Hi Frank,
I will do all of the above this weekend. I know of a working junker in the yard next town over- I can also pull a few injectors and throw it in mine to see if it makes a differnce but will also work with air flow meter. I had mine rebuilt during this process and the car is behaving the same before and after the rebuild. The filter is brand new and clean. There are no particulates I even had 2 filters at one point but removed it because my gas tanks were brand new and it was making my fuel pump angry. I may pull an ingector line also to see if fuel is at least getting to the injector. Easy enough to do.
If you can pull the injectors out then why not just turn the engine over with the coil disconnected and see if the injectors fire any
Liquid out? Save yourself a trip to the next town.
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With the coil disconnected, the ECU gets no trigger signal and will not fire the injectors, Robinā¦?
Frank
xj6 85 Sov Europe (UK/NZ)
Not sure about that, I know that it works with the AJ6 engine, not too familiar with the EFI on the S111
The efi sees what the coil terminal does and uses that as speed signal/ trigger.
Not unlike the tachs in the 60sā¦80s cars do.
Pulling the injectors is lots of work. Then ignition on for a few minutes, not more, and fire the injectors by tapping the bullet connector 
See if there is roughly the same amount and spray pattern on them. Even cleaned injectors can clog up.
Cleaned injectors can and have clogged.
Whatever and however, it is of great import to see if the injectors squirt.
Neutralize the coil Safely crank sans spark in a fuel atmosphere. Connect the center HT from the coil to a spark plug that is still screwed in. Any spark safely contained in a combustion chamber.
Crank do the exposed injector nozzles squirt???
When I had a bit of trouble firing up my LT1. Teh recycle guy suggested that I fire the injectorrack over a pan. Found issue elsewhere. No need. Great sound V8 outta the down pipesā¦
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Indeed, David - a sort of final, but decisive, verification when easier test reveals nothing, or are inconclusiveā¦
Since he had the fuel pressure measured, likely with an engine in running order - a simple verification that the fuel pump now is actually running in ācrankā may be in orderā¦?
Frank
xj6 85 Sov Europe (UK/NZ)
Which he can easily do by disabling the starter (shift lever in D) and turning the key to the cranking position. If the pump can be heard, and ideally if the pressure regulator can be heard hissing shortly after, he has fuel at the rail.
Hi David- Garage tested the fuel pressure and it was good. They left a valve on for me so i will test myself. Fuel circuit is good and pump works well (It was replaced when I did the tanks about 1000 miles ago and I re-tested the pump. Fuel is at the rail. I think the others on here are right. I need to see the spray (or lack there of) coming from an injectors. Will also pull the cold start to see if that sprays- tho that is separate of the FI System. More to come.
The cold start will likely be clogged - forever. But as you say itās separate and not so important.
If you know the fuel pump keeps working while you crank the engine your next step is to pull the injectors (whether just a few or all is up to you) and find some small cups or towels to collect the fuel.
I have to say Frank mislead me a little earlier, as the engine will at least cough when the pump is disabled and the rail still full.
Good luck.
Ok Gents,
Some progress on testing. I pulled 2 injectors and used a 9v and they sprayed nice and consistent. I then reconnected the injectors to the harness and tried to start the car and nothing came out of those injectors. Then I pulled the harness off another installed injector that I hadnāt removed and tried to start using a 12v batter and it tried to start.
So. It looks like its getting pulse/signal but the power to the injector is not strong enough to spray the fuel.
Any thoughts on that? Thanks all of you for your help so far.
Frank- I measured ohms across the (relatively new) Coolant Temp Sensor and Iām getting .002. Does that sound right? Doesnt seem to align with your reading
Injectors get voltage on both sides, the ecu will ground one side. There is a āresistor packā under the air filter so the injectors donāt burn through.
Maybe the car thinks itās hot or the air flow meter is not signalling (but then there wouldnāt be any fuel since it activates the pump in the run position, for safety)
Thereās a CTS table somewhere on the forum, with values@Ā°C.
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At which scale on the ohmmeter, Jeffrey??
If you actually read 0,002(!) ohm the CTS is dead short - and very little fuel, if any, is commanded as the ECU reads a very hot engine. Remeasure the CTS - you should get some 2,5Kohm! And do also check the resistance on the plug as describedā¦
The injectors are powered from the main relay via the injector resistor pack - the ECU just provides the ground. You can use a test lamp to verify injector power; plug power wire to ground. Snce the injectors actually click - there is enough powerā¦
Frank
xj6 85 Sov Europe (UK/NZ)
Finally found it! This is a graph showing the CTS response in ohms (vertical scale) vs the temperature in degrees Celcius (horizontal scale). This was an actual CTS that I used to replace the one that was massively overfuelling my XJ6 S3.
Con
Hm, Con - the curve does not follow the table given in the workshop manualsā¦
Or rather; the tables extends in both direction compared to the curveā¦?
Frank
xj6 85 Sov Europe (UK/NZ)
I hope not?
ā¦
the table is on the old site. mine followed the values closely. looks similar.
OOps sorry yes degrees F on the horizontal scale. The curve is similar to my eyes but I do wear glasses. 200 degrees gives a value of 200 ohms, 100 degrees gives around 1400 ohms, 150 degrees gives just over 500 ohms. Surely for these devices that sort of accuracy is always going to be close enough. I canāt imagine that the CPU hasnāt lost some of its tolerance with age.
Con
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The xk ECU and its sensors are crude analogue devises, Con, and the engine will run reasonably within a fair range of mixture - it just doesnāt like āleanā fueling. Lack of precision is reflected in the specāed CO settingsā¦
Frank
xj6 85 Sov Europe (UK/NZ)