[shuvc]

Phew ! This is almost greek to me, though I'm trying hard to understand.

To respond to some queries:
# PUC readings are taken at idle (car idles around 700-800rpm IIRC) after a few kms of driving on both occasions, at the same shop.
# It's a EURO III car
# Flood happened end Sep 07. Received car from workshop in early Nov 07 after repairs and service.
# Complained of FE in Dec. Spark plug gaps were adjusted (not much improvement)
# Completed 30K service on 3rd March 08 (this week). Complained of FE again and also mentioned the PUC numbers. Maruti ran an 'engine-scan'. Did not find anything of note. Finally changed plugs from cheap OEM Champions to a bit more expensive OEM NGKs.
# I have a feeling that the FE drop is greater when revving hard or using the AC. Don't have data yet to support this perception.
# Just checked with Maruti. O2 sensor costs around 5K :(

This was the level of water. Car was not driven. It got water logged in the garage.

Originally Posted by 1100D

The confusion is that, all this suggest a rich running car, reinforced by his car giving lower FE, EXCEPT the fact that, the O2 content is also high, which contradicts the Rich running theory.

# Does a faulty O2 sensor support the increase in O2 numbers in the PUC check?
# Is there anyway to confirm whether the O2 sensor is faulty, before taking a decision of replacing it?

[shuvc]

Since the plugs were changed this week, I went and got a new set of readings today (another PUC certificate for 100 bucks from the same shop). New readings in bold.

July 07, Dec 07, Mar 08

CO - 0.004, 0.019, 0.053 (% vol)

HC - 1, 15, 1 (ppm)

CO2 - 11.15, 4.93, 11.49 (% vol)

O2 - 0.75, 11.63, 2.91 (% vol)

Lambda - 1.047, 2.648, 1.175

PEF - 0.542, 0.542, 0.542

AFR - 15, 38, 17

The CO has increased further, whereas the other numbers are somewhat similar to the July 07 data.

[1100D]

The 02 reading is still high.

Ask the Maruti Service center, if they can test the O2 sensor (employing the use of a multimeter).

this might be your answer.

Originally Posted by ananthkamath

And the open-loop lookup tables ALWAYS, ALWAYS, no matter what, cause the car to run pig-rich in the absence of any way for the ECU to know what's actually happening.

[ananthkamath]

if its a Euro III car I suspect it has two O2 sensors, one before and one after the cat.

Anyway, the car still seems to be running lean from that 1.175 lambda number. see if you can get the o2 sensors checked.

[chetanhanda]

Originally Posted by 1100D

Now I have no doubts that the first check should be O2 sensor

ok ..

Originally Posted by 1100D

Maybe why he does not face any drivability issues is because its always running open loop based on default lookup tables.

1] Im assuming Baleno is Obd2
a] Obd2 gives u the switchover from open to closed loop, Im sure the maruti guys may have noticed this
b] the o2 sensor voltages are easily given in obd2 so u dont even need a multimeter, if its not in spec maruti guys would have caught it
Now if we give the monkeys at the maruti service station the benefit of the doubt that they noticed the point (a) and (b) then the ECu is not in open loop

2] Lets assume lambda is correct
Your lambda is greater than 1 which means its lean.. In open loop lambda will be less than 1 assuming the PUC machine is working properly
so we can rule out open loop issue based on the lambda reading only.

3] Lets asume lambda is incorrect
Now lets assume the the o2 sensor is asking the ECU for excess fuel in the closed loop itself and not the open loop (if and only if we assume the lambda is incorrect) .. what do we have now ?
Very high STFT values.. they will max out and push the LTFT to higher values, at a certain point they will again max out , if ur LTFT maxes out u get a MIL after some run cycles..
question - do u have a MIL ?.. NO so again even if we assume the lambda is incorrect we are not in open loop

4] Can u reset the ECU, drive it for some 100 KM with lots of WOT and some part throttle also.
send me a screenshot of your STFT and LTFT

Im assuming the car is mantained well and everything is within specs as far as the servicing goes as mentioned by shuvc and 1100D..but still we are getting very low FE.

If not the o2 sensor, then we will look at something else..could be 1000 other things also

BTW whats the mileage ... ?

[chetanhanda]

Originally Posted by ananthkamath

if its a Euro III car I suspect it has two O2 sensors, one before and one after the cat.

Anyway, the car still seems to be running lean from that 1.175 lambda number. see if you can get the o2 sensors checked.

yes could be having 2 sensors ...
we can put it on a ramp and see from below if there are any bungs/sockets after the cat etc...

[chetanhanda]

Originally Posted by shuvc

maan Im surprised how the car is working...
that looks pretty messed up..

[shuvc]

@chetan, am getting around 1 to 2 kmpl less. Used to get 11.75 to 12.5ish in the city. Now getting 10.5 to 11.25ish. Both figures with zero AC.
But 120kmph+ highway runs have been worse. Sub 10 with full AC where I used to get 12+. The highway runs were right after taking delivery in Nov.
The car was under 1ft to 2ft water for 5+ days. I'm amazed I got away with only damage to the climate control electronics and clutch.
One thought - based on what 1100D mentioned earlier. The PUC guys just use an analyser hooked to the exhaust. Nothing else. Hence the lambda figure is probably back calculated. Which of the parameters can be read directly by the analyser?

[chetanhanda]

Originally Posted by shuvc

@chetan, am getting around 1 to 2 kmpl less. Used to get 11.75 to 12.5ish in the city. Now getting 10.5 to 11.25ish. Both figures with zero AC.
But 120kmph+ highway runs have been worse. Sub 10 with full AC where I used to get 12+. The highway runs were right after taking delivery in Nov.
The car was under 1ft to 2ft water for 5+ days. I'm amazed I got away with only damage to the climate control electronics and clutch.
One thought - based on what 1100D mentioned earlier. The PUC guys just use an analyser hooked to the exhaust. Nothing else. Hence the lambda figure is probably back calculated. Which of the parameters can be read directly by the analyser?

1 to 2 KMpl less should not be so much of a concern..so before floods around 12 and after floods around 10 approx right.. ?
Lets not worry about lambda for now...maybe the car just needs a proper servicing
Can u list out for us what all has been serviced and u are 100% sure it is Done correctly and when ?

[1100D]

Originally Posted by chetanhanda

1 to 2 KMpl less should not be so much of a concern..so before floods around 12 and after floods around 10 approx right.. ?
Lets not worry about lambda for now...maybe the car just needs a proper servicing
Can u list out for us what all has been serviced and u are 100% sure it is Done correctly and when ?

Thats what the Maruti guys are also saying and we would not like to take it that way.

All external parameters (traffic, driving style, weather) being same, an almost 15-20% drop in FE is an indicator of something wrong with the engine functioning (ultimately pointing towards pre-mature engine wear, which we would not like to beleive at this point as the car is still at its infancy from the miles covered point of view and the fact that it is infact a well trusted engine)

This was his flood repair summary

Flood repair summary
1. ECM was not damaged and hence not replaced
2. All climate control dash electronics were replaced. Otherwise AC was fine.
3. Water did not enter the engine. Engine oil was replaced as a precaution.
4. Clutch was damaged. Whole clutch assembly was replaced.
5. Air filter, Oil filter was replaced
6. Gear oil was changed
7. Coolant changed
8. Spark plugs were changed and when I went with the FE complaint a month later, Maruti workshop cross checked the plug gaps, said they were not ok and altered accordingly. No improvement still.
9. Water in the exhaust was drained. As per Maruti, catcon is fine.

The PUC reading, though within the limits of passing, is an indicator of the engine functioning differently post flood repairs.

[chetanhanda]

Originally Posted by 1100D

Thats what the Maruti guys are also saying and we would not like to take it that way.

All external parameters (traffic, driving style, weather) being same, an almost 15-20% drop in FE is an indicator of something wrong with the engine functioning (ultimately pointing towards pre-mature engine wear, which we would not like to beleive at this point as the car is still at its infancy from the miles covered point of view and the fact that it is infact a well trusted engine)

This was his flood repair summary



The PUC reading, though within the limits of passing, is an indicator of the engine functioning differently post flood repairs.

Ok, lets reconsider again.. can u answer these questions ... ?

1] hows the ignition timing ? is it prefect ?
does Baleno have a distributor or have coil on plug ..?
has this been checked ?
2] whats the total running of the car ? is valve clearance checked or applicable at this stage ? can we get this set as per factory specs to rule this out ?
3] Do u also feel any loss in power ?
4] What abt the brakes etc.. the car was underwater for sometime ..rear drums ..?
5] Can we get the 02 sensor checked ..?
1st check it visually if there is any rust etc how is the connector ? something should get affected as it was underwater ..
After that check whats the voltage output at open and closed loop ?
6] is there a leak in exhaust downsteam the o2 sensor ..causing ur 4 gas reading to show lean AFR ? ..i.e engine is not lean but test equipment is getting confused..

# I'm confused abt ..freakin lean AFR coinciding low gas mileage..
are there any vacum leaks .. ? but then u would have noticed it ... rough idle, stumbling, misfire etc..


# Can u get me screenshots of the STFT and LTFT from a decent obd2 software after resetting ECU and doing some runs.. ?I had asked this question earlier also...

# Also another thing .. can u check what the spark plugs look like now after u replaced them.. plugs will tell me how lean we really are ..
can u upload some photos of all the plugs from all 4 cylinders...? good close up.. etc. I'd really like to see this...

[1100D]

Originally Posted by chetanhanda

1] hows the ignition timing ? is it prefect ?
does Baleno have a distributor or have coil on plug ..?

Its coil on plug as far as I recall


2] whats the total running of the car ? is valve clearance checked or applicable at this stage ? can we get this set as per factory specs to rule this out ?

Possible

3] Do u also feel any loss in power ?

He doesn't!

4] What abt the brakes etc.. the car was underwater for sometime ..rear drums ..?

Will not affect PUC readings

5] Can we get the 02 sensor checked ..?

1st check it visually if there is any rust etc how is the connector ? something should get affected as it was underwater ..
After that check whats the voltage output at open and closed loop ?

Ask MASS people if they know how to check it? For both Open loop and closed loop operation, closed loop happens after the engine is sufficiently warmed up and for testing the rpm should be 2000+

6] is there a leak in exhaust downsteam the o2 sensor ..causing ur 4 gas reading to show lean AFR ? ..i.e engine is not lean but test equipment is getting confused..

# I'm confused abt ..freakin lean AFR coinciding low gas mileage..
are there any vacum leaks .. ? but then u would have noticed it ... rough idle, stumbling, misfire etc..

Ruling out vacuum leaks, he would have noted by engine behaviour. He is quite savvy.


# Can u get me screenshots of the STFT and LTFT from a decent obd2 software after resetting ECU and doing some runs.. ?I had asked this question earlier also...

This is a good idea, but will the MASS folks agree (assuming obviously that they have something basic as a OBD2 or the corresponding diagnostic reader)

# Also another thing .. can u check what the spark plugs look like now after u replaced them.. plugs will tell me how lean we really are ..
can u upload some photos of all the plugs from all 4 cylinders...? good close up.. etc. I'd really like to see this...

Call up your service center and ask the service engineer whether he is aware of how to check the O2 sensor. If he does not appear to be hearing hebrew, ask him about checking for open loop/closed loop operation.

[chetanhanda]

hey shuvc..can u fill in the blanks in 1100D's replies ...

[shuvc]

My service guy is on leave. Will pop the valve clearance and O2 check queries to him next week. Will also ask him abt getting the scan shots, if possible. I suspect it may not be feasible.
Will post snaps of the earlier plugs today. Wondering if the plugs could be the culprit. I've run 100+ kms on the new plugs and going by the fuel needle, it seems things are slightly better. Fingers crossed. Will know when I top up later next week. I always top up till auto cutoff, after the needle hits red - ie with minimum 40 litres (tank is 51).

[1100D]

Originally Posted by shuvc

My service guy is on leave. Will pop the valve clearance and O2 check queries to him next week. Will also ask him abt getting the scan shots, if possible. I suspect it may not be feasible.
Will post snaps of the earlier plugs today. Wondering if the plugs could be the culprit. I've run 100+ kms on the new plugs and going by the fuel needle, it seems things are slightly better. Fingers crossed. Will know when I top up later next week. I always top up till auto cutoff, after the needle hits red - ie with minimum 40 litres (tank is 51).

Off topic, but then, free advice, refuel after reaching about 1/2 tank.