I've lost track whether you think you've moved your "lpg" issue or not?
So had I earlier this evening.
Feels like a game of this at times:
Borrowed coilpacks kill the higher load misfire and improve idle behaviour. Improve, not cure. With the reliable spark, you can recalibrate and it highlights other things - I'm hoping for the last time.
Cylinders 2 and 3 would not behave. Pronounced miss when they were activated, though less bad when active with other cylinders on that bank than on their own.
Cylinder 1 behaved perfectly. So I swapped the injector 1 onto it, with the feed from distribution manifold-injector left intact, and the pipe from the injector-manifold straightened as far as was practical. I fed this via the wiring for injector 1. (fed the car's injector 2 through the gas ECU's injector 1 wiring) I used the spark plug from injector 1 and the coil pack from injector 1.
Not one bit of difference.
I then went old school with the setup. Stuff the auto-cal and the trims and adjust multipliers one cylinder at a time.
Cylinder 1 wanted 1.4
Cylinder 2 wanted 2.3
Firing order of the 4.0 Jaguar V8 is:
(Bank) . Cylinder
A1, B1, A4, A2, B2, A3, B3, B4.
To cut a long story short, the gas is disappearing back up into the plenum/chargecooler at idle type flows. It is least bad on 1 and 5, due to the design of the manifold/chargecooler. A2/A3 are worst. B3/B4 suffer a little.
Crank the injector corrections (labelled with "last resort, do not use" in the AC software) to +25% on A2/A3 and +15% on B3/B4 and it idles just as on petrol. This all goes to pot when you load it up though, and the neat airflow is such that farting in the doorway results in it going outside. (pishing in the wind is easier to direct)
So it needs to come apart again. The drawing board:
Very short intake runners due to packaging constraints
Heads with "intake manifold" and petrol fuel rail
There is *just* space for a 6 mm OD copper pipe between this fuel rail and the head in this area.
This was my original gas inlet location, just to the side of the petrol injector. You can't get a 5 mm hose off this and between the fuel rail/head for love nor money though. Gap is too small and angles for the hose are too tight.
The fuel rail has stiffening ribs where the hose would foul. These could be removed and not leak fuel, and you'd then get a 5 mm rubber hose past, but I'm assuming that there was a flippin' good reason that they were there.
Plan B that I went with was putting the feeds here. This isn't working.
I think that Plan A was better, but I need to use something other than 5 mm ID / 11 mm OD rubber hose on an M6 nipple.
The HANA injector outlets are 4 mm ID. No point going any larger than this.
How small can one go on hose bore or stub/connector bore before flowrate becomes an issue?
Are "directional nozzles" any use, and how do they affect performance/aiflow? (they stick out a fair way)
I do have some of these, but their ID was only 2.5 mm which concerned me with regards flow rate:
http://translate.googleusercontent.com/ ... vMzQmo0eqQ
Are these available anywhere with a 4 mm bore?
Poking about I see these devices for sale too:
http://translate.googleusercontent.com/ ... YkZr-NFD8g
PTFE tube and a brass bulkhead fitting (I think compression type with an olive, then to a nipple) that then takes normal tube. I almost want the opposite of this - a bulkhead fitting/nozzle with the thinwall PTFE tube on the outside, leading to a nipple for a sort length of hose to connect it to the injector once is is out of the complicated/inaccessible part of the intake system.
Tinley Tech sell a variation of the theme:
http://www.tinleytech.co.uk/acatalog/Bi ... _2dINJNOZD
The screw-in nipple for the outside end of it looks good, but the quick-release pneumatic hose fitting for the intake manifold side has the potential to leak. (these are designed for pressure seal, not vacuum, and rely on internal pressure to seal themselves)
The kit that the Nitrous boys use looks well thought out, but I don't see that exact stuff in their standard catalogue:
Suggestions as to how you would get to that injection location welcome. It wants to be << 10 mm OD, and capable of a tight turn without kinking. 6 mm copper pressure line won't do it/can't be bent tightly enough. Thickwall Kunifer hydraulic pipe might do the trick (clutch type size rather than brake pipe size) but I don't know how you'd terminate it into the manifold easily/compactly.