Starting woes

Tips and help requests for your cars mechanics. points gaps, timming settings all those sorts of things

Starting woes

Postby OllieParkes » Mon Nov 18, 2019 9:40 pm

Hi,
I'm having a problem with starting my 1256 viva. It seems to catch but doesn't run, no matter what I do with the timing and carb tuning. This problem has been getting worse with time as it started with the engine running rough and spluttering when I rev the engine.

This started happening ever since I changed the power brake vacuum hose, which had a big split in it before.
The car seemed to be running fine before this happened. I have disconnected the vacuum advance and it still won't start.

The last time the car was ran, it refused to start as it had a bad battery earth cable. I removed the starter (and alternator) in diagnosing what was wrong before finding out it was the earth. I since changed the earth cable and the one time I started it seemed to work fine (I think).

I have since replaced the ignition coil which didn't change anything, and the car is fitted with electronic ignition.

Does anyone know what is going wrong here? Is it a bad spark? I have really been struggling with this problem for a while now and any help would be greatly appreciated. :help3:
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Re: Starting woes

Postby HC Fairley » Tue Nov 19, 2019 9:56 am

The electronic units have been known to fail over time. I personally have kept my old points ignition system as I have had no problems with it and I carry a spare set in case I ever need to change them down the road.

I would suggest getting your ignition unit tested or sticking in a set of points to see if that makes any difference, that is probably the quickest and cheapest fix should it be successful. I'm not sure if it is used on the electronic ignition or not but there is an earthing wire that screws into the base plate of the distributor. This has worked loose on me before and caused the car to not start.

Check all your connections under the distributor cap, all your leads are pushed in properly and maybe even check the distributor shaft is pushed down fully into the slot (caused another breakdown for me on a winters night)

Keep us updated.
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Re: Starting woes

Postby droopsnoot » Tue Nov 19, 2019 10:37 am

When you say it seems to catch but won't run, are you saying that you can crank it, and in the split second between you letting go of the key and the engine stopping turning, it coughs as if it's about to start?

If so, that suggests voltage getting to coil is too low, to me. There's a resistance wire in the loom that drops coil voltage to around 9v, but while you're cranking, the resistance is by-passed and the coil gets higher voltage, to compensate for the load taken by the starter. The moment you let go of the switch, the starter loses voltage, so the coil gets a little bit more voltage, and that can sometimes be enough to make it fire. Then momentum is lost, and the engine stops again.

But, it depends on exactly when this is happening. For the above, it has to be just at the moment you let go of the key.

Do you have a multimeter of some kind, so you can check the various voltages going to each part?
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Re: Starting woes

Postby Fred Dukes » Tue Nov 19, 2019 6:19 pm

If you want to test for the problem droopsnoot is suggesting move the coil feed from D4 to D5 which will eliminate the ballast wire - this should have been done anyway when the electronic ignition was fitted? Is there any clue to be had from the fact that it was running ok prior to you sorting the feed pipe to the servo - is that all as it should be?
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Re: Starting woes

Postby OllieParkes » Tue Nov 19, 2019 10:05 pm

Hi All,

Thank you for your suggestions, I had another go at starting the car this evening.

I looked at the coil feed and it was in the D4 position, so I swapped it over to D5. This didn't make it start, but made the starting more consistant.

Here is a video of it trying to start https://streamable.com/0t4q0. It's not at the point you suggested droopsnoot, I hope this video give a clear explaination of that is happening.

I measured the voltage across the coil with the ignition on and it measured 10V exactly. Is this what is wrong? The coil is brand new (Lucas DLB105 Gold ignition coil)

I did try and change it back to points, but didn't get any success as there was no spark. This could have been a faulty dizzy though. I checked all the connections and they seemed to be all tight. I rebuilt the dizzy, which didn't make a difference unfortunately.

Thank you all for your help so far, and I hope this sheds some light on a potential fix.
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Re: Starting woes

Postby droopsnoot » Wed Nov 20, 2019 10:28 am

I can't tell much from the video, to me it seems to be what I meant (even if that might not have been what came across) - the point where it seems to catch is where you let go of the key.

On the original coil feed wire position, you would see about 9v across the coil, with the in-line resistor. That drops to around 6v when cranking. With the feed wire moved so it doesn't use the resistance, you should be seeing 12v before you start cranking, dropping to about 9v during the cranking process.
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Re: Starting woes

Postby Mike Attew » Wed Nov 20, 2019 2:25 pm

Before starting have you tried a couple of pumps with the throttle to squirt some fuel in? then use the throttle a bit when trying to start. It may be the mix needle?
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Re: Starting woes

Postby lord13 » Thu Nov 21, 2019 12:59 pm

wind in the throttle stop screw, so the butterfly is open a little... It seems like a lack of fuel to me . . .
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Re: Starting woes

Postby OllieParkes » Mon Dec 02, 2019 7:23 pm

Hi, it works!
Sorry for the late reply. Turns out it wasn't fuelling properly as you said, and the mixture screw was clogged. Replaced that, gave it a tune, and it ran well!

It didn't last long however, as after a day of running it around one of the wires on the accuspark module wrapped itself around the dizzy arm and ripped itself out. This is a good indication that I should probably park it until the spring and stop playing around.

Thank you all for your help.
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Re: Starting woes

Postby Bob perry » Sun Dec 08, 2019 6:00 pm

Yep, like the rest of us Ollie, wrap her up and put her in hibernation until the New Year!!

Happy Christmas.
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