[amit_mechengg]

Originally Posted by ASHISHPALLOD

Good to know that your car is back to normal.
Can any one clarify that ecu resetting suggested by DADU can solve such problems?

yes ECU resetting helps when u change or do some performance mods. but ecu resetting in that way wont help you to erase the error code.

i have done ECU resetting on several occasions after swapping between the OE air filter and the K&N filter.

Can someone explain the functioning of the map sensor.

[DKG]

Originally Posted by amit_mechengg

Can someone explain the functioning of the map sensor.

MAP stands for manifold absolute pressure, or commonly referred to as pressure sensor as pointed out earlier in the list of sensors to check. The ECU varies the air/fuel mixture ratios to obtain optimum fuel economy/performance depending on the driving conditions. The Air Intake sensor should be measuring the temperature.

Glad to hear the problem was sorted out. BTW the engine malfunction light should lightup when certain sensors are malfunctioning. Have that tested the next time you visit so you get a clear warning, should a problem arise in the future.

[amit_mechengg]

yes the problem is sorted out completely and i am feeling as if fresh new horses are added under my hood.
with ac on my car is easily touching 80 kmph on most of the upslopes over the flyovers, whereas yesterday it was struggling even at 60kmph.

the acceleration in 2nd and 3rd gears has become just amazing and i hardly need to shift from 4-3 gears. it effortlessly pulls in 4th gear.

i inquired with them regarding the engine check light. they said that light will glow only if the sensors has some problem. if error code is caught in the ecu then it doesnt. however i think this is a weird answer.

[im_srini]

Hi Amit, congratulations on getting your car sorted out

Originally Posted by amit_mechengg

they have TECH1 and TECH2 which does all the detail analysis.

The list price of the Tech-2 & Suzuki-Diagnostic-Unit is around 3.65 lakhs So not all service centers have them.

Originally Posted by amit_mechengg

connected it to the tech2 and started the engine, the MAP SENSOR ERROR popped up.

Funny, I had a similar issue this weekend in my Alto too. However, in my case the MIL, or Malfunction Indicator Light, lit up indicating a fault.

If the MIL comes on & you don't have a Tech-2 you can still troubleshoot the issue. There's a 6-pin female coupler inside the fuse & relay box in your engine-bay - this is called the monitor coupler. One of the 6 terminals in the coupler is called the diagnostics-switch-terminal & this needs to be grounded (you can do this with any normal wire).

I don't have any pics for now, but will upload some after I get my car back from the garage.

On correctly grounding the diagnostics terminal, the MIL will flash the error code - sort of like Morse code ! For example, the MAP sensor error code is 11 - you'll see two flashes, a pause, two flashes again, pause, & so on... Each sensor has it's own code & 12 is normal. In fact this was how the MIL error was diagnosed in my car. Went back home & checked the service manual & found that this was indeed the recommended procedure to troubleshoot MIL faults if you don't have access to a Tech-2.

Originally Posted by amit_mechengg

* 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.

The service manual mentions that not all electronic systems are capable of turning on the MIL - one such system is the EPS. In these cases, you have to use a Tech-2 for diagnosis.

I guess your MAP sensor issue was intermittent & the sensor was sending values which were incorrect, but within the range the ECU expects it to be - hence no MIL. Another problem could be your MIL circuit itself - the service manual in fact has a procedure to detect this too !

P.S. - Will post a pic of the monitor coupler & the terminal to ground in a couple of days...

[amit_mechengg]

thanks a lot srini, this is very important information. please do post the pics so that next time i can diagnosis myself.

but anyways maruti people are very eager to sort out such issues and that too without charging a single Rupee. others like honda and tatas wouls have charged atleast 500Rs

[im_srini]

Hi guys,

Here's the monitor coupler, on the car & in the service manual...



Any piece of wire would do for the grounding bit, when it's good, the MIL starts flashing the DTC.



In my case, there was a MAP sensor failure - so the code was 11 (two flashes between pauses). Here are the rest of the codes for the MIL.



Incidentally, you can erase the DTCs stored in the EMS (ECU) if the negative terminal is disconnected for 30 secs or more. A funny thing is that this is valid only if the ambient temperature is more than 0 degrees C, so the advice the manual has if it's freezing outside you ask ? Move to a place that's not 0 degrees C

P.S. - These manuals really impress on you the amount of effort that must go into compiling a document such as this, what with all those illustrations & stuff. And this is just for a small car, I can't imagine the manual for a 747 !?!

[amit_mechengg]

do you mean to say that in the diagram i should ground the terminal named '3' to the body and check the signal on the dashboard.

your post was very informative, thanks a lot for that.

[im_srini]

Originally Posted by amit_mechengg

do you mean to say that in the diagram i should ground the terminal named '3' to the body and check the signal on the dashboard.

Hi Amit, no - you ground it using the ground terminal in the coupler, not the frame. You use a piece of wire & connect said terminals in the coupler.

An illustration of how it's done can be found here.

[amit_mechengg]

I got my car: Alto LX serviced recently in which following works were carried:
1. Valve Tappet setting.
2. Exhaust cleaning: catalytic converter removed.

KMS on ODO : 39500

it happened that after the above work was done my car was washed and the water entered one of the spark plug cables as the cap of the rubber was cut off. due to this my car was facing lot of jerks. then i went back to the service centre and got the water out by blowing pressurized air. then the jerks were gone. later on with idling the RPM started fluctuating. so i got my throttle body cleaned and this was sorted out.

But still now my engine is not smooth as before. the gear vibrates and so does the engine during idling. before the valve tappet setting my engine dint vibrate much.

now the question is whether this is due to valve tappet setting or the exhaust cleaning(catcon removed) or due to some other problem

[Vid6639]

Is it only rough on idle and does it smoothen out when you rev.

If it's only on idle then your idling rpm has been set lower for FE. A 50rpm change will make the car vibrate on idle. Just get the idling set. Also check the timing to ensure it has not been retarted.

[amit_mechengg]

i dont think they have fiddled with idling setting. the engine is very smooth on the revs. its only on idle that it vibrates. i dont remember exactly the rpm reading on the tech2 but i think it was within the limits. the timing is perfect.

can you tell me what is the idle RPM for alto with upper and lower limits?

[humyum]

Originally Posted by vid6639

Is it only rough on idle and does it smoothen out when you rev.

If it's only on idle then your idling rpm has been set lower for FE. A 50rpm change will make the car vibrate on idle. Just get the idling set. Also check the timing to ensure it has not been retarted.

Idling is Ecu controlled..cannot be set or reset in an alto.
Go to the service station and ask them to hook a tech2 and check the idling rpm with and without AC, maybe the area of fault is somewhere else.

[SirAlec]

Now! again its a simlar case of 'Don't fix that ain't broke'

Why do you have to go out and set the tappet in such a low mileage vehicle. That too in a car like Alto which is one of the least maintainance needing car in this Planet.

There is a chance that the Gap on valve and cam-lobe is not appropriate, that changed the timmings. Hook it up with a scanner at any MASS.

[Shan2nu]

I dont think tappet settings can cause such a drastic change. My OHC engine tappets have been set for performance and although they're a bit noisier than before, there is no engine vibration.

But when i got the exhaust pipe cut to just after the center muffler, i could feel a lot of vibration in the chassis (since the end of the exhaust pipe which used to absorb all the vibration had now been removed).

Shan2nu

[Vid6639]

Originally Posted by humyum

Idling is Ecu controlled..cannot be set or reset in an alto.
Go to the service station and ask them to hook a tech2 and check the idling rpm with and without AC, maybe the area of fault is somewhere else.

Nope it can be set manually the same way you would set in an old carb car. You just need to adjust the idling screw. Even my Lancer it's the same way.

If you complain of low FE during serviceall they do is reduce the idling rpm by adjusting the screw.

The ECU manages accordingly.