OMVL LPG Injector fault

[thijs]

Good afternoon,

I am Thijs from the netherlands. And i am having some problems with my Range Rover Classic 3.9i V8 running on lpg.
It's an omvl dream xxi system with the AEB2568 ecu.
Unfortunately a few months ago the wires running from the ecu to the change over switchs where melted on the exhaust manifold...
This caused an ecu failure. We replaced the wires and the ecu. But now something strange is happening.

When the system changes over from petrol to lpg it switches back to petrol. The diagnostics show an injector fault on injector 5. When i switch off injector 5, it gives a fault on injector 6. And so on. The hole B bank won't run on lpg. When i switch injectors 5,6,7 and 8 off, bank A runs on lpg and bank B runs on petrol. Next thing to check are the wires and injectors.
So i unplugged the connectors going from the ecu to the injectors and put the bank A wires on the bank B injectors and vice versa.
This gives the exact same fault codes on the diagnostics sofware!

I got in touch with the company that supplied the ecu and they were kind enough to send me an King ecu to test. But that didn't fix the problem. It gives exactly the same faults.

I am hoping some of you know the solution to my problem. I am running out of ideas.

Kind Regards,
Thijs Perdok

[LPGC]

Is the fault that the ECU diagnosis reports LPG injectors or petrol injectors?

If the reported fault refers to petrol injectors, it may be that the wiring is correct to petrol injectors on one bank of cylinders but incorrect on the other bank of cylinders. If this is the case it may be that the petrol injector break wiring uses plug on looms and on the effected cylinder bank the installer used an incorrect polarity plug on loom (the type where you move the standard petrol injector plug from the petrol injector and just plug it into a socket in the LPG loom thus avoiding any soldering). An older AEB2568 could disregard this type of problem if it was set to run the engine as a single bank of 8 cylinders, but the new AEB2568s need wiring to be correct to every petrol injector.

Do any crosses appear against petrol injector times in the diagnosis screen? If the readings seem correct on 5678 until you try to switch one of those cylinders to petrol and they you get a cross, the striped and unstriped wires in the loom may be wired incorrectly (correct is stripe to petrol ECU, unstriped to petrol injector on the negative pulsing wire).

Simon

[thijs]

Thanks for your reply Simon!

The fault is with the LPG injectors. The car was running fine before the wires melted. No problems with the injectors. It was running with a AEB2568 ecu. The ecu i have now are both AEB268D. Do you know the difference between the D version and the non D version?

When the car is running, there are no crosses on the screen. I can read all 8 petrol injection times.
I will check the petrol injector break wiringloom for the right connections to the right injectors.

[LPGC]

I touched on the main difference between versions above - Old AEB2568's only read petrol injector pulse duration from the blue petrol injector break wires, which connect to the front cylinder on each bank, each LPG injector gets pulse length calculated from just the blue wires / newer AEB2568's read all petrol injector durations, so all petrol injector break wires (blue red green yellow) have to be wired in properly. There are two pairs of each of blue, red, green, yellow petrol injector break wires -if the previous ECU was an old enough type it may have been enough that only one pair of blues was wired to a petrol injector correctly (but would most likely take both pairs of blue wires), none of the other colour wires would matter with the old ecu but they would with a new ECU. Just to clarify - do you get a cross beside any injector when the engine is running of you switch to LPG?

if the problem points to LPG injectors not petrol injectors nothing related to the above will be the problem. In which case, was wiring to the LPG injectors damaged too? Are the loom and it's plugs in good general condition? Assuming this is a new ECU, the pins on the ECU won't be corroded or tarnished.

Have you ticked the box for rpm detection wire connected?

Do all 8 LPG injectors pulse if you disable error reporting?

What do your LPG injectors look like (including colour of coils)?

Is there an external emulator such as a Pitagora box wired in to the system somewhere (in case at some earlier point the vehicle had a single point LPG system fitted which an installer didn't remove when fitting the sequential system)?

Simon

[thijs]

Thanks for your good tips Simon.
I just checked the wiring. Al petrol injectors are connected with proper plugs to the lpg wiring loom. I have also made some photos and printscreens. There are no crosses. Al petrol and lpg injectors are connected.

These are the injectors:

Injectors by Thijs Perdok, on Flickr

Injectors by Thijs Perdok, on Flickr

Injectors by Thijs Perdok, on Flickr

The rpm signal is connected and it reeds good values. There is only the omvl lpg system wired to the car. No other systems. If i diable error reporting, it won't run on lpg either. The change over switch starts bleeping when it changes over to lpg.

This is what the diagnostics look like when it is running on petrol

injectortijden by Thijs Perdok, on Flickr

And this is what it looks like when it runs on lpg. (just bank A, injectors on bank B are switched off)

half lpg by Thijs Perdok, on Flickr

As you can see it is reading the petrol injector times of al 8 injectors. When i change over to lpg with all injectors on. I can see the injector times of the other injectors too. Just for 1 second. Then it gives and error and switches back to petrol.

Should there be anything wrong with the lpg injectors?

[classicswede]

What you have there is the old high resistance injectors. The new ECU does not support those injectors and its most likely the resistance being wrong is what the ECU is picking up

[thijs]

What you have there is the old high resistance injectors. The new ECU does not support those injectors and its most likely the resistance being wrong is what the ECU is picking up

Thanks! If that is the problem. I should be able to shut the lpg injectors of bank A off. And then try if just bank B wil run on lpg. Right?
I will check this tonight.

[LPGC]

If you do that then of course only half the engine will run on LPG, the other half of the engine will run on petrol.

Probably a far better idea to replace your old injectors with some new ones (suggest OMVL Superlights with blue coils), your old injectors are probably worn out anyway!

Simon

[thijs]

If you do that then of course only half the engine will run on LPG, the other half of the engine will run on petrol.

I understand. I only had it running with bank A on lpg and bank B on petrol. Now i would like to check if bank B wil run on lpg with bank A on petrol.
Just to check if the wiring ect. on bank B is fine.

Are there other options on injectors? Are there different sizes? Which size do you think is the best? It's a standard 3.9L Rover V8 engine.

[thijs]

What you have there is the old high resistance injectors. The new ECU does not support those injectors and its most likely the resistance being wrong is what the ECU is picking up

Thanks! If that is the problem. I should be able to shut the lpg injectors of bank A off. And then try if just bank B wil run on lpg. Right?
I will check this tonight.

I checked it. It won't run on lpg when I switch any injector of bank B on, while the injectors of bank A are off. So maybe there is something else wrong?
Or should i order new injectors anyway?

[classicswede]

Try turning the diagnosis off

As the wiring had been damaged you need to check that out.

You will need new injectors regardless

[thijs]

Another thing i noticed is the firmware version. The old ecu that was on the car was running on firmware version 20.0. Both the new omvl and king ecu are running on version 11.52.
Does anybody have the latest firmware version for these ecu's? I can't find a higher version than 11.52 online.

[thijs]

Try turning the diagnosis off

Just turned the diagnosis off. Then the car keeps running on lpg. But only on 4 cylinders (bank A). The interface progam shows al 8 lpg injector times. But the injectors on bank B aren't opening and closing.

With the engine running the multimeter reeds 12ohms between the wires of the lpg injector plug on bank A(just on the plug, no injector connected). And on a plug going to bank B it only reeds 5ohms. Does this mean anything?

[LPGC]

Can you just clarify which pins on what plugs you measured the resistance, and why you did it with the engine running?

[thijs]

I was trying to find a difference between the puls signal going to bank A and bank B.

I messured the ressitance between the two wires going to a lpg injector. Not sure if this was right to do.

But according to the diagnostics software the ecu is sending pulses to bank B. And i just don't get why the injectors on bank B are not working.
1. The bank B injectors are working fine when i connect the bank A wires to them.
2. When the diagnose is turned off, the ecu sends pulses to the bank B injectors.

What stops them from opening and closing?

[classicswede]

Is there power going to the bank B loom at teh injector plugs?

[thijs]

Is there power going to the bank B loom at teh injector plugs?

How can I messure this? Between the Positive wire on the plug and the earth of the car? With the engine running?

[classicswede]

Yes that would work.

[thijs]

There is no power on the plugs going to bank B. Bank A messures 14volts.
I will check connection on pin 21 and 49 tonight.

[thijs]

I found the problem. There was no power going to the bank B injectors.
The power wires from the injectors are connected to pin 21.
So i think there is a bad connection in the big plug. Or the ecu doesn't send power out.
Now i connected the power wire of bank B to the power wire of bank A and the cars runs fine

Thanks for all the help!