Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[The Cambelt Kid]

Hi Guys,

I wonder if i may pick at your brains once again?  

As some of you may know, i have just installed LPG into my 2.6 MV6.  All seems to be working ok on the car and on the money side and i'm very happy i've patched the hole in my bank account!!

Anyhow, i have just bought a OBD code reader from Fleabay and read just my codes.  The reader came back with the following...


1300 Ignitor Circuit
P0170 Fuel Trim Malfunction (Bank1)
P0173 Fuel Trim Malfunction (Bank2)

The latter two faul codes only appear if running on LPG, the first i'm not too sure of.  Anyone have any idea what the fuel trim codes could be? i'm no too sure if i'm running lean or rich?  and what the hec is the ignitor circuit?  maybe this is related to the LPG?


Cheers
Cambelt Kid

[TheBoy]

Hi Guys,

I wonder if i may pick at your brains once again?  

As some of you may know, i have just installed LPG into my 2.6 MV6.  All seems to be working ok on the car and on the money side and i'm very happy i've patched the hole in my bank account!!

Anyhow, i have just bought a OBD code reader from Fleabay and read just my codes.  The reader came back with the following...


1300 Ignitor Circuit
P0170 Fuel Trim Malfunction (Bank1)
P0173 Fuel Trim Malfunction (Bank2)

The latter two faul codes only appear if running on LPG, the first i'm not too sure of.  Anyone have any idea what the fuel trim codes could be? i'm no too sure if i'm running lean or rich?  and what the hec is the ignitor circuit?  maybe this is related to the LPG?


Cheers
Cambelt Kid

The lamdas are trying to adjust the fuel trim for correct mixture, but for some reason unable to.

[Kevin Wood]

I would imagine the Lambda trim has hit its' limits because the LPG ecu is not giving exactly the same fuelling as the petrol injectors.

Running around with a Tech 2 showing live trim readings while adjusting the LPG ECU to give middle-of-the-range values is probably the best solution.

Kevin

[The Cambelt Kid]

Nice one Kev and TB.

Funny you should mention the T2 there as i think my PLG ECU has x2 wires for the lambda sensors.  My LPG supplier said i'd only need to use them if we have running problems... such as this.  So i might be able to use the LPG ECU as a test rig.

So i understand that if the lambda voltage is below the threshold (or histeresis band?) it could be running lean and if it's above it will be running rich.  Or the other way around, i'm not too sure?

does this sould like a good plan?

[The Cambelt Kid]

Right finally got this problem sorted!

Turned out that the injector nozzles were too narrow and were restricting the gas flow nearly all through the rev range.  I could see this as the LPG injector timing was quite a bit more than the Vx ones, hence not enough gas flowing.

The nozzles are 1.9mm diameter from the manufacturer and are supposed to be drilled out depending upon the power of the car.  I drilled then to 2.05mm when i first installed the gas and today i drilled them to 2.3mm.  2.3mm seems to have done the trick!  No error codes and slightly better peformance...  

Cheers
The Cambelt Kid

[TheBoy]

So the LPG is now fully on, and fully sort?

[The Cambelt Kid]

So the LPG is now fully on, and fully sort?

Sure is TB!

Pretty much done.  I need to stick some pretty wire loom wrap on the wire loom and secure all the pipes and looms.  As soon as this is done i need to email a picture of it my my LPG supplier who'll then post out the LPGA cert.  He's already seen 99% of the install so it's not a dodgy cert, it's just a few tweaks he wanted me to do before he gives it the thumbs up.  He trusts me enough to make the final mods to bring the install upto his standards, so thankfully i don't need to re-visit London again.

Apparently he wants a good pic of my engine bay to put up on his site as an example...    www.autogas-micromise.com

CK

[TheBoy]

So the LPG is now fully on, and fully sort?

Sure is TB!

Pretty much done.  I need to stick some pretty wire loom wrap on the wire loom and secure all the pipes and looms.  As soon as this is done i need to email a picture of it my my LPG supplier who'll then post out the LPGA cert.  He's already seen 99% of the install so it's not a dodgy cert, it's just a few tweaks he wanted me to do before he gives it the thumbs up.  He trusts me enough to make the final mods to bring the install upto his standards, so thankfully i don't need to re-visit London again.

Apparently he wants a good pic of my engine bay to put up on his site as an example...    www.autogas-micromise.com

CK

Excellent, and well done

[The Cambelt Kid]

Thanks!!

Only possible thanks to this forum, so not 100% my effort.

CK  

[Kevin Wood]

Right finally got this problem sorted!

Turned out that the injector nozzles were too narrow and were restricting the gas flow nearly all through the rev range.  I could see this as the LPG injector timing was quite a bit more than the Vx ones, hence not enough gas flowing.

The nozzles are 1.9mm diameter from the manufacturer and are supposed to be drilled out depending upon the power of the car.  I drilled then to 2.05mm when i first installed the gas and today i drilled them to 2.3mm.  2.3mm seems to have done the trick!  No error codes and slightly better peformance...  

Cheers
The Cambelt Kid

Excellent news. This makes sense. If the lpg nozzles don't give a similar injector duration as the petrol injectors it can run out of duration to inject the gas at higher engine speeds hence the lambda correction can't pull the fuelling in. Absolute maximum time available to inject the gas / petrol at 6500 rpm is roughly 18 ms as that's how long you've got between "bangs" on each cylinder. Not that Lambda correction would be active that fast, but you get the picture.

Kevin

[The Cambelt Kid]

Kev, thats bang on!  8-)

Still can't get rid of 1300 - ignitor circuit error though.  It does not activate the EML and i can only see it on the computer code reader.  In fact it only pops up once in a while and I doubt it's related to the gas install...  or maybe i should ignore it as the car is running very sweet now  

[Marks DTM Calib]

Kev, that the nail on the head!  8-)

Still can't get rid of 1300 - ignitor circuit error though.  It does not activate the EML and i can only see it on the computer code reader.  In fact it only pops up once in a while and I doubt it's related to the gas install...  or maybe i should ignore it as the car is running very sweet now  

Its just a miss fire code......if it gets bad you will notice it.

[Kevin Wood]

Hmm. Ignitor circuit? Does that mean the feed to the coil pack primaries perhaps?  :-/

Do you pick up the RPM signal for the LPG system from a coil pack feed or from the RPM output onthe petrol ECU?

Kevin

[The Cambelt Kid]

I've not noticed it at all, other that looking at the computer screen.  I'm just wondering if it flags up when the gas switches on and the GM injectors loose control to make way for the gas, the engine give out a light knock when it does.  I suppose this is classed as a ignitor error.

[Marks DTM Calib]

Hmm. Ignitor circuit? Does that mean the feed to the coil pack primaries perhaps?  :-/

Do you pick up the RPM signal for the LPG system from a coil pack feed or from the RPM output onthe petrol ECU?

Kevin

His setup uses the RPM output....

I suspect the ECU detects a momentary miss fire on switchover to gas....and hence stores an igniter error (it uses the knock sensors to detect firing).