Ruby starts after 4 tries cold

First thank you everyone who has helped me. My sisters xj6 Ruby,is running so well,even at idle.What a relief for me .Yet when first starting her up, cold,it usually takes four,or sometimes five tries,then it starts up. I can use some help again. I make sure to use high test gas also. Thank you all ,Mark
The rubber flaps in back of the cut out openings on the back side of the radiator frame housing ,are not flexible ,they are hard from so many years.They dont appear to flex at all for air flow cooling. Any solutions,or help please.

Yes, take the surround out and get some 3/4mm neoprene from a pool shop. They need to seal the openings when the car is stationary but flex open when moving forward.

When it starts, Mark - what is the cold idle? And what is the idle when hot? And when hot - it starts promptly?

To overcome cold engine ‘drag’, high friction etc, idle is increased by the AAV, open when cold. This increases cold idle by some 200 - 400+ rpms above hot set idle to increase engine power. An engine that is too weak to idle won’t start.

Then there is the CSI, which squirts extra petrol into the manifold at cold starting - this compensates for loss of fuel due to condensation. Check CSI and thermotime switch…

Generally, the mixture must be fat with the engine cold to compensate for poor fuel ‘carburation’ - fuel comes in droplets rather than vaporize.

Certainly there might be other factors, like slow cranking, or whatever - a well behaved engine should start within 3 - 4 seconds of cranking…

xj6 85 Sov Europe (UK/NZ)

It’s probably not your problem here, but high test fuel is harder to start than regular.

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On my 78 xj6 I turned the key just enough to make some engine turns without starting it, its like priming it, on the 3 rd. try it turned over and it started up.
I tried that summer or winter and worked.

Cold and hot idle are at 900 rpms

If cold and hot idle is the same, Mark - your AAV is likely not working. This will definitely delay starting…

Disconnect upper air hose of AAV and look at the slide, hot and cold - it should be about half open when cold, closed when hot. If not; ‘exercise’ the slide with a small screw driver.

If the idle has been set with a malfunctioning AAV or the engine not fully warmed up, hot/cold idle and starting may be affected. The CSI/TT may be involved in delayed starting, but will not affect the prescribed difference between hot and cold idle…

Got to start(!) somewhere, but for the record; I assume you are not touching the gas pedal while cranking…? :slight_smile:

xj6 85 Sov Europe (UK/NZ)

thank you, I am not touching the gas pedal, csi/tt? cold start injector? Mark

Indeed, Mark…

The CSI spray extra fuel into the manifold while cranking, compensating for cold manifold condensation loss.The thermotimer varies the duration of the spray depending on engine temp - and is reasonably easy to check. Checking that the CSI actually sprays require removal and testing, though of course checking that it ‘clicks’ with power applied is easy enough…

But, as said; an AAV malfunction will also cause starting problems, mainly cold - the equal cold and hot idle is indicative of an AAV malfunction. And is even easier to check…

xj6 85 Sov Europe (UK/NZ)

And says nothing. They often clog for good but the car will start without, just takes longer.

Is it just the first start of the day that takes longer?

Thank you Frank very much, To my surprise, when I start ruby up.just sitting at idle, the odometer runs like i am driving down the road! Seems the car is possessed! weird . help

David is likely the one to comment further, Mark - he had a good description of the speedo insides some weeks ago…:slight_smile:

The odo is driven by electric, that supposedly should only get power from a turning transducer, converted to DC. However, there is power present everywhere in a car - and some of it obviously is getting to the motor. What to do about it is another matter - you probably have access the inside of the speedo…

It might be of interest if it only occurs with the engine running - or also with just ignition ‘on’. And of course if the the speedo (and trip computer, if fitted) otherwise behaves as it should while driving…

xj6 85 Sov Europe (UK/NZ)

I‘ll do my best, Frank…

The transducer sits on the transmission and sends so many pulses per revolution up to the tacho (and trip computer and cc if fitted).

Inside the tacho, a little board converts the pulses into a voltage that drives the needle.
The board also, separately, powers the electric motor that in turn drives the two counters.

I assume it’s a stepper motor that will simply turn a certain distance with each pulse received: either the board is faulty or somehow, there is pulses arriving that drive the motor.
The transducer is the most likely thing to fail and sits on the tail end of the transmission. The PCB inside the tacho is badly made and also suspect. Does the counter misbehave all the time or does some tapping stop it? Does it work while driving and what about the needle - is it working normally?