Landi renzo switches off on deceleration

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lamb190
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Re: Landi renzo switches off on deceleration

#41 Post by lamb190 » Wed Apr 29, 2015 7:35 pm

both lamdas show working when hooked up to laptop so will ignore those wires for now.

I plan to continue to drive the car on gas to see how regularly It switches off etc.

in the mean time I hope to get the new interface cable working and drive the car with the laptop hooked up & check RPM/pressures and temps. (when it switches over to petrol will it show up in diagnostics?)

I will also look to replace the gas pressure/temp sensor as Gary confirmed that he changed both filters but the sensor is old and not been checked or replaced as far as he knows.
(ill check resistance between the "new" and old sensors.)

and towards the end of the year I may invest in a new vapouriser. perhaps a prins. as I cannot service mine as there are no parts or specs for it (motogas.com vapouriser)

57jam89
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Re: Landi renzo switches off on deceleration

#42 Post by 57jam89 » Wed Apr 29, 2015 7:39 pm

lamb190 wrote:both lamdas show working when hooked up to laptop so will ignore those wires for now.

I plan to continue to drive the car on gas to see how regularly It switches off etc.

in the mean time I hope to get the new interface cable working and drive the car with the laptop hooked up & check RPM/pressures and temps. (when it switches over to petrol will it show up in diagnostics?)

I will also look to replace the gas pressure/temp sensor as Gary confirmed that he changed both filters but the sensor is old and not been checked or replaced as far as he knows.
(ill check resistance between the "new" and old sensors.)

and towards the end of the year I may invest in a new vapouriser. perhaps a prins. as I cannot service mine as there are no parts or specs for it (motogas.com vapouriser)
Hi, I have this sensor on ebay for sell - http://www.ebay.co.uk/itm/171766190344? ... 1555.l2649

Don't buy a prins one as they are over priced.
Nissan Skyline 350gt Lpg fitted by Lpgc.

lamb190
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Re: Landi renzo switches off on deceleration

#43 Post by lamb190 » Thu Apr 30, 2015 7:13 pm

ive got a new interface from LPGSHOP.co.uk. (I cant get it to work at all. tried everything. just wont connect.)

so I re installed my old interface cable. I was able to run diagnostics. here is what I got....

any suggestions??

Image

rossko
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Re: Landi renzo switches off on deceleration

#44 Post by rossko » Thu Apr 30, 2015 8:25 pm

You don't know when those happened. Clear, and see what comes back (money on 'low pressure')
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lamb190
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Re: Landi renzo switches off on deceleration

#45 Post by lamb190 » Thu Apr 30, 2015 9:00 pm

the cars switching back to petrol daily now.

I have cleared the diagnostics.

what would be the cause of pressure malfunction? duff sensor?

57jam89
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Re: Landi renzo switches off on deceleration

#46 Post by 57jam89 » Thu Apr 30, 2015 9:26 pm

lamb190 wrote:the cars switching back to petrol daily now.

I have cleared the diagnostics.

what would be the cause of pressure malfunction? duff sensor?
Maybe faulty pressure sensor or faulty vapouriser.

My bets on vapouriser.
Nissan Skyline 350gt Lpg fitted by Lpgc.

lamb190
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Re: Landi renzo switches off on deceleration

#47 Post by lamb190 » Thu Apr 30, 2015 10:32 pm

ok well some things gone t*ts up. at best i can only drive 1/4 mile for it kick back to petrol (and each time laptop diagnostics says "low pressure")

i assume if it was a gas leak it would be highly obvious to smell while parked up running on gas?

so do i dive in and buy a vapouriser? :roll:

LPGC
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Re: Landi renzo switches off on deceleration

#48 Post by LPGC » Fri May 01, 2015 1:02 am

When you 'wound up the regulator pressure half a turn', did you note the pressure before and afterwards in the software?
If not the original reducer, did you fit the same spec temp sensor on the replacement reducer?

Just to confirm, your original reason for posting was that the car cut back to petrol on over-run / now it won't switch to LPG at all...
Are you sure you got the conditions of it cutting back to petrol (on overrun) correct the first time, not just a coincidence etc?

Your old interface worked in a fashion, if you can't use the new cable try the old one again - what errors / readings for pressure and rpm do you get now?

Simon
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lamb190
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Re: Landi renzo switches off on deceleration

#49 Post by lamb190 » Fri May 01, 2015 2:34 am

LPGC wrote:When you 'wound up the regulator pressure half a turn', did you note the pressure before and afterwards in the software?
If not the original reducer, did you fit the same spec temp sensor on the replacement reducer?

Just to confirm, your original reason for posting was that the car cut back to petrol on over-run / now it won't switch to LPG at all...
Are you sure you got the conditions of it cutting back to petrol (on overrun) correct the first time, not just a coincidence etc?

Your old interface worked in a fashion, if you can't use the new cable try the old one again - what errors / readings for pressure and rpm do you get now?

Simon
before i touched the pressure i checked its setting (in running condition) and it was 1.4bar

when i wound up the pressure it went to 1.5 bar,

ive since lowered it to 1.3bar.

my reducer does not have any sensors fitted, just the solinoid. i have the stand-alone prins filter (1 in 2 out) with the 4 pin sensor (pressure and temp) i have not changed any parts yet.

correct - original posting was that the car cut back to petrol on over-run (its doing the same now just all the time) so switches and runs to gas fine. runs well, just kickes off when revs lower (some times on gear change or deceleration)

i didnt get the new cable to work so have been working with the old one as i started out.. and im getting "low pressure" in the diagnostic each time it cuts out (reset diagnostics each time)

to be clear - other than inspecting the ecu wiring i have NOT disconnected or messed with anything.

it would say that since i first had the fault it been rapidly getting worse to the point it is now where it will cut back to fuel shortly after switching over to gas.

as said before, i get pressures of 1.3bar at pressent on idle when reving mildly.

bear with me on this, is it possible the diaphram is failing on the reducer/vapouriser? when the throttle body closes on deceleration/gear change, the engines vacuum increases, if the diaphram fails what symtoms would this cause?

function of the vacuum: Regulator The second function is to regulate the amount of LPG supplied to the engine. Just like a carburettor it tries to keep the mixture of LPG and air at the optimum proportion. This is achieved by default as engine vacuum and fuel demand is very much linked. Therefore the vaporiser/regulator delivers LPG pressure to the engine at a rate, controlled mostly by engine demand.


cheers

Brian_H
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Re: Landi renzo switches off on deceleration

#50 Post by Brian_H » Fri May 01, 2015 9:24 pm

lamb190 wrote:
LPGC wrote:When you 'wound up the regulator pressure half a turn', did you note the pressure before and afterwards in the software?
If not the original reducer, did you fit the same spec temp sensor on the replacement reducer?

Just to confirm, your original reason for posting was that the car cut back to petrol on over-run / now it won't switch to LPG at all...
Are you sure you got the conditions of it cutting back to petrol (on overrun) correct the first time, not just a coincidence etc?

Your old interface worked in a fashion, if you can't use the new cable try the old one again - what errors / readings for pressure and rpm do you get now?

Simon
before i touched the pressure i checked its setting (in running condition) and it was 1.4bar

when i wound up the pressure it went to 1.5 bar,

ive since lowered it to 1.3bar.

my reducer does not have any sensors fitted, just the solinoid. i have the stand-alone prins filter (1 in 2 out) with the 4 pin sensor (pressure and temp) i have not changed any parts yet.

correct - original posting was that the car cut back to petrol on over-run (its doing the same now just all the time) so switches and runs to gas fine. runs well, just kickes off when revs lower (some times on gear change or deceleration)

i didnt get the new cable to work so have been working with the old one as i started out.. and im getting "low pressure" in the diagnostic each time it cuts out (reset diagnostics each time)

to be clear - other than inspecting the ecu wiring i have NOT disconnected or messed with anything.

it would say that since i first had the fault it been rapidly getting worse to the point it is now where it will cut back to fuel shortly after switching over to gas.

as said before, i get pressures of 1.3bar at pressent on idle when reving mildly.

bear with me on this, is it possible the diaphram is failing on the reducer/vapouriser? when the throttle body closes on deceleration/gear change, the engines vacuum increases, if the diaphram fails what symtoms would this cause?

function of the vacuum: Regulator The second function is to regulate the amount of LPG supplied to the engine. Just like a carburettor it tries to keep the mixture of LPG and air at the optimum proportion. This is achieved by default as engine vacuum and fuel demand is very much linked. Therefore the vaporiser/regulator delivers LPG pressure to the engine at a rate, controlled mostly by engine demand.


cheers
Usually if a diaphram fails it will cause gas to get somewhere you dont want it - either into the manifold via the vacuum pipe, or into the coolant. Did you actually check the unit itself is getting hot though (not via the software, as it seems you have the cars own sensor connected to that reading, but physically see if it feels hot to touch?)

if it isn't getting hot theres either a plumbing issue/airlock etc, or an issue with the reducer itself (sometimes when they start leaking it will allow the unit to freeze up if the leak is bad enough). The way to tell which would be to monitor if the temperature is normal when the car is on petrol compared to on gas.

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Re: Landi renzo switches off on deceleration

#51 Post by rossko » Fri May 01, 2015 9:49 pm

Folks - those pink wires in the earlier photo are I feel probably the car's OBD or Canbus wiring. The "orange wire" thought to be temperature sensing is possibly the L-R's OBD wiring.
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lamb190
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Re: Landi renzo switches off on deceleration

#52 Post by lamb190 » Sat May 02, 2015 7:44 pm

Big thanks to 57jam89 for looking over my car today. and for the better software!

ive now set the: automatic return to petrol - "lower pressure read for a certain period" from 0 (zero) to 6 secs. see if that helps. need to give the car a decent run to test it.
Last edited by lamb190 on Sun May 03, 2015 8:24 pm, edited 1 time in total.

57jam89
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Re: Landi renzo switches off on deceleration

#53 Post by 57jam89 » Sun May 03, 2015 11:47 am

lamb190 wrote:Big thanks to 75jam89 for looking over my car today. and for the better software!

ive now set the: automatic return to petrol - "lower pressure read for a certain period" from 0 (zero) to 6 secs. see if that helps. need to give the car a decent run to test it.
No problem at all, happy to help.

The vapouriser was nice and hot so I connected my laptop up (i have the full software) with my lead which connection fine and everything looks fine on all the settings/reading, all temps and pressure ok. At idle the gas pressure was about 1.3 and then driving it don't drop to below 1.0.
The only thing was the 'switch back to petrol then low pressure' was set at 0 sec so we changed it to 6 secs.

If this does not sort the problem he's going to change the settings so it does switch back to petrol then pressure drops and try.

Lamb190 now has the full software also.
Nissan Skyline 350gt Lpg fitted by Lpgc.

lamb190
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Re: Landi renzo switches off on deceleration

#54 Post by lamb190 » Sun May 03, 2015 8:31 pm

cant thank you enough for the full software!!

ok so i can up date on the cars problem, and unfortunatley even with the tweek on the low pressure switch over setting its still switching back.

so we have prove the software if functioning ok.

i will change the sensor to the one i got off you (worth a try) - but i doubt its that.

i know we found my vapouriser to be work and performin fine (temp/pressure). but my thoughts are not that perhaps when it happen on deceleration (high vacuum) im wondering if gas is getting sucked into the vacuum pipe. if the diaphram in vapouriser was playing i wonder if this would be possible. it would explain why all software/ECU is running fine.

trypical that the car wouldnt switch over when you had ur software on the car. but it did as soon as i set off. !

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Re: Landi renzo switches off on deceleration

#55 Post by Brian_H » Sun May 03, 2015 8:42 pm

Take the end of the vacuum pipe off at a convient point, or use another piece of pipe and connect it to the vapouriser connection, and stick the open end in a bit of water like checking an inner tube for punctures. If you can see bubbles in the water then its leaking.

57jam89
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Re: Landi renzo switches off on deceleration

#56 Post by 57jam89 » Sun May 03, 2015 9:46 pm

Brian_H wrote:Take the end owould he vacuum pipe off a convient point, or use another piece of pipe and connect it to the vapouriser connection, and stick the open end in a bit of water like checking an inner tube for punctures. If you can see bubbles in the water then its leaking.
Great idea, but the pipe/tube would have to reach the passenger seat as it only does it at speed.
Nissan Skyline 350gt Lpg fitted by Lpgc.

lamb190
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Re: Landi renzo switches off on deceleration

#57 Post by lamb190 » Mon May 04, 2015 12:00 am

instead could i not gently pressurise the vacuum part of the vapouriser? and see if it holds pressure?? or will i be fighting againt gas pressure the other side?

Brian_H
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Re: Landi renzo switches off on deceleration

#58 Post by Brian_H » Mon May 04, 2015 12:05 am

You could pull the pipe off and see. If its leaking you should be able to tell even at idle. The ecu may be automatically correcting it under some conditions but unable to ay others. There should be no pressure there unless it's broken.

57jam89
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Re: Landi renzo switches off on deceleration

#59 Post by 57jam89 » Mon May 04, 2015 8:06 am

lamb190 wrote:instead could i not gently pressurise the vacuum part of the vapouriser? and see if it holds pressure?? or will fighting againt gas pressure the other side?
Why not undo one of the lpg hoses which fed injector rail so there's no gas pressure in vapouriser and then do the above. If the vapouriser is leaking then pressure will be present at the undone pipe.

Also there was a rpm signal to the lpg ecu all the time.
Nissan Skyline 350gt Lpg fitted by Lpgc.

lamb190
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Re: Landi renzo switches off on deceleration

#60 Post by lamb190 » Mon May 04, 2015 9:08 am

ok guys ill spins some spanners on it in a bit.

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