Early pre-HEs like yours are slowly getting rare.
They are amazing cars when they run right.
The hardest part is to find a repair shop with a clue.

 

Will try a new pump for better pressure first

 

Did you get the trigger board figured out? A 1976 has two reed switches in the trigger board. They are prone to failure. SNG Barratt has a conversion kit to hall sensors.

 

I found a frayed wire on the harness from the trigger board and patched it, injectors are getting a pulse now, it tries to start bit still seems to be starving for fuel,,only things left are weak fuel pump or maybe clogged injectors, I did run power to each injector and they are all clicking but still may have clogged micro filters I'm them, this car sat parked in storage since 1992

 

I think I read this once, maybe more than once... One of the real guru's here says that while the injectors are still connected and in situ you can tap on them with a hammer while someone turns over the car. Turn it over, tap on 2 or 3 at a time, then stop, give the starter a good rest, then try again. Small hammer quick light taps. If you can get it running eventually, even if running rough and rugged, I guess the same approach could continue until they all wake up.

 

Is it just me who's digging the pre HE XJ-S? I had one a few years back but due to too many cars, I let it go. I just don't see any more sale anymore.

 

Pre-HE's are the finest of them all. If you use SearchTempest, you can search all 27 Craigslists nationwide. Once in a blue moon, a good pre-HE shows up. But they are getting rare.

 

I'm a Mercedes Benz guy and I own 4 V12 Jaguars. That's why I no longer use searchtempest :-)

 

Have you checked the throttle switch and MAP sensor? Both of them can be trouble. Just an idea.

 

Have a look here...
TO'Day may be your lucky day...

 

my 76 xjs is still a work in progress, if i cycle the switch on and off a few times, it attempts to fire, a node light test shows the injectors getting a pulse and each does click, however, the cold start injectors do not seem to be getting a pulse, i get plenty of fuel at the filter under hood so its not a pump issue, getting spark too, and the trigger board also seems to be working fine, so what powers the cold start injectors ?? is there a relay maybe

 

Hello. I had the same issue with mine.The problem was the aav(( auxiliairy air valve)) stuck open.and some vacuum hoses were cracked.This way no gas was getting in the cylinders all the vacuum needed to get in there was sucking only air no gas..Check all hoses.remove the left air cleaner and block the 3/4 inc hole.TRY to start if it does the aavalve need to be cleaned or replaced..AN easy way to check vacuum leaks is a smoke pomp tht you connect to a vacuum line on the intake then you see where is the leak..Pump can be borrowed at your garage or you can buy one at a place where they sell party stuff..Good luck. Keep me informed of your results Yvon Have a nice day

 

I'm gonna give that a try right now and see what happens

 

well, gave that a try, plugged the holes, still a no start, checked all the vacuum lines and all is good, i'll keep at it, feeling energetic today and its not too cold out right now.

 

I've moved your posts to a new thread instead of tagging onto a years old thread.

 

All the PreHE that have been involved with, and there have been many, the cold starts are deleted. More troubke than they are useful.

The start sequence I developed for these PreHE acars is:

1) Ign ON.
2 )Ign OFF
3 )Ign ON, NOW, SLOWLY press the accelerator pedal to the floor and back to idle position.
4) Go to START, and it will fire every time.

The reason for #3 is that when the D Jetronic (PreHE) Injection System Throttle Switch is opened SLOWLY, the last 6 Injectors that fired prior to shutrdown, will be triggered again, 9 times, as the Internal wiper passes over the segments. This will squirt fuel INTO the cylinders, 6 only dont forget, and the spark plug will produce the required BANG, and the other 6 will catch up in less than a human heart beat.

GREAT for HOT start on the PreHE and HE also.

AND

Just because you have flashing lights and clicky clicky, does NOT mean the Injectors are actually opening the needle and passing fuel, so dont be fooled. Taht is where teh tack Hammer is the tool of choice.

The Cold Starts dont really get a pulse as such. They are triggered by a "jump" wire from the starter relay, and ONLY operate when the Ign Switch is the START position and that relay is energised, if they work at all. Same as the HE basically.

 

I've already moved one of your threads on this same topic from General Tech Help and merged it with the one here. Norri has also moved another of your posts from the end of an old thread and done the same. Now I find you've started yet another thread on the same topic:






I've again merged these threads. Any more new threads on the same topic and I'll use one of the other options available to me and DELETE it.

Experienced members are trying to help you but asking the same question in multiple threads will soon stretch their patience and they will stop contributing to the discussuion.

Graham

 

@Vinman12 ,,,, take a look at post 30, follow the link and reach out to the forum member... He may have FI for your car he's willing to part with.

 

I have a new trigger board in the way (ebay $100.!) And a rebuild kit for all 12 injectors for $102.00, maybe that will do the trick.

 

OK,

Check the magnet in the heel of the Rotor. If that is weak, missing, whatever, it will never run.

ALSO

"New trigger board". I am assuming a 4 wire trigger board??, as apposed to the original 3 wire board.
That 4th wire is to be connected to a 12V Ign supply. Most people cheat, and attach it to the coil +ve, NO GOOD, that is only 12V during cranking, and runs at 7ish volts at all other times.