XJ6 S2 non starter

I have a series 2 4.2 XJ6 that has been standing for 3 months. Water has got into the tank, but before I realised this I tried starting it. I now have rid the petrol of the water and re-used the fuel. However, no fuel at all is getting to the plugs. Fuel is getting to the carbs, and there is a strong spark at the plugs and when fuel is poured directly into the cylinders it does run for a short while. Can anyone tell be where the problem lies?

Reply to
De.signer
Loading thread data ...

Reply to
Jo Bangles

Hi Jo

Hi have just connected a compressor to the fuel pipe into the carbs (with the air filter off)- it started straight away for 3-4 seconds and then died again. I

Reply to
De.signer

Reply to
Jo Bangles

The following thoughts are generic to carbureted automobiles, not specifically to the series 2 Jaguar.

I'm a dummy on series 2, but doesn't it have 2 fuel tanks? Or is that just series 3? Is the fuel pump mechanical or electrical? Is the carburetor choke working?

How do you know fuel is not getting to the plugs... are you looking down the carburetor throat when the starter is running? If you pull back quickly on the throttle linkage, (ie, jazz the throttle) even without the starter running, can you see that the accelerator pump is NOT shooting fuel into the carb throat? It should be.

It may still be possible that there's water in the system... I don't think water is miscible in gasoline (and vice versa)... since water is heavier than gasoline, perhaps it displaced the gasoline in the fuel pump and feed line from the tank while it sat so long. You didn't say HOW you rid the system of the water when you discovered it. If you didn't drain the system at it's lowest point(s) there may still be water present. Or, you could disconnect the fuel line at the carb and use the fuel pump to pump a few quarts of "fuel" into a container to clear water out of the line.

And, if you disconnect the fuel line at the carburetor and run the fuel pump, you can collect some fuel from the line into a glass container... then pour some clean gasoline from another source into the glass container and let it sit a few hours, and perhaps you'll be able to see whether the gas separates from the fuel (I haven't done this, but it may be possible to see the separate layers when they stratify... you could test the theory by trying this first with some tap water and some uncontaminated gasoline from another car)

If you haven't already, you may need to block the line at the tank, disconnect it from the carb, and blow the line out with air, wouldn't hurt to remove the carb to tip & drain it, also. I'm not familiar with your carb, but usually there is an air vent tube (about 1/4 inch diameter) sticking up from the carb... you can pour gasoline down that tube to pre-fill the float chambers after you re-install the carb, before you start the car, which may give enough running time to remove the air from the tank-to-carb line and allow normal fuel flow. BTW, if you aren't seeing fuel being squirted into the carb throat when you quickly rotate the throttle linkage (as I mentioned above), then try this "fuel down the vent tube" approach and try jazzing the throttle again to check for squirts of fuel.

Alternatively, the engine can tolerate water along with fuel once it is started, as long as it gets more fuel than water, so perhaps another approach might be to remove the air cleaner, start the car using engine starting fluid, and continue to spray starting fluid down the air horn to keep the engine running for at least a few minutes... eg, as long as it takes to use up any fluid in the tank-to-carb line.

Beyond that I suppose it's possible the water corroded something inside the carburetor that's causing, for instance, the float needles to stick, but that seems unlikely, especially since the water wouldn't have made it to the carb until you started it after the 3 months, so water hasn't been in the carb very long.

Good luck.

Reply to
WayneC

Thanks for your help Jo.

Tony

Reply to
De.signer

Hi WayneC, and thanks for your reply. My Daimler has two fuel tanks. Fuel is pumping to the carbs - I checked this by disconnecting the pipe at the carb, but I will check the carb throats to be sure. I assume that no fuel is reaching the cylinders as all the plugs are dry - no evidence of fuel. I separated the water and fuel by pumping the petrol into a clear bottle - and pouring the separtated fuel into a clean container. But I will by some fresh fuel to mix. Something I have forgotten to mention before, when it does run, there is a massive backfire from the front carb - both when petrol and 'spray starts' have been used. Its gummed up somewhere, I think Im going to have to take the carbs off to find where this has happend.

thanks again

Reply to
De.signer

More random thoughts...

If there are two carbs, and a quick pull on the throttle does not elicit a strong squirt of fuel in the throat of either, I can't figure out what would cause that, except....

  1. stuck float needles (or saturated floats), either stopping the flow of fuel or flooding the engine with fuel (but you say plugs show no sign of flooding)
  2. dry carb; some carburetors have a small filter in the fuel inlet housing, between the fuel line and the carburetor itself, so check to see if yours do and replace them before you pull the carbs, as possibly they are blocked. The fact that you used a compressor on the fuel line and got the car to start and run briefly suggests this is a possibility.

I think it is difficult for backfires to be caused by a carburetor fuel problem, but it's possible; generally carb backfires are a sign of bad timing (cylinder firing with intake valves open) due to an incorrect timing adjustment or mechanical failure in the distributor (sheared drive gear, stuck vacuum advance), or crossed/incorrect plug wire installation, or even bad/stuck valves. Did you mess with the plug wires during the time the car was not in use? Are there guides keeping the wires from touching each other?

Reply to
WayneC

Backfire might be caused by intake valve stuck open. It might be well to verify compression on all cylinders before proceeding.

Don Young

Reply to
Don Young

Hi, just my two peniths worth, but does the series 2 run on SU carbs, similar (but bigger) than those used on minis and most British cars of that era. If so, they DO NOT have an accelerator pump, as such opening the throttle will not squirt fuel into the inlet manifold.

Please correct me if im wrong.

P.S. If they are SU type carbs, with seperate float bowls on the side. Its worth taking the top off (3 flat bladed screws) checking the float neddle, look for sediment in the bottom of the chamber and the small (spring wound) tube that connects the bowl with the base of the jet.

hope this helps

Mr Smooth.

Reply to
Mr Smooth

Thanks, I could not see an accelerator pump. I have taken the carbs and AED (Automatic Enrichment Device) to find that water had corroded the aluminium. They are SUs with the floats attached to the bottom. I do think that the floats are causing the problem as when I connected my compressor to the fuel line it did run for the duration of the fuel in the line, so the high pressure fuel was being pushed around the floats. I will re-set the main floats and cross my fingers.

Reply to
De.signer

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.