air/gas mixture ratio??? - Nissan Murano

ensaar · 12-16-2011, 08:32 AM

Hi Everybody,

I'm newbie on this forum. I need some help.

I recently imported an US 0'4 Murano in Europe. I installed LPG system (which is quite popular in Europe, 1 liter is double of the price of regular fuel) After while all 3 cats went bad (which is normal as the exhaust gas is completely different) so I removed the "honeycomb" and put back the shell. (the LPG is considered as ecological fuel so it can pass the emission tests)

Now let's go to my problem/question. The LPG (liquid petrol gas) system is set to read air/gas mixture ratio from Mo's ECU. But the ECU is confused because of getting wrong info from O2 sensors (no cats) and the end result is the higher fuel consumption and loss of power @ higher RPM.
The LPG system can be manually adjusted and it is possible to set preferred air/gas mixture ratio. Does anyone know what is normal ratio (when it has all cats and everything works just fine) at this type of Mo's?
NOTE: Usually the car's normal petrol and LPG ratio should be the same.

I must say I really love the car and I hope I'll enjoy it as much as possible.

Tnx a lot in advance.

**njjoe** · 12-16-2011, 09:16 AM

ensaar-

You are not alone. Another member converted his MO to run on LPG. I can not recall his name at this time but he was based in Europe and had some issues with burnt valves I believe. Hopefully another member will remember his name and then you can contact him for the particulars on the installation.

-njjoe

ensaar · 12-16-2011, 11:22 AM

tnx njjoe,

I installed the valve lubiractor so I hope I will not have problems with burnt valves. The LPG is more dry than regular unleaded petrol. My wish is to get somehow the normal gas/air ratio so I can set up the LPG processor.

Warhammer · 12-16-2011, 12:15 PM

There are a lot of companies in the US that handle gas to LPG conversions. Might want to consult them. Also a copy of the service manual might help you. It will let you know what the expected voltages are supposed to be before and after the cats.

**njjoe** · 12-16-2011, 09:00 PM

ensaar-

I found him! I found the member who converted his MO to run on LPG. His name is adiadrian. You may want to send him a PM. He may have the specifics you are looking for.

I am also including a link to a thread he initiated that may interest you. Apparently he had issues with the engine after the conversion that he suspected had something to do with the valve clearance. Here's the thread: engine arythmia at idle speed and/or CVT failure

-njjoe

ensaar · 12-17-2011, 07:32 AM

tnx buddy, I just sent him PM, and hopefully he'll be able to help me.

oh...and tnx again for going trough the old threads...

lgt · 12-19-2011, 04:55 PM

Optimum air fuel ratio depends on what fuel you are running. For normal fuel injected gas it 14.7:1. Having no cats does not affect the AFR since the sensor used to adjust fuel trims is pre cat. The post cat sensor is only there to monitor the effectiveness/health of the cat.

**njjoe** · 12-19-2011, 08:53 PM

Quote:

Originally Posted by lgt

Optimum air fuel ratio depends on what fuel you are running. For normal fuel injected gas it 14.7:1. Having no cats does not affect the AFR since the sensor used to adjust fuel trims is pre cat. The post cat sensor is only there to monitor the effectiveness/health of the cat.

The 14.7:1 ratio you reference (called the stoichiometric mixture) is a target that is only used during low-load conditions, otherwise knocking and pinging will occur. The ratio is usually lower (richer) than 14.7:1.

-njjoe

lgt · 12-19-2011, 09:47 PM

Actually the target is usually 14.7:1 since a majority of driving is at low load cruising speeds. Richer AFR's are targeted under moderate to heavy load. As far as avoiding knock it depend on the tune. You can tune out knock by running richer and slowing down flame speed or you can run stoich and run less timing. Tuning is a balancing act and most use a little of both.

ressull · 02-26-2012, 04:18 PM

Hi Ensaar,

I just had my Murano converted a few days ago, I used the BRC Supermax kit with electronic flash lube - what kit did you go for?

Not sure about the gas/air ratios to be honest so sorry I cant help you out on that one.

cheers

ensaar · 03-06-2012, 04:23 PM

Hi ressull, I put the latest Zavolli system + the valve lubricator. What is your city/hwy milage on gas?

12-16-2011, 08:32 AM	#1 (permalink)
ensaar Registered User Join Date: Feb 2010 Posts: 6	air/gas mixture ratio??? Hi Everybody, I'm newbie on this forum. I need some help. I recently imported an US 0'4 Murano in Europe. I installed LPG system (which is quite popular in Europe, 1 liter is double of the price of regular fuel) After while all 3 cats went bad (which is normal as the exhaust gas is completely different) so I removed the "honeycomb" and put back the shell. (the LPG is considered as ecological fuel so it can pass the emission tests) Now let's go to my problem/question. The LPG (liquid petrol gas) system is set to read air/gas mixture ratio from Mo's ECU. But the ECU is confused because of getting wrong info from O2 sensors (no cats) and the end result is the higher fuel consumption and loss of power @ higher RPM. The LPG system can be manually adjusted and it is possible to set preferred air/gas mixture ratio. Does anyone know what is normal ratio (when it has all cats and everything works just fine) at this type of Mo's? NOTE: Usually the car's normal petrol and LPG ratio should be the same. I must say I really love the car and I hope I'll enjoy it as much as possible. Tnx a lot in advance.

12-16-2011, 09:16 AM	#2 (permalink)
njjoe Super Moderator Join Date: Jul 2005 Location: Jersey Shore (not THAT Jersey Shore, the real one) Posts: 11,745	ensaar- You are not alone. Another member converted his MO to run on LPG. I can not recall his name at this time but he was based in Europe and had some issues with burnt valves I believe. Hopefully another member will remember his name and then you can contact him for the particulars on the installation. -njjoe __________________ 2005 SL AWD, Platinum -OEM HID conversion & HID fogs -OEM iPod interface -Upgraded (non-Bose) speakers - Pioneer TS-A1702C & TS-G1643R -Muth signal mirrors -Valley Industries hitch and wiring harness -Aluminum fuel tank shields

12-16-2011, 12:15 PM	#4 (permalink)
Warhammer Registered User Join Date: Jun 2008 Location: Rio Rancho, NM Posts: 2,421	There are a lot of companies in the US that handle gas to LPG conversions. Might want to consult them. Also a copy of the service manual might help you. It will let you know what the expected voltages are supposed to be before and after the cats. __________________ *Ain't nothin' MO fun than drivin' a MO.*

12-16-2011, 09:00 PM	#5 (permalink)
njjoe Super Moderator Join Date: Jul 2005 Location: Jersey Shore (not THAT Jersey Shore, the real one) Posts: 11,745	ensaar- I found him! I found the member who converted his MO to run on LPG. His name is adiadrian. You may want to send him a PM. He may have the specifics you are looking for. I am also including a link to a thread he initiated that may interest you. Apparently he had issues with the engine after the conversion that he suspected had something to do with the valve clearance. Here's the thread: engine arythmia at idle speed and/or CVT failure -njjoe __________________ 2005 SL AWD, Platinum -OEM HID conversion & HID fogs -OEM iPod interface -Upgraded (non-Bose) speakers - Pioneer TS-A1702C & TS-G1643R -Muth signal mirrors -Valley Industries hitch and wiring harness -Aluminum fuel tank shields

12-19-2011, 04:55 PM	#7 (permalink)
lgt Registered User Join Date: Dec 2009 Location: Nor Cal Posts: 167	Optimum air fuel ratio depends on what fuel you are running. For normal fuel injected gas it 14.7:1. Having no cats does not affect the AFR since the sensor used to adjust fuel trims is pre cat. The post cat sensor is only there to monitor the effectiveness/health of the cat. __________________

12-16-2011, 11:22 AM	#3 (permalink)
ensaar Registered User Join Date: Feb 2010 Posts: 6	tnx njjoe, I installed the valve lubiractor so I hope I will not have problems with burnt valves. The LPG is more dry than regular unleaded petrol. My wish is to get somehow the normal gas/air ratio so I can set up the LPG processor.

12-17-2011, 07:32 AM	#6 (permalink)
ensaar Registered User Join Date: Feb 2010 Posts: 6	tnx buddy, I just sent him PM, and hopefully he'll be able to help me. oh...and tnx again for going trough the old threads...

12-19-2011, 09:47 PM	#9 (permalink)
lgt Registered User Join Date: Dec 2009 Location: Nor Cal Posts: 167	Actually the target is usually 14.7:1 since a majority of driving is at low load cruising speeds. Richer AFR's are targeted under moderate to heavy load. As far as avoiding knock it depend on the tune. You can tune out knock by running richer and slowing down flame speed or you can run stoich and run less timing. Tuning is a balancing act and most use a little of both. __________________

02-26-2012, 04:18 PM	#10 (permalink)
ressull Registered User Join Date: Feb 2012 Posts: 5	Hi Ensaar, I just had my Murano converted a few days ago, I used the BRC Supermax kit with electronic flash lube - what kit did you go for? Not sure about the gas/air ratios to be honest so sorry I cant help you out on that one. cheers

03-06-2012, 04:23 PM	#11 (permalink)
ensaar Registered User Join Date: Feb 2010 Posts: 6	Hi ressull, I put the latest Zavolli system + the valve lubricator. What is your city/hwy milage on gas?

Remove Advertisements Sponsored Links
Nissan Murano Forums Advertisement

Thread Tools
Show Printable Version Email this Page
Rate This Thread
Rate This Thread: