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MG Midget and Sprite Technical - Electrical problem when it rains.

Can anyone help on this one? I'm posting it on behalf of someone who doesn't use this Bulletin Board (yet)

For quite a time now, in fact about four years, my car dies in heavy rain. On opening the bonnet there is no sign of moisture around the plugs, distributor, or coil, indeed everything seems perfectly dry

I have gone through two electronic ignition systems, I have changed the leads, the dizzy cap and fitted a mini style boot, the coil is compatible with now new points, condenser and original Lucas rotor arm, and I have fitted a solid state fuel pump. All is plastered with damp start concoctions, even the fuse board but the problem persists, the engine simply dies. Wait 20 seconds, pull the starter and the motor more often than not fires up but I cannot be sure of running 100 yards or 100 miles The car runs very well as long as it does not rain heavily. Please help?

Geoff Hunter
Gary Lazarus

Logic says must be HT. And your 'friend' seems to have all bases covered.

BTW - no sign of moisture does not mean dampness is not affecting the HT system... thinking about it, the steam/water vapour driven by the heat of the engine can be a problem.

To shut the engine down means the attack must be between the coil / rotor arm / distributor cap...

Will be interested to see what others turn up...

A
Anthony Cutler

When it stalls does your "ignition" lamp come on? If not then you're losing 12v low tension rather than HT. Does the rev counter do anything when it stalls other than drop to zero? What's it like at cold starting normally? Any background to the issue? Has it always happened? Started since you did another job on the car? Questions questions.

Ant
Ant Allen

If the HT side has been replaced twice, then it could be water in a random connector somewhere (indicators, headlamps, etc..)dragging down the low tension or a chaffed wire shorting to chassis with the water aiding the conductivity.
Brad (Sprite IV 1380)

Ant and Ant, thanks for the speedy replies (as always).
I have asked Geoff to check this thread on the BBS so that he can give feedback and answer additional comments.

Many thanks

Gary
Gary Lazarus

The distributer cap can be a suspect even if it has been substituted. these caps can ingest antifreeze if you have had a leak. Although they appear dry the solution remains in the pores of the cap and attracts moisture. I know that I cannot realy clean a cap that has had antifreeze on it. Try a new cap. Bet it works.
Sandy
Sandy Sanders

I like sandys thinking, But I was thinking along the same line as Brad.

Does the car get any moisture from under the dash...(with the top up)

Id say look for moisture around the back side of the tach and around the connections in the UK driverside door piller/dash area, and also around regulator area thats bolted to the fire wall...agian like brad, this could be a shafed wire insulation...does rain get up under the rubber seal at the bottom of the windshild...if so where does that water go?

Btw is the coil located in a place that catches mosture thur the grill?

Prop
Prop

I can't see how moisture would affect the LT side; however, it's not impossible.

Don't forget you can have moisture on the inside of the cap as well...

A
Anthony Cutler

I would suggest getting some dielectric grease and putting it into the boots for the plugs and dissy cap, then spraying WD40 on the entire ignition system (it DOES stand for "Water Displacement, 40th attempt")
David "But don't get me started on duck tape" Lieb
David Lieb

Try & get hold of some 3M III grease for the connectors, expensive but excellent stuff.
Brad (Sprite IV 1380)

Its the condenser!!!
Must be you haven't changed it yet.

Sorry for been facecious Geoff but a few years ago that used to be the standard reply from many members of this BBS to this kind of problem, and whilst there is a .005% chance that it might just be the condenser it would be far more beneficial to take out the guess work to fault finding and actually diagnose the problem in a professional manner.

You need to decide if the problem is possibly 1 of 3 things.

Fuel
Low tension circuit
High tension circuit

Ant has the right idea in so much as one of the best diagnostic tools you have to hand is the Rev counter.

If at the time of the cut out the rev counter drops to zero immediately then the problem is probably in the low tension circuit. If however the rev counter keeps working and slows down in sypahy with the engine speed dieing then the problem is with the HT circuit or remotely the fuel supply.

If you want to differentiate between the fuel supply and the HT circuit then simply fix a timing lamp to a plug lead and route the lamp into the car. Take it for a run in the rain and when it cuts out again note if the lamp continues to flash as the engine speed (driven by the car in gear and slowing down) deminishes. Of course if the lamp extinguishes immediately then the problem is not fuel related but is in fact in the HT circuit.

When these test are done you will then know which part of the car the problem is associated with and further advice can be given.

This kind of problem can be a nightmare to resolve and many times it is beyond the abilities of the amateur, so from your point of view it would be nice to know where you live and hopefully one of the members of this board with the ability to solve such problems will be on hand to sort if for you. However it doesn't rain every day does it.

Good luck with resolving the problem Geoff, I am in North Lincs, but even if you are I will unfortunately be on holiday for 2 weeks from tomorrow so I can not help.
Robert (Bob) Midget Turbo

Hi Gary,

Looking at what Bob mentions, regarding Fuel as the culprit. If the engine is spluttering prior to cutting out, just perhaps it's water getting into the electrical connections around the fuel pump. The area above the axle is quite exposed to the elements. Could be, dare I say it, a 'bad earth' problem. How is the new fuel pump earthed?

Mark
Mark '74 Midget

Thanks a million all who have offered help and advice.
I like the idea of the light inside the cab illuminating or not on over run once the engine dies. Also I have a new condenser which has been tested by running through a small puddle last weekend and the engine coughed but fortunately kept running so I think the condenser is not the culprit.
The rev counter is mechanically driven off the back of the dynamo so we can eliminate that as a source of problem, and guidance.
I think I will be brave on Sunday when heavy rain is forecast . I was going to Silverstone but the forecast is a deterrant so I will not stray far from home. I'm in Worcestershire--not near enough to Lincolnshire other than on fine days.
I have tried silicone grease inside the rubber/plastic compound dizzy cap cover, the leads were very tight passing through the holes and I used it principally to lubricate and ease the fitting.
I have used both silicone and copper leads without success, or a least no difference.
I had considered the fuel pump (Bob-turbo) and the solid state pump was fitted at the same time as the new condenser and points ie before the near miss in the small puddle.
I think some better expertise than I can muster might be beneficial and have located an "old school" electrical systems mechanic to whom I hope to consult if all else fails.
I need to carry out further checks under the dash ( Prop- Missouri) when it dies, wish I wasn@t so fat!
Let us see what Sunday brings----and thanks again everybody.----Geoff.
Gary Lazarus

>>> I had considered the fuel pump (Bob-turbo) and the solid state pump was fitted at the same time as the new condenser and points ie before the near miss in the small puddle. <<<

Perhaps a long shot, but are you sure the output pressure of the fuel pump is compatible with the carbs?

-:G:-
Gryf Ketcherside

By the way, that wasn't me posting that last bit but as I sent Geoff the link to this thread, I guess he's logged on as me. No problem though.
Gary Lazarus

Sounds to me as if you could have a cut out due to a poor connection on the wiper circuit. The wiper motor connects to the fuse box and that goes to the ignition switch. On early cars a lot of connections were screw attachments and these all go dodgy sooner or later. A extra load to a poor connection can temperarily disable a car only to magically restart moments later, so I'd suggest you look at the wiper diagram and check and reestablish all the connections, including all those at the regulator and fuse box. Also check the temperature of the coil next time it conks out. If its feels hot it may be the regulator giving it too much juice and cutting the sparks - but usually with this you get a few hundred yards of spluttering before it dies.
f pollock

Thanks Gryf Missouri but there is a good direct earthing to the fuel pump and the original delivered fuel ok. The fuel flow is more than adequate, I am running a 1275 motor with a single HIF 6 carb and a 3:7 diff. When it is dry I can easily cruise at 80mph. I changed the pump in desperation but to no avail.The pump is located under the bonnet on the nearside of the sloping part of the bulhead/scuttle.
Thanks for the wiper motor idea--fp-Warks. Since I have to use the wiper motor there could be a link.It is located next to the fuel pump.
I have not mentioned previously that whilst in Germany in heavy rain in June I wired the coil direct to the battery, thereby eliminating the ignition switch. The car still died. It doesn't usually splutter, it simply dies.
Keep them coming--I'm most grateful.
Geoff
Gary Lazarus

Geoff,

If you want me to have a look at it I will.

I still think its your leads.... You can borrow the ones off my frogeye to try if you want?

Regards

Andrew Smith
A D Smith

Thanks Andy but I have two spare sets of leads which I have tried with no improvement which is why I tried the exposed connectors so that there is no possibility of creating a moisture trap at the plug connection. Besides there is more often than not no missing suggesting misfire of individual plugs which leads me to believe in a breakdown of the HT lead or the dizzy cap.Alternatively it is a failure of the cap itself or within the cap ---but only when it rains. Thanks for the continuing interest. Geoff.
Gary Lazarus

Gary - Have you considered moving to Arizona? ;) Cheers - Dave
David DuBois

Hello all my new found friends.
Well true to form UK weather had a summers day so out I went in moderate rain to try the car again after the usual checks. No improvement. So I fitted a new coil--desperate measures, but no better.
The ignition light does not come on when the car overuns after dying. Only when I come to a halt (Ant-Allen Staffordshire) so where does that take me. There is no moisture under the dash that I could see. The engine never failed to start almost immediately after stopping at the road side.
Gary Lazarus

Your engine is cursed.

The only remedy is to sacrifice a virgin on the bonnet, at midnight in Milton Keynes, with fairy lights and a gospel choir.

Night all.
Nick

Nick, i like your thinking, but where do you find a vigin in Milton Keyes? LOL
Arie de Best

Wait for a damp night and fire it up with the bonnet open in the dark, watching for the sparks. My 2002 VW GTi had a problem with the HT leads at the coil-pack sparking to earth when things were damp. I pulled each HT lead off the coil-pack, lubricated it liberally with dielectric grease and reinstalled. 20,000+ miles without a problem since then.
David "sparky" Lieb
David Lieb

Does it just die or splutter & cough first?
Brad (Sprite IV 1380)

Sorry to complicate things but as Geoff seems to be logged on as me, I just have to confirm that it is Geoff who has the problem, not me
The real Gary Lazarus

Geoff. Perhaps you could register as a member here to stop any confusion.
Gary Lazarus

I'm steering clear of Milton Keynes, much too old to encounter the wrath of she who must be obeyed. Arie-you get worse-I suppose you have looked. I am registered Gary but don't know how to divert these messages to me, I think I need to attach a magneto.
I have in the past run the engine on a fast tick-over and hosed the engine, dizzy etc (David- sparky Illinois) but it still ran without faltering. I know the engine isn't under load but if water was getting to the points or inside the dizzy cap then surely it would have then. The motor didn't cough or splutter previous to yesterday but after I had fitted the new coil it did after only about 200 yds then picked up and eventually died completely. It restarted and stopped a couple more times ,in all about a quarter mile run and I returned to base and gave up for the day. Arizona might not be a bad idea but the car is a right hand drive model.
Gary Lazarus

If the ignition light does come on when it stalls then you're not loosing the 12v ignition feed.

If I were you I'd rig up some test lamps to help diagnose it when it next fails. Put one between the 12V coil feed and chassis ground. That should be permanently on with the ignition on so if it goes out when it stalls you know that it's lost the coil 12v line. You could put another between the battery 12v and the permanent ground at the disi. If that goes out then you're lost the ground at the disi. If it stalls and they both stay on then it's between the disi and the coil, of in the HT.

It's a bit of a faff, but the only way to diagnose intermittent faults is to either narrow down what happens to initiate it, or be ready with some extra instrumentation for the next time it fails.

Ant
Ant Allen

Gary,
In future, when sending someone a link to an interesting post or whatever, it would be advisable to navigate there from scratch rather than using your bookmarks. Your bookmarks include your account in the "&access=
David "imagine someone trying to emulate these siggies" Lieb
David Lieb

Thank you Ant. Is wiring the coil direct to the battery, i.e. permanent ignition not the same as wiring a test light from the coil to the cabin and an earth.
The permanent live is the fat brown wire at A on the control box is it not? I could use this to the same effect-yes?
My email is : hunters360@btinternet.com
Gary Lazarus

I still think you should check the wiring for low insulation, have you a megger?
Brad (Sprite IV 1380)

I have to be curious, where in Worcestershire are you?
Roly
Roly Alcock

All appears OK brad-I take it you mean the short white/black wire from the dizzy into the loom emerging to connect to the neg side of the coil. I now have another rebuilt ditributor to fit perhaps tomorrow but will check again first.

Wolverley-2 miles north of Kidderminster Roly, not too far if you feel like a first hand test run-but I can't come to you if it rains.
Thanks for the contiued interest everybody.
Gary Lazarus

Don't know if this helps but I had the same symptoms with a Rover Metro. Ran fine when it was dry but would die sometimes when it was wet. Would then restart and run again only to die later. Worst time was breaking down 5 times on the M6 - die, leave it a while start and run then die again.
There was a very small crack in the fuel pipe which ran under the wheelarch and was sprayed with water from the wheel when raining and the water found its way to the tank/engine. Engine died then fired after water drained/evaporated then died again when more water got in. Strange there was no evidence of fuel leaking maybe because it was being sucked (like yours) raher than pumped.
Just a thought as you seem to have covered just about all other bases.

Good luck

Jeremy
Jeremy 3

Thanks Jeremy, that sounds very plausible. The symptons are very similar to fuel starvation,hence replacing the pump. There is a short length of flexible fuel pipe fom the tank upwards joining the copper fuel pipe over the axle which then travels the length of the car to almost the pump.There two or three places where a fracture could have occurred but I too have not experienced any evidence of fuel leakage.
Geoff
Gary Lazarus

Fine fuel pipe cracks - particularly perished rubber hoses, between tank and fuel pump rarely leak out fuel as the rubber swells and acts as a valve to close the crack. Or leakage is very slow and the petrol evaporates off rather than dripping on the floor. But when the pump is working it can draw in air - and presumably water too. This might suggest that if there is no real evidence of leaks, it could still be perished rubber or poor rubber-to-metal connections.


Guy
Guy Weller

Geoff,
If I could throw my 2p worth into ring, rather than a component fault, could the problem be caused by water being thrown up from underneath and for instance getting on the plugs ? or distributor ? could water be running along underneath the bonnet a dripping on something electrical, as soon as you lift the bonnet the cause disappears and when you close it, it reappears. Just a thought.
Another thought, you are running a HIF ? what sort of air filter are you using ? could that be getting wet either from water being thrown up from the road or creeping along inside the bonnet ?
As we have some ideal testing weather at the moment perhaps you could try wrapping some Tesco (or Waitrose) plastic bags around the distributor and coil and taking it for a spin to see, not very elegant but it might prove or disprove a theory. Not sure if you do this over the filter or not(leaving a suitable hole for the engine to breathe !)
Hope some of this may help.

Alan
PS Good luck
A Pritchett

Hi Alan, I have been pre-occupied with daughters wedding using wedding cars sevenoaks these last few days and so have not completed the necessary investigation. I hope to do so shortly and for the benefit of all who have followed this baffling saga will report asap.--Geoff
Gary Lazarus

No ones mentioned it yet, but you could use a garden hose pipe to try & simulate the rain, may be worth a try.
Brad (Sprite IV 1380)

condenser....
David (davidDOTsmithAT stonesDOTcom)

Brad...
<<No ones mentioned it yet, but you could use a garden hose pipe to try & simulate the rain, may be worth a try.>>

I think Geoff/Gary has tried that already - see post on 27th july @ 10:08

Jeremy's fuel hose suggestion sounds very interesting. Might be worth investigating.

More rain forecast for tomorrow, I believe. (sorry, later today!)
Dave O'Neill 2

I had a car that used to die in the rain. Usually making right hand turns. Try running the car in the dark when I did that I found a damaged coil wire that would short when moved just right.
VinceG

Vince, I had exactly the same problem on a Mk1 Cortina GT that I owned many years ago. Make any turn right and the engine would cut out... That was a gaulty coil....!

Mark.
M T Boldry

I doubt that it is water splashing up off the road - Spridgets are not very susceptible to this and others would suffer the same if it were that. And besides, he describes the underbonnet area as dry and well protected.

Maybe a windscreen or scuttle (wiper wheelboxes?) leak allowing water to get in behind the dash and run down onto the ignition wires? Or maybe a wire behind the dash which gets trapped by the moving wiper mechanism and momentarily shorts?

Guy
Guy Weller

This thread was discussed between 23/07/2009 and 03/08/2009

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