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hot starting.......NOT!

PostPosted: Fri Sep 01, 2017 9:16 am
by Elanconvert
Hi all...posting this in general cos I'm not sure wot the problem is....

so.....mot day for elan......started easily, drove to mot staion [4 miles] ..no issues...temp not above 75 [ewp fitted].....parked up.....tester ready so started up and waited by ramp.........tester called away to phone, so car left to tick over for about 10 mins....noticed temp had climbed to 90, so turned on fan.....temp stopped climbing but after a couple of minutes, car cut out and would NOT restart......car pushed onto ramp and underside inspection completed......temp back down to 75 so tried restart, which it did but lumpy....changed plugs, and it started, just, but only firing on two......so turned it off...

fed up, paid bill, chatted to tester for a while, thought about dreaded breakdown truck, but tester wanted it out of the way, so with temp back down below 70, giave it just one more chance.....started ok [firing on all 4 and I hadn't swapped plugs back].....pulled away, drove home without issue or incident.....

back story..
car has always been a problem starting when hot in my ownership [4 years] and sometimes to my acute embarassment but usually ok after cooling down for a few minutes ...the reason for recently fitting an auxiliary electric fuel pump...
PO had fitted 'aldon electronic ignition'.....any views on its reliiability?
I have replaced coil [btw only slightl warm during the 'incident], distributor cap, rotor arm, new plugs [BP6ES], carbs [dellortoes] just professionally serviced.....
tester/mechanic suggested a timing issue......is it time to dig out the strobe light?

any advice /suggestions welcome!!
thanks in advance
:D fred :D

Re: hot starting.......NOT!

PostPosted: Fri Sep 01, 2017 9:54 am
by alan.barker
When it is hot next time and does not start check with multimeter the supply to coil. While someone turns the Ignition Key.
Does your car have a pre engaged Starter Motor fitted.
Alan

Re: hot starting.......NOT!

PostPosted: Fri Sep 01, 2017 10:07 am
by Grizzly
Is there Thermal paste under the aldon electronic ignition? i had a similar ignition, when i first fitted it was fine (with the supplied paste installed) but i had to swap the Distributor and the ignition went back with little to no paste on it, since then it would play up when the engine was hot (guess it overheated) i endd up fitting a Luminition set up which cured it.

I suggest you carry a spare plug with you and next time it does it check for a spark. I know coils tend to do a similar thing when their going but from my experience a coil fails quite quickly so it wouldn't drag out over months/years.

Re: hot starting.......NOT!

PostPosted: Fri Sep 01, 2017 10:16 am
by rgh0
The electronic ignition units , especially those fitted into the distributor body can be subject to failure when hot. I would swap back to points to see if it makes a difference.

cheers
Rohan

Re: hot starting.......NOT!

PostPosted: Fri Sep 01, 2017 11:12 am
by Gray
The anti theft switch in the glovebox can cause similar problems if still fitted

Re: hot starting.......NOT!

PostPosted: Sat Sep 02, 2017 7:56 am
by Elanconvert
thanks for all the replies guys...
I will replace the aldon ignition and see how it goes....thanks rohan and grizzly....

:D fred :D

Re: hot starting.......NOT!

PostPosted: Sat Sep 02, 2017 10:29 am
by LaikaTheDog
There is a similar story on the esprit forums.. turned out to be a faulty coil,
Caused intermittent spark when hot

Re: hot starting.......NOT!

PostPosted: Sun Sep 03, 2017 7:52 am
by englishmaninwales
I was advised on this forum to try wide open throttle hot restarts (twin 40s) and works every time. Just ensure the throttle pedal is depressed slowly so not to activate the acc pump jets.

Re: hot starting.......NOT!

PostPosted: Sun Sep 03, 2017 9:35 am
by richardcox_lotus
That advice works for Weber's but is not recommended for Dellortos

Re: hot starting.......NOT!

PostPosted: Wed Sep 13, 2017 7:43 am
by Elanconvert
thanks for all the input......BUT....fast forward to yesterday....cut and paste original post...

yep amost exactly the same.....differences - I switched the fan on before leaving, short shifted all the way, and coasted down quite a long hill in neutral.....result - temp barely above 70 on arrival at mot station.....switched off as a bit early for appointment......after 10-15 mins started up again no problem......drove to ramp, and switched off again......well that was it....would not start......noted no spark....but couldn't establish why....coil only hand warm ..after 20-30 mins of trying, just about to give up [again] when she fired up and managed to take me home, stuttering to a stop on the drveway.....

so..snce last episode, have fitted new ignition module supplied by aldon automotive [ignitor].....checked all connections......also ordered new set of magnecor plug leads.......

BUT....I am tearing my hair out....I know intermittent faults can be a bu***r to sort out but I am runnng out of optiions.....I have ordered another coil although the one fitted is only a few months old.........and to cap it all, now have fuel leaking from the drain plug on the tank..... AND what am I going to do about the large toe of boot sized dent on the rear lower wing....?:evil: :evil:

fred

Re: hot starting.......NOT!

PostPosted: Wed Sep 13, 2017 9:07 am
by Chancer
The more new components you fit the more the chances of multiple failures, never replace any original equipment unless you are 100% certain that it is faulty and thereafter treat the new item with maximum suspicion.

Re: hot starting.......NOT!

PostPosted: Wed Sep 13, 2017 11:33 am
by nmauduit
Elanconvert wrote:noted no spark....but couldn't establish why....

no spark no joy, so that's where I would start : is the coil still duly powered when there is no spark (wire could be traced to the fuse box, and I had a case of the fuse box not liking the heat in the engine bay and the brass fuse holder releasing its grip enough to cut off coil power...)

Re: hot starting.......NOT!

PostPosted: Wed Sep 13, 2017 1:10 pm
by ericbushby
Fred,
Finding that it is lack of spark is a breakthrough.
I agree with nmauduit above and expanding on Alan Barkers post , it seems likely that you have an electrical fault which occurs when hot. A thermal fault.
Intermittent faults can be difficult. The way to find them is to monitor something on a longer term basis.
I suggest that you try to divide the problem in two.
Can you run a twin wire from the coil terminal and the local earth, out from the bonnet and into the car through the passenger window to a 12v lamp on the passenger seat.
Next time it fails you will know immediately whether the fault is before or after that point.
If before then you can move the test point upstream.
If after, then that is the time to check the ignition system.
Eric in Burnley
1967 S3SE DHC

Re: hot starting.......NOT!

PostPosted: Thu Sep 14, 2017 12:11 pm
by Elanconvert
the mystery deepens......went to start it this morning.......battery flat....
now before you ask if I left the ignition or lights on...no.....and anyway have a battery cut out switch which I routinely turn off when I get out of the car......battery new earlier this year....

now I know there was a lot of cranking the other day but there was enough left to start it eventually.....
so do I assume that the battery drained on the way home?.....hmm maybe not charging......will check that when I get it started.again.....

anyway eric I will try a coil power warning light .......must admit I hadn't thought of that .....many thanks

:D fred :D

Re: hot starting.......NOT!

PostPosted: Thu Sep 14, 2017 1:18 pm
by alan.barker
On my TVR 3000M it run perfect when HOT but if i stopped the engine and tried to restart impossible.
When HOT trying to restart ALL the power was going to the Starter Solenoid and NONE to the Coil.
Someone had fitted a pre engaged Starter with integral Solenoid but still had power going through the old Solenoid.
I bypassed the old Solenoid and powered the pre engaged Starter using a fused Relay direct from Battery.
Now HOT starting is no problem and FULL power to Starter and Coil when HOT.
I also fitted a new Ignition Switch.
I hope this helps
Alan