A bit thirsty - any ideas?

[Martin_1962]

16mpg on LPG average.

Feels just a tiny bit sluggish as well.

What should I check then? - going to check plugs this weekend.

Don't fancy removing the plenum unless I really have to! (You all know why)

Had an Italian tuneup for a couple of miles - that solved a sticky throttle

How do I clean the TBs if I do the dreadfull removal? Remember I can't remove plenum completely it has to stay connected by the pipes and wires.

[Taxi_Driver]

16mpg on LPG average.

Feels just a tiny bit sluggish as well.

What should I check then? - going to check plugs this weekend.

Don't fancy removing the plenum unless I really have to! (You all know why)

Had an Italian tuneup for a couple of miles - that solved a sticky throttle

How do I clean the TBs if I do the dreadfull removal? Remember I can't remove plenum completely it has to stay connected by the pipes and wires.

Thats worse than my 2.2 Martin  

Try air filter as well

James asked me on Sat, when revving it, has it always coughed/hesitated....yes its always done that.

When i get time.....im going to clean the throttle body (following AA's how to) to see if that makes a difference  :-/

[Martin_1962]

Air filter is OK

Plugs first I think, mind you I haven't closed the gap up for gas.

What are the best plugs to use, O/E, Bosch or NGK?

Definately hesitant - I may take the gas hose off and check for sludge.

Is there any servicing option for the DBW motor?

[Omegatoy]

Martin,
if im right you fitted this from your other car? ergo its now done a couple of thousand on your car? and now its using to much gas? easy answer really mate,
basically your engine is now used to running on gas and the combustion chambers are now scoured free by the gas of many carbon deposits that were there before you put the gaS KIT ON!! so now that the engine is used to the gas and is clean , you need to have it retuned to run properly!! believe me on all the cars i have converted this happens on every one!!!! they always need retuning to get the best out of them both power and economy wise!!
Omegatoy

[Taxi_Driver]

Air filter is OK

Plugs first I think, mind you I haven't closed the gap up for gas.

What are the best plugs to use, O/E, Bosch or NGK?

I thought if single electrode, you opened up the gap a tad to get a bigger spark.
Tho on twin/quad electrode you dont touch the gap.
I use vx plugs.

[Martin_1962]

Air filter is OK

Plugs first I think, mind you I haven't closed the gap up for gas.

What are the best plugs to use, O/E, Bosch or NGK?

I thought if single electrode, you opened up the gap a tad to get a bigger spark.
Tho on twin/quad electrode you dont touch the gap.
I use vx plugs.

I'll get 6 at the weekend, Halfords only sell in boxes of 2/3rds

[Martin_1962]

Martin,
if im right you fitted this from your other car? ergo its now done a couple of thousand on your car? and now its using to much gas? easy answer really mate,
basically your engine is now used to running on gas and the combustion chambers are now scoured free by the gas of many carbon deposits that were there before you put the gaS KIT ON!! so now that the engine is used to the gas and is clean , you need to have it retuned to run properly!! believe me on all the cars i have converted this happens on every one!!!! they always need retuning to get the best out of them both power and economy wise!!
Omegatoy

Yes - good memory

This makes sense, thanks. I'll do the plugs then call Bernard to check my settings next week. I have a lead and software just no laptop.

[JamesV6CDX]

Martin,
if im right you fitted this from your other car? ergo its now done a couple of thousand on your car? and now its using to much gas? easy answer really mate,
basically your engine is now used to running on gas and the combustion chambers are now scoured free by the gas of many carbon deposits that were there before you put the gaS KIT ON!! so now that the engine is used to the gas and is clean , you need to have it retuned to run properly!! believe me on all the cars i have converted this happens on every one!!!! they always need retuning to get the best out of them both power and economy wise!!
Omegatoy

Yes - good memory

This makes sense, thanks. I'll do the plugs then call Bernard to check my settings next week. I have a lead and software just no laptop.

You're welcome to borrow my laptop for as long as you need it Martin, it's got a real COM port and USB.. we'll surely use it on my conversion anyway...

[Martin_1962]

Martin,
if im right you fitted this from your other car? ergo its now done a couple of thousand on your car? and now its using to much gas? easy answer really mate,
basically your engine is now used to running on gas and the combustion chambers are now scoured free by the gas of many carbon deposits that were there before you put the gaS KIT ON!! so now that the engine is used to the gas and is clean , you need to have it retuned to run properly!! believe me on all the cars i have converted this happens on every one!!!! they always need retuning to get the best out of them both power and economy wise!!
Omegatoy

Yes - good memory

This makes sense, thanks. I'll do the plugs then call Bernard to check my settings next week. I have a lead and software just no laptop.

You're welcome to borrow my laptop for as long as you need it Martin, it's got a real COM port and USB.. we'll surely use it on my conversion anyway...

Thats a nice offer, but I think I will be OK as long as Bernard has RISN or wants mine installed. I will contact him later today. Might even get it checked when I drop your injectors off. So play it by ear.

[Marks DTM Calib]

Do the LPG ECU's not monitor exhaust O2 content and MAF and self adapt the maps accordingly.......or are they primative beasts?

[Martin_1962]

Do the LPG ECU's not monitor exhaust O2 content and MAF and self adapt the maps accordingly.......or are they primative beasts?

Actually the most modern SGI systems don't do much at all, they are quite simple beasts and don't bother with MAF or Lamda  probe stuff at all.

Only adjustments are flow of evaporator, and the carburation matrix.

The carburation matrix basically allows percentage changes of petrol injector time for different RPMs and different throttle positions (I am guessing manifold vacuum or injector duration is used).

Any fiddling is carried out by the Cars ECU, which is what causes the running at edge of map so trigger the emmisions light which both Dave TD and Me get.

I think mine is running rich at low throttle and lean at full throttle. Getting it checked soon.

[Marks DTM Calib]

Theres a buisness opportunity.....do a decent LPG controller....one that monitors MAF and O2 and self learns.....looks like the current setup will require 10K tune ups....

[Martin_1962]

Theres a buisness opportunity.....do a decent LPG controller....one that monitors MAF and O2 and self learns.....looks like the current setup will require 10K tune ups....

Costs of course!!!

Car ECU driven systems SHOULD theoretically work a lot better than lamda driven systems, they piggyback off the cars ECU which is generally more sophisticated. But they need setting up and to my mind the matrix is not flexible enough, it should have more like double the amount of elements.

If the LPG ECU started too many adjustments there would be the risk of the car ECU and the LPG ECU BOTH adjusting at the same time.

On a carb car a closed loop mixer system should be quite easy to work with.

All the injection systems appear to have some issues, OMVL suffer with fragile injectors. Romano injectors can get overpressured very easily, but are reliable.

There is also liquid injection but this needs all pipes to be kept cool.

I personally think that for road use LPG has a medium future - say 20 or so years, until bio fuels come on stream.

The best way to control a system would be an ECU which did the lot and held two different maps for the two different fuels.

[Kevin Wood]

Theres a buisness opportunity.....do a decent LPG controller....one that monitors MAF and O2 and self learns

Any one know what LPG injectors are like to drive electrically? Are they similar to petrol injectors? (pulse width and coil impedance, etc?)

I wonder if you could drive them with a Megasquirt? //www.megasquirt.info

they piggyback off the cars ECU

What does this mean? Are they monitoring the injector duration from the car's ECU and then making corresponding changes to fuelling on the gas side?

I think the best solution would be a separate controller maybe fed from a wideband Lambda sensor so you can keep the mixture correct for LPG. What's right for petrol isn't necessarily optimum for LPG. On the other hand, you've then got to fake the Lambda signals to the car's ECU so it doesn't throw fault codes. If you can make that ECU self-learning so much the better. It can be done. I mapped an engine in 30 miles on the road with a WB O2.

You'd have thought car manufacturers would have started making it easier for LPG conversions by now.

Kevin

[sounds2k]

bear in mind that if you have Vx trade club access, O/E plugs are cheaper than you'll get equivalents for at Halfrauds ... or off fleabay for that matter!!