciated. Thanks. Tom Greasel
 

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Have you checked / replaced the classical with the right parts : fuel filter, spark plugs, air filter, ignition rotor and cap ....
The plugs, ignition wires and air filter were recently replaced. I plan to replace the fuel filter, distributor cap and rotor. There is a "control module?" that attaches to the distributor which supposedly can cause the symptoms that I have but I cannot get much information on this. Thanks Tom Greasel
 

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Search the Australian site for info on the Opus control module. There was a lot of discussion on it recently.
 

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Some sensors can do this. I had a CX25GTi whose crank position sensor did not like heat. Did the same - run for a bit, then dead until cool.
If possible, try hitting likely sensors with something to cool, water or some such. Might show itself this way.
 

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The following is from FTP posts I have made on the Australian RR forum in the past. Most of these tests will be applicable to you to diagnose the fault except for the float bowl vent pipe of course. Your symptoms are indicative of a failing coil or distributor rotor in my experience. The tests below will help you figure out exactly what the issue is without throwing parts at it.

Every Shadow owner should carry a spare ignition rotor in their car unless they have installed a red one from the Distributor Doctor.
Red rotor arms: The Original and Genuine Red Rotor Arm, Lucas part numbers 400051, 418726, 54422803, 43D, 45D, 59D, 400052, 418731, 425620 from Distributor Doctor

And should read this:
Top quality Lucas distributor rotor arms, Reconditioned Lucas distributors, rebuilt Lucas distributors, recurved Lucas distributors from Distributor Doctor

Even if your rotor was new a year ago, it means nothing if it is one of the poor reproductions on the market. Your symptoms are in line with a defective rotor. I'm not saying that is the fault, but it is an easy thing to check and/or replace. I have seen lots of them fail in client's cars over the years, it has even happened to me in my own Shadow.
If you get one of those spark plug testers as I mentioned previously you can quickly place it on either a spark plug or the coil high tension lead. If you place it between the coil HT lead and cap you can confirm if you have spark or not. If you have spark there that eliminates a whole bunch of possible culprits. Next, place it on a plug lead. No spark - shorted rotor. Spark - fuel issue. If you have spark at the plugs, before you go checking pumps and filters, remove the vent hoses from the carb float bowls. This will eliminate the weakener and anti run on solenoids as possible faults. With over 40 years of working on these cars you learn to diagnose and narrow down the cause of an FTP quickly.

A handy test gadget you can make up and drive around with is a small 12 volt light bulb or LED. Use either a small socket and wires for the 12 volt bulb or solder wires to the LED. Ground one wire (observe polarity with an LED) and attach the other to the coil negative terminal. Lay the bulb/LED up onto the cowl under a wiper arm and tape it to the windscreen so it is in plain view. Next time the engine quits, observe the light. If it is flashing when you crank and try to restart, then you know the ignition switch, start relay, ignition module, are OK. This test confirms that the module is triggering the coil to fire. If you are quick you can glance at the light just as the engine quits and see if it is still flashing as the engine stops turning over. Then if it is flashing you can go on with testing for spark at a plug to confirm operation of the coil and rotor. If that all works then you know you have to look at fueling issues.

Also, how to test for a faulty rotor. Remove coil lead from distributor cap. Remove cap and tie out of the way so the rotor cannot hit it. Using insulated pliers, hold the coil lead within 1/8th of an inch from the centre of the rotor where the carbon brush contacts it. Have someone crank over the engine for you. IF a spark jumps to the rotor, it is shorting out through the plastic to the distributor shaft underneath. You do NOT want to see a spark jump to the rotor.
 
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