lambda problems

[kopron]

I did a Turbo conversion on Saxo 1,4 , 8 valves.
And I also changed injectors .
But now the problem occoured , that lambda sensor is not giving enough voltage 2 computer and to air/fuel meter ( gauges) .
It is shown as poor mixture , while exhaust is black , spark plugs are black, and everyone can smell gas on exhaust pipe.
( 2much fuel )

I changed lambda sensor with new : no change .
I changed lambda sensor with 4 others : no difference .

And as I measured, Lambda is constantly giving 0.185 Volts ( 2 poor mixture ), instead of cca 0.500 Volts ( normal mixture ).
Voltage for lambda heater, that I measured, is 11,75 Volts ( normal ? ).
At first I had placed Lambda before turbine .
Than I placed it after Turbo .
Still no change .

This problem occoured , exactly when i changed injectors .
But even before that, the car was not running smooth at low RPM's ( low idle, 2000 RPM ).

The computer is Magneti Marelli IAW 1AP 40 .
I had 2 change fuel map , to make the car running .
Before that it was even not runing .

I was wondering,if anyone has another idea, what is wrong ( why is too weak lambda signal) until I'm waiting on my friend-expert 2 come from Italy 2 Slovenia ( my country), on/in Monday.

Thank you 4 helping me .

Boschtyan

 

[Lou Scannon]

Adding a turbocharger to a normally aspirated electronically controlled engine is not a trivial exercise, and I think you understand that. Changing to larger injectors is one of the steps, but you have to have a means to correctly measure the increased air flow under boost and correctly meter the fuel in accordance with the measured air flow.
You say you changed the fuel map, so apparently you have a means to modify air & fuel parameters in the controller. But the modifications have to be made based on data. Trial and error will take a long time. If your friend-expert has done this successfully before, I suggest you wait for him to arrive and learn from his experience.

 

[kopron]

Look . I've done this before, and I will do it again . Except not on this block .
I have also changed Peugeot 206 1.6 , 8 v into Turbo engined.
And it was very easy + big success .
Also I did it on VW 1,6 Diesel .
And Fiat 1,4 is included .

And this my friend has never done Turbo conversions like I am doing .

But now my knowledge has gone . So I'm still waiting on my friend, because he has other experiences + knowledge.

But in the meantime, I was wondering , if maybe you have some other ideas ( till Monday) ?

Again thank you 4 your cooperation + may Lord bless you.

Boschtyani + #

 

[dgallup]

I have been told (not first hand experience) that if you get out of range on a wide band O2 sensor that excessively rich condition will show lean on the sensor.

 

[JSteve2]

Sounds like an electrical problem. Did you check the wiring harness or lambda sensor circuit? Can you put a dumb resistor in just to see what the voltage is? Some ECMs are built to show a residual voltage with an open circuit.

 

[Bribyk]

You should be running a wide-band (0-5VDC) for this kind of tuning.

Also, if you're running so rich that the engine is misfiring your sensor will read lean (low voltage) because of the unburned oxygen in the exhaust. This is common tuning problem and the tuner will usually add fuel because the sensor reads lean; making the problem worse.

 

[kopron]

YYYOOOOUUUU, Brothers ! NoooOOOuuuuUUU. I yust found this stupid mistake this morning . It was at the beginning , right in the wiring diagram 4 AFR Meter .
In the script, there was shown, that the "signal" is coming from the Grey cable .
But, mistake ; it is Black cable, that is giving the right voltage .
Now, as I changed cables, it is working properly, and showing very rich mixture .

O.k. from now .
So, in the afternoon i also remaped chip ( againnnn,... in sixth time , heh ).

Now, since AFR meter is working as it should, ... another problem is showing ( I hope, that there won't be much more problems... ).

The AFR meter is jumping up + down , as we all know at low idle . ( at higer RPM + 1.5 Bar of Boost it becomes still )

But in this case , AFR Meter is also jumping at 2000 RPM , at "cruising mode" .
But the main problem is, that engine is having the same trouble as showed on indicator : it is shaking like hell .

But, as I remembered, this the same problem, was there all the time - even before i did this Turbo modification.
It's yust, that now it has increased much more obviously .

So, I think, that the Computer is not delivering constant mixture , as it is shown in AFR-Meter, because it is jumping right sinchronized with "jumping" of the engine .

It is really hard 2 drive, because engine is constantly pulling forth + back , at "cruising mode" . ( some mess, ... eh )

Maybe any another idea , what I can do to repair this cheap computer , to get it work more smoother at middle/low range ?


Like before I really thank you 4 all your help .

May Lord be with you .

Boschtyan from Slovenia .

 

[kopron]

P.S. ;
I also tought , of computer "misfiring" lambga signal . But since yesterday, i know , that I it was not hapening .
Thanks 2 Lord 4 that.
And , as you, many others also told me of buying wide-band lambda sensor .
But I think, that - because I wont go over 200 HP/Liter, ( 280 HP in this case of 1400 CCM, 1.4 L ), that won't be needed .
I consider this only " a small tuning" .
For me , a "bigger" engine tuning is over 200 HP/Liter .

Today , I will be changing wiring on injectors , because now I have right oposite way : 4-3-2-1 , instead of 1-2-3-4 .
This happened, when I changed injectors , and I had no spase left for connectors .
So I had 2 turn all cables with connectors in oposite position ( upside-down ) .

Maybe also this is one of reason, that there is no good combustion ( because of timing of injection ).

Till next time ...
seee yaaa

Boschtyan, EU

 

[Bribyk]

Injection timing won't change your combustion that much. I'm no injector expert but if the polarity was switched they may be normally open instead of closed, which would cause you to run rich.

 

[cheapcharlie]

If injector timing has no effect on combustion then how would it have any affect on the way the engine runs. If it has no effect on how the eng runs then why not just open all 4 at the same time? All injectors I,m fiamilar with are spring closed and electrically opened.
have never tried this but can,t see how reversing polarity would cause inj. too stay open or closed.

 

[cheapcharlie]

sequential injection requires correct timing just as ign does

 

[dgallup]

Many (esp. older) injections systems are not sequential with very little effect on power. Reversing the polarity will not change the fuel injection duration.

 

[cheapcharlie]

Many older systems were non sequential but were fired in pairs. So, are you saying just plug em up any where they will reach with no or very little difference.maybe you wanna rethink your answer. I agree reversed polarity will not affect pulse width.

 

[Ataloss]

How does the specific output (hp/L) of an engine have any bearing on the need for a wide band lambda sensor? A wide-band sensor will allow you to get an accurate reading of your air/fuel ratio over a wide range of a A/F rations, unlike a typical lambda sensor which basically is only good for letting you know if you're rich or lean.

Bob

 

[Bribyk]

I was thinking the same, Ataloss.

Kopron, if you're running boost you should be running too rich at WOT for a narrow-band lambda sensor to read properly.

Here's an experiment for those that think injection timing has a big effect...On one of our single cylinder quad engines, the ECU blew-up and would not open the injector. We ran a power and ground and you could keep the engine running by tapping the ground lead to the chassis to open the injector.

We also played with injection timing on our four-cylinder sequential setup and could not measure a difference in hp.

 

[JonKBmw]

Its going up and down while cruising because you're using a narrowband sensor/meter that is targeting 1 lambda while in closed loop (cruising, idle..) and going open loop WOT which is what you're mapping. You will never get the car dialed in properly, EVER, with a narrow band meter/sensor.

 

[kopron]

Hmm, JonKBmw, okay . but, why did we achieved it properly at Peugeot 206 1.6 , 8v ?
The only diference was in Bosch ( motronic ) computer which we also remapped.

 

[kopron]

And, CheapCharlie, till now I saw 3 kind of ways for wiring of injectors .
And only in this case, which is "simetrical" wiring, ( 2 outside + 2 inside ) changing the sequence from 1234 to 4321 makes no diference .
See ?

But now , as I changed wiring, it has shown as I predicted , that there is no diference .

Now we move on . Today I will replace fuel-pump with "stage 2" Cosworth .
I hope , that I will manage 2 do it, because it is much bigger than original pump . ( like 3.5 times )
And it is inside the reservoir, so even more trouble on the way because of less space .

Hear ya till next time .

Till than, may Lord be with you .

 

[kopron]

Well, brothers, after a , long time, I'm here again.
I would end this case, because we' re going on MegaSqirt computer, because this MagnetiMarelli has some bad extra maps in it, and it is not working as it should. I hope, that with MS we will solve the problem ( problem of unconstant running of the engine at low power ).
See yaaa, somewhere

Boschtyan Zupanchich, Slovenia, Europe,

 

[carnage1]

report back on the megasquirt, because I would like to try one this summer.
As for some of your problems with engine surging you might run your O2 sensor into a opamp set to zero gain with a delayed feedback loop so the controller sees an average of the last few signals, this might calm the computer down a bit so it isn't chasing every transient signal it sees.