I think installing a lambda sensor and having an onboard gauge for reading it and plus, an onboard vacuum meter combination would help me adjust LPG and advance curve better.

 

I'm currently calculating total costs & feasibility of such a modification to the exhaust pipes.

 

- Is this a suitable place for drilling and welding a lambda sensor nut? Of course the sensor will be above that part. (Marked with red circle. )

 

- I know a lambda sensor needs to be hot to get accurate readings. Felicia MPI has shorter exhaust down-pipe and the sensor is much closer to the engine. Does the place I chose will be hot enough?

Felicia lambda sensor location.

 

- Injection Felicia or Favorits have this style of exhaust down pipes. Two main pipes exiting from exhaust manifold is connected together very shortly compared to pre-cat carb. Favorits. Is this exhaust style more restricting?  Will I lose some HPs if I adopt this down pipe to be able to install a lambda sensor correctly? (A straight pipe will be placed to compensate the lost distance under the car)

 

Post regulated-CAT and pre-CAT down pipes comparison.

 

- Last question. Does using a cheaper narrow-band sensor will give me what I need?

Edited 20 October, 20223 yr by R_Blue

6 hours ago, R_Blue said:

Does using a cheaper narrow-band sensor will give me what I need?

No it does not, for YOU its useless

 

6 hours ago, R_Blue said:

Is this a suitable place for drilling and welding a lambda sensor nut? Of course the sensor will be above that part. (Marked with red circle. )

assuming the seal right behind it doesnt leak its A OKEY

 

6 hours ago, R_Blue said:

I know a lambda sensor needs to be hot to get accurate readings. Felicia MPI has shorter exhaust down-pipe and the sensor is much closer to the engine. Does the place I chose will be hot enough?

they have built in heaters for that reason, i think the elements are your biggest challenge, still these are the secondaries, which will be preety damn hot

 

6 hours ago, R_Blue said:

Injection Felicia or Favorits have this style of exhaust down pipes. Two main pipes exiting from exhaust manifold is connected together very shortly compared to pre-cat carb. Favorits. Is this exhaust style more restricting?  Will I lose some HPs if I adopt this down pipe to be able to install a lambda sensor correctly? (A straight pipe will be placed to compensate the lost distance under the car)

do not procced to change to shorter secondaries, ive spent many years calculating exhaust, INCLUDING SOME SPI high performance ones for the favorits,
the tunning of the engine will change, scavenging will now happen at much higher rpm and low end torque as well as fuel milage will suffer.
Since carbs did not produce torque such low down (mpi was at 2600rpm) longer secondaries were used to compensate (primaries were cast and not really altered)

Edited 20 October, 20223 yr by Thefeliciahacker

Thanks for the detailed info. Especially about the exhaust.

2 hours ago, Thefeliciahacker said:

i think the elements are your biggest challenge

Like water splash?

 

2 hours ago, Thefeliciahacker said:

No it does not, for YOU its useless

So you mean this one has no use for me:

https://www.aliexpress.com/item/1005001324663483.html

 

This kit has a very common lambda sensor. (Peugeot 206, 307 etc. Still millions of copies on the roads. I could find a replacement easily)

3 hours ago, R_Blue said:

Like water splash

Exactly 

 

3 hours ago, R_Blue said:

This kit has a very common lambda sensor

If it is actually a narrow band it will show afrs from 14 to 15.

Only useful when cruising. 

Not tuning for power and fuel efficiency. 

https://sites.google.com/site/chrishoppersprojects/-73-scout/Fuel-Injection/wide-band-o2-sensor/narrow_band_o2_reference_page

Edited 21 October, 20223 yr by Thefeliciahacker

19 hours ago, R_Blue said:

I think installing a lambda sensor and having an onboard gauge for reading

 

You are talking for something like this?

https://www.aemelectronics.com/products/gauges/digital-gauges/x-series-wideband-uego-afr-sensor-controller-gauge

 

A gauge like this has his own Lambda sensor

 

 

 

but the price is too high and only some skilful guys like ECU-programmers can work with it on the road making adjustments with their laptop.

The cheap ones i don't think worth nothing for and an every day driver other than just reading indications while travelling.

The lambda sensor on my old Felicia was exactly where you want to put it: go for it!. My sensor boss was professionally welded on the top of the joint of the Favorit secondary pipe joint: there is just enough clearance for the wires, and you can buy a sensor for the Favorit with wires long enough to reach without modification!. The best bit is that the Favorit secondary pipe produces more torque with the MPI engine. Mine was modded four years ago and has just passed a third MOT in the hands of her new owner. 

On 21/10/2022 at 11:32, D.FYLAKTOS said:

You are talking for something like this?

https://www.aemelectronics.com/products/gauges/digital-gauges/x-series-wideband-uego-afr-sensor-controller-gauge

 

A gauge like this has his own Lambda sensor

 

 

 

but the price is too high and only some skilful guys like ECU-programmers can work with it on the road making adjustments with their laptop.

The cheap ones i don't think worth nothing for and an every day driver other than just reading indications while travelling.

But I'm a skillful carburetor programmer too.

 

The real challenge is using LPG with a Pierburg 2E3. Which has an auto choke mechanism and engine load dependent second barrel operation. Also there is the distributor itself with centrifugal advance mechanism coupled with vacuum advance unit*. (*= On stock engines. I have R12 distributor) All of those advance mechanisms are tuned for gasoline. LPG advance curve is different.

- Issues with cold start. (<10ºC)

- Issues about switching between fuels.

- Issues about setting up the static advance and advance curve. (Since I have R12 distributor, probe light doesn't work for me! It shows an awkward position on degree marks near the pulley. Because, original Favorit ignition circuit has its own delay!)

- Advance curve and fuel ratio is connected with each other but I can't put at least one variable to a constant with LPG.

- Issues about keeping the carburetor clean. (LPG setup is pouring a black sticky muck right into the carb.)

Think about this; second choke on the carburetor opens at a certain vacuum level from the engine but its movement is blocked when gas pedal is not pressed at a certain degree. Because of this, you can't adjust LPG when the car is stationary. It's useless. (You can over-rev the engine with second choke completely closed, when the car is stationary)

A carburetor is designed to keep the A/F ratio constant under variable airflow but the vaporizer of the LPG unit solely depends on vacuum. It increases LPG output based on vacuum.

 

Long story short, it's a nightmare to properly setup and use LPG on a Pierburg 2E3 mounted engine. This deserves its own topic.

 

I have some home brew solutions to address some of the listed issues above but they won't just cut it all. The car can keep 120Km/h on flats with acceptable LPG consumption in the city but I can hear the engine pinking when climbing hills on second gear with revs more than ~3000-3500 (depends on air temperature and engine temperature).

Also, there is evident power loss between LPG and gasoline. You can tell the difference easily. On injection cars, when their LPG installment and ECU programed correctly, there is almost no power related difference between LPG and gasoline.

 

After some deep dig from past-time Czech sources, the real masters of using Pierburg 2E3 with LPG is no one than Czechs themselves! They are mentioning modifying the second choke operation. Remote controlling some of the parts in the carburetor for LPG use. On top that, they built a system with a SMV (Stepper motor valve) as a LPG power valve, receiving signals from a lambda sensor. They did this in the early 2000s. 😱 WOW! Just WOW!

 

If you want to up your game, you need better tools. I think, monitoring a lambda sensor value is a good start to see whats going on. (I mean getting some meaningful numbers)

 

17 hours ago, Favorit Fan said:

The lambda sensor on my old Felicia was exactly where you want to put it: go for it!. My sensor boss was professionally welded on the top of the joint of the Favorit secondary pipe joint: there is just enough clearance for the wires, and you can buy a sensor for the Favorit with wires long enough to reach without modification!. The best bit is that the Favorit secondary pipe produces more torque with the MPI engine. Mine was modded four years ago and has just passed a third MOT in the hands of her new owner. 

Thanks! Many thanks! That's really what I've needed! A live world experience.

 

Using the original secondary pipe will save me a lot $$. Now I'll have to decide whether to obtain a wide band Bosh LSU 4.9 or a more basic lambda sensor. Expensive sensors will setback the project for sure. But I'll post info whenever I can achieve some progress.

Edited 23 October, 20223 yr by R_Blue

3 hours ago, R_Blue said:

Now I'll have to decide whether to obtain a wide band Bosh LSU 4.9 or a more basic lambda sensor.

 

Check carefully, i had few months ago a nightmare with those Bosch Lambda sensors because the same parts store 1st time gave my one which was for Before the Cat Converter and the 2nd time suggested me to buy a different code which was for After the Cat Converter.

16 hours ago, D.FYLAKTOS said:

Check carefully, i had few months ago a nightmare with those Bosch Lambda sensors because the same parts store 1st time gave my one which was for Before the Cat Converter and the 2nd time suggested me to buy a different code which was for After the Cat Converter.

Very important info. Many thanks.

20 minutes ago, R_Blue said:

Very important info. Many thanks.

 

https://www.briskoda.net/forums/topic/503246-confusion-with-bosch-lambda-sensors/

 

Here are both of them in photos, thank God some members helped me and found the proper (NGK) one.

Hm have you thought of going fir an spi mod? 

To me the lpg installer didn't inform you about the drawbacks... 

On 26/10/2022 at 06:53, Thefeliciahacker said:

Hm have you thought of going fir an spi mod?

Good point. I could use the same LPG system on a SPI system. A throttle body, which has a single flap may be more compatible.

 

Even just installing a throttle body instead of a carb. could ease the LPG settings but I need a complete SPI system from a donor car to be able run it on gasoline. The law mandates dual-fuel cars to be able to run on both fuels.

 

I checked the parts stores for Felicia SPI system parts, especially the throttle body. It is not available but  new carburetors are available.

I also saw some SPI felicias converted to carb. I think people revert their SPI systems back to carb. when there is an expensive problem happens to their fuel system. Of course that is a cost related choice. So lack of SPI parts makes it harder for a SPI conversion. Even from donor car, all parts will be very expensive and their reliability will stay as a question mark.

 

On 26/10/2022 at 06:53, Thefeliciahacker said:

To me the lpg installer didn't inform you about the drawbacks... 

The car already had LPG installed when I bought it.

 

On 30/10/2022 at 01:22, R_Blue said:

. I think people revert their SPI systems back to carb. when there is an expensive problem happens to their fuel system. Of course that is a cost related choice. So lack of SPI parts makes it harder for a SPI conversion. Even from donor car, all parts will be very expensive and their reliability will stay as a question mark

Cmon that's the lamest of ways of dealing with a problem. 

Like converting it to a carbie. 

Downgrading...