Hello all,
I have been hard at work on the gifted Series II XK12 recently. My initial post described a 1976 Series II XK12 that had been sitting on my local airport's taxiway for years. Just over 14k original miles and in near perfect shape on the interior. I was worried about corroded cylinder walls, rotted out hoses, and the like. No leaks that I have found yet, and I can get this car running by spraying brake cleaner in a vacuum hose that connects to both intakes. It's not great, but the ignition system has been proven to work. Thanks to a more recent YouTuber, Living With A Classic, I have come to a reasonable conclusion that the fuel injection system works by having the ignition on, quickly moving the throttle pedestal, and hearing a set of injectors firing. While I have only heard one set of three fire (Cylinders 4 thru 6) through several attempts of cranking the engine, I am hopeful that the rest will function.

My problem currently is the fuel system. I have drained the 25 year old fuel (nasty stuff) and proceeded to pressure wash the tanks from the top and bottom with JetA and then a blast of 87 Octane pump gas. A lot of residue came out, but most of the rust, if not all, has been expelled. I added 6(ish) gallons to the left hand tank, pushed the dash "Fuel" button in, and nothing. Fuel pump was seized, so I dug in and rebuilt it as far as I could without replacing o-rings. I expect that to be an issue in the future, but I don't want to spend money until I know this is a viable car. Fuel pump works great on the bench, primes when I turn on the ignition and runs when attempting to start. Fuel changeover valves are totally stuck. Did my best on the fuel feed valve with light pressure on the plunger, while letting it soak in AeroKroil, and ruptured the rubber plunger. Cool...But oddly, no fuel coming out with 6 gallons in the tank. To be sure, I opened up the lines on the return valve with no sight of the fresh fuel. I blew compressed air through the fuel feed line and noted massive resistance until the pressure finally gave way, and I could hear air through the filler.

From cursory searches, I found the pre-pump strainer (CBC5649) rests just above the large fuel tank sump drains. I didn't realize that was a strainer when I was cleaning the tanks...so duh. Based on some pictures, it's a plastic body with metal mesh. Can anyone confirm this? I don't see an o-ring either, so is this just a simple compression fit going into the tank? Do I just need to pull down on this with some effort and reinstall after cleaning/replace?

Has anyone just simply bypassed the fuel selection system? I don't see any need to keep the tanks split. Why not put in 2, three-way T-fittings (Fuel hose is 12mm, correct?) so the fuel tanks are shared, and the fuel return system is shared? I do see a potential problem with the fuel return not having enough pressure from the pump as the fuel would then be working twice as hard to return rather than going one at a time, but a higher pressure external pump would surely be a reasonable response to that, were it an issue.

Also, could someone point me to the right fuel injector hose replacement kit? Living With A Classic provided this as a resource: https://mrinjectoruk.co.uk/default.aspx
There are quite a few options, and I am not positive about which kit I will need in the future.

Thanks in advance!

 

Poked around at it last night. I dropped the sump cover on the right-hand tank as it didn't have fuel in it and attempted to remove the strainer with no luck. I only had my medium size Knipex Cobras handy and I just couldn't quite get a grip. For kicks and giggles, I went around with all the hoses disconnected from the valves and was checking flow with compressed air. Both tanks were closed at this point and I blew into the return line for the left-hand tank (that has 6-ish gallons in it) and oddly, fuel started to come out the main line. When I was looking around on the right-hand tank, I did notice that there was quite a bit of tubing from the bottom of the tank to the top and figured some form of suction to prime the fuel pump would be necessary. In a roundabout way, I did that with compressed air through the return. The fuel caps did vent, but most of the pressure was being fed through the main fuel lines. Put everything back together, hit the ignition on and sure enough, I heard the fuel pump grab fuel. Did that a few more times trying to get fuel into the engine and decided I was dumb enough to open the fuel line going to bank "B"s cold start injector, promptly spraying me with fuel. Tried to give it a start and it fired! Didn't fire well, but it did fire.

I could only hear 3 injectors going, so I went around with a test light and cranked the engine for each injector input. All injectors had an incoming signal, so I went around with test leads and decided to give all the injectors a little "boost" with a quick couple of dashes of straight 12v. Not safe for the injector I know, but a couple of injectors were stuck that now open freely. The car still doesn't run on all cylinders, but I believe that is due to a fair amount of fluid I had put into the cylinders before I started working on the engine in case it was seized (Aerokroil again). I also believe that ignition timing may be off. It is more than evident that whomever worked on this last was messing around with the A bank and with the distributor. I know timing is done with the engine at a 500RPM idle, but is there a basic static time that I could set on this? 1A should be on TDC with the rotor pointing onto the #1 lead, but is there a more precise way to just get started? I can't get this thing to hold an idle currently, either due to the residue in the cylinders, or just really bad timing.

Fuel valves are still bad, but I figured with the main fuel valve being open to both tanks and the return feeding into just one tank, an equalization process should be occurring.