Unusual starting issues

Seikoking

Well-Known Forum User
Looking for some guidance and advice from the knowledgeable folk on here :)

A few weeks ago, after a couple of months without being started, the car really struggled to get going, I managed after a number of attempts to get it going and went on a drive. Returned fine (after stopping for fuel and successfully restarting) and parked back in the garage. Since then, it simply wont start.

I have been through all usual checks...fuel delivery, coil, plugs, distributor and came to the conclusion that the 280ZX distributor and/or the electric module had simply failed. So, I bit the bullet and ordered a 123 ignition unit - I fancied one anyway since reading AliK's write up. Booked in with my local garage for the install (I'm quite an amateur and it needed MOT anyway!). New dizzy fitted and started OK initially, however, soon after when I was about to collect, the garage reported starting problems and mentioned a concern about the ignition itself...

Since purchasing my 260Z it has always been a little odd in the way it starts - especially from cold after a rest. Turn the key a couple of clicks, wait for the fuel pump to prime, a few pumps on the throttle then turn to the key to the start position. The engine would crank fine but never fired up until you release the key off again, when the engine sparks into life. You just had to be quick to "catch" it on the throttle and balance the revs (Webers). The garage think this is actually the issue, not the dizzy. Now awaiting an auto electrician!

Anyone had this problem before or have any ideas what the problem might be?
 

uk66fastback

Club Member
Sounds a strange one. Does the garage say whether it is just as it was and they can’t catch it ... Ignition switch maybe? Interested to hear about how the 123 is, as I’m thinking of getting one. Can I ask where you got it from?
 

jonbills

Membership Secretary
Site Administrator
There's two wires go to the coil ballast resistor - one is from the 'start' circuit, the other is from the 'run' circuit. If the 'start' one was disconnected, then it wouldn't fire until you release the key.
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
Does your car have a ballast resistor circuit?

I'm thinking the circuit for starting is different to the circuit for running.

EDIT Jon beat me to it.
 

Seikoking

Well-Known Forum User
There's two wires go to the coil ballast resistor - one is from the 'start' circuit, the other is from the 'run' circuit. If the 'start' one was disconnected, then it wouldn't fire until you release the key.
Does your car have a ballast resistor circuit?

I'm thinking the circuit for starting is different to the circuit for running.

EDIT Jon beat me to it.

Thanks Gents,

There is no ballast resistor on my car?
 

Seikoking

Well-Known Forum User
Sounds a strange one. Does the garage say whether it is just as it was and they can’t catch it ... Ignition switch maybe? Interested to hear about how the 123 is, as I’m thinking of getting one. Can I ask where you got it from?

Hi

I've not spoken to the garage in much detail as yet, will get more info in due course and feedback.

The 123 came direct from 123 in The Netherlands. Service was spot on. Delivery into the UK inside of 2 days. The 123 site displays home country pricing, so the price you pay is less than advertised, however, you'll get hit with customs charges from UPS ;)
 

jonbills

Membership Secretary
Site Administrator
you may not have a ballast resistor, but the car did used to have one, and it will have a supply wires for the run circuit and the start circuit. If they're not joined together at the coil then you'll only have sparks when cranking or running.
Are there any spare wires around the coil area?
 

Seikoking

Well-Known Forum User
you may not have a ballast resistor, but the car did used to have one, and it will have a supply wires for the run circuit and the start circuit. If they're not joined together at the coil then you'll only have sparks when cranking or running.
Are there any spare wires around the coil area?

I'll take a closer look later and see if there are any spare - I suspect there may be I'll post a pic or 2.

Would it be feasible though for this problem to arise suddenly when its been possible to start relatively easily for the past couple of years? Maybe the wires have become disconnected...
 

jonbills

Membership Secretary
Site Administrator
Yes, easy for the wire to get knocked off. I had a problem like it at Santa Pod a couple of years ago where the movement of the engine pulled one of the wires off.
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
you may not have a ballast resistor, but the car did used to have one, and it will have a supply wires for the run circuit and the start circuit. If they're not joined together at the coil then you'll only have sparks when cranking or running.
Are there any spare wires around the coil area?

You meant only sparks when running not cranking.
 

Seikoking

Well-Known Forum User
Right, so first chance I’ve had to check the car since being returned from garage today and this is how I find the wiring...

BEB2E91C-C5BD-49C5-9168-C940921E794D.jpeg
Original Green white wire not connected to anything. Original Blue wire connected to positive side of coil. I assume these are the ‘run’ and ‘start’ circuits? New wiring for 123 looks as it should as per instructions.

If I understand correctly the blue and green white need to be joined together and connected to the positive side of the coil?

Cheers
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
Sometimes cranking takes all the power from the battery (if poor earths etc) and leaves insufficient to get a good spark?

Nigel may be correct too.
 

jonbills

Membership Secretary
Site Administrator
Right, so first chance I’ve had to check the car since being returned from garage today and this is how I find the wiring...

View attachment 44441
Original Green white wire not connected to anything. Original Blue wire connected to positive side of coil. I assume these are the ‘run’ and ‘start’ circuits? New wiring for 123 looks as it should as per instructions.

If I understand correctly the blue and green white need to be joined together and connected to the positive side of the coil?

Cheers
Green and white is one of the two I've been talking about, although on my car there isn't a blue wire (my other wire is black/white). see this thread: https://zclub.net/community/index.php?threads/lumenition-optronic-coil-connections.24201/

does your tacho work?
 

Seikoking

Well-Known Forum User
Green and white is one of the two I've been talking about, although on my car there isn't a blue wire (my other wire is black/white). see this thread: https://zclub.net/community/index.php?threads/lumenition-optronic-coil-connections.24201/

does your tacho work?

The tacho did work, but seems it now doesn’t!

On the plus side, I’ve taken your advice and joined the wires (blue and green/white for reference on my car) and connected up to the coil. BINGO she’s running.

The timing curve the garage had set in the 123 was way off, so a quick play with the 123 app and I’ve already got a much smoother idle. On the road testing and tweaking to follow.

Really pleased that the car is running again, but a slight annoyance that the tacho has stopped working. That’ll need to be for another day now, I’m done for tonight

Thanks to all who contributed, really appreciated.
 

MCBladeRun

Club Member
The tacho did work, but seems it now doesn’t!

On the plus side, I’ve taken your advice and joined the wires (blue and green/white for reference on my car) and connected up to the coil. BINGO she’s running.

The timing curve the garage had set in the 123 was way off, so a quick play with the 123 app and I’ve already got a much smoother idle. On the road testing and tweaking to follow.

Really pleased that the car is running again, but a slight annoyance that the tacho has stopped working. That’ll need to be for another day now, I’m done for tonight

Thanks to all who contributed, really appreciated.
Ah, well done m8. I had the books out and was looking for the disconnected wire on the diagrams and saw your reply.
 

Seikoking

Well-Known Forum User
Ah, well done m8. I had the books out and was looking for the disconnected wire on the diagrams and saw your reply.

Thanks mate. I did the same, and despite the colours not matching Jonbills guidance, I couldn’t see they could be anything else so gave it a go.
 
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