Analogic Sound

Analogic Sound

Archive for October, 2013

Lada Samara 1.5MPI r&r

without comments

Russian car LADA(AUTOVAZ) SAMARA, can this be a subject for a serious repair&restore project?
Yes! Why?

Because this car developed in 1998(last generation, with mpi) had multipoint injection(from GM) with a single oxygen sensor and a catalytic converter(EURO2 standard) with carbon canister system and compared to romanian products it was a rocket, speaking in therms of technology used in it at that time.

It also has a nice bodyline, young and classic view( I read some time ago that the team who developed the car was very young and I could tell that before reading that article).

It is a very simple car, nothing complicated, no steering assist, no power windows, no central door lock.

The best points are : low mass, good non-interference powerful engine(51kw) with EURO2 standards, a very economic vehicle, maintained with very little money, something that it is hard to see nowadays.

Some photos of the car:

The beginning…

I purchased the car back in 2007. The car was good, excepting the wipers for the front lights. They were missing.
After 2 years of service the car suffered an accident, it was flooded. I thought “this is the end”, I rescued it and parked it for future repairs.

The first part of the restoration project included a paint job , overall cleaning, fluid changes, windshield replacement.

I would not insist in mechanical part of the project but there were some electric/electronic repairs that were performed. This is why this restoration is here at

At that point the car looked like this:

A new(from donor car) ECU ISFI-2S(GM) was purchased.This was a must to get the car started since the old ECU was in bad shape due to severe corrosion.Though the car started, it didn’t worked very well and soon the “check engine” light appeared.

This ECU has selfdiagnostics so it was preety easy to get the codes out by making a bridge on the OBD diagnostic socket.This is a list with the error blink codes specific to ISFI-2S ECU system:


The error code was 53 “CO adjust potentiometer failure”. This was a joke since such device was not present on our car, the car is equipped with an oxygen sensor to adjust mixture in closed loop operation.There was a mismatch, this new ECU was developed for non-export russian cars wich were not having an oxigen sensor but a potentiometer to adjust the mixture.

The EPROM in ECU was a wrong one and that needed to be changed in order to achieve the EURO2 standards, basically this was our focus in this r&r project, to achieve the best consumption/pollution numbers for this little beautiful car, as we do consider the environment.

I will use this opportunity to thank to Mr.Sim Oleg from who provided us the original ECU hex file for the EPROM in order to update our ECU calibration data.You know great people when you find them!
Their support was impressive, free, and without it, we could’t push forward this beautiful project – Lada Samara.

Here are some photos of the ECU and electronic programming procedure:



ECU updated, electrical wiring rechecked and a nice rebuild of the generator(80A) was all needed in order to proceed to the next stage:
road testing and gas analyser system check.

I will post some more pictures with the generator charging voltage(this is an older type 14v regulator system) , engine bay , cleaned&completely resoldered fuse box:




Some of the relays have been refurbished, some replaced as you can see in the fuse box picture. A spare fuse kit was included there.
Another fact is that we used a very limited budget as major components are from donor cars, as I already said, considering money and the environment.

With all the effort, car continued to act like crazy, showing up code 44(lean oxigen sensor) and other mixture related codes.Things were not good, something was missing, project was abandoned for a few months…

Further tests with the gas analyser showed a very rich mixture, high level of non-environment friendly chemichals at the tailpipe, car was a shame though it was running preety strong at that point.

Next step was a catalytic converter change(from a donor car-renault) and a “new” oxigen sensor(from another donor car-alfa romeo, BOSCH type).

This was also a nightmare change because the ECU dropped code 13 wich is “oxigen sensor failure”.

This is the old oxigen sensor AFS79 made by AC DELCO, a rare find these days, wich we replaced it with the newer BOSCH unit:

More investigation was necessary as it seemed the newer BOSCH sensor was not compatible with the GM ECU. That was partially true as the old style oxigen sensor used the ground (-) from the exhaust manifold.
The newer type needs a ground signal to be provided by the ECU , so all we did was to provide a ground signal wire to the ground signal wire of the BOSCH sensor.That was so easy!

The final result is a car who behaves as it should, a 15 year old Lada with perfect emissions, like the new car you’ll buy it tommorow.

In the end I will post the gas analyser log for our nice little project, Lada Samara 1500i :




More r&r projects in the “Automotive repair” section soon!


Written by admin

October 25th, 2013 at 9:19 pm