P38A LPG setup

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kermit_rr

kermit_rr

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Right that's it, I'm stuck now, haven't a clue how to proceed.
Runs fine on petrol runs rich on LPG, to the point today where i reset back defaults, re-ran the auto calibration then went for a 30 min drive with 'adaptive' turned on.
When i stopped again, petrol long term fuel trims were both +25!! Way too rich.
When i look at the LPG injector timings, bank 2 is approx 8 percent longer than bank 1, but any offset adjustment between them in the LPG software has no impact.
Other than nobbing about for weeks and randomly making changes to the LPG fuel map, does anyone have any ideas?
The LPG ecu is wired in to the OBD port and as per manufacturers instructions, not connected to the O2 sensors (not sure why, if the option is there)
Help!!
 
Ah...OK.
I was hoping it may have been the same as mine (BRC) as it's become almost undriveable on LPG.
After hundred's of troubled miles, I've discovered it IS driveable as long as long as the throttle is
almost feathered and kept to slow speed...defeats the object of having a glorious V8 under my right foot!
How - and with what - do you get the error codes please?
Mike.
 
I have the aeb software which allows me to set everything up and also shows live data also have nanocom for the bosch side of things.
I've not had any error codes yet, it just seems that the fuel map is way off. I get the feeling I'm just going to drive up and down the bypass at different speeds and engine loads and keep twiddling until it gets better
 
kermit_rr said:
When i stopped again, petrol long term fuel trims were both +25!! Way too rich.
Click to expand...

That's the bit I don't understand. Shirley when you switch to LPG the petrol side should ignore whats going on??

I also don't understand why you "shouldn't" connect the O2 sensors when on LPG to trim the LPG (have read the instructions you posted previously)

What sort of fuel map info do you get? and how do you change it?
Any live data?

J
 
marjon said:
That's the bit I don't understand. Shirley when you switch to LPG the petrol side should ignore whats going on??

I also don't understand why you "shouldn't" connect the O2 sensors when on LPG to trim the LPG (have read the instructions you posted previously)

What sort of fuel map info do you get? and how do you change it?
Any live data?

J
Click to expand...
The bosch ecu thinks it's still running on petrol and adjusts the trim accordingly, it doesn't 'switch off' when it's on LPG, the LPG ecu simply cuts the connection to the petrol injectors
I don't understand why you shouldn't either, but the printed instructions are quite explicit
I can post live data if that's what you're asking?
16410402868440.jpg
 
kermit_rr said:
The bosch ecu thinks it's still running on petrol and adjusts the trim accordingly, it doesn't 'switch off' when it's on LPG, the LPG ecu simply cuts the connection to the petrol injectors
I don't understand why you shouldn't either, but the printed instructions are quite explicit
I can post live data if that's what you're asking?
View attachment 255727
Click to expand...

Yes I read the instructions:confused:.
The way I see it is if the petrol ECU sees the O2s then yes it will want to go rich when you switch back, does it settle back quickly? I would think it would on take a few combustion cycles to see it right again?

For the LPG side what adjustments do you have and how, but without the end result, from an O2 then what can you change if you dont know the result:confused:.

I had APEXI on the RX7 and it had loads of maps that all worked in conjunction with each other, But without the O2 readings nothing would know what was a good change on not:).

J
 
marjon said:
Yes I read the instructions:confused:.
The way I see it is if the petrol ECU sees the O2s then yes it will want to go rich when you switch back, does it settle back quickly? I would think it would on take a few combustion cycles to see it right again?

For the LPG side what adjustments do you have and how, but without the end result, from an O2 then what can you change if you dont know the result:confused:.

I had APEXI on the RX7 and it had loads of maps that all worked in conjunction with each other, But without the O2 readings nothing would know what was a good change on not:).

J
Click to expand...
Sorry, misread what you said :)
The guide says for a given speed/load adjust the lpg fuel map such that when you switch from petrol to lpg, the injector pulses commanded by the petrol ecu don't change.

I seem to be making progress, but on light throttle, bank 2 goes wildly rich on lpg, so i need to investigate that before i go any further, i wonder if it's a plug not doing so well on lpg or a dodgy lead... I can switch individual cylinders to see if that had any effect and narrow it down that way
 
marjon said:
does it settle back quickly? I would think it would on take a few combustion cycles to see it right again?

J
Click to expand...
I've not run it for long today, just a minute or so at a given mph/rpm to get the timings right, but the other day the long term trim went to 25, which would take an age to get back to normal
 
kermit_rr said:
Sorry, misread what you said :)
The guide says for a given speed/load adjust the lpg fuel map such that when you switch from petrol to lpg, the injector pulses commanded by the petrol ecu don't change.
way
Click to expand...

It just seems all guesswork to me.
To follow that instruction you would need to be running LPG rich? Lean?
Petrol 14.7
LPG 15.6

Did it ever run right on LPG and if so what’s changed?

Does this company not supply a map for the setup they fit?

J
 
marjon said:
It just seems all guesswork to me.
To follow that instruction you would need to be running LPG rich?
Petrol 14.7
LPG 15.6

Did it ever run right on LPG and if so what’s changed?

Does this company not supply a map for the setup they fit?

J
Click to expand...
I ripped out the ancient system because it went pop, also i didn't have any software for it so I've no clue, though it appeared to run fine.
That's the change, it's a new ecu and loom with the same injectors and reducers.
I didn't get anything tailored to the rover v8, just the ecu, loom and sensors
 
kermit_rr said:
I didn't get anything tailored to the rover v8, just the ecu, loom and sensors
Click to expand...

Sounds like a world of hurt to me.

Is there not a website with a forum for that make of system? Because starting with no map:(:(.

How much was it?

It’s a bit much for my brain right now, but if you only have input fields to adjust and no output (O2) readings how do you adjust accurately:confused:
J
 
marjon said:
Sounds like a world of hurt to me.

Is there not a website with a forum for that make of system? Because starting with no map:(:(.

How much was it?

It’s a bit much for my brain right now, but if you only have input fields to adjust and no output (O2) readings how do you adjust accurately:confused:
J
Click to expand...
I hear what you're saying, it came with a factory default map, it's also supposed to auto calibrate but that didn't seem to work. I wonder if that's related to the rich running on bank 2 I've most recently seen?
I understand the concept of adjusting the lpg until the petrol timings are the same, while it's not output readings, it is by proxy.., though does seem hit and miss.
This is the chicken I've installed
https://tinleytech.co.uk/shop/lpg-p...tems/gasitaly-5-8-cylinder-electrical-pack-2/
 
kermit_rr said:
Right that's it, I'm stuck now, haven't a clue how to proceed.
Runs fine on petrol runs rich on LPG, to the point today where i reset back defaults, re-ran the auto calibration then went for a 30 min drive with 'adaptive' turned on.
When i stopped again, petrol long term fuel trims were both +25!! Way too rich.
When i look at the LPG injector timings, bank 2 is approx 8 percent longer than bank 1, but any offset adjustment between them in the LPG software has no impact.
Other than nobbing about for weeks and randomly making changes to the LPG fuel map, does anyone have any ideas?
The LPG ecu is wired in to the OBD port and as per manufacturers instructions, not connected to the O2 sensors (not sure why, if the option is there)
Help!!
Click to expand...
"adaptive" in which setting? Lpg or on fuel?
 
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