lack of beans on LPG (101 v8)

the 101 now has shiney new ignition and should now have a monster spark. The timing has been advanced to 9btdc.

However it is still suffering from a severe lack of beans when on gas. tops out at 50 in 4th, and 3rd seems to make lots of noise but refuse to get me past 40 mph :(

2 weeks ago on petrol i could take on the boy racers at the traffic lights by abusing first and 2nd gear (honest! - though the shock factor may have also been in my favour!) but i cant now and all the panels in the back vibrate when i pull off!

ive just about got through one tank of gas and it was only set up briefly on the gas tester at the installers when we first commissioned the gas tester. have had my gunsons tester on it today and turning the knob on my vaporiser out by 180degrees knocked the co up a bit (to 2% ish) and made it respond better to stationary revving but it still feels slow.

this vaporiser has more settings than im used to.. in addition to the idle screw and the in-line mix adjust after the vaporiser i have another knob on the vaporiser which i belive affects the response of the diaphram or similar?

am i likely to be noticing the slight loss in power on LPG?, and it needs some proper setting up again or is my shagged cam just making itself much more evident on gas than it is on petrol? (it is ticking away like a bomb again so i have atleast one pot doing very little due to lack of valve lift)

Reply to
Tom Woods
Loading thread data ...

This sets the pressure of the gas leaving the vapouriser, as you say by adjusting the spring load on a diaphragm. I was told to set this so it blew a hemispherical soap bubble on the outlet hose (you do need to short out the ignition pulse sensor to keep the gas on while the engine is stopped. You also need to allow for the change in depression in such a long air intake. I know someone here (Steve T??) fitted a pan scourer to increase the depression seen by the mixer (and hence such more gas out).

I brazed an 18mm nut for a lambda sensor in the exhaust down pipe on the 110 to check mixture strength ( generally weak on lpg particularly when accelerating) and I've never managed to get as good running on gas as petrol. I put this down to cruder control over the range and possibly inadequate sized mixers for full power. That's why I asked if vapour injectors could be fitted to a carbureted engine.

When I fitted mine I was unaware leo controllers were available and these should be able to correct small irregularities in mixture strength over the throttle range if they are still available.

AJH

Reply to
AJH

IS it right on idle and revved ? It sounds like mine did - running too lean under load = not enough vacuum.

Steve

Reply to
steve

my gunsons CO gauge is fairly shit so my figures may be out here - but i think it lets you know if its getting weaker or richer even if the numbers themselves are wrong....

after screwing the extra knob one the vaporiser out by 90 degrees or so it made it such that the reading on the gauge didnt actually change by much as i increased the revs. It was maybe 2% at idle and dropped slowly down to 1.7 or so as the revs went up. originally it did drop.

made no difference to how it feels though.

it does start better now though - except the lpg changeover switch is playing up by not opening the solenoids until it gets a coil signal. it got a tad wet though as my windscreen has now sprung a leak...

Reply to
Tom Woods

i'll wang a test lead onto the solenoids and see what it does..

Steve has told me where to shove my scrubbers :)

ive got a wideband o2 sensor and controller fitted on one of my cars. i might pull it off and go and buy 2 18mm nuts and bolts on tuesday and weld them into both down pipes so i can balance the carbs too.. (or maybe just make up a braket to hold the lambda sensor itself in the end of the tailpipe for now) I can datalog it all then which would be interesting. Providing i can get the shitty software to work on my laptop!

whats a leo controller?

Reply to
Tom Woods

They're non standard fine thread, I had to order 6 of them, you can cut them in two before welding them on. I used a 4 wire sensor with heaters permanently on with the ignition.

What software? What data logger?

It's a Leonardo controller, I googled this:

formatting link
It looks like it's about 135quid and consists of a stepper motor for a valve in the gas supply hose with feedback from lambda and rpm.

AJH

Reply to
AJH

ive actually got a tap for an 02 thread so could just drill a hole in something and weld that on. i think it needed something like a 3/4" drill..

ive got an innovate LC-1 controller.

formatting link
use it on my car to check it is getting enough juice under boost.

it is alright but the software it comes with isnt the best and seems to refuse to work fairly often till i reinstall xp.

so its just the stepper motor to replace the manual tap. something like this would do it cheaper:

formatting link

im not gonna spend that much on it. i shall move over to injectors and an ecu before spending £135 :)

Reply to
Tom Woods

ok. my local engineer supplies place dont sell m18 nuts, and i dont want to spend £8 each for them off ebay again (stainless weld in bungs). buggers

Reply to
Tom Woods

Sounds like a case for running xp in vmware, I finally got it installed but not patched properly.

Maybe but I thought the leo came with programming software for a laptop. It also allows to cut the gas completely on overrun until you get near idle rpm.

My thoughts too but I would buy a used one to play with.

AJH

Reply to
AJH

found a spare stainless threaded bung, so gonna see if i can fit it in somwhere after the banks join. ive got xp running in microsoft VM, dunno if it will have the serial connection properly though. probably easier just to reinstall an old laptop with something windows-like and use that.

Reply to
Tom Woods

I carefully posted a tea towel down the air filter box inlet and i think it actually made a positive improvement! Tried a bit more but the wooly hat i found in the back was actually fleecy and too dense as it smothered it.

its now alright from a standing start again but still tops out at

50ish.

Definately going to datalog it properly and go get some brillo pads! :) and tighten all the jubilee clips up to elimiate any possible leaks internally.

Reply to
Tom Woods

In message , Tom Woods writes

Sounds like it's Going lean at the top end. Number of possible reasons for this.

How old is the system? Has it ever run right?

You should be able to run an open lop system quite adequately on a carb engine without resorting to stepper motors and injectors etc.

The extra knob on your vaporiser probably sets the sensitivity of the diaphragm to give better response to increased demand.

I should get it on an analyser and see what is going on a the top end.

Reply to
hugh

In message , Tom Woods writes

What is it about 101s? Yours runs on a better with a tea-towel up its nose, mine with sellotape on its elbow ... Any idea what we should carry in a toolbox? Germolene? Plasters? :-)

Reply to
AJG

still on its first tank of gas!. i installed it, installers checked it and had it on the gastester there for about 5 minutes to set it up. Theyve been a bit busy recently and i wanted to get a few miles on it (and new ignition) before bothering to get it set up again...

aye. be interesting to see.

Reply to
Tom Woods

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.