LPG calibration issues

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ollyd

Active Member
Posts
111
Location
Poole, Dorset
Just got my GEMS 4.0 SE running on LPG again after replacing vaporizer, liquid and gas filters and new temp sensors for coolant and gas. Its a Zavoli Alisei N system. Ran calibration and was fine under no load. Driving it about it just about managed but horrible pulling away and well down on power and response.

Ran software again using Tinley guide and noticed MAP not coming up on configuration but does on all other screens. Then noticed that on diagnosis it has big green tick top left but gives no information on petrol or gas injectors in the boxes. Can't select anything on this screen except the run diagnosis tick box.

Ran calibration again and major issues. Says maintain 2750 to 3200 revs. Runs pertrol then switches to gas. Spends ages on gas increasing injector pulse from 4 all way up to about 60 when it starts backfiring and I switch off. Has done this twice now. Its picking up injector timings for both petrol and gas. Its getting MAF and temperature readings. I believe this means the wiring is correct. Lambda stays at 4.5v for both so I guess these are not connected.

Any body got any ideas about what could be causing this or am I supposed to let it run through the backfiring before it starts trimming back to correct settings?
 
Done a little more digging about and it seems the system does not connect to O2 sensors at all. So runs open loop referencing initially from the petrol map. I now need to fine tune the LPG map using manual calculations under different loads. However still not sure why I can't get petrol or gas injector info up under diagnosis as getting injector timings in other screens so connections must be right.

Anybody any ideas how I can get diagnosis running or why it's not allowing injector on/off control? Not sure if the system ever worked on this vehicle before and suspect it was previously on something else as software says 1200 hours run but had no temp sensors fitted when I got it so could not have operated.
 
Successfully completed a calibration but the scale for injectors is in the first of the too small boxes. Does this mean my nozzles are too small or the pressure from regulator is too low? Adding 10% to maps at a time until all values are maxed out does not seem to improve drive-ability much.

Anyone got any ideas??
 
Hi, wouldn't run on LPG before I changed vapouriser. All plumbed up correctly ang gas and coolant get up to temp according to software. Switches over above 30 degrees and 1600 revs. Vapouriser settles about 70 degrees. Have mapped it so gas inj matches petrol inj at tick over but cable is not long enough to drive about under load mapping. I suspect it was all too rich before as reduced gas inj a lot after calibration to get same as petrol inj, Tick over then improved a lot.

I think I need to wait for longer cable to arrive and map across the various loads to see if it becomes more drivable.

My main concern now is can't run diagnostic as does not display injector timings. Guide suggests wires may be wrong but it picks up timings in all other modes.
 
Ok, major discovery. Have PAN injectors on right bank and matrix injectors on left bank. Might explain why it runs when PAN or Matrix selected as believe it is running just one bank hence poor power. The PAN's are hidden under the plenum so can only see the end of the block which is why I did not notice until further investigation.
Still get injector timings for both banks though. Tested Lamda's and both outputting 0.3V so think they may be shot and causing rich running. MAF gives 0.4v at tickover and 1v at about 2000rpm which I believe is about 1v down on ideal in both cases.
Anyone know if I'm best with two PAN or two matrix rails?
 
Supplier claimed vapouriser was non adjustable but it clearly has a bolt in back of spring housing which I have turned to get 1.4 bar. Was running ok at 0.92 bar but big injection times and petrol addition at high rpm.
Now getting about plus 1.5ms across rev range with about 160 across the map. Will live map properly once I get a willing passenger.
 
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