I admit defeat! Can anyone help?

[KILOCHARLIE]

I've been having issues with my stag 3000 on my l322 range rover for about a year now and absolutely nothing I have tried has solved the problem and if anything the issues has got worse. The car now just misfires, errors to the point it reverts to petrol or even stalls when switching to lpg.

The problem used to only occur either when idling or heavy load but no does it any time I switch to lpg. So far I have...

Changed all spark plugs
Changed temp sensor on reducer
Checked all filters
Coolant change
Swapped coils between cylinders to rule out coil faults
Swapped lpg injectors between cylinders to rule out
Adjusted everything adjustable such as pressure setting on reducer
Replaced pcv valve on engine
Checked stag software, reset all settings, tried adjusting trims etc

Each time the software shows gas injector error 8 or sometimes 6. When trying to auto calibrate, the car misfires and stalls when bank 5-8 switches over to lpg. The car runs superb on petrol with no issues at all.

I've spent hours and hours trying to sort the problem all no to avail and I now admit defeat. Is there anything anyone car recommend before I either sell the car or find a specialist to take it too? All lpg places I've tried so far have no idea and seem more interested in installing a new system rather than fixing a 4 year old good condition one with the sole problem.

Very grateful for any advice.

[LPGC]

Software is spelling out there is an electrical problem with LPG injectors on 8 / 6. You have ruled out injectors as the problem by physically swapping them around - so this is pointing to a Stag ECU fault.

But - You're sure Stag software is spelling out LPG injector faults and not petrol injector faults? If you have mixed up LPG injector wiring then, during switchover, an engine cylinder may stop receiving petrol but not get any LPG, meanwhile another cylinder will get both petrol and LPG, result a misfire on 2 cylinders. This would be with only 2 injector plugs mixed up (problem worse if more cylinders mixed up). If you get a misfire on a cylinder then the petrol ECU can stop pulsing the petrol injector on that cylinder, result an 'no petrol injector pulse' error on LPG ECU.

Other issues during autocal at engine idle (as with Stag) can be due to incorrect pressure / injector nozzle size physical (the hardware bits not software) setup.

Would:
Check colour of wires to petrol injectors match colour of wires to LPG injectors for each cylinder.
Reset software, re-enter all basic settings (injector spec, pressure, etc) but set cylinder switchover time to zero, don't run autocal but try switching to LPG at 2000rpm instead of at idle and be ready to adjust multiplier manually.

Simon

[KILOCHARLIE]

Thanks for the reply Simon. 99.9% sure its not the wiring mixed up as the car was running on lpg fine for the first year I had the car. Started erroring and switching back to petrol under really heavy load and generating the same error before I started swapping injectors etc. The lpg wiring to the injectors is all numbered up too and are correctly labeled to the relevant cylinders. I haven't checked the wiring to the petrol injectors previously as I guess they must be under housing somewhere but I'll double check to rule this out anyway.

The injector nozzle sizes (i guess this is what are connected to the end of the pipes coming out of the lpg injectors, where the actually enter the engine?) haven't been touched since the car was running fine on lpg. Can I rule this out because of it or do the fail? When autocaling when the engine first developed the fault (under heavy load) I always had the error message nozzles too big but if i remember correctly this was stated as normal when doing some research. On the l322 anyway.

I will try adjusting the multiplier manually as you say although I have not done this previously. I take it I need to drag the graph to match the petrol map? Also what are the specs I should be changing on the software? All i have done previously is to change it to what it was originally set up as (zavoli temp sensor and reducer if I remember correctly as the autogaz one isn't listed in the drop down). What pressure should I set as I have adjusted the pressure setting on the reducer many times to see if this was the issue. I just leave this on the highest now as it seems to make no difference to my problem.

Thanks again for your replies, they're much appreciated.

[LPGC]

Since you have LPG injector wiring labelled, it's unlikely there's any mix up with wiring - Unless the wiring to petrol injectors has been altered (would mean plug on injector connections rather than soldered in connections).

Injector nozzle sizes can't have changed themselves (of course!). By injector nozzle size, we mean the size of the nozzle on the actual injectors, nozzle size at the (other) end of the pipe on the 'spuds' in the manifold will be larger than injector nozzle size. There will be no mix up regards nozzle size, I was referring to the fact that some combinations of injector nozzle size and reducer pressure (if the combination is not near enough correct for the engine) can cause the engine to stall or misfire.

You're correct about dragging points on the multiplier map to make petrol injector time when running on gas the same as they would be under same engine load/rpm combination as running on petrol. Settings - you seem to know already! Injector type, temp and pressure sensor specs. Since you haven't adjusted working pressure in software, take a note of what it is already set at (before you reset the ECU) and set it to the same again afterwards - Also, since you've been adjusting pressure at the reducer, when you get the engine running on gas adjust physical reducer pressure to same as the software setting you noted.

As said before, does seem likely you have one or two duff LPG injectors or duff LPG ECU, wouldn't be the first Stag ECU with duff LPG injector drivers...

Simon

[hardcorepit80]

Check harness for any damage all the way from injectors to ecu.
Also check ecu plug if there's any sign of water, there been some cases of water getting into the plug or even ecu.(should be mounted plug facing down)
Open up ecu and check for any visual damage.