Merak SS getting hard to start

[Oneball]

Starter solenoid usually either works or doesn’t, if it’s spinning over it’s working.

I’m still going for it not getting 12v to the coils on start up. It might not be but it fits your symptoms.

Did you try a new earth?

Could also be a fuel issue but I’d rule out the ignition first

 

[Belfry]

It’s still starting and running fine so I’ll see what happens tomorrow morning on a cold engine.
I do have this tool that shows whether each cylinder is sparking and all 6 are firing fine.

 

[Belfry]

I’m still going for it not getting 12v to the coils on start up. It might not be but it fits your symptoms.

With ignition on and the tester between the positive on the coil and the earth (chassis) there are 4.9 volts. But it starts ok on this right now (not cold)

 

[Oneball]

With ignition on and the tester between the positive on the coil and the earth (chassis) there are 4.9 volts. But it starts ok on this right now (not cold)

Nominal 6v is normal for ignition on, what’s the voltage between earth and the power into the resistors? It should be 12v

When you turn the starter over it should deliver 12v to the coils by bypassing the resistors which gives you a fatter spark.

Hardest time for it to ignite the fuel is on a cold engine, so if it’s not bypassing the ballast resistors and only giving you the running 6v it’ll be tricky to start when cold but run normally.

Presuming you’ve got Webers are you pumping the accelerator and then starting or using the choke?

 

[Belfry]

The car started straight away this morning from cold. I was once told to never use the choke so I pump the accelerator instead.

4.8 v at both of the positive terminals on the coils with ignition on. 9.9v at the positive side of the resistors. The battery is 12.6 volts.

I will try cleaning the ground to the luminition boxes next. Would a poor ground there affect the voltage?

the battery ground has been tested and cleaned.

 

[Oneball]

Yep that’s what I was taught too.

The voltage does seem a little low. The Luminition isn’t on the -ve side of the coil. Check the voltage at the -ve feed to the coil and ground with it disconnected from the coil and ignition on. If it’s still much lower than the battery try moving the earth end of the multimeter to the battery earth terminal and if it’s still low then there’s something wrong in the feed.

 

[fphil]

... then there is something wrong with the starter which takes all the current and pull down the voltage?. To explain myself, suppose the starter is in shortcut what would be the battery voltage?

 

[Belfry]

... then there is something wrong with the starter which takes all the current and pull down the voltage?. To explain myself, suppose the starter is in shortcut what would be the battery voltage?

How would I check this please?

 

[fphil]

You can take the voltage at the battery (+ battery and - battery) before and while running the starter. From 12,3V if it goes under say 9V->no good. Have you done it?. With 2 batteries in // you start? right? What's the voltage then at the battery?

 

[CatmanV2]

You can take the voltage at the battery (+ battery and - battery) before and while running the starter. From 12,3V if it goes under say 9V->no good. Have you done it?. With 2 batteries in // you start? right? What's the voltage then at the battery?

This is the way of it. Certainly sounds like something is shorting and causing more drain on the battery than it's able to provide. But internet diagnosis is tough at times.

C

 

[philw696]

Has the battery been drop tested to make sure a cell or two not down ?

 

[Oneball]

The car started straight away this morning from cold. I was once told to never use the choke so I pump the accelerator instead.

4.8 v at both of the positive terminals on the coils with ignition on. 9.9v at the positive side of the resistors. The battery is 12.6 volts.

I will try cleaning the ground to the luminition boxes next. Would a poor ground there affect the voltage?

the battery ground has been tested and cleaned.

I made a big assumption when reading this that the ignition was on and the engine NOT running. If it was running then the figures are about right.

There would also be the possibility that it’s in firing position in which case the figures are ok. But I don’t think both coils can be at that point unless there’s an oddity in the wiring. Disconnecting the one side of the coil and measuring again will confirm if the 9.9v is due to the ignition system or due to voltage drop in the power feed to it.
You could also measure the voltage on some other system controlled by the ignition switch see if that’s getting 12v

 

[Belfry]

Just enlisted my wife to read the voltmeter while I started the engine.
At the +ve and -ve battery terminals the volts were as follows:
12.46v ignition on
11.4v starter operating
14.6v running and idling.

 

[BennyD]

Try turning the key harder, and swearing profusely. It generally works with 3rd world machinery, especially Italian water pumps. You're welcome.

 

[Oneball]

Based on that I’d say nothing wrong with your starter, battery, alternator or engine earths.

 

[philw696]

Just enlisted my wife to read the voltmeter while I started the engine.
At the +ve and -ve battery terminals the volts were as follows:
12.46v ignition on
11.4v starter operating
14.6v running and idling.

Very healthy indeed.

 

[Belfry]

Great. So those elements are proved. I will give one of the Luminition suppliers a call to see if they have an idea why both resistors and coils are getting lower than expected voltages.
I did discover 2 disconnected wires but the wiring looks original and I cannot recall them from when I installed the electronic ignition 4 years ago. They may be red herrings. The colours are grey and grey/black if anyone knows where they are from?

 

[Belfry]

Thank you everyone for helping me with this (esp. Oneball who has been super helpful).

The Luminition boxes were silver/aluminium bit I sprayed them black to disguise them better in the engine bay.

With the Luminition wire disconnected from the resistor the voltage at the resistor is 12.4v, and with the Luminition wire connected it drops to 9.9v, so the Luminition is reducing the voltage.

Could it be spark plug related? When the car has not been used for a month the extra boost from another car is needed, but once this has been done the car will start easily on it's own thereafter until another month long period of inactivity. I guess that I need to wait for another no start and then take a look at the plugs then?

 

[Oneball]

I posted this and then deleted it as I wasn’t sure but Ive had a google and think I’ve caused you to chase your tail a bit.

I think the ignition is all perfectly ok. The Performance Lumenition that I’ve used on MGBs turns off the earth side of the coil when the engine isn’t running so you’d expect to get 12v at the resistor. Looking at adverts the normal Luminition doesn’t list this as a function. So with ignition on, engine off and it all connected you’ve got the coil +ve grounded (points closed in a normal dissy). With all the windings in there that’ll explain why you’ll get a voltage drop. Sorry my fault.

Doesn’t help you with why it’s difficult to start after sitting though, but your one coil did look bad and I think you got a much greater voltage drop than the other so maybe all is ok and it was a faulty coil.

 

[Gazcw]

I know nothing about these, but if ignition, starter etc. is proved as OK is it fuel? Do they have a non return in the feed that is not operating and fuel is draining back?
Sorry if this has been discussed already