I have a Volvo with B5254T (2.5L low pressure turbo, 193hp) engine. It is equipped with KME diego G3 LPG system. I have problem to adjust it to work properly. Here is modeling tab. Diego G3 modeling tab. From manual (page 28-29):

Mult – parameter enables to change Tg value of all model points by a given percentage. It changes the ratio of slope (gradient) of the model curve. Recommended mult for groups of engine types:
Engine type => Recommended mult
Sequential turbo => -5 – 5 %
Sequential => 0 – 15%
Semi sequential => 10 – 25%
Full group => 15 – 30%

Offset – parameter enables to change Tg value of all the model points by a given value in milliseconds. Offset depends on reaction times of gas injectors.

Time to time i got P1171 error. I googled, that it is related to "Long term fuel trim-Bank 1" witch mean it can be lean or rich. This error is related to LPG. I drove about 350km with petrol and no errors are reported. MAF and oxygen sensor is OK.

I also tried to set mult to lower values, like suggested in manual (5 - 10%) - but then vehicle is very slow and accelerate very very slowly.

So, maybe someone have experience working with KME diego G3 LPG system.

Questions are:

  1. What represents that thin blue line, does it must have exact values in all model points? And what represents that values?
  2. What exactly offset does? it just moves all model points or it is connected with petrol injector opening times?
  3. First model point - in manual it is at position 1.1, in my case it is 0.5. Is important first model point coordinates?
  4. How i can increase LPG injector opening time?
  5. What parameters i must monitor (with odb2) while try to adjust LPG system? The idea is - monitor that parameters with petrol and then try to achieve the same with LPG.

1 Answer 1


I am done with adjusting. So, learned this video https://www.youtube.com/watch?v=oRX2V6_a3dc googled about fuel trim (long term and short term). I monitored short term fuel trim and drive around in various conditions. short term fuel trim must be close to zero. Long term too. So, adjusted LPG parameters until short term was close to zero (+/- 5%) in various load conditions. Short term i monitored via ODB2 connection.

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