error 44 misfiring

[Xavier T]

I own for 20 years my S2 and use it everyday for work (summer, winter..

Many parts were changed during those 20 years (injectors, CAS etc...) and I can say that this car is a good one.

But I have for many monthes problem with misfirings and code 44.

I changed the O2 sensor but nothing changed.

So i have decided to make an elanscan cable and now i can use elanscan program.

I created a file and if someone could help me that would be great

[chrism]

Hi Xavier T. No reply for you so far.

I'm not an expert with EScan but I looked at your data.

I noticed you have code 44 - lean - but your air to fuel ratio of 8.1 shouts 'RICH'. I don't understand this...

You have 400 000 faults?

There's 0 spark advance - it ought to be around 16 - so I reckon timing/CAS needs attention

I overlaid my O2 sensor EScan on yours and noticed that your sensor takes a while to warm up and seems to 'drop out' at times so I wonder if it's getting a full 'voltage'; does your ignition light flicker whilst it's running? The sensor gets 'voltage' when this is 'off' whilst the engine is running...

Since you're new to EScan you might not know what the numbers ought to be so I'm sending you a short scan I took recently to check my own air:fuel ratio (my sensor de-pinned recently and I wanted to make sure that it was still pinned). EScan lets you overlay your results on mine, which is running okay, so you can see how different yours are.

ecu6.zip

(8.8 KiB) Downloaded 113 times

Hope this helps until someone more 'specialist' can respond

[RonR]

Hi Xavier,

It looks like your O2 sensor is working, but you have an intermittent connection between your ECU and the O2 sensor:

The disconnection occurs when the RPM changes so possibly a broken wire being moved when the engine rocks back & forth.
If I were to hazard a guess I'd say check the wires on the car side of the O2 sensor plug, or the next plug along the loom - RHFHC

[Xavier T]

Thanks a lot.

I am going to check this next we.

I keep you in touch

[Tuga2112]

It looks like your O2 sensor is working, but you have an intermittent connection between your ECU and the O2 sensor:

O2V+RPM.jpg

The disconnection occurs when the RPM changes so possibly a broken wire being moved when the engine rocks back & forth.

What about the alternator regulator being on its last leg ? or like i had just a month ago (on the way back home from CC) the plug getting disconencted ?

[chrism]

Good point Tuga - I was going to suggest this, too and I 'feel' for your recent experience...

And also agree RonR. When I lost the proper mixture setting on my '90 SE (so might be a slightly different S2 response) the (next plug along) RHFHC loom must have moved and de-pinned an O2 sensor connection behind the right wheelarch.

Xavier T In your case it might be intermittent here - but I reckon your timing might be worth checking as well, though.

[Xavier T]

Well, job done.
I have tested the O2 sensor and checked wires and plugs.
Great news, engine runs perfectly now.

Then i settle the timing CAS using Karl Keil instructions (https://www.lotuselancentral.com/lec/cas.htm) and the result is fantastic ; it totally transformed the car's performance.

Thanks to everybody for your advices.

[chrism]

Hi Xavier T. Was it the O2 sensor wiring after all then, as RonR suggested?
And have you a newer, working scan to share? It's always good to get feedback

[Xavier T]

Good morning

Sorry for this late response but my car was at my garage engineer for body repairs and I was on vacation.

To answer to your question Chrism, the problem was with the RHFHC plug as RonR said. I disconnected it and used electrical contact cleaner.

Well so yesterday I picked up my Elan from the garage and I Wanted to send you a new scan.

On the way back I suddenly had a loss of power. I stopped and at idle there was a cylinder that was no longer working.
I took the car home and connected my ElanScan;

What do you think about it ?

[chrism]

Hi Xavier T. Here's your current EScan O2 sensor pic.

Glad to know you found the RHFHC problem, but looking at your EScan pic it seems your O2 sensor has 'struggled' then failed again - even quicker than the last time

I wonder if your sensor multiplug fell apart again - or possibly could your O2 sensor have 'died' as a seperate issue?

Spark advance seems sorted though. Let's see if others can add any comments...

[Xavier T]

This morning i Have tested the O2 sensor ; ou are right Chrism, the sensor is dead.
But it doesn't explain why i have a cylinder which is not working.

[Tuga2112]

This morning i Have tested the O2 sensor ; ou are right Chrism, the sensor is dead.
But it doesn't explain why i have a cylinder which is not working.

take it 1 step at the time.

for a single cylinder not firing I would personally start the diagnosis by

1 - inspect each spark plug for any sign of obvious difference between them. if one is clearly different, test if it can make sparks (stop fuel delivery, using inertia swich, run car until it starves, then pull plug out to test it. )
if the plug doesnt spark, swap it.
2 - with a multimeter, check if each of the leads has continuity, and if the resistance reading of them is rougly the same
if any of the leads has no continuity, replace it.
3 - use the "long screwdriver method" to listen for the injectors clicking. (as described by others)
if one of them sounds different to the others, thats a avenue to look into

worth noting im specifically assuming ONLY 1 of the cylinders are not firing.

if there are 2 not firing. the most likely problem is none of the 3 components i mentioned.

[RonR]

Xavier,
It's worth checking if the ECU is at fault before replacing the O2 sensor.
The ECU supplies a voltage of 0.45 Volts to the sensor on pin D7. If you run an Elanscan with the sensor unplugged you should see that constant voltage in the 'Oxygen Sensor Volts' graph. Of course the check engine light will come on after a while, but you should see the results in the first 30 seconds before that happens.

[chrism]

+1 for all the advice issued.

I'm thinking that if you ('I changed the O2 sensor but nothing changed.') replaced the sensor with a new(?) one it's rather unlikely to fail so soon?

Plus, Tuga's alternator regulator advice might still be relevant here; remember the regulator voltage output directly powers the O2 sensor and there might not be enough voltage left over to heat up the sensor sufficiently?

And there could well be two seperate issues at play here?

Sorry, all questions and no answers...

[Tuga2112]

i dont know if this was asked before. but..

does the alternator warning light come on when you flick the key, and then go off after the engine starts ?

[chrism]

...and presumably if the light stays ON after start-up, there's not enough current being generated by a poor regulator voltage to get the O2 sensor heated up sufficiently?...

Just a thought...on your second O2 sensor graph I noticed that the voltage started off at Ron's 0.45V figure then fell away very quickly. On my own sensor it starts off at 0.45V then rises gradually whilst starting its wavy lines between 0.1 and 0.8V - so it could be that your regulator is the object that's 'dying' rather than the O2 sensor.

[Xavier T]

Hi everybody

Thanks a lot for all your good advices.

To answer to Chrism and to Tuga2112, the alternator warning light come on when i flick the key then go off after engine starts.

I have doner a new scan considering what RonR said ; i have unplugged the O2 sensor then run the car.
Youu can see the new scan ( when you talk about the "Oxygen Sensor Volts" graph i can't find it under the popup menu "curve parameters" I have CO potentiometer/Oxygen sensor and Oxygen sensor integrator.

About my cylinder not firing :
1 - inspect each spark plug for any sign of obvious difference between them. if one is clearly different, test if it can make sparks (stop fuel delivery, using inertia swich, run car until it starves, then pull plug out to test it. )
if the plug doesnt spark, swap it.[/quote]
Well, one spark plug is really black but it sparks.[/size]

2 - with a multimeter, check if each of the leads has continuity, and if the resistance reading of them is rougly the same
I have tested them and the resistance is the same for all of them.

3 - use the "long screwdriver method" to listen for the injectors clicking. (as described by others)
if one of them sounds different to the others, thats a avenue to look into
I have tried to use this method but I think i am not good enough to manage to hear a difference.

[chrism]

Hi Xavier T. Yes you should get a red light when you turn to position1 - and if the red light goes out after position2, when the engine has started and is idling, then everything seems normal to me. When the red light goes out this means there will be enough voltage from your regulator to supply the O2 sensor- and you can see the 450mV at your ecu that Ron pointed out earlier.

I've got your scan reading of your oxygen sensor:- Yours is blue and I've overlaid mine in black with the sensor connected for you to compare:-



Ron wanted to see if your ecu provides a voltage with the oxygen sensor disconnected and you can see that your blue voltage stays steady at ~450mV as Ron predicted. My black sensor varies, correctly I think, with the O2 sensor connected...

I haven't a disconnected scan of my own to compare yours to but I suspect it would be exactly the same as yours.

You have the ecu voltage that Ron pointed out so my first thoughts are - if not another faulty O2 sensor itself that you said you'd substituted - then one of the 3 leads isn't 'healthy'. This is what Ron said earlier?... I think the black is an earth and this might be the one I'd check first (vaguely...)

Interested to see what others say...

ps here's a close up of your disconnected O2 sensor voltage details in case you didn't see this option:-



pps I've got a vague feeling that your very black spark plug might be a different issue...

[Xavier T]

Thanks Chrism

I don' t know which ElanScan version you have but mine has "CO potentiometer/Oxygen sensor" instead of "Oxygen sensor Volt" (on the photo on the left under "MAT"

[chrism]

This is my version. And yes I can see the problem from your screenshot.
I'm wondering if/how I can send a link to you?
I've sent you my version of the EScan_beta zip file by email (I think )