Damp start problem - coil?

[midlife crisis]

Hi,

Just a quick question on damp start problems. I was bought a 1987 Mk1b by my wife for my birthday last month (permission to grin like an idiot..!!) and the guy selling it said the coil was dodgy and to keep the car covered overnight if rain was forecast. True enough, on damp mornings it will either turn over but not start, or start, run for a few minutes but die if you try to pull off, or let the revs drop too low. Once it dies, it won't restart until later in the day.

Does this sound like the coil? I've been looking for one, but then thought I should check the opinion of you knowledgable types before spending my hard-earned cash...

When it's dry, it will start and run with no problems at all. Would really appreciate any thoughts on this one, as it's getting annoying having to drive the Focus if rain is forecast!

Thanks loads, Dave.

[greglebon]

Without knowing all the details, I would at this stage say the coil is the least likely culprit...if it was dodgy, it would be dodgy all the time....

Check the spark-plug wells: they may be half-full of water / condensation, ec, after rain, causing a misfire / cut out.

Does the car idle ok when it starts, or does it misfire slightly?

It could be the leads.....

Maybe the igniter ground is dodgy....etc..etc..

Basically, you need to check the ignition system components: check you have a strong, regular spark at each plug.
If you have a problem with one or a couple, its probably the cylinder leads..if all are playing up, its probably the "king" lead...check the dizzy cap.

It may be easiest to simply replace the rotor arm, dizzy cap, leads and plugs...?

Then you'll know hre you are, and probably prevent a fair bit of grief in the future.....
I generally replace those bits, and the battery, as a matter of routing when buying a s/h car...for peace of mind.

First things first, though.....!

Check the wells....

[crazylegs]

if it was water in the plug wells the water would be still there the next day. so it would still not start. so this could be a factor but not the only one. try a fault code reading.
as it turns over freely you may be able to rule out the battery, if it was struggling then thats possible but would not explain the days wait after it dies. as said check the earths and connections including the one in the boot (N1) and have a good look at the ignition side. run your hands over the leads when its running , you will soon find out if they are dodgy ! or... a safer way would be to have a look in the dark to see if there is any arking at the coil.
by the way where are you? someone could be just round the corner with the answer.

[phil mk1]

Hi had this problem with mine turned out to be the distributor cap not sealing changing cap sorted it

[midlife crisis]

Hi, I checked the wells first of all, as I had similar problem on my old Mk1. Dry as a bone. WD-40 just to be on the safe side Thanks for the suggestion on the dizzy. Will get that checked over tomorrow.

Concerning the earths, would these only play up in the wet? Again, with the leads, the car pulls and runs fine in the dry, although will do all the usual checks, see if there's any frayed insulation letting water in.

Crazylegs, I'm in Birmingham. Know there's a few Mk1'ers around here, seems a social bunch so may get chatting...

Will check the car over tomorrow, and report back with anything odd-looking (the wife says anything odd-looking apart from the car... ). Thanks for your help so far

So, is the general thought that it may not be the coil. Maybe a cracked casing letting water in?

[Goto10]

I had the same problem with the exact same symptoms, turned out to be dizzy cap seal - new cap & it was as good as new.

[monkeymax]

Hi Dave,
As others have said, check the distributor cap first. It's on the drivers side, front of the engine bay (follow the HT leads). If I remember correctly, it's held in place by two screws on the Mk1 engine.
Note down which HT lead goes into which socket of the cap, then remove the cap. Have a look at the condition of the contacts inside; if they have white deposits or are pitted, that's a fairly good sign that moisture has got inside and so arcing has occurred. If this is the case, replace the distributor cap & rotor arm (most Motor Factors have these in stock, but Toyota aren't that expensive in my experience - for these - and you know you're getting half-decent parts).

If you don't see evidence of the moisture in the distributor cap - or you change them and things don't improve - personally I'd then check the electrical plugs for the ignition system. Any that are loose would get a quick check over at the state of the contacts then a spraying of WD-40 to clean them up. Same with the grounding points.

HT Leads are expensive, so I wouldn't replace those straight off without knowing they're the problem.

[midlife crisis]

Hi,

It stopped raining long enough to test out, and although it started OK first time, but turned it off, and it wouldn't re-start. Took the dizzy cap off, no sign of arcing or anything else, actually looked like it had been recently replaced (will find out if previous owner changed it...), but no sign of a seal, just plastic cap against metal of the distributor.

Plenty of WD-40 on the contacts and rotor arm, and liberally inside the dizzy, and it started, spluttered once then ran fine. Re-started OK too. So thanks for all the pointers, I think there were several suggestions for the distributor cap.....

the key issue is that it will generally start after rain, but misfire a little, then cut out under load, then not restart. Does the fact that it starts first, but then die make any sense?

Will wait for next rain, and see what happens... Thanks for the advice and help so far.

Should there be a rubber seal on the distributor cap that I'm missing?

Thanks again, Dave

[MartG]

Should there be a rubber seal on the distributor cap that I'm missing?

Yes

[System-G]

I have the same issue with my 1a at the mo.

Dissy is newly refurbished.
Plugs, leads coil etc dry and looking OK.

The car cranks fine and idles/runs fine once started.

No fault codes.

I am assuming at the moment it's a dodgy earth somewhere.

[Goto10]

I tempted fate by posting in this thread - the problem returned, starting sounding like a Subaru yesterday in the rain (running on 3), luckily i was seconds from home so coasted most of way back.
Taken the cap off today and it was damp inside (the cap seems to be missing one of those rubber drainage hoses), so I've cleaned it all up & given the contacts/rotor a good scrub with wet & dry - the car then fired up perfectly running on all 4 - took it out for a test run and it was all good until boost reached 8psi, at which point it just misfires, back off boost it's ok again... So definitely an ignition issue somewhere (was still raining, so damp related again by the looks of it)
Cap is definitely fine (copper contact one), so I'll stick a new rotor arm in and keep fingers crossed!

[midlife crisis]

Don't you just hate that? (problems coming back after you think you've sorted them. As well as sounding like a Subaru...)

I'll keep you posted if I find a solution. Just fitted the new Toyota dizzy cap, cap seal (as there wasn't one on the car...) and rotor arm. Just gonna go with it for a bit, when it rains see what happens. Guess I'll spend a bit of time checking earths, etc. Am also trying to get a replacement coil in case that is the problem.

Thanks for the advice so far though. Been a huge help. Guess I'll know if it's fixed next time it rains. Until then , will live in denial and assume it's fixed

[monkeymax]

Dave, if you still have problems when it rains again, next step I reckon is to check the Earths are clean and clear. Unbolt them and see what the connecting faces look like. Personally, I'd rule this out before spending on an ignition coil...

On top of this, if you can get yourself a multimeter you can check the ignition coil before replacing it. Buying a new one could be a large expenditure you don't need to make, and buying a second-hand one could be buying another faulty one.

Get a multimeter and set it to measure resistance. Measure the primary coil resistance by measuring the resistance between the small positive and negative terminals. The resistance should be between 0.5 and 0.7 Ohms. Then check the secondary coil resistance by measuring the resistance between positive terminal and the high-tension socket the king-lead connects to. The resistance of this should be between 11 and 16 kilo-Ohms.

While you have the multimeter near the engine, also measure the resistance of the HT leads - they should be consistent and less than 25 kilo-Ohms per lead.

Hope one of these helps!

[System-G]

I tempted fate by posting in this thread - the problem returned, starting sounding like a Subaru yesterday in the rain (running on 3), luckily i was seconds from home so coasted most of way back.
Taken the cap off today and it was damp inside (the cap seems to be missing one of those rubber drainage hoses), so I've cleaned it all up & given the contacts/rotor a good scrub with wet & dry - the car then fired up perfectly running on all 4 - took it out for a test run and it was all good until boost reached 8psi, at which point it just misfires, back off boost it's ok again... So definitely an ignition issue somewhere (was still raining, so damp related again by the looks of it)
Cap is definitely fine (copper contact one), so I'll stick a new rotor arm in and keep fingers crossed!

There's a difference in MK1 & MKII dizzy caps then. The AW11 that this thread is about does not have drainage hoses in the cap. TBH, I don't rememebr my Rev3 having drainage hoses in the cap either... perhaps it's a tubby thing?

[midlife crisis]

Hi,

Thanks for all the info and suggestions people. My distributor cap didn't have a seal on it, and last time it didn't start, I sprayed the inside of the cap and around the dizzy and it started.

So, one new cap, seal and rotor arm later the car started after a night of rain, and also started the other day after washing the car and a major hail storm

So, I'm gonna assume it's fixed unless proved otherwise. Tho I'm gonna take monkeymax's advice and check earths, leads, coil (did this on my old Mk1 so OK with this one, but thanks for the specs), and other electriccy bits!

System G, there's def no drain hose from the Mk1. TBH I've never seen one before on a car. I can sort of see why you'd have one, but surely it might actually let moisture into the cap? Have you checked if your cap is a Toyota genuine bit?

Thanks again for the help, looks like the new cap and seal sorted it, although if anyone's got any pics or help as to whether I've fitted the seal right, would appreciate it. It didn't really seem to fit anywhere, but it's in and the car goes so if it ain't broke...