"appears correct" isn't very comforting


Cheers
DD

 

No clicking of injectors. I removed the front injector and motored engine over. No fuel spraying out

 

-How long were the injectors laying around while the engine was being rebuilt? I had *twelve* injectors stuck after sitting in the trunk of my car for a year while other aspects of the project were being worked on. According to Dave at Jaguar Fuel Injector Service, it is a somewhat common situation.

-Can you get your hands on a known good ECU to try? The ECU grounds/earths the injectors to operate them. ECU failures are rare, but 'rare' isn't the same as 'never'.

-Check the big connector at the ECU. Any corrosion, bent or broken pins, or the like?

-With a meter and wiring diagram you do a wire-by-wire continuity check to make sure all the wiring is OK from the ECU to the engine bay.

-Check wires at the coolant temp sensor plug and/or jump the contacts, just for the heck of it. If the engine is running and the connector is removed the engine will die instantly. Some say this is because the system will grossly over-fuel the engine. Others have said that an open CTS circuit will actually prevent the injectors from working. Not sure which is true.

Cheers
DD

 

I have tried another ECU. No better. engine was out for about 3 months. I was having an intermittent problem of hard to start before the overhaul. THe engine would not start when I could not here the clicking (injectors ) and would start when I could here them. The car was cutting out when driving. I think this intermittent problem is now a full time problem
-ECU pins are clean (like new) and not bent
-Shall try pin by pin continuity check
- Make no differnce with Coolanttemp plug fitted, removed or shorted. This loom which includes coil is new last year

 

I have put a light on cold start injector and no light on cracking. 18 ohms resistance on white/black trigger wire at ECU. So this should be good enough to say I have continuity. Where to next

 

Well no, not necessarily . . . in fact, you may have pointed to the solution. Do you understand Doug's explanation of the "earth seeking" nature of the wiring? If you simply connected "a light on cold start injector" then the light should be LIT whenever your ignition is ON because you are connecting it from +12V to ground. To be OFF when cranking suggests you have no +12V feed to injector(s).

But perhaps I have misunderstood your comment above. If so, another good reason for using a meter (never a test light) around these cars' electrics and electronics. Anyways, let's return to Doug's other comment -

I would go further . . . 3 months is ample time for "no use" sticking to occur. Whilst your earlier experience suggests you had either a pre-existing electrical "no power feed' or electronic "no ground control" issue, which has now deteriorated further . . . be very suspicious of this problem of sticking from "non use". It is a known and well reported issue . . . perhaps more common than simple electrical failure.

Suggest you start (with a meter) and test for +12V power (with IGN ON) at each injector. Then briefly and on only any 1 injector, test again while engine is cranking. All these tests should show +12V at the appropriate power feed connector to injector. If all OK, remove and test injectors for electrical "click" as they snap open. Only if all these tests prove OK, should you move toward the ECU . . . and then, first lift, clean and refix all earth/ground connections.

Cheers,

Ken

 

I connected the light across the injector plug terminals. The ECU as I understand it should ground one of the pins turning light on. This is not happening. I am going to fit my ECU and AFM to a running jag to confirm they are not US. The only component I have not checked is the AFM. Will let you know how it went. Bought myself a XJS convertible today so I'm going to need all the education I can get to keep that ***** purring.

 

Neat, If one Jaguar is having a hissy and will not respond, get another !!!!!


Seriously, getting the injectors to fire is a gotta be.


Carl

 

Just FYI any testing at the cold start circuit won't help diagnose a problem with the fuel injection. The cold start injector circuit is totally separate from the other six injectors.....no connection to the rest of the fuel injection system. The cold start injector is powered up by the starter circuit and grounded by the thermotime switch.

A dead cold start injector shouldn't prevent the engine from starting. It'll just take a bit more cranking if the engine is cold.

Best to use a noid light to check for injector pulse on the regular injectors

https://www.amazon.com/Performance-T...X04C0E3EQSBGAZ

Most auto parts stores will rent or even loan the kit. Or you can probably find the individual light you need for $5.00. It's just the 'old style Bosch injector' type.

Cheers
DD

 

I was using a small 12 volt light bulb. Will this work. Shall buy a noid lamp set today

 

Is there any way I can manually fire the injectors. Ie put an earth on to a pin to make it work fire

 

I don't see why not. Lot's of guys use a little 9v battery to fire injectors---off the car---for testing or cleaning.

Do you want to leave them all in place and fire them all? Or just individually?

I'd want to disconnect the injector harness from the ECU so that a mistake (of some sort) doesn't end up doing damage.

This might take a bit of mulling.

Others will chime in as well

Cheers
DD

 

I *think* the problem with a typical bulb is it can't operate quickly enough to capture the firing event

Did you get the noid light and, if so, what was the verdict?

Cheers
DD

 

No. Awaiting public holidays to go away so I can buy a test kit. Will advise as soon as I get it. I did test my ECU in another car. No problem. When I put my AFM in tat car it did not run. I then put his AFM in mine but still no good. Will refit his AFM to his cat to confirm it's still working. How particulars are they to fuel rail type. His is the different fuel rail to mine.

 

Early vs late fuel rails (straight vs looped) shouldn't have any bearing on this issue.

Cheers
DD

 

I finally got the old girl going. Doug I have to eat humble pie. I checked the timing was roughly correct and it was. Today I decided to pull the whole distributor out and check everything. As I did so it turned in my hand . The overhaulers had run the engine so I expected it to be timed. The clamp was loose and thus timing out enough to not start. I would have expected a back fire or something. As they say assume makes an *** out of u and me. The upside is I know my way around that engine quite well now with a good understanding of injection and electrical system. I still have to get to the bottom of the coolant coming out under the 2nd from the front LH head bolt. It actually squirted out when it started but will continue that on my other thread. Thanks for all your help. Now it's on to learn about xjs 12 cylinder

 

Congratulations !


Cheers
DD

 

DITTO:


An engine that runs is far "easier" to tolerate needed fixings and the incentive to do them.


How "big" is the space between the head stud and the head casting? Enough space to warrant considering a "packing"? That would be odd. But, just possible. corroded head opening + a corroded stud? Each in itself not good. Together, oh, oh.


I once fancied Barr's Leak. It does work, but, at a cost. Better crystalline sealers are available. I still have some, left over from the ancient days of flat head Ford V8 "weepers".


Son used a similar product, K-W, I think to seal the cylinder liners in his ancient Case tractor.


V12 fun coming up???


Carl

 

The engine has just been rebuilt by a jag engine guy. Does it work putting an oring under the washer

 

+1 on "off the car" or, if in situ, then "disconnect the injector harness" . . . probing around any powered control module, even remotely, is not a smart way to accidentally end the life of one of these expensive items. Most tend to be fairly robust around the internal output semiconductors that do the actual switching, but why take any chances?

I have always used a neat little test mod made years ago . . . solder an injector connector from a wreck onto red and black leads terminating in large alligator clips from a dead battery charger. Designed to use full +12V as per Jaguar's usage . . . but I do like Doug's advice to use a 9V battery.

Cheers,

Ken