Remind me?

[flippin'eck]

Sorry I know this has been covered in detail before.

Fully charged battery.

When I turn the key in my Mk1b to start, all the lights light up, and the starter kicks in. The engine turns over healthily, and kicks in no prob without any real hesitation. But then, the starter motor seems to stay engaged and there's a corresponding whine for a good few seconds. So far, each time this has happened, the starter has eventually dropped out after say 3 4 or 5 seconds and normal running has resumed.

ISTR Paul Woods telling me something about the starter relays and ISTR following his directions and getting down to the root cause but 4 years of small child have elapsed since then & the memory fades..

Anyone shed any light? It was something about, check a particular connector for a signal and if present, it was one fault, if not it was the other.. sorry to be so wooly

[PW@Woodsport]

I remember that thread, either your starter motor is faulty or the relay is sticking/being held open by the ignition.

Locate the M2 connector (large grey plug at the base of the passenger rear strut tower) , and within that connector is a thick black with white stripe wire, this is the starter relay output to solenoid wire.

Wire a bulb to this wire and ground, you will note the bulb comes on when you crank the engine.

If the bulb goes out the second you let go of the key then the ignition switch and relay are doing their job, and the starter still hangs in, then you have a faulty starter- remove and replace.

If the bulb stays lit AFTER you have let go of the key and the starter is hanging in, then you either have a faulty starter relay or ignition problem- replace the relay and try again- if the starter still hangs in replace the ignition switch.

The igntion switch wears where the aluminium keyway on the barrel eats into the plastic keyway slot on the ignition switch itself, this means the switch doesn't fully retract from the start position when you let go of the key.

I would favour the relay or starter as causes though.

Hope that helps, don't forget it this time

[flippin'eck]

ISTR going through it all back then, and it was the relay. Either I dismantled & cleaned the relay contacts or just replaced it, can't recall which.. and things seemed sorted. But, it started doing it again.

Luckily I have a spare everything in the shed, so hopefully should be okay, thanks for the info. Been putting up with it but getting worried about knackering the ring gear on the flywheel!

[flippin'eck]

hmm.. bit puzzled. Had some time to really look at this properly this afternoon, restarting over and over with cooling down time in between.

I got the light rigged up & illuminating off the starter relay output to solenoid wire in the M2 connector just fine.

Managed to catch the fault red-handed a couple of times and the result was, the light stayed illuminated even when the key was released, for 3 seconds or so until the starter finally dropped out each time. So, I thought, righto, it's either the relay or the ignition switch.

Located the relay, sticker was missing off the relay box cover but a quick google sorted that, and the relay is a pretty distinctive green one that actually says "starter relay" on the side so I'm reasonably sure I picked the right one. It's absolutely pristine, and the cover comes off easy so a look inside confirmed everything to be bright & shiny clean with absolutely zero 'stiction' or burning apparrent on the contacts - I'm pretty sure now I did replace this relay a year or max 2, ago.

So.. I figured, right, it's going to be the key barrel / key barrel switch. I have got a spare on a different car, but it's bugging me because, the fault is repeatedly, only ever apparrent on the very first turn of the key after the car has been left to go stone cold for at least a good half hour.

Once the key has been fully turned once, however briefly, regardless of whether the engine fired, you'll never be able to invoke the fault again until the car's been left completely alone for another good long rest.

So I'm still kinda split between, is it the starter motor or is it the key switch / key barrel!

Logically I think the answer is 'deffo the key barrel' because of the light staying on. Wondering does the key switch get hot inside or something when the fault occurs, loosening it off for a bit or something.

How easy is it to strip down the ignition switch, do I need new bolts with breaky-off heads etc..

Is it the sort of thing a spray of WD40 in the right place would sort? or is the whole thing too 'sealed' to be able to get any in without dismantling?

The spare barrel I have is okay but, I only have one key and it's orrible and rusty. Would I be able to get copies at a reasonable price?

Would I even need to change the barrel, would changing the switch alone be possible and a likely remedy?

[PW@Woodsport]

The switch changes independantly of the barrel, it seems the most likely culprit going by your post.

Test the starter relay input wire, you have tested the output, so that confirms the issue is either the relay or the ignition switch..... so repeat the test on the starter relay trigger wire, that runs from switch to relay.

Pull the relay out and test which pin becomes live with ignition turned to start, use your test bulb to confirm if it stays lit after the key is released.

That should tell you more.

[flippin'eck]

Thanks Paul, good idea, we'll try that first thing tomorrow. Gone dark out there now & my 4 year old second man has run out of steam for now. He's insistent it's "radio interference" that's causing the problem.

[flippin'eck]

weird.

looking at the relay socket from the back of the car, the top 2 terminals are the relay's coil & the bottom 2, the contacts.

of the top 2 I found, the left hand one lights the test bulb if the other end is touched to the battery positive, regardless of key position. so I concluded the top left hand relay socket terminal is a ground, and the other one (the top right) must go to battery positive via the ignition switch.

so i connected the top right socket terminal to one end of the test lamp & grounded the other end of the test lamp.

the test lamp then came on and off in concert with turning the ignition key to start and releasing it - very reliably. tried for ages to coax it into sticking 'on' but it just never did, it was faultless.

took the test lamp away & re-plugged the relay. 1st trial - stuck on for 3 seconds. 2nd trial - same again, stuck on for 3 secs. after that, tried ten times or so and it seemed alright.. like usual. it'll not do it again now till it's all had a chance to rest / cool.

really don't think it's the key now, or the relay.

car's going in tomorrow for a load of mot work, might get them to swap the starter while it's on the lift, see what happens

the test lamp staying on when connected to the black / white stripe wire on the M2 connector doesn't seem to support the faulty starter theory though, that would still seem to indicate the relay sticking / being held on. I wondered if the starter, being held in engagement, was somehow running as a generator and 'backfeeding' the test bulb but thinking about it, the solenoid would stop anything like that yes?

there is an immobiliser on the car. don't know how standard / factory fit it is, it's a little tiny socket right by the ignition key & you touch a fob to it to make the flashing red light go out - once it goes out you can start the car. the fob has a tiny metal ring at the end with a spring loaded pip in the middle. inside the fob, the ring and pip are soldered to what looks like 2 of the legs of some kind of small black plastic cased transistor.

could the immobiliser be causing the problem?

edit/ it's a "cobra 8510 thatcham category 2 immobiliser" certificated install august 2004

[PW@Woodsport]

From what you've said, it sounds to me like the starter is the issue, when the relay engages the starter solenoid, the solenoid itself is sticking (when cold) and backfeeding to the relay, which is giving you the results you have found.

If you never got the bulb to light on the key energiser then it is either the relay or starter, but if you have renewed the relay then it only leaves the starter to blame.

For price of a relay and ease of fitting i would try that, but it's looking more like a sticking starter solenoid now.

[kaiowas]

I really should get around to doing some of these diagnostics on our car. I've had similar issues for a while, always on the first start of the day but not every day. I'd always assumed it was a mechanical issue preventing the starter from disengaging and have swapped it out every now and then for one of my spares. Hadn't even considered that the issue might be elsewhere.

It's one of those faults that you only really think about when it does it then you forget all about it so it never gets sorted.

[flippin'eck]

I was so sure the relay couldn't possibly be at fault, given it was a brand new one from Mr T a year or so ago. Pulled a 20 year old grimy one out of my scrapper this morning & thought, can't harm to try..

Problem gone away. Can't invoke the fault for love nor money now. So maybe it really was a dodgy new relay

[PW@Woodsport]

Sounds like it, wouldn't be the first time a new part failed....glad you got there.