i was drviing my 1970 Series 2 OTS and noticed that the battery gauge was pegged at 16 volts suggesting that the voltage regulator had quit. However before I could get home the engine quit and would not restart. I got a tow home and I have been trying to get the engine running again.
The only thing that I found non functional was the fuel pump so I replaced this but the engine still would not start. The starter motor cranks fine but it appears there is either no spark or no fuel
I disconnected the fuel line to the carbs and with the ignition on the fuel pump works fine. I took a spark plug out and grounded it but I couldn't see a spark when cranking the engine so I assumed it was an electrical fault.
I have :-
1) repalced the voltage regulator
2) replaced the contact points and condenser and confirmed they are working OK. Stil no start
3) replaced the ignition switch to eliminate that although the one I tooked off checked out fine ( what a job getting the electrical part of the switch out!). Still no start
4) replaced the ignition coil with another 1.5 ohm coil and also bypassed the ballast resistor and hooked up a new 3 ohm coil . Still no start
5) Checked that there is 12 volts on the ignition coil when the engine is cranking as there should be via the starter motor relay
6) Checked that there is 12 volts on the inlet side of the ballast resistor when the ignition is on
7) removed , at the distributor end, the HT lead that goes from the ignition coil to the distributor and held it close to a good earth then grounded and then open circuited the negative side of the ignition coil and observed a spark when the circuit is opened as there should but, to me, it is a very weak spark
7) I supplied 12 v driectly from the battery to the inlet side of the ballast resistor. Still no start
8) The distributor cap doesn't show any signs of an earth path but I will get a new on and probably a new rotor arm.
I am at my wits end. I am obviously missing something. Any advice and suggestions would be gratefully received.
Stuart Greenwood in Ramona California

 

I had a similar issue with my 69 S2 coupe, built Aug. 69. Car would die for no reason. Had my techs scratching their heads, until they did a rotor swap and the car started. It turned out there was a hairline crack in the rotor. After that, given the propensity of lack of quality control on points ignition parts, I moved to a 123 Distributor. I would be very interested in reading how this is resolved.
You did a spectacular job of testing each component area to eliminate the possibilities!

 

Thanks for replying Valerie. I agree that the lack of quailty control of replacement parts is a big problem. Sometime ago I also had a rotor problem on a 1970 series 2 FHC I had. I decided to replace the rotor with a new one just for the hell of it. Well the rotor arm was a little too long and when I started the engine the end of the rotor arm wrecked the distributor cap. Moral is don't replace anything unless you are forced to.
I've been looking closely at the wiring diagram for series 2 cars. I am suspecting the alternator relay might have burnt out. I don't see why this should be causing my problem but it's worth a try. Only thing I have to do is find where this relay is situated on the car!
Stuart

 

I'm no where near your paygrade in automotive electrics, but did find this for the alternator relay...

The Jaguar E-Type Series 2 uses Lucas 6RA relays for various electrical components, including the alternator. Specifically, the alternator relay is a 20A 4-pin relay, often identified by the part number 33209F (or SRB121). It's located on the left side in front of the heater, mounted on the inner mud shield. This relay controls the power to the alternator's field (F+) and the voltage regulator.

https://forums.jag-lovers.com/t/alte...ies-2/455102/4

https://forums.jag-lovers.com/t/rela...ocation/349924

 

I would get a can of starting fluid and spray some in the carbs and put the air cleaner back on. Then try starting it. If it fires then its the fuel system. I'm thing that since the fuel pump died, it may have sucked up some crud from the tank and jammed the pump. Do strombergs have filters in the carb fuel inlet like SU? If so they may be clog or there is crud in the float bowls.

Hope this helps.

 

Thanks Bob. The carbs are recently rebuilt and there is a fuel filter before the carbs which is new. But I take your point and will get some starter fluid and do what you suggest
Staurt

 

Hi Stuart, just wondering if you were able to come to any conclusion on the non-start?

 

I must admit that I am so pissed off with the car that I have left it alone in the garage to teach it a lesson!
I ordered new ignition parts from SNG and they arrived Friday 8/8/25. but I am still awaiting a new ignition switch.
To-day, Monday 8/11/25 I am going to check the ignition timing which is a bear since turning the crankshaft is difficult . I fail to see how the timing can have slipped but I'll check
Once I have done this and put on all the new parts I will use two voltmeters that I have. One to connect to the plus side of the ignition coil and the other to connect to the live side of the fuel pump. So when I turn the ignition on the pump should read 12v and the coil 6v ( due to the ballast resistor if the point happen to be closed, if not 12v.). Then when I activate the starter both should go to10 to12v.. If they don't then this will give me a clue.
I haven't replaced the plug leads or checked behind the dash that all the wires to the fuses look OK , i.e not burnt out.but I will do the latter. Maybe the 6 and 7 fuse plastic block has overheated due to the high voltage when the regulator failed.
will letyou know my findings.
Stuart

 

Well, all of us surely know that state of mind.. PO'd. best to do as you did, leave it alone and think about it. I have no where near your skillset electrically, but when in any of my old BCs something just quit, it usually meant that some component failed. Against my better judgement when I was having failures of standard ignition parts, i agreed to have a Petronix put in. Of course, it failed. Just driving in town and the car quit and would not restart. I went to the base 123 XK distributor and all seems well. Another time I noticed my charge was really low. turned out the alternator field wire was connected with only about 2 or 3 wire filaments. One time I suddenly had no lighting on the front end and that massive round plug had somehow worked its way out. Sometimes these cars seem to do stuff just to keep us on our toes.
Hoping that your issue can be readily resolved. These cars are not rocket science and there is just something somewhere that it doesn't like.

 

I've read that the 123 distributor has 16 advance curves which are accessed via a "hidden" switch. I know you are not "electrically minded" but do you know how the decision was made to select a particular advance curve and is this switch accessable with the distributor installed in the engine or do you have to take it out to get at it?
My new ignition switch arrived to-day 8/12/25 from SNG. it has no marking on it to identify which wires go where but I figured this out using my continuity tester. Less electical minded people migth be stumped.
Stuart

 

The quest to find out why the engine will not start.


Driver's seat removed, steering wheel removed so I can lie upside down in the footwell to remove the ignition switch.First time I did this I wondered whether I could ever get out. Not recommended unless you are less than 75.

Off side front wheel removed and front of car on jack stands so I can lie underneath and turn the crankshaft for timing purposes. it is dam near impossible to get a socket on the crankshaft because of all the front end supporting structure. It occurs to me that the fire wall must be immensely strong to take all the loads passed to it through the front frames

 

I have just discovered that this site is not Jag lovers forum so I will post my problem on there and see if anyone has any ideas
STuart

 

Here's a link that can explain it better than I can. It depends on several factors like fuel.
https://123ignition.com/support/create-curve-tutorial/

• Curve Selection:
  The 16 curves are pre-programmed, and users can consult the distributor's manual to find the best curve for their specific engine and setup. Some users have reported success with the default curve, while others have experimented to find the optimal setting for their engine.

and here is a forum post on just this topic
https://forums.jag-lovers.com/t/123-.../410111?page=2
as well as this, which really drills down into the "why"
https://jaguaretype.wordpress.com/ho...3-distributor/
It's a rotary switch and in the above piece, the author says you do have to take the dizzy out to change settings.

This forum site is just as good as J-L. Many great minds and many of us consult both.
I chose the base XK 123 because I had no interest in dinking around to tune my E. It runs just fine with the base 123. There are probably others who are well versed in those sort of adjustments and perhaps they will chime in.

 

Thanks Valerie
I found https://forums.jag-lovers.com/t/123-.../410111?page=2 a a bit todeep for me with all chat about vacuum settings but
"htttps://jaguaretype.wordpress.com/ho...3-distributor/ was very informative
stuart

 

More info on 123 distributors for XK engines.
Early 123 distributors had selected curves for you to pick from, none are perfect for a long stroke XK engine. Insufficient advance at lower RPMs and too advance between 2500 and 3000 RPM. Worst of all they only mate to a 3.000 ohm coil. The later programmable 123 distributor is complicated programming with EU metric system parameters, and you need to have the right ignition curve to input.. mates to 1.00 ohm coil. You can adjust to any advance at any RPM for comparison.. I think you will have to be on a dynamometer, to notice the difference.

https://www.jaguarforums.com/forum/x...utions-278865/

RGds
David

 

I would replace the HT plug wires. You should have a bright spark and my champion plug caps did not work well with certain HT plug wire cores. Also even a tiny small crack in the distributor cap or moisture can cause havoc

 

I have got the engine to start!.
I am happy to report that I got the engine started but it took me by surprise that it did. I checked the timing by turning the crankshaft until it was close to 10deg BTDC and removed the distributor cap to check that the rotor arm was pointing to number 6 plug which it was. I decided to reset the timing to 8 deg BTDC so I slackened the distributor and turned it until the contact points just opened ( using a timing light). As I had just bought a new rotor arm I thought, what the hell, lets just put the new one one even though I couldn't see anything wrong with the old one. I installed voltmeters to monitor the voltage at the ignition coil and at the fuel pump. I switched on the ignition and both voltmeters read as expected. So I thought OK now I'll crank the engine and see it the voltmeter on the coil goes to zero indicating that when in the crank position on the ignition switch there was a fault in the ignition switch. To my surprise the engine started and ran OK!.
I know that running the car with the high battery voltage fried the electronic fuel pump which I replaced as I mentioned previously. So I conclude that when I replaced the contact points and condenser, which required removing the rotor arm, I must have damaged the rotor arm in some way. Hence my attempts to start the engine after putting back the original rotor arm were doomed to failure and was the reason I couldn't get a spark at the plugs but I could get a spark by holding the HT lead from the coil close to an earth hence indicating that the coil and contact points were working OK. I've looked at the original rotor arm and cannot see any cracks in the plastic or evidence of arching to the distributor shaft but that's what it must have been.
I hope that that's correct and I will have my heart in my mouth when I take the car out for a run.
By the way I did replace the alternator voltage regulator and, at least in the garage, by reving the engine it seems to be working OK but the battery guage is very sluggish so it will only be on a run that I can truly say I've fixed the over charging.
Thanks to everyone who offered suggestions etc.

 

You indicated that you have a multimeter. Before driving and relying on the battery gauge just connect the meter to the battery and start the engine.
If things are working correctly, you should have about 13.8 to 14.2 volts.
Cheers

 

In reply to Piper888. I would have liked to replace the HT plug leads but mine are encased in a tube that is fixed to the cylinder head using some cylcinder head nuts. I was affraid that taking these nuts off to remove the tube would disturb the hold down force on the head. So I reasoned that I might have to losen all the nuts and go through the retroque sequence. This sounded like a scary thing to do
Stuart

 

Reply to Bill Mac. I think that putting s voltmeter directly across the battery is a good idea . I can run wires from the battery to a volt meter sitting inside the car and go for a run and compare the battery gauge with the volt meter.
I read in the ROM that the voltage regulator originally fitted to E types was adjustable. The one on my car and the ones you can buy don't have this adjustability. Anybody know if the adjustable ones are available?