Team-BHP - Strange Behavior of my ALTO, Expert's Advice needed

Quote:

Originally Posted by humyum (Post 1014585)

Bhaiyo,If something was truely wrong with your car, it would never function perfectly with awesome pickup even once and go back to sluggishness the 2nd time,It would be sluggish all the time.

ya thats what i feel. if there is some problem then car will never be fast at any times. to update on the same yes eve it was slow , but now while coming to the office it was zooming crazy.

Quote:

Originally Posted by amit_mechengg (Post 1014520)

Is this the same for BS II models , mine is BS II. does the EGR need general cleaning/ servicing ?

Let me make this simple for you:

If your car is a BS II then the following malfunctioning can affect performance

1. Fuel pressure delivery

2. Manifold pressure sensor

3. Oxygen sensor

4. Temperature sensor

If your car is BS III apart from the above you further have the EGR to worry about.

You really do need to take the car to an authorised service centre where they can electronically diagnose which of the above are failing, albeit intermittently, and correct the same. The ECU is like a brain that runs off all these devices' current outputs. Any erroneous output will cause the ECU to compensate to the detriment of engine power

Quote:

Originally Posted by DKG (Post 1014613)

Thanks a lot moderators, now the experts peep in.
Well DGK sir, good that you are assisting. are u trying to say that some/one of the above components are giving error codes?

does this make the car behave funny, i mean move fast at times and then sluggish on the next day?

well one more strange thing i observed yesterday evening was that i drove in continuous city stop and go traffic for a while with AC on.
Suddenly the RPM started fluctuating over a wide range, the rpm shooted very high for 3-4 seconds and the next 3-4 sec it went normal again next 3-4 second it reached the peaks. this was with AC on.
the compressor was kicking in and out in a cyclic patters like a AC current wave.
the sound was like " Vrooom (3-4 sec)......blank (2-3 sec)...Vrooom (3-4 sec)....blank" this was continuously happening till i switched off the AC.

Then later on i parked my car and again drove after 2-3 hours and then it was completely back to normal. the ac compressor kicked in for long minutes then after attaining temperatures it again went off for long minutes.

Quote:

Originally Posted by Technocrat (Post 1014644)

Amit was it just the sound that was increasing or you had RPM climbing which would mean you would have had to press clutch to control the car?

in neutral too the RPM was increasing and decreasing over the wide range. the AC compressor was clipping for every few seconds. i was driving in LAXMI road traffic. the engine temp was normal. i even opened the bonnet and checked the engine was reeving wild and the rpm was increasing and decreasing in a cyclic pattern :deadhorse

Quote:

Originally Posted by amit_mechengg (Post 1014637)

does this make the car behave funny, i mean move fast at times and then sluggish on the next day?

Most certainly. The ECU fiddles the fuel/air mixture, advances/retards timing, works the EGR (in case of BSIII) all in an effort to minimise emissions. If any of the sensors/devices we mentioned start to malfunction, albeit intermittently, the resultant mix of settings used by the ECU are compromised and leads to less than optimal engine performance. There's no reason for you to worry. Its a systematic diagnosis which will spot the culprit. You do need a diagnostic tool to evaluate the feeds to the ECU, hence my recommendation you go to a fullfledged Maruti workshop.

Quote:

Originally Posted by DKG (Post 1014661)

the problem is when i take my car to the service centre she behaves normally so the guys there dont understand what i want to show them.
i will ask them to clip on the computer and check it.

Quote:

Originally Posted by Technocrat (Post 1014671)

This is certainly weird, must be very difficult to drive in such condition.

You havent shown it to My car yet ?

ya i have to do the clutch brake combination . i need to ask MY CAR guys to diagnosis it with the help of a computer.

Quote:

Originally Posted by DKG (Post 1014703)

They can hook a laptop and you guys can go for a drive to see different conditions and the ECU readings

Thanks a lot sir, i will right away go to them. i have spoken with the service advisor. i hope he has a laptop. the only thing i have seen with them is the TECH2 and they check the readings only in idling condition.

VOILA!!clap:

as said i hurried up to the maruti service centre SAI SERVICE in pune and caught hold of an engine expert. they dont have any laptops and they said MUL doesnt provide any. they have TECH1 and TECH2 which does all the detail analysis.

connected it to the tech2 and started the engine, the MAP SENSOR ERROR popped up. cleared the error. he said he reset it. then again started the engine and went for a spin on manual mode of the tech2. everthing seemed to be okay. the IAC was 50-69% and many more records were there which i dont remember.

then again went to the DTC screen and checked. there was no DTC found.

Reason behind this : All this happened due to pressure cleaning in the engine compartment. all my fault, i asked him to clean neatly:Frustrati
Rust/Water/moisture forms on some of the sensor components and it malfunctions for a while and it throws a error code and then it gets captured in ECU. it doesnt go off untill and unless its cleared or reset by tech2. even if the sensors work properly the feedback loop of the AIR INTAKE SENSOR and the MAP SENSOR doesnt work properly.

Now my car has sprung back into the action. its revving smoothly and quickly in the 3rd gear everything has become normal now.

i have learnt a good lesson now.

* one think i dint get. after all this blunder why doesnt the engine check light glow? whats the use if one doesnt come to know that his ecu is having errors? its people like me who critically hear the engine for every km i drive. what about people who just drive the car as it is ? there should be some system to alert.

Thanks a lot to all the people who have helped me in agony, also special thanks to DKG sircheers: