Wiring

Brendan · Post by **Brendan** » Thu Apr 04, 2013 8:33 pm

After 18 months of problems I am thinking rewiring the dash and engine (67 ots). The car will start and run fine but after a while, say 30 miles, mis-firex and dies. Will turn and not restart. Leave it alone for a bit and all ok.

Have had new coil, plugs, leads, distributor and ran with emergency filler cap on tank (ie breather). Same symptoms and angst.

Have an odd config as steering column has ignition key but starter on dash penel. Dash key is not used at all. Also seems that with washe on left (rhd) and horns on frame something else is unusual too. Probably nothing too surprising with Jaguar in late 60s.

So just about to embark on rewire as I suspect break in wire is causing breakdown in LT supply. And will add relay to ignition too.

So othe than taking pictures and labeling. ....anyone any sage word sfor rewiring front of a car?

Brendan

Post by **Heuer** » Thu Apr 04, 2013 9:45 pm

All symptoms of a failing coil. Have you tried another known good one? Unlikely to be a wiring fault but if you want confirmation try running a wire from the battery to the coil so it is permanently live and take it for a drive.

ChrisC · Post by **ChrisC** » Thu Apr 04, 2013 10:04 pm

The horns being on the frame is correct. As far as I know only the 3.8s had the horns inside the bonnet by design although to be fair so did my very early 4.2.

When I bought a 4.2 loom it came with horn wiring to the frame and not into the bonnet plug.

Like David - I dont think it is a wiring fault - the symptoms feel like a coil that is overheating and breaking down. So when you leave it - it cools down and is of course fine again.

Its not unknown for new coils to fail out of the box but to reduce costs - can you borrow one from a friend just to prove it?

I have rewired the entire car so can offer a little advice but its a lot of work and I recommend you dont do it unless you need to...

Cgarside · Post by **Cgarside** » Fri Apr 05, 2013 7:33 pm

Sounds very like a problem I wrestled with on my S1 E over a number of years. Eventually the problem was traced to the rotor arm. The insulation progressively broke down as the engine temperature approached normal operating temp. This caused the coil to overheat to the point where one of the new coils I had bought actually pushed out oil - clearly overheating in the extreme. I tried a number of different rotor arms, but all exhibited the same problem (from what I have read, I understand there were quite a number of poor quality repro rotor arms in circulation). Eventually, I obtained a good quality rotor arm from Retro Classics.
Hope this helps

Post by **Heuer** » Fri Apr 05, 2013 8:08 pm

Good point! As the engine gets hot the rotor spindle expands and can exacerbate any crack in the rotor arm. SNGB have a new re-engineered rotor arm which may be worth fitting.

Brendan · Post by **Brendan** » Fri Apr 05, 2013 10:07 pm

Thanks guys

I fitted an SNGB arm last month but will try taking a coil off the Sprite to see if that works. More runs up and down road on test this weekend maybe :-)

Brendan

daykrolik · Post by **daykrolik** » Sat Apr 06, 2013 9:17 pm

I had two "new" coils, from different suppliers, fail on me in succession, giving similar symptoms to yours. After replacing the first, I incorrectly assumed I had another problem which I was unable to diagnose. In desperation, I swapped the second "new" coil for a good used Lucas Sports coil from the 1970s. Problem solved.

Brendan · Post by **Brendan** » Sun Apr 14, 2013 7:03 am

Well I took the coil off the Frogeye and it runs OK on that. And made it the couple of miles for MOT yesterday. ...passed with no advisory too.

So now waiting for rain to stop for longer trip up and down main road, tools and test lead in boot, to see what happens next.

Will keep you posted.

tim wood · Post by **tim wood** » Sun Apr 14, 2013 9:34 am

Not at all related but its good to hear on someone else with a frogeye and an e type.

Mine sit side by side in the garage although the sprite hasn't turned a wheel in 20 years. It didn't go far in the 20 years prior when my dad had it.

I guess one day when time allows I will get on to the job of working on it.

Also used as an occasional use of common spares ( must stop cannibalising it)

Tim

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