Cold Start Issue
#1
Inherited a 1976 XJS, cranks but no start
It's a great car,
white, tan interior, great condition with no rot, nice interior other then headliner, 55000 miles, cranks and will fire with a shot in the breather, good fuel pressure, not getting fuel to the cylinders.
white, tan interior, great condition with no rot, nice interior other then headliner, 55000 miles, cranks and will fire with a shot in the breather, good fuel pressure, not getting fuel to the cylinders.
Last edited by GGG; 12-25-2021 at 05:32 PM.
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Mkii250 (12-24-2021)
#2
With the ignition on, slowly open the throttles by hand in the engine compartment, and listen for the injectors to click. If you don't hear clicking, I'd suspect stuck injectors from sitting. This video, a few minutes in, shows a trick to get stuck injectors to unstick. Otherwise, they'd have to becremoved and sent out for cleaning.
You can also check for injector pulse with a noid light or a scope on the injector connectors.
#3
With the ignition on, slowly open the throttles by hand in the engine compartment, and listen for the injectors to click. If you don't hear clicking, I'd suspect stuck injectors from sitting. This video, a few minutes in, shows a trick to get stuck injectors to unstick. Otherwise, they'd have to becremoved and sent out for cleaning.
https://youtu.be/nMaOtaaI4Yk
You can also check for injector pulse with a noid light or a scope on the injector connectors.
https://youtu.be/nMaOtaaI4Yk
You can also check for injector pulse with a noid light or a scope on the injector connectors.
#5
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#6
Making progree
I did get 11 injectors to fire, just one stuck a d it does attempt to start but I believe the plugs are fouled from all the cranking, I'll keep tinkering with it in my spare time but I ha e listed it for sale, too many other things to do and may be moving so it's up on the chopping block
#7
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#11
76 xjs not firing up, sat for many years
76 xjs not firing up but fires with a shot of fluid but not staying running,, seems to be getting fuel pressure well at the filter under the hood , and working the throttle from under the hood, can here clicking, i did run a jumper to each injector indepenantly and each is free and clicking, so they are not stuck,, whats next ????
#12
i did manage to to get the injectors free, but still does not seem to be getting fuel, good pressure at the fuel filter under the hood and will attempt to fire for a few seconds on starter fluid, so i know its getting spark. its worth keeping at it because it is a rot free car with still a good original finish and pretty nice interior and only 50,000 miles on the v12.
#13
Bugga.
The XJS Section has a lot of info, stickies etc at the top. Granted, most is the HE beast, yours be Pre HE and has its own little oddities that mainly us Senior people remember.
Just because the Injectors be clicking does NOT mean they are opening the needle to pass the Bang Juice.
When operating the capstan with the Ign ON, SLOWLY, you shoud get 9 clicks as the internal wiper passes the segments. It appears you are getting something?
I have taken a SMALL Hammer (down here called a Tack Hammer), and GENTLY, tap, tap, tap each injector as you SLOWLY work that capstan. Has worked 100% of the time for me on many a PreHE.
I am assuming the fuel lines have been flushed with clean fuel, and the filter replaced??
Injector pulse whilst cranking is a "special thing" on these engines, and I can walk you through the testing/sorting/fixing of that if need be.
Oh,forgot.
When operating that capstan for the "clicks", the system only fires the last 6 Injectors that were operated prior to shutdown. How a purely Analogue system knows this, I simply dont know, and it really makes little difference, it is what it is.
The XJS Section has a lot of info, stickies etc at the top. Granted, most is the HE beast, yours be Pre HE and has its own little oddities that mainly us Senior people remember.
Just because the Injectors be clicking does NOT mean they are opening the needle to pass the Bang Juice.
When operating the capstan with the Ign ON, SLOWLY, you shoud get 9 clicks as the internal wiper passes the segments. It appears you are getting something?
I have taken a SMALL Hammer (down here called a Tack Hammer), and GENTLY, tap, tap, tap each injector as you SLOWLY work that capstan. Has worked 100% of the time for me on many a PreHE.
I am assuming the fuel lines have been flushed with clean fuel, and the filter replaced??
Injector pulse whilst cranking is a "special thing" on these engines, and I can walk you through the testing/sorting/fixing of that if need be.
Oh,forgot.
When operating that capstan for the "clicks", the system only fires the last 6 Injectors that were operated prior to shutdown. How a purely Analogue system knows this, I simply dont know, and it really makes little difference, it is what it is.
#14
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Grant Francis (12-23-2021)
#15
#16
i did manage to to get the injectors free, but still does not seem to be getting fuel, good pressure at the fuel filter under the hood and will attempt to fire for a few seconds on starter fluid, so i know its getting spark. its worth keeping at it because it is a rot free car with still a good original finish and pretty nice interior and only 50,000 miles on the v12.
Pull what plugs you can and have a look at em...? A few fouled plugs is no good.
Have you had a look at what's going on in the distributor cap?
Where is the loom to the injectors? Down in the valley?
Can you post a picture (if you haven't already) of the engine bay,,, getting as much of the engine in the snap(s) as you can?
If you are not worried about AC at this point, you can just cut the AC belt to remove,,, undo the AC lines and remove the HUGE A6 compressor,,, and then the cruise control bellows and get all that out of the way temporarily... That's just me. Will make this part of your process much much less painful. A smaller and more modern AC compressor might be in your future anyways - unless someone has already updated it...?
You'll get this thing going, no doubt.
#17
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Grant Francis (12-26-2021)
#18
well, been at it today, found a broken wire from the trigger board harness on my "pre he} 76 xjs, not getting a pulse and spark and fuel pressure, it appears to be that maybe the injectors are clogged, they are free and getting a pulse but still not feeding fuel to the cylinders, it will fire for few secondes on starting fluid, i see tone of injector rebuild kits for 81-91 but dont seem to be able to find a complete kit with hoses,clamps, micro filter and seals for the 76 model, anyone have a sourse for a kit for these older "pre he" models ?? vince, philadelphia pa USA
#19
Someday very soon you will want and need to redo them injectors, there hoses, there seats in the intake and stuff.
When I walked up to my car several of the injectors were clogged and having read here I knew a whole refresh was in my future so, a newbie and new to working on cars, it was a scary but empowering feeling to just grab a set of large wire cutters and go around and cut the hose between the rail and the injector, take it away and then remove the injectors one by one. The injectors are rugged and can be brought back to life. Takes a solvent, soaking, some pressure, a small hammer and a 12v source TAPPED on the leads of the injector. Most folks will take a spare FI plug, plug it into the injector and quickly TAP the wire ends to 12volts... Again,,, only touch the wires super fast to the 12volt source or you could fry the injectors. Short taps.
Later, I bought a set of remain and tested injectors and installed them. By then I had the XJS bug. They are awesome cars to work on! They just are
When I walked up to my car several of the injectors were clogged and having read here I knew a whole refresh was in my future so, a newbie and new to working on cars, it was a scary but empowering feeling to just grab a set of large wire cutters and go around and cut the hose between the rail and the injector, take it away and then remove the injectors one by one. The injectors are rugged and can be brought back to life. Takes a solvent, soaking, some pressure, a small hammer and a 12v source TAPPED on the leads of the injector. Most folks will take a spare FI plug, plug it into the injector and quickly TAP the wire ends to 12volts... Again,,, only touch the wires super fast to the 12volt source or you could fry the injectors. Short taps.
Later, I bought a set of remain and tested injectors and installed them. By then I had the XJS bug. They are awesome cars to work on! They just are
#20
Vince,
See here: If you're not sure of what you need, drop him a line.
Cheers
Paul
Jaguar - Mr Injector UK
See here: If you're not sure of what you need, drop him a line.
Cheers
Paul
Jaguar - Mr Injector UK