LPG and Petrol setup with bad fuel economy

[brainhax]

Hi There,

1FZ-FE, Auto, (1997, LPG & Petrol)

Cylinder Head O/HAUL has been done 40K ago and ODOmeter sitting at 300K now. Spark plugs were also changed then. Getting pretty bad Economy on Petrol. Below is the description of the work done by the shop, may be LPG effected the valve clearances etc by now:

* Reface head, cut seats, face valves & lapp into seats.
* Reassemble fitting new valve stem seals.
* Prepare surfaces & fit back to engine block.
* Adjust valve clearances, tune engine

What would you do to improve its fuel economy? I have a Manual 1FZFE with 580KM and no maintenance history and fuel consumption is better then the AUTO 1FZ-FE


----------
1FZ-FE, Auto, (1997, LPG & Petrol)

 

[AussieHJCruza]

What fuel economy are you getting?

When were the air filter, spark plug leads, distributor cap and rotor last replaced?

 

[robnicko]

i run LPG and Petrol and KM's are very similar, you need to quote what km's you're getting.

 

[petegangies]

What I'd want to know is the following:

• What ignition timing you're running?
• Has the fuel filter been replaced recently? Ever had the injectors cleaned?
• How does the car drive in general? any hesitation, bogging down, misfires etc?
• Have you checked the ecu for any codes by bridging TE1 and E1 in the diagnostic port?

Automatic petrol 1FZ-FE's are very thirsty cars, what we need to determine is whether consumption is normal or excessive. Providing those figures will help determine that.

 

[MVZ]

What would you do to improve its fuel economy?

I have an LPG system, adjusting the valves every 30,000-40,000 km (they go from maximum to minimum), set the ignition to 7 degrees, the LPG system is configured using OBD1 corrections (Cartester8000 via cable), switching to gasoline at 2700 rpm. The lambda sensor is working properly - checked using a sine wave in the LPG software via cable.

 

[petegangies]

I have an LPG system, adjusting the valves every 30,000-40,000 km (they go from maximum to minimum), set the ignition to 7 degrees, the LPG system is configured using OBD1 corrections (Cartester8000 via cable), switching to gasoline at 2700 rpm. The lambda sensor is working properly - checked using a sine wave in the LPG software via cable.

Thats relatively quick valve seat recession. Are you running Valvesaver or similar fluid?

 

[MVZ]

Thats relatively quick valve seat recession. Are you running Valvesaver or similar fluid?

I don't use lubricating fluid. Unfortunately, this is the average usage statistics for LPG systems in Russia (PBT and PBA gas), not just on my car but also on other 1FZ-FE and similarly 2UZ-FE models (exhaust valves 0.1-40,000 km) – they deliberately increase the exhaust valve clearances by 0.1 to coincide with timing belt replacement. What are your statistics?

 

[petegangies]

I don't use lubricating fluid. Unfortunately, this is the average usage statistics for LPG systems in Russia (PBT and PBA gas), not just on my car but also on other 1FZ-FE and similarly 2UZ-FE models (exhaust valves 0.1-40,000 km) – they deliberately increase the exhaust valve clearances by 0.1 to coincide with timing belt replacement. What are your statistics?

I had mine done for the first time at 150,000km. Has been running LPG since about 50,000km, so in 100,000km. This was my mechanics report.

"All of the exhaust valve clearances were excessively tight — on some valves, even the smallest feeler gauge I had would only just fit. The inlet valve clearances were also on the tight side.
I was able to reshuffle most of the existing exhaust shims over to the inlet side to bring the inlet clearances back within spec, and I’ll be sourcing new shims for the exhaust side to achieve the correct valve clearances there as well."


He did have all the measurements written down on paper but I dont have a copy of them unfortunately.

 

[MVZ]

I had mine done for the first time at 150,000km. Has been running LPG since about 50,000km, so in 100,000km. This was my mechanics report.
"All of the exhaust valve clearances were excessively tight — on some valves, even the smallest feeler gauge I had would only just fit. The inlet valve clearances were also on the tight side.

So, the exhaust gap, while your average was 0.3, now reads 0.05 (using the smallest feeler gauge). That's 0.25 decreased per 100,000 km = 0.1 per 40,000 km.

 

[petegangies]

So, the exhaust gap, while your average was 0.3, now reads 0.05 (using the smallest feeler gauge). That's 0.25 decreased per 100,000 km = 0.1 per 40,000 km.

Indeed.. so the valvesaver hasn't given me any additional protection or prolonging over you. Good to know.. it's not cheap stuff! that's based on your assumption my starting clearance is 0.30mm at least, anyway.

 

[robnicko]

Indeed.. so the valvesaver hasn't given me any additional protection or prolonging over you. Good to know.. it's not cheap stuff!

what valvesaver are you using?
I use flashlube and when i did mine in January they were all still within spec 0.030 (exhaust) with only 2 close to 0.028mm clearance and that was after 100,000km post HG being done. I did have stainless hardened seats for LPG installed. Intake were all mid way in the spec which is what i set them at when i did the HG

that being said I always run on petrol for at least 10-15min before switching to LPG and always ensure its on petrol when its turned off

 

[petegangies]

what valvesaver are you using?
I use flashlube and when i did mine in January they were all still within spec 0.030 (exhaust) with only 2 close to 0.028mm clearance and that was after 100,000km post HG being done. I did have stainless hardened seats for LPG installed. Intake were all mid way in the spec which is what i set them at when i did the HG

that being said I always run on petrol for at least 10-15min before switching to LPG and always ensure its on petrol when its turned off

Yep Valvesaver from Flashlube. I thought the level of recession over 100,000km wasnt too bad. I'll continue using valvesaver. I toggle my fuel/lpg like you do. My old man never did though.