Sprint absolutely refuses to start when cold

[sprint-revival]

Hi All,

After a sanity check. XLK 467S has been continuing to test my patience. Having got the engine running last autumn, it quickly became apparent that the head gasket wasn’t sealing and that coolant was getting into cylinders 1 and 4. Having carried out the remedial work XLK 467S is now running and not showing any head gasket related issues, however it just will not start from cold. This has been a constant from day one, even with its engine in its original state before its rebuild. You end up cranking for I would estimate up to 10 minutes before you get so much as a cough, once you have a cough the car will gradually attempt to catch/kick, after a further 30 seconds or so the car will then burst into life as if to say what was all that about, I want to run now! When running the engine sounds sweet with no issues. After being able to start the car even for just a few seconds, you can shut off and then start the car again in an instant; it doesn’t labour or show any of the cold starting issues.
The car has a new set of points, condenser, leads, distributor cap etc. A new ballasted coil has been fitted (using the old coil makes no difference to the cold start issues). I have cleaned the connection to the coil, and the connection on the starter (paying particular attention to the ballast feed). When cold and not run I measured 5.3v at the coil, once run up and shut off this rose to 5.6v. I have checked plenty of fuel reaching the carbs, have tried running with or without fuel filters which makes no difference. Once started the car can be restarted with ease for up to an 1hour after it ran.

Its most odd. I was perhaps thinking of fitting a standard 12v coil as my next test.

Just after some words of wisdom, as it feels like I’m chasing my tail with this and not getting anywhere fast!

Thanks,

Olie

[yorkshire_spam]

Not trying to be insulting or anything (I know I've missed some obvious stuff in the past!) but is the choke operating properly?

[Mad Mart]

What voltage do you get at the coil during cranking?

[sprint-revival]

What voltage do you get at the coil during cranking?

Just had an assistant crank while I measured voltage at coil with king lead disconnected. It jumps around from about 2v to a peak of 3.2v. I could hear a spark jumping from the coil outlet to the heater hose jubilee clip occasionally while cranking.

Of course with the king lead re connected the car started, instantly! Typical. Engine still feels warm though.

Voltage at coil while cranking sounds low to me.

Olie

[Mad Mart]

What voltage do you get at the coil during cranking?

Just had an assistant crank while I measured voltage at coil with king lead disconnected. It jumps around from about 2v to a peak of 3.2v. I could hear a spark jumping from the coil outlet to the heater hose jubilee clip occasionally while cranking.

Of course with the king lead re connected the car started, instantly! Typical. Engine still feels warm though.

Voltage at coil while cranking sounds low to me.

Olie

Yes, it should be battery voltage.

[sprint-revival]

I'm measuring across the coil, voltage is approx 5.3v with ignition on but not cranking, but drops to between 2 - 3.2 when cranking if I disconnect the white with yellow stripe wire from the coil and measure between battery negative post and the white/yellow wire I get 12.2v.

Any other test I can do to pin point the poor connection. I have already confirmed I have full battery voltage at fuse box connections

[sprint-revival]

Further testing of coil voltages. When measuring between coil positive (white and yellow wire) and battery neg with ignition on get the 5.3v. However while cranking get the full battery voltage at about 12.3v. This sounds better, when I think about it when measuring across the coil, the coils resistance comes into play, so that is likely why I was getting such low readings when measuring across the coil. With the engine running I'm now seeing between 9 and 10v when measuring between coil positive and battery neg post.

I have also found the choke cable was sticking and allowing perhaps only 1/5th of it's full movement, now this is free I'm hopeful it may start when cold now, we can only hope!

Thanks for the input.

Olie

[ian.stewart]

Do you have a Ballast resistor fitted with a non resistor coil?

[sprint-revival]

Do you have a Ballast resistor fitted with a non resistor coil?

Think its a resistive wire that feeds the coil rather than a ballast resistor, all wiring to the coil is factory. The coil is a ballast 1.5Ohm type.

Olie

[sprint-revival]

Not trying to be insulting or anything (I know I've missed some obvious stuff in the past!) but is the choke operating properly?

Think you are on to something here. The choke cable only seemed to give about a 1/5th of the overall movement it needed to at the choke mechanism on the carbs. After some adjustment of the cable and freeing off the linkage, I have lots more movement at the linkage and the cable pulls out further in the cabin, so am hopeful this may cure the cold start issues.

Thanks for the tip.

Olie

[Robert 352]

I have a somewhat similar issue on my car trying to start from cold and if the car has been left to sit for a few days).

In my case I have established that the fuel has evaporated out of the two carburettors and it will only fire after the engine has turned sufficiently to operate the fuel pump and pumped up enough fuel to refill the carburettors.

I lift the tops of the float chambers and part fill them by hand, screw the tops back down and that has the engine fire on almost the first revolution.

Robert

[matt of the vivas]

You have an issue with the bypass connector for the ballast resistor at the starter motor.
Your coil voltages while cranking are far too low.
Look at the starter, there is two thin wires. One of them is to trigger the starter, the other (smaller) connector is to bypass the ballast under cranking. That's not connected, or loose.
Matt

[Carledo]

You have an issue with the bypass connector for the ballast resistor at the starter motor.
Your coil voltages while cranking are far too low.
Look at the starter, there is two thin wires. One of them is to trigger the starter, the other (smaller) connector is to bypass the ballast under cranking. That's not connected, or loose.
Matt

Don't think this is the case Matt, Further up the page, the OP say's he's getting 12.3v while cranking, which would tend to indicate the ballast bypass is working as intended.

Steve

[Richard the old one]

One of my 1500hl Dolomite is reluctant to start when it is very cold. It will start but the engine needs to be turned over a lot longer than normal however if I spray some cold start into the air filter box it starts instantly. It is very easy to spray cold start into the airbox by pulling one of the air input hose off the air box.

I have not been able to find anything wrong with the set up so I am wondering if the fuel has aged so I am running the tank low so that I can fill it up with fresh petrol.

You might like to get some cold start and give it a go.