Hello guys Hope for some help... learning a lot but not enough to solve my problems. My 1986 XJS is going through it's own crisis......... car ran great till it started getting cold real cold below 20 first it would run like it was running out of gas then it would run smooth.. when it would run rough it would also smell like raw gas if you were behind it on the road.. then...... 1 cold morning 20 degrees or so it turned over started and quickly stalled. now nothing... for awhile the fuel pump would just run and run, it was pumping raw gas into the intake to the point of leaking out of the exhaust at the clamp joints of the cats both sides, as well as out of throttle bodies both sides.. now when i turn the key on i can hear everything run pressurize and shut off, as it should... didn't really mess with anything so I don't know where i stand now. is it now just flooded. should i just go through the car and clean up connections and grounds.....

 

Wow, that's a lot of raw fuel!

My first guess is that you have a fuel pressure regulator problem. In this case most likely the outlet (left side) regulator is stuck closed. Since fuel isn't being returned to the tank it has only one place to go: into the engine.

I'll add that when the the problem is fixed, whatever the fix ends up being, you'll want to pull the plugs and spin the engine on the starter to push accumulated fuel out of the cylinders. And change to engine oil, too.

Cheers
DD

 

Doug thanks.. it has stopped pumping fuel into the intake. and i removed the return line at the engine and gas is being pumped back into tank. i pulled a injector and no fuel to it, it is dry...Also i looked at relays and the fuel pump relay had a small pcs of wire jumping 2 terminals I think the 87 terminals.. what do you think.. is there any special way to get those plugs out with removing parts.... i changed them when I replaced the cam cover gaskets..thanks again... Doug..

 

Ok here's the latest on the beast..... as per Doug's advise I removed the plugs and they weren't real wet but they were oil covered (dry old oil as with any old motor) smelled like fuel I think.. also I turned the key on and the fuel system cycled as it is supposed to do.. I then aimed the fuel line out of the right pressure reg into a cup and turned over motor to blow out any fuel from the cylinders, nothing came out of the cylinders but a little dirt, but fuel did come out of the fuel line.... I then turned the key on again, but not start, just to make sure pump still ran and it was still cycling
correctly, fuel came out of the right fuel line, should the system keep fuel from coming out if engine is not being turned over, as it did earlier? should the pressure regs be closed when not in use. I removed the left (return) reg and when I blow into it, air does not come out the other end.. correct? I did remove the left front injector earlier to check the see if any fuel was coming out, the first time nothing came out but later (few minutes) I did it again and fuel did squirt out and pulsed.... I cant understand how all that fuel could get into the exhaust as well as the intake and not have anything blow out of the cylinders...hope this thread is not too confusing. per my earlier threads, The Jag went from running strong to running like it was starved for fuel, to not running at all... Anyone local in Michigan (oakland county) that could assist in testing the various items... it has 2 new fuel relays both the same part number....











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