Alfa 75 TS starting problem – ignition switch or starter solenoid?

[alanm]

Hi all,

Occasionally I turn the ignition key to start the car when it is hot and the starter doesn't crank the motor at all.
All of the other electrics work when this happens, lights indicators, heater fan etc.

This problem never occurs from a cold start, probably not from a warm start, only when the temperature is at or approaching 90 degrees.

So... is it something to do with the ignition switch, something to do with the electric fan drawing power, or is it the starter solenoid failing when the engine is hot.
Or is it something else that i haven't considered.

I am thinking about buying a new ignition switch (along with new door locks) so that I can eliminate this from the equation.

Any thoughts?

Cheers,
Alan

[pasey25]

When I had a 75 TS, there was a connector from the ignition switch wiring in the steering column that I had to reseat every once in a while since it wouldn't start. On the odd occasion it wouldn't idle either. That is, if I kept driving, and foot on the accelerator when stationary, the engine would run, but it would stall if I let it return to idle.

reseating that connector solved the issues. I recall it was white and at least a 6 way connector, possibly bigger.

[GTVeloce]

You could rule out the electric fan just by disconnecting next time it won't start and see if that makes any difference.

Do you have a starter relay? If not, a very good idea. It may fix the problem and extend the life of your ignition switch. I'm sure you probably already know how to, but just in case; take the solenoid wire (spade terminal) and use that as the feed to a relay. Take power from the drivers side junction point and earth from the main point on the front of the drivers side of the engine bay. Then run a decent wire down to the starter solenoid from the relay.

While you are there, if you haven't already, run a much bigger wire from the starter (+12V from battery) to the junction box mentioned above. That should solve any starting problems unless your ignition switch is completely stuffed.

Or, as pasey25 said, it could just be a poor connection somewhere. That could take ages to find but the new relay should only be 30 mins and will be worth it even if it is not the main culprit here.

[alanm]

The relay seems to regularly come up in conversations about electrical gremlins as do dodgy connectors. I will discuss these things with my Alfa workshop when I'm getting some other stuff done.

I had another thought about my problem... Next time the car won't start, can I use a voltage tester on the power wire on the starter motor (solenoid ?) to see if it's getting power? If its not, does that confirm that it's a faulty switch?

I want to try to work this out so I that my workshop has a better than 50 per cent chance of fixing it first time.

Cheers,
Al

[alanm]

Following up on previous posts... reconditioned starter fitted.
It's a lot quieter than the old one, and cranks noticeably faster – one way or the other the old starter was probably pretty knackered.
Al.

[alanm]

 
Still got the starting problem, happened again after driving in heavy traffic.
Unfortunately I was on my way to the airport...
New ignition switch I think so that it can be ruled out as a cause.
Al

[Neil Choi]

Alan,


Did you check those four relays on the top left hand side of the engine bay, one of them (I think is related ie fuel pump).
Pull them all out and clean the contacts.  Doesn't hurt to clean them anyway if not solve issue.  Had similar situation, drove 150kms to PI, stopped to fuel up, got back in, no start.  Pulled relays and put back in, started again.  But this may not be your case, but anyway.


Also install a starter relay, I also installed a momentary bypass from terminal 30 onto terminal 85/86 (depending which is earth) as emergency.

[alanm]

Thanks Neil, I pulled out the relays and the terminals were filthy.
Cleaning them was quite therapeutic... I am sure I have done some good, related or not to my starting problem!
My knowledge of the electrical system is pretty average so I can't follow your instructions re the relay.
I will talk to Bruno about it tho.

Pic of car just because I like it so much (despite gremlin).

Cheers,
Al.

[GTVeloce]

Whilst a good idea to clean the relay contacts, they won't be your problem if the starter motor isn't turning at all. The can easily stop your car from starting but it should still turn over when the starter is applied. The starter motor wiring is very simple on the 75. See the attached but basically you have +12V coming direct off the battery (R4) and and black wire (N1) coming direct from the ignition switch. There are only three things that can fail; the ignition switch, the starter motor or the wiring between them.

Replacing your ignition switch may very well fix the problem but it will eventually fail again unless you relay the starter. It's a very simple job. Take the black wire off the starter and connect it to terminal 85 on a standard relay. Run a new wire from terminal 87 to the starter solenoid (where the black used to be connected). Then run a new wire from the terminal block on the drivers inner fender and to terminal 30 on the relay and a new wire from terminal 86 to any convenient earth point nearby (most likely the row of earths just behind the drivers side headlight.

This may actually save you from having to buy a new ignition switch and will cost peanuts compared to a new switch and will be easier than installing a switch. If for some reason you ever decide to return to original (no idea why you would) its as simple as taking the black wire from the relay back to the starter solenoid and removing the relay with its three new wires.

[MD]

alanm,

Advice from GTVeloce is 100% gold and correct. Install solenoid relay before you do anything else. All cars should have one from the start.

[alanm]

GTV, thanks for your detailed instructions regarding the addition of a relay - the only problem is you are dealing with a graphic designer... Only good for making things look pretty

I will have a go at following instructions but I am going have to start by asking a really dumb question. How do I identify the terminals 85, 87 etc?

Cheers,
Al

[Neil Choi]

Google is your friend.
The first one is really helpful and explains it well.

I can help you next time we meet up at Bruno's.  Bring a relay and a bunch of wires and spade bits.

[GTVeloce]

Neil has pretty much covered it except the numbers are usually stamped onto the bottom of the relay, right next to each male spade terminal. Pull one of the silver ones from the four starting sequence relays and have a look. I'm fairly certain you will see the numbers on the bottom.

[alanm]

Awesome, thanks guys!

I pulled out one of the bank of 4 relays on the passenger side of the engine compartment and had a look at lunch time. Yes, the numbers are stamped into the base of the relay next to the terminals.

Neil, I will have a crack at this on the weekend (thanks for your offer of help).
You can survey my work at Broadford!

My understanding of your collective instructions – tell me if I've got this right

[MD]

alanm,

Nice try but your circuit is a foul up.(of sorts).

I don't want to be part of the "too many cooks" syndrome so I will just suggest you take Neil's offer and let him help you wire the relay in.

Some pointers to your misunderstanding :
1 The heavy current carrying wire from the relay does not go to the starter motor. It goes to the solenoid. The intention of the relay is not to replace the solenoid but to help it work. Additionally, this connection from the relay needs to go to the positive terminal on the solenoid and not the negative terminal as shown because this would create a dead short. So two foul up in just one connection.
2 You show two T86 connections. There is only one on the relay.

Clearly you need some practical help which has been offered. There is no shame in accepting it. It's what the Alfa mateship is proud of.