omvl second hand setup, pressure way too high??

[ronniecourt]

i dont think there is anything drastically wrong here?

I do ... where's the Tinj petrol ? Crucial to slaved gas triggering..

i did note these werent working like my v6, but i thought it was due to the system not being calibrated in?

but its not processing those signals to the lpg side??

It is vital to get the injector cut wires the correct way round, they are polarity sensitive.

the loom was already pre made, a little mini loom for the petrol injectors, the car loom plugs into this, and this plugs onto the petrol injectors. could it be possible that volvo and vauxhall have their polaritys the other way round?

[rossko]

could it be possible that volvo and vauxhall have their polaritys the other way round?

Quite possible. Why one out of four works is a mystery though, but there is nothing forcing manufacturers to wire up injectors the same way round even on the same engine. Look for an identical wire at each petrol plug as the likely power feed side.

As an aside unrelated to this thread, this does rather blow up the theory that AEB ECUs only ever take timing info from cyl 1

[ronniecourt]

could it be possible that volvo and vauxhall have their polaritys the other way round?

Quite possible. Why one out of four works is a mystery though, but there is nothing forcing manufacturers to wire up injectors the same way round even on the same engine. Look for an identical wire at each petrol plug as the likely power feed side.

As an aside unrelated to this thread, this does rather blow up the theory that AEB ECUs only ever take timing info from cyl 1

makes sence, the injector plugs have a little lobe one side to make sure they can only go on the desired way, but thats the desired way for a volvo, posibly not a vauxhall. i will look at the common positive on the mini loom and see if it matches the vauxhall loom too.

[ronniecourt]

So, todays findings:

i decided to look a bit more into this pre-made mini loom for the petrol injectors. this is how the loom came off the donor car and i havnt chopped or changed anything, just plugged it in. there is a 9 pin plug between this loom and the dream ecu, here



and looked at the wire colours to see whats what, i focused my attention to the relationship between this plug, and the 4 plugs from the car ecu that used to control the petrol injectors. this is what i found, i couldnt find any pin numbers on the plugs, so ive labled them myself as per picture at the top, but have matched the wire colours.



seems pretty standard at first, all the top line are the voltage side of the petrol injectors 1-4, number 5 is the ignition feed to power up the lpg ecu, this actually piggybacks off cylinder 4 only. and 6-9 are the switched signals from the petrol ecu. BUT if you look again theres someting different on clyinder 2, the constant voltage and signal wires are the other way round from the rest of the 4, the plugs on the right hand side of the picture are the vauxhall car loom that used to plug straight into the injectors and are now interupted by this plug in mini loom. the numbers in the plugs are where i buzzed these out to on the 9 pin lpg miniloom plug.

so seeing this i guessed somehow cly 2 pins/wires have been crossed over when on the volvo?? so i swapped them back so they followed the pattern of the rest of the plugs.

but started it up and a few strange things happened, it now says its receiving all 4 petrol injection signals, where as before it was only showing cyl 2/b



but it wont switch to gas at all, where CUT OFF normally comes up on over run, its on all the time, and its just sitting in the 'change over' mode on the button, lpg level lights on, petrol light on and lpg light flashing, and still no petrol tinj readings?



if i swap the cyl 2 wires back again to how they are in the top diagram its just as described yesterday...

so with cyl 2 the 'wrong way round' just lpg injector B works feeding cyl 2, and none of the rest, suggesting the positive polarity is oppisite on vaux and volvo, how ever this cant be the case as the ecu is getting its ignition live from piggybacking cyl 4 plug, if i swap all the 5v's to the bottom row of the plug, the the ecu wont gets its ignition live and why is just one set different to the others??

[andy evans autogas]

ok the best way i can describe this the same as everyone else ,on the injector loom away from the 8/9 pin plug there will be 4 different coloured wires red ..yellow...green...blue these will have a wire opposite them in the plug with a black trace on them. when the petrol injector is unplugged and the ignition is switched on one terminal on the 2 pin plug will go live ,go to the other terminal and follow the wire back to suitable place and cut it ,back to the injector loom and find (for argument's sake)the red wire connect this to the cut wire comming out of the petrol injector plug and the red /black trace to the other cut wire going back to the cars ECU ...complete this for all 4 injectors and hey presto .....2 very simple rules black goes back(to petrol ecu) and cutting out the plugs cuts out the problems.........simples.....

[Gilbertd]

No idea how you are measuring 5 Volts at the injector plugs, they will have an ignition switched 12 volt supply on one side and a pulsed negative when running on the other side. Bear in mind that when not running, you'll probably still measure 12 volts at the switching pin as the drive will be held high rather than left floating with nothing on it. As you have identified, the wires are paired and the solid colour should go to the injector with the corresponding striped wire coming from the petrol ECU. This is a diagram of how it would be wired if you weren't using your plug in loom, hopefully you'll be able to work out what wire needs to go where.

[ronniecourt]

brilliant, thanks for the replys, i think the best thing to do is to open up this mini loom and see what we're dealing with. and if its not like the diagram above, make it so, or cut into the car loom as per pic as this will get rid of alot of un needed loom

[rossko]

It's not just which way round the coloured/striped wires go, they need to break into the correct one of the two wires feeding into each petrol injector.
If the break is in the common positive supply side to the injector, it won't work correctly.
If the break is in the individual switched-low for each injector, we're on the right track ...
But the coloured/striped pair must connect across the break the right way round as well.

A pre-made mini-harness that is of the wrong 'polarity' will be breaking into the wrong side of the injector wires too. If you look for the short linking wire joining the male/female pairs of connectors, that needs to carry the common power feed. Leaving the coloured wires to go to the injector other pin, and the stripes to car's ecu.

It is possible to pop the pins out and rearrange them if you are careful.

The white/red ignition-on wire will work pretty much anywhere, as in normal running both sides of an injector are at +12v mostly, and pulsing low won't be noticed.

Your meter needs a new battery

No idea why you have one oddball in the mini-loom, it's been messed with before.

[ronniecourt]

Well thought i'd report back for a happy ever after ending i took the injector loom apart and discovered the polatries were different from volvo to vaux, apart from the odd ball cyl2, so took it all apart and redone how it should be, and all works perfectly calibrated up first time and runs and changes over spot on. So thanks for all the help and pointers.