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 Post subject: Injectors Fully Open
PostPosted: Wed Apr 25, 2018 7:20 pm 
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Joined: Tue Apr 09, 2013 12:12 am
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At 100% load and high RPM on LPG I'm getting a rev limiter type feeling. The car is a Range Rover P38 4.6 with an LPGTech system (Tomasetto Antartic reducer, Hana Injectors). The lpgtech software reports "Injectors fully open" for all 8 cylinders. It happens around 4700-5000rpm.

I've logged some data using the software which is attached. Is just a case of the map being too lean at high rpm/load or something else?

Thanks

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 Post subject: Re: Injectors Fully Open
PostPosted: Wed Apr 25, 2018 9:38 pm 
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Joined: Mon Jan 23, 2012 12:21 pm
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Location: Milton Keynes
It might help to confirm what jets (Nozzles) your using?


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 Post subject: Re: Injectors Fully Open
PostPosted: Wed Apr 25, 2018 9:54 pm 
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Nozzles too small or gas pressure too low. Petrol injector times are 24.7mS while gas times are 45.9mS giving a multiplier of 1.85 when it wants to be between 1.2 and 1.5.

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'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

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 Post subject: Re: Injectors Fully Open
PostPosted: Wed Apr 25, 2018 10:31 pm 
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Nozzles are 1.9mm I believe. I also have the 2.1mm version nozzles that I could swap to.

Is the gas and petrol not showing different times due to the app not sampling at the same time? If I look at one of the G1 peaks I get 49.9ms. Here's another picture:

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 Post subject: Re: Injectors Fully Open
PostPosted: Wed Apr 25, 2018 10:55 pm 
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That's showing the length of time the injectors are open for. Petrol injectors open for as long as is needed for complete combustion and the LPG ECU adds a few milliseconds to that pulse length to get the correct duration for complete combustion on gas. That adding needs to be 1.2 1.5 times the petrol injector time. If too low then the clunky LPG injectors will need to be open for a shorter time than they are physically capable of achieving so you'll get lumpy running at idle. If too high then the time between 2 revolutions (and one firing cycle) is less than the injectors are being told they need to be open for. At 5,000 rpm and 50mS opening, they are never going to have time to close before they need to open again so are open permanently, hence the error. Fitting larger nozzles or increasing the gas pressure will reduce the length of time the injector needs to be open to get the required amount of gas in so they won't be maxed out as they are at the moment. But, it may need the ECU calibration to be done again once changed have been made unless it is connected to OBD to adjust itself from that.

According to this chart http://www.lpgtrade.com/valtek-injector ... -diameter/ at 1.2 bar as your graphs show, even 2.1mm are a touch on the small side. Depending on whether you have GEMS or Thor, you are looking at 26 or 28 bhp per cylinder so 2.3mm would be nearer the mark.

_________________
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

Proud to be a member of the YCHJCYA2PDTHFH club.


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 Post subject: Re: Injectors Fully Open
PostPosted: Sat May 12, 2018 11:15 am 
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Joined: Wed Sep 29, 2010 5:01 pm
Posts: 3098
Location: Yorkshire
Since you say you can swap nozzles on your Hana injectors you must have Hana Gold injectors (that have interchangeable nozzles). You don't need to buy new pre-sized Hana nozzles, you could remove yours and drill them out.

You have an Antarctic reducer, these are adjustable to unusually high pressures but even at it's near max pressure your 1.9 / 2.1 nozzles will be too small. The antarctic reducers don't seem to live long if set to pressure much above 1.6bar and your injectors will work better at more average pressures anyway. Would advise drilling nozzles to 2.5 and in increasing pressure to 1.5bar for now, or if you leave pressure at 1.1 bar drill nozzles to 2.7mm (or 3mm if you don't have a 2.7mm bit).

Following nozzle swap and/or pressure change a complete re-calibration will be necessary. If it were me I'd reset the ECU and switch it to 'standard mode' rather than the 'tech mode' default setting, this way you get a lot more control over calibration and calibration won't mess itself up over time if a fault such as a duff lambda probe occurs.

Simon

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