RPM shoots up...

[gkrishn]

So i have this sail 1.6 for 4 months now. Done 4k+ kms.

For past 1 month or so i am seeing this strange behaviour. During the early morning (i leave for office around 7.45 or so...) start, the engine revs up, and the tacho shoots upto 2k. It then settles down at aroung 1200, and then when engaged in gear it goes down to 1000. All this at idle.

Never behaved like this before. Took it sundaram. The guy there said its mpfi engine saar, all mpfi engine behave like this saar, this is common saar, like that. Furhter pushing, he told that, since the engine check light was not on, there is no problem with the engine. Also that fellow brought that ECM reading kit, attached it to the car, and showed all the display. (BTW some time back the engine check light was on for me for a breif period of time, 30 mins or so). The kit showed no error code.

These guys dosnt seem to accept problem unless it shows up on that kit. What u guys think? Is this normal? Tommorow going down to bandipur. Hopefully nothing shows up on the way.

[sridhar24]

Yup its very common with MPFI engines, since it doesn't has a choke it automatically keeps the revs high and then comes down after the engine gets heated. I guess it so because I have observed the same thing in the MPFI engines in maruti cars.

[Firestarter]

Yup no problem this is how the MPFI engines behave when they r cold.

[Domnic]

Hi,
True its common. The computer takes readings from the water temperature sensor, when it reads cold, the ecm automatically goes into a rich state. So the car will warm up faster and attain the nominal operating temperature. Once the car reaches the preset temp the computer will return from the loop.

Cheers
Dom

[gkrishk]

I had a related problem on my 1.6 Siena. One day after it was parked at a store by a parking attendant it started revving up intermittently (even when warm) without my touching the accelerator pedal. I thought the ECU had 'learnt' the higher revs because the attendant might have revved it up more than I normally did. However the throttle body sensor was faulty and had to be replaced.

[SLK]

ya.. happens.. even with the 800.
but the wagon R and alto revv up more than the 800.

And wagonR and Alto seem to have a strange thing. Engine revvs up... and u start driving while its still revving... and u have driven some.. 20kms...
And you let the car idle and see the rpm..... lol.. 1500+

The only situation these cars revv down is when all of the following happen along side. (then it revvs down in about in 6-7 secs)
1) The car is stationary
2) There is no load on the engine (i.e. no a/c)
3) Engine has heated up properly.

So if any one of these is not met.. the cars don't revv down.
I have seen this in .. other people's cars also. No one notices. (just seen with maruti though).

Remember some people say Palio specially 1.6 are so free to roll that they can travel kilometers in 5th gear without much on an engine braking.
My guess is... its not the engine braking which is low..... its that the car was never given time to idle properly before shooting.
This happens in the WagonR and Alto at least if they are not allowed to idle.

What say?

[drifter]

Its normal dude,

used to happen on my petrol indica as well in the mornings...everything went back to normal once the engine heated up.

Drifter

[gkrishn]

Thanks for that guys.

So what the service center guy said was correct. Due to usual mindset, never tend to believe what they say.

Now it looks like I was too sarcastic about his “saar”. My apologies to that fellow.

[X-Machine]

Originally Posted by [b

Quote[/b] (gkrishn @ Nov. 12 2004,20:36)]Now it looks like I was too sarcastic about his “saar”. My apologies to that fellow.

Just go back to him tomm and tell him 'aiyyo saar,imma sorray ji'.

X

[drifter]

Originally Posted by [b

Quote[/b] (X-Machine @ Nov. 13 2004,02:03)]Just go back to him tomm and tell him 'aiyyo saar,imma sorray ji'.

X

hehehe

Drifter

[turbo_c]

Originally Posted by SLK

ya.. happens.. even with the 800.

And wagonR and Alto seem to have a strange thing. Engine revvs up... and u start driving while its still revving... and u have driven some.. 20kms...
And you let the car idle and see the rpm..... lol.. 1500+

The only situation these cars revv down is when all of the following happen along side. (then it revvs down in about in 6-7 secs)
1) The car is stationary
2) There is no load on the engine (i.e. no a/c)
3) Engine has heated up properly.

So if any one of these is not met.. the cars don't revv down.
I have seen this in .. other people's cars also. No one notices. (just seen with maruti though).

What say?

You are right on the money SLK ! My Esteem does this too !

In an emergency situation where u need to start off on a cold Maruti MPFI engine, "rebooting" the system (switch off the car completely for a second and then restart) makes the ECU behave in a sane manner again.

What surprises me is that although MPFI Marutis are pretty common, many people (including other MPFI Maruti owners) laugh and crack jokes on me letting my car warm up for a couple of minutes! My dad & bro call it "pre-flight checks" and announce "Control tower, we are ready for take off!" after the warm up is complete and I get into gear !

I let the temp get upto the "C" mark on the temp guage before starting off, by then RPMs have settled down just under 1000. When the engine reaches operating temp. (middle of the temp guage) it settles down to about 500 RPM.

[v1p3r]

Originally Posted by turbo_c

many people (including other MPFI Maruti owners) laugh and crack jokes on me letting my car warm up for a couple of minutes!

That, my brother, is the difference between "us" and "them"!