King ECU diagnosing connection issues, can't switch to gas

Post Reply
Message
Author
optimus
New member
Posts: 17
Joined: Sat Aug 27, 2011 7:49 pm

King ECU diagnosing connection issues, can't switch to gas

#1 Post by optimus » Tue Nov 13, 2018 8:53 am

Good morning all

I have a Subaru Legacy Twin Turbo that has an lpg system fitted controlled by a KING (aeb) ECU. Over the past couple months me and my friend have been trying to sort the GAS map out and refine it as the original installer hadn't tuned it to well and had it set to add petrol mid rev range when the 2nd turbo is starting up.

During this period I have had issues getting the system to switch over from petrol to gas and wouldn't start and switch immediately to gas on a warm engine. Sunday morning I drove the few miles from my flat to my mothers and it switched to gas effortlessly however when I left my mothers to take her shopping I noticed on the switch in the car that only the amber light ( petrol mode ) was lite. I tried pressing the button a few times and got no response from it.

Last night I tried to connect to the GAS ECU and i was getting various errors from it saying 'the ECU is not compatible' to ' cannot run data the loading/storing', as test we installed the software for connection on another machine and got similar issues however it also flagged up saying 'new firmware available' but wasn't connected and had the 'ECU not compatible' message behind the firmware message.

Current thinking is the ECU has had it but looking for 2nd opinion before looking into ripping out the electrics and installing a new system :(

LPGC
Installer
Posts: 3208
Joined: Wed Sep 29, 2010 6:01 pm
Location: Yorkshire
Contact:

Re: King ECU diagnosing connection issues, can't switch to g

#2 Post by LPGC » Tue Nov 13, 2018 9:54 am

Got no response from the switch or the LPG system didn't switch to LPG when you pressed it?

What version of software are you running? What King ECU is it (classic style metal bodied / plastic / MP32)? What version of Windows and is it 32 or 64 bit? Some combinations give strange results if they even connect to the ECU.

Sometimes pulling the LPG fuse, putting it back in and trying again allows you to connect.

In some cases if the switch is broken it can seem like you haven't connected because you don't get any readings on screen.

Simon
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240

optimus
New member
Posts: 17
Joined: Sat Aug 27, 2011 7:49 pm

Re: King ECU diagnosing connection issues, can't switch to g

#3 Post by optimus » Tue Nov 13, 2018 4:11 pm

Hi Simon,

Thanks for your response

No response from Lpg switch at all just Amber light, no green indicator lights.

Don't know the version of software but has connected before.think it's 6 something. Will look later.

Had the battery disconnected for over 10mins and didn't fare any better.

Running windows 7 32 bit on laptop and 64 bit on mates tower.

ECU is metal bodied 2001NC ? King stickered but aeb on back

We were wondering if it was a switch problem which is why I attempted to connect with laptop to see if there were any error codes and see if it would switch through the programme

Hope these answers help in someway

LPGC
Installer
Posts: 3208
Joined: Wed Sep 29, 2010 6:01 pm
Location: Yorkshire
Contact:

Re: King ECU diagnosing connection issues, can't switch to g

#4 Post by LPGC » Wed Nov 14, 2018 9:49 am

Does the amber light go off after running the engine for a while (all lights on switch go off)? If so and if it's set up expecting the rpm wire to be connected it could point to lack of rpm signal on that wire. But this wouldn't explain you not being able to connect with the interface.

Switches can seem 'locked' to a certain fuel if injector break wiring isn't done properly but can't see this being the case on your install.

Would expect Win7 32 bit to work properly but there can be problems with win7 64 bit.

So far it's seeming either a switch or an ECU internal fault is the problem. Unless you fitted an incompatible switch such as a Piro switch which looks very similar to the usual AEB119B switch.

If you disconnect the switch you might be able to connect to the ECU if the switch was faulty, but this won't totally prove the ECU is good because the software doesn't show readings properly with the switch disconnected.

Have you gone through all the wiring checking for shorts/breaks /water ingress including the connector to the ECU?
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240

optimus
New member
Posts: 17
Joined: Sat Aug 27, 2011 7:49 pm

Re: King ECU diagnosing connection issues, can't switch to g

#5 Post by optimus » Thu Nov 15, 2018 9:49 am

I haven't had time to look over the wiring yet, just got in car this morning and before turning on ignition looked at the lpg switch and noticed the Amber light was still lit, could this be an indicator of faulty switch?

If it looks more like a faulty ecu I might aswell take out the king system and replace with an an old AC stag 4 system I had on my previous car.

LPGC
Installer
Posts: 3208
Joined: Wed Sep 29, 2010 6:01 pm
Location: Yorkshire
Contact:

Re: King ECU diagnosing connection issues, can't switch to g

#6 Post by LPGC » Fri Nov 16, 2018 10:32 am

Could be an indicator of a faulty ECU or wiring, still possibly switch but less likely.

Bear in mind that the installer set it up with some petrol addition but the Stag ECU doesn't feature petrol addition. You don't seem to know yet why the installer set the car up with some petrol addition.. Some installers see it as another way of helping prevent VSR, could be that your other LPG components (tank valve / reducer / injectors) are incapable of fuelling the car properly at high engine loads without petrol addition (at least in the way they're set up with nozzle size / pressure / etc)... this would be poor component choice or poorly setup components. Could be that your ignition system needed a bit of petrol to prevent misfires. But if you replace an ECU that features petrol addition capability with one that doesn't you might also have to change other components.

Worth asking what components you have fitted and what's the spec of your car?

Simon
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240

rich r
Junior Member
Posts: 223
Joined: Tue Aug 26, 2014 2:48 pm
Location: South end of North Yorkshire

Re: King ECU diagnosing connection issues, can't switch to g

#7 Post by rich r » Fri Nov 16, 2018 11:10 am

Simon - if it helps (as a former Legacy twin turbo GTB owner), the twin turbo system on these engines has a few quirks that could be a challenge for fueling which may explain the petrol addition choice. Though having said that there are several LPG GTBs that I've known of in the owner's club that have performed well.

The turbos are sequential, with the primary turbo being connected up conventionally between the exhaust and intercooler. The secondary turbo has a vacuum actuated valve between the exhaust and its inlet, and another on the intercooler inlet. It's the usual top mounted Subaru intercooler, but with two inlets. At low loads and rpm the valves are shut so only the primary spools up as normal. Once it gets to about 3000rpm under sufficient load the secondary exhaust valve opens. Then about a second later when a differential pressure sensor detects the secondary is producing the same boost pressure as the primary it opens the valve to the intercooler and now it's in twin turbo mode (giving around 280bhp).

When the exhaust valve opens, the pressure of exhaust gas in the (quite long, given it's a flat four) pipes drops as the flow changes to feed the secondary turbo. This causes the primary to slow down a little causing a very noticeable flat spot. In the Legacy world it's know as the 'valley of death' or VOD - because to the unaware if you stamp on the accelerator and pull out to overtake, the sudden drop in power can make you panic! The trick is to accelerate first, get through the valley, then pull out of course :)

When in transition the petrol injectors would overfuel as the boost pressure drops briefly, but the ECU knows it's in transition and so handles it differently. Depending on where the LPG ECU picks up a vacuum reference from, it might get odd readings during transition too.

Alternatively they may have gone for petrol addition to get around the quite different fuel flow characteristics between low rpm (single turbo) and high rpm (twin turbo) mode - and we all know how short Subaru petrol injector pulses can be. The twin turbo ones flow a decent amount when flat out - maybe the installer compromised on LPG injector size to get something that they could get to work at both low and high rpm?

I really liked by GTB, but after big end bearing failure (very common), I took ages to rebuild the engine and discovered LPG (on a Legacy of course) so decided I could live without the issues my high mileage GTB was starting to develop (blowing coolant hoses and rusting body panels).
-
2004 Subaru Outback 3.0Rn auto (LPG)
1991 Mitsubishi Pajero 2.5 LWB (WVO)
2008 Volkswagen Caravelle (Diesel)

optimus
New member
Posts: 17
Joined: Sat Aug 27, 2011 7:49 pm

Re: King ECU diagnosing connection issues, can't switch to g

#8 Post by optimus » Fri Nov 16, 2018 2:30 pm

Rich R - Thanks for that excellent explanation on how the system works :)

Simon - the system has a Emer - Palladio Vaporizer and Hana A+ Blue injectors ( originally looked like it has some sort of Hana copy injectors ) and has an electronic Flashlube system installed.

When we have been mapping my friend has been getting it running nicely on full gas ( no petrol addition ) but as said before even before we started looking at the mapping I was having switching problems and essentially is why I got the lead so my friend could have a look at it.

LPGC
Installer
Posts: 3208
Joined: Wed Sep 29, 2010 6:01 pm
Location: Yorkshire
Contact:

Re: King ECU diagnosing connection issues, can't switch to g

#9 Post by LPGC » Sat Nov 17, 2018 7:27 pm

A great explanation Rich but there's no aspect that should be a problem for LPG conversion. The obvious place to pickup engine manifold pressure is the manifold. Systems that don't feature an engine manifold pressure sensor but try to predict it (such as some BRC systems) are at best disadvantaged on these engines, at worst (and in my view) not suitable for these engines - Which is exactly what I explained on a certain Subaru Legacy forum to a few owners who had always had problems with their Subaru's running properly on LPG when fitted with certain BRC systems. I got banned from that forum for my explanation and for implying that installers who didn't understand this were inconveniencing their Subaru customers and p****ng in the wind with many failed attempts at sorting problems they didn't understand or have a clue how to put right whilst their customers had to do without their car. For the benefit of others, Rich knows this isn't me having a go at him, there's no argument between us, we probably think alike. This is me having a go at the Legacy forum's admin, the installers that don't know their jobs properly and the owner (on that forum) who didn't like me pointing out the obvious after I'd helped him and his installer.

Optimus, parts should be up to the job but I would have fitted a different ECU (to either you have) and probably different injectors if starting from a clean slate. I could go on to write a book here on what parts I'd fit and why but suffice to say parts I'd advise would deliver results even if the engine is overfuelled on petrol during transitioning between turbos etc. Regardless of engine spec, how boost comes in, if the engine is overfuelled during transition between turbos, etc, well suited LPG components should be able to match fuelling of the petrol system without petrol addition. If parts are less well suited then petrol addition facility may be useful. King doesn't feature some of the controls that I might implement to maintain driveability when running on LPG on an engine that might overfuel during certain 'transistions' (between turbos etc) but it does feature petrol addition.

Simon
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240

optimus
New member
Posts: 17
Joined: Sat Aug 27, 2011 7:49 pm

Re: King ECU diagnosing connection issues, can't switch to gas

#10 Post by optimus » Tue Nov 20, 2018 8:50 pm

Sorry for not getting back sooner, had a play with trying to connect to the LPG ecu with and without the switch connected. I was able to connect to the ecu with the switch disconnected but it wouldn't load the saved file with the settings and wasn't able to do much as suspected by Simon.

I ordered a new switch as i believed that was the next cheapest course of action, tried the new switch and still couldn't access ecu ( was getting same errors ), going by these results it looks like it's the ecu that could be the problem.

On a side note, when i was swapping between the 2 switches, i noticed the old one took a couple seconds then the amber indicator led came on, the new switch as soon as it was plugged in everything lit up then just showed the amber indicator led like the old one. Could this indicate anything?

LPGC
Installer
Posts: 3208
Joined: Wed Sep 29, 2010 6:01 pm
Location: Yorkshire
Contact:

Re: King ECU diagnosing connection issues, can't switch to gas

#11 Post by LPGC » Wed Nov 21, 2018 4:47 pm

Daft question but you got the correct switch AEB119B? Other switches such as Piro look very similar and use the same connector but are not compatible. Before I knew that (long time ago) I tried mixing switches and (as memory serves) think I found the amber light came on but with a delay like you're seeing. Long shot you bought the wrong switch though.

Before buying another ECU make sure the system power connections (especially earth) are connected properly and check the ECU's connector pins for corrosion/tarnish.

They're usually reliable and even when they break they don't usually break in this way. It hasn't been pressure washed, steam cleaned, fitted in a location where it's likely to get a lot of road splash etc has it?

You didn't try changing the firmware just before it went wrong?

Simon
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
Twitter https://twitter.com/AutogasSimon
07816237240

optimus
New member
Posts: 17
Joined: Sat Aug 27, 2011 7:49 pm

Re: King ECU diagnosing connection issues, can't switch to gas

#12 Post by optimus » Wed Nov 21, 2018 7:35 pm

Simon - ordered same switch that was fitted to lpg system aeb119b as you mention

No corrosion in the connectors, even opened up the ecu to see if there was any water ingress or blown components. Was clean inside.

The ecu is located in front of the battery behind the headlight.

As said in opening post it was not of it working one minute then not the next.

Was travelling from my flat to my mums on the Sunday morning to take her shopping as normal, gas kicked in couple miles down the road as the engine had warmed up. Gas was working all the few miles to mums, parked up and turned ignition off as normal . Was inside for maybe 30 - 40 mins watching some of the remembrance day ceremonies before going out shopping , it was about a couple miles from the house that I noticed the switch indicators weren't lit up like normal and just Amber led was showing only.

The lpg system has been on the car a few years now and never been quite right. Even more annoyed when I found about the petrol addition which was right in the cruising range for motorway travel which I was doing alot :(

Post Reply