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MG Midget and Sprite Technical - Hard starting, if at all, problems continue....

Hi Guys,
I'm still having starting problems with my midget. These started last year and I took the suggestion from these boards to replace the carb diaphragm.(thanks Clare). At first, I thought I was good. Had a couple of good days. Then one morning, I couldn't get it started. Next day, it started. It's subsequently stranded me in a few places. It seems if I wait a while, it will then start. Could a new carb diaphragm be bad when new?
This is starting to make me crazy. I hate not having any confidence in the car anymore, ie, not being able to take it to an appointment, for fear of not making it. I've been driving this car for years without this difficulty.
Does anyone have any ideas. I've pulled the diaphragm out a couple of times to make sure it's ok. Nothing I can see wrong. As a matter of fact, the old one looked fine too.
Put in a new fuel filter last Summer and I can see the fuel pump is doing it's job.
Thanks.....Paul
Paul W 1976 1500

Hi Paul.

Can't remember your previous thread, a simple question first for clarity. Does it spin over and not start or just do nothing at all?

Malc.
Malcolm Le Chevalier

Im assuming you have the zenith stromburg carb...not SU carbs

Do you know for a fact it is fuel related
1 Paper

Does your rotor arm have a rivet? (my answer to everything at the moment LOL)
Jeremy MkIII

Hi Guys,
Yes, the engine turns over just fine.
I suspect fuel because after prolonged cranking I don't smell anything (gas).
Zenith Stromburg is correct.
I've gone back to the original rotor. Two years ago I bought the 'red' rotor.
I was having intermittent shut down trouble two years ago and last year also. It's done that a couple times to me this season. Over the past two years I replaced the ignition coil, ballast resistor, distributor cap, rotor and wires. I suspected a crimp in the rubber fuel line (possibly closing off when hot) so I put a solid tube in that spot so this could not occur.
I'm beginning to suspect the ignition switch on the shut down problem. It shut off on me this morning and I 'jiggled' the key like I was going to re-start the car. I did this while I was still rolling and in gear. The engine fired right up. So , now, I'm thinking that maybe my ignition switch is goofy.
Thanks again, Paul

Paul W 1976 1500

I think you're onto something about the ignition switch Paul. Easy to check by linking out the switch. Good luck. Let us know if you want help with the wiring diagram. (Need to know what model of car). Cheers.
Greybeard

Paul. If you turn the ignition switch to start position, what happens?

If nothing, check if you have lights and other electrics that do NOT go through the ignition circuit.

If the engine cranks over, the ignition switch is OK.

My 79 MGB has gone through 4 switches.

Let us know your outcome

Cheers

Gary
79 MGB
gary hansen

If it's the ignition switch, or any other part of the low tension side of the ignition circuit, then the tell-tale is that the the rev counter will flicker violently as the fault occurs.
GuyW

Yes, it 'turns-over' just fine. I did notice though, one time last week when I couldn't get it started, the tachometer needle would 'spike' up to 1500 rpm's a couple of times while I was cranking the engine over. While the ignition switch appears to be fine, I have had an intermittent 'shut-down' problem for a couple of years now. I seriously suspect the contacts of that switch while in the 'run' position.
When I had a rough ride last week (couldn't get over 20 mph.) I popped off the distributor cap and the pick-up coil (electronic ignition) seemed to be loose. I re-set that gap (.015") and it's still running a little crappy. I'm going to dig out my timing light and get a look at the timing.
I've made several adjustments of the carb needle (1/8 turn at a time) it hasn't seemed to help.
I'll know more this week when I get back under there.
Thanks for chiming in guys....Paul
Paul W 1976 1500

Hello Paul;

Sorry I suggested the carb diaphragm but that was the source of my mystery non starting problems after running on a hot day.

It sounds as others have said, that the problem is in the switch as you fiddled with it and the car started back up again while rolling along.

Next time I start mine, I will have to watch the tach and see what it does. Just never really noticed how it behaves when the car is starting.

Still have not crawled under the bonnet to change out that stop light switch yet. Soon though as it is supposed to rain tomorrow so nothing better to do.

Clare
Clare Ravenwood

Paul, does this car have the ballasted coil system? Is it wired correctly for this?
GuyW

Guy, Paul's car should have the ballasted system.

Clare
Clare Ravenwood

Exactly Clare. That is why l asked if it has, and if it is wired correctly !
GuyW

Hi Guys,
Yes, it does have a ballasted system. I'm sure that is wired just fine as it has been fine for the last 15 years.
Clare, I'm sure I needed that diaphragm. Last Summer I got stranded in so many places it wasn't funny. The possible ignition switch thing is another problem entirely.
I hope to get back under the hood tomorrow afternoon and see what is going on.
Paul
Paul W 1976 1500

A very common problem is low voltage to the coil whilst cranking, usually caused by poor fusebox condition. One usually finds, if one takes the key back to run position the engine starts as the momentum to the flywheel keeps the engine spinning and the restored full voltage to coil allows it to spark. One could also use a spare battery to provide independent power to the coil.
Peter
Peter Burgess Tuning

<<is wired just fine as it has been fine for the last 15 years>>

Paul that may appear to be a very logical statement, but equally if contacts have corroded or crimped connections loosened, what worked perfectly for the first 14 1/2 years may not be ok now! Check the wire connections on the wire between the starter solenoid and the coil. I think it is a white wire with a green trace on the ballasted 1500s.

And as Peter says!
GuyW

Hi Guy,
I've checked the connectors in the ignition, in the distributor and the harness around it. They're ok.
I'm starting a carb thread, as it appears now that there's where many problems are, that I've created I'm sure.....Although I'm pretty sure I have an ignition switch problem. I'll deal with that laterr.....
Paul W 1976 1500

On your key ring... what all is on it ?

Keys + other nic nacks

If your key ring is loaded up, it will definatly have an effect on the ignition switch

On my car i keep just a glow in the dark fob and the key to the car... nothing else which is great insurance against wearing out an old ignition switch

Prop
1 Paper

Interesting Prop, I do similar with just the ignition key on its own fob and for the same reason.

Paul, I had a non starting issue on a Wolseley 1500 when it was a mere 9 years old, so a while ago :)
It was traced to the low tension wire breaking - externally it was fine but the internal wire had snapped, God knows how, I found it purely by chance as it was a braided cloth cover which moved too much when I accidentally caught it.
More difficult to check the plastic covered wiring now but either a multimeter check or jumping the wiring might rule it out if you've done this already.
Jeremy MkIII

I'm aware of problems with heavy key rings. All of my vehicles have 'stand-alone' key rings. I've seen people wear out the key holes on their ignitions before.
The exasperating thing about this engine 'shut-down' is that I can't cause it. With the engine running, I can grab, bend, wiggle and pull on the ignition wires and nothing will happen. The only real clue so far was was the jiggling of the key while dead and still moving in gear the other day, and the engine fired back up. Normally, when the engine dies, I'm in traffic and I have to hit neutral and coast to an off-street spot. Or I'll be stopped at an intersection or a corner and then I nave to push myself to a safe spot.
I just have to wait until it happens again, every few days or so, and try the key thing again. The switch is quite suspicious at this point though.
Paul W 1976 1500

This thread was discussed between 02/06/2017 and 08/06/2017

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