Ecu remapping and LPG

Hi,

Please be indulgent with my English, I'm French (Nobody is perfect).

I have a Thor 4.0 on lpg : Romano Sequential injection.
I want to remap the engine ecu to avoid the "lean mixture problem", and ad some low end / mid range torque.

Does the remaping will also change the LPG management?
In fact I want to know if the LPG ecu is using the engine ecu map?
In this case any optimization on the engine ecu map will benefit to the gpl installation, so I will have improvments on fuel and lpg?

Regards,

The LPG and Engine ECU's are two different units setup to run independantly of eachother...

A remap on the Engine ECU will have no effect on the LPG ECU...and Vice Versa....

So you can remap the LPG system and leave the Engine ECU alone....and this will effect the LPG fuelling alone.

that will be true of a "mixer" system but not a "sequential" system as the op has.

Thx for your comments, if I am asking this question it's because I saw on different lpg "specialist" sites some infos saying that the lpg ecu is fonctionning like a "slave-master" system. The engine ecu is still doing his job, he is the master, the engine ecu drives the lpg injection via the lpg injectors, the gpl ecu is only doing an interface job, he is the slave, simulating the fuel injectors and sending the injection pulse to the lpg injectors.

This is why I am confuse, what the lpg ecu is really doing, and what the engine ecu is really doing?

the engine ecu is running the show,it has no idear that the lpg ecu is there.the lpg ecu intercepts the petrol ecu injector "pulses"and substitutes its own values

sassanach said:

the engine ecu is running the show,it has no idear that the lpg ecu is there.the lpg ecu intercepts the petrol ecu injector "pulses"and substitutes its own values

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Isn't that what I said that you said wasn't the case...??

As I said you can remap a Petrol ECU and it won't affect the LPG ECU and also if you remap a LPG ECU it won't effect the Petrol ECU...

if sequential you CAN remap the lpg (lgp) ecu if you have software..

any remap of the engine ecu will always affect the lpg ecu as the lpg side takes its timings from the petrol side,but the petrol ecu dose not know that the lpg is there,therefore when the petrol ecu injects a quantity of petrol into the engine it looks to the lambda sensor to see if it got it right and constantly adjust's the mixture. what the lpg dose is intercept the signal from the petrol ecu and puts in the equivalent amount of lpg, if the lpg ecu gets it wrong then the petrol ecu "ups the amount of petrol injected" to compensate, this signal gets intercepted by the lpg ecu which ups the amount of lpg injected.you cannot remap an lpg ecu independantly of the petrol ecu as the petrol ecu and lamdas will automatically throttle it back to suit its own internal mapping. you could triple the lpg mapping if you liked but all that will happen is the petrol ecu will try to throttle it back,fail, and bring on the eml

Ok with the point that remapping lpg ecu will not work, but we are back to my question : If I remap the egine ecu, will it also improve the lpg ?

If I understand what you are saying, sassanach, the answer is yes.
The remapped engine ecu will send a longer pulse, this longer pulse will be intercepted by the lpg ecu, which will put the equivalent amount of lpg.

bingo !!! we have a winner!! got it in one mate.
at the end of the day all the lpg ecu is trying to do is copy the petrol ecu map

The lean fuelling map story is rubbish - it simply isnt true.It was put about by people/companies who tried to make money out of it.Its just an engine taken beyond its proper design limits and built with variable quality control.
As far as I'm aware nobody has ever done remaps for the Bosch Motronic system on a Thor engine.If you try to richen up the LPG trimming during cruise operation all you will do is to narrow the trim limits which will have the effect of making it run VERY lean on petrol - not good.
The best thing to do is to make sure the LPG is trimmed accurately to match the petrol trims and make sure its well maintained.(Plugs,leads and cooling system etc)

so If i have the main ECU remapped the car will have similar performance with LPG as the LPG ECU will mirror the remapped car ECU ?

The lean fuelling map story is rubbish - it simply isnt true.It was put about by people/companies who tried to make money out of it.

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+1...RPI have alot to answer for!

Go with what Eight is saying. The Bosch system is pretty good, any poor running will down to a poorly setup LPG system.