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MG MGB Technical - Car got a bath now won't start

I washed my car (70GT) yesterday, including the engine bay (although people think I am mad when I do that). I was careful to make sure nothing electrical got wet then when I finished I made extra sure it was all dry. Car started fine and I put it away in the garage with the front wheels up on ramps.

Today I got underneath it to fix an exhaust bracket then afterwards found the car just won't start anymore. It it turning over fine and getting fuel but I don't think I am getting any spark.

The coil gets 12 volts OK when the ignition is on. I tried hooking a lead to a spark plug lead with a small gap to ground and also from the coil itself to ground but I see no spark. Well, I did see one the first time I tried. Something to do with the cap charging first time I guess?

One thing I did notice when checking the distributor was the white and black wires insulation was all ripped and missing inside the distributor. I think it is a 25D4.

What is the best way to check for spark? And is there anything else I should be checking in the distributor? Should I replace that dodgy white/black wire right away? Can I hook a scope meter to the white/black wire and see it switching when I turn the car over?

Thanks!

Simon
Simon Jansen

I'd bet you a buffalo nickel your distributor is wet. As well as the not so good sealing cap there is also holes in the bottom of the distributor for drainage. Open it up and wipe the cap down best you can. Then take a hair dryer or other heat source and warm the hole thing up.
If you still won't start, the best way to check for spark is to remove a plug and with insulated gloves/pliers/ect.. to hold it against the block and have someone turn the engine over. To further diagnose, take a voltmeter/test bulb to the wire going into the distributor and put the car in forth. If you ground one end and put the other on the wire as you move the car forward the light/meter should go to 12V and 0V in a cycle. This is a basic check to see if the points are working. If you still have problems, take the coil and attach a plug straight to it, using a spark plug wire. If your coil is good, you should get a spark if you very quickly ground the plug to the block and remove it, again using some sort of insulator.

Hope this helps,
John
J Arthurs

Problem solved! It did turn out to be that dodgy flexible wire. The insulation had completely gone from the middle of it. I replaced it and the car runs great again. Lucky I noticed that in my garage and not out in the middle of the wop-wops somewhere!

Unfortunatley as the car has been sitting with it's front end up on ramps the last day or so it seems water pooled behind the drivers seat. I suddenly wondered why my knee was all wet when I was reattaching the battery. Must have been happening in the past since an inspection of the carpet revealed it was quite rotten.

Next job, cut the bottom of the vent drain tube. No matter how careful I am washing the car I always seem to get water in through the damn heater vents!

Cheers!

Simon
Simon Jansen

Simon,

Be sure and clean out the vent scuttle tube that goes through the heater vent on the right. When the ball space on the tube gets clogged water will back up in the tupe and come out the heater vent.

Steve
Steve

Hi Steve, as far as I can tell the tube is clear thanks to a screwdriver last time I was under the car. I thinkI will cut off the bulb part though. The plastic seems very hard there and that little slot looks like it'll restrict any water from flowing through. I'll add that to my list of things to do :)

Thanks!

Simon
Simon Jansen

This thread was discussed between 25/08/2002 and 26/08/2002

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