automatic choke

[Orlando St.R]

This is the mech I made for my XJ to get rid of the abysmal AED, it pulls down the jet levers giving a variable choke the same as the E Type.

That's clever, Nigel.

I may have an issue.

John, do you hear a very loud hiss when the choke is on? If so, it is working.

However, you can (and may need to) adjust the height of the needle in the jet to give the necessary enrichment. Instructions for doing this are on page C.11 of the Service Manual: http://www.jagstyperegister.com/images/ ... manual.pdf.

[johngosnell]

Yes there is some form of hiss, but not that loud, she runs so well when warm?. It seems like over chocking to a point it will backfire then cut out, and then restarts fine as long as I don't try to rev it will tick over with the coke on.


john

[cass3958]

To check the choke is working correctly electronically anyway if you turn the ignition on when the engine is cold and open the bonnet. On the top of the AED there are two wires. One is power in and the other is the earth. It does not matter which one you remove but if you do take one wire off you should hear the solenoid click as the power is disconnected.By touching the wire back on its terminal you should hear and feel the solenoid jump back in to position.

If you then start the car if the AED is working there is a very loud audible hiss as Orlando stated. When the car is warm you will suddenly hear this hiss stop as the Otter switch opens and cuts off the earth and power circuit.

If the AED solenoid does not jump when disconnecting the wires with the ignition on then it is possibly your otter switch which is defective. To check this disconnect the wire from the top of the Otter switch and touch it on a cam cover nut so it goes to earth and the solenoid should jump. The Otter switch as described before is just a clever way of earthing the AED. If it does jump the Otter switch is defective.

If it does not jump then you will have to check there is power going to the AED via the other wire. If there is power and earth then the AED solenoid is defective.

For adjusting the power ie fuel flow of the AED follow Orlando's link.

[johngosnell]

The choke does as described but just to remind you it has a on and off switch that I operated from under the dash and it is definitely working again yes there is the hiss sound when on choke


John

[Glyn Ruck]

I think that one of the inherent issues/limitations in the design is setting up the needle in the "hisser" for all conditions. Some cold engine stumble is inevitable under some conditions. A short warm up before driving helps.

We have all got so used to perfect enrichment from fuel injection that allows faultless performance from ice cold in all conditions. I think we forget what we used to tolerate even with cars with conventional manual choking.

Engine stalling & stumbling cold was even reported in early road tests of the car by certain scribes.

[Orlando St.R]

I think that one of the inherent issues/limitations in the design is setting up the needle in the "hisser" for all conditions. Some cold engine stumble is inevitable under some conditions. A short warm up before driving helps.

Yes, agreed. Because my car lives in an integral garage, it's never likely to be colder than 12C and I probably wouldn't be driving it in ambient temperatures much below that either. Because of that, and the way I have set up the needle, I can drive my car more or less straight away and turn the choke off once rolling. If it was kept outside and the ambient temperature was 2C, I expect some warming up would be required.

John, it does sound as if you might benefit from adjusting the needle to make it run slightly richer. If you remember the starting point (count the number of turns or quarter turns you adjust it by - adjustment is fairly coarse), you can always return to the original setting if it makes no difference.

[johngosnell]

firstly as my car is in a large garage away from the house ( about 30yds) it always feels freezing cold that's why I cant work in there during the winter months so I guess that is a contributing factor, with regard to the mixture I will have a chat with the jag man who looks after it for me to see if he can improve things. I really appreciate the comments guys .


John

!B1257BW