How Rpm Change With Engine Heat?

[sampathapg]

How RPM change with Engine heat? (Petrol)

[Rumesh88]

Various methods - beginning with mechanical, electrical and then electronic - have been devised to enrich the fuel mixture at cold start. Vintage cars had a manual choke which was later replaced by an auto-choke usually operated by a bi-metallic strip. The method currently in use on almost all EFI engines is monitoring of the coolant temperature (using a negative temperature coefficient thermister) and use an electro-mechanical device (IACV) to adjust the amount of air at cold start. The idle speed can be something is the region of 1,500 RPM at cold start which is reduced to the region of 800 RPM as the engine warms up (exact values depend on the model). Also ECU ensures that the mixture is kept enriched slightly until the working temperature is reached as you drive immediately after a cold start.

[IceBurg]

Hi Guys,
Im new to Autolanka forum post but im reading lots of posts from you guys and gain good knowledge out of it.
Recently i got a problem on my Allion 240 - (2006).Cold start RPM goes upto 2000+ and once engine comes to working tempreture it goes down to normal 800. sometimes morning start check engine light also on. scanner says TPS sensor fault. but does this relly mean to replace the TPS sensor or is it something EFI related Issue.i clean throttle body recently but im not sure that how far its sucess.

1. can it be a problem with (IACV) as Rumesh mention in above post

2. How to find TPS sensor is fault.
2. what is wheel speed sensor and what it actually does. can it be causing problem.

Rumesh i red lots of posts that you have posted related to this and learn lot.please advise me on this. or is there any good macahnic for these type of issues.if so please send me the Number.

Thanks In Advance

Edited December 3, 2014 by IceBurg

[Rumesh88]

Hi Guys,

Im new to Autolanka forum post but im reading lots of posts from you guys and gain good knowledge out of it.

Recently i got a problem on my Allion 240 - (2006).Cold start RPM goes upto 2000+ and once engine comes to working tempreture it goes down to normal 800. sometimes morning start check engine light also on. scanner says TPS sensor fault. but does this relly mean to replace the TPS sensor or is it something EFI related Issue.i clean throttle body recently but im not sure that how far its sucess.

1. can it be a problem with (IACV) as Rumesh mention in above post

2. How to find TPS sensor is fault.

2. what is wheel speed sensor and what it actually does. can it be causing problem.

Rumesh i red lots of posts that you have posted related to this and learn lot.please advise me on this. or is there any good macahnic for these type of issues.if so please send me the Number.

Thanks In Advance

Your TPS is the easiest sensor that can be tested. It is simply a variable resistor either with a home position contact (four terminal TPS) or a one without the contact (three terminal TPS). All one need is an "analog" multi-meter to test the smooth variation of resistance value over its entire movement range. Usually it gets worn out close to the idle position. If it is four terminal one the idle position contact should also be tested. (Last time I was searching for a TPS of a Vitz, it was not available with the agents but got it down from amayama.com in 10 days for less than Rs. 4,500.00 in fact thanks to our buddies on AL who prompted me. Of course it was not taxed). Did anyone try to adjust your idle speed by turning the Throttle position screw (It usually comes factory adjusted with a yellow color paint mark on the screw. Check if it is disturbed)? In your case I wouldn't suspect IACV before getting the TPS tested.

Wheel sensors can be easily located by tracing the wires connected to the hub of each wheel. You can see them on the front wheels when you turn then either way. Front wheel sensors can be removed and cleaned easily but not the rear ones in your model AFAIK (they come sealed with the hub and does not require cleaning). Usually it is the front ones that collect dirt easily and may require cleaning once in a couple of years. I can recommend someone in Moratuwa area if it is OK with you. Pls PM me.

[IceBurg]

@Rumesh i Contacted the Guy in moratuwa and he told me to replace the TPS as the same error code occured in several times and do a full engine tune up.seems to be he has good knowledge in that area and very cool guy. T**L** price for the TPS is too high so i orderd it through amayama.com and it cost me nearly 5300/=. still its on its way. Thanks for that direction.

As im running out of time to get the Revenue licence, recently i did Eco test and it was failed. so i'm loking for a quick Engine Tune up.

1. what is the best way of doing engine tune up and what are the parts i should replce with tune up (Ex : Injector oring, Filters that comes with injectors)

2. Is it ok to do the engine tune up with current TPS as it has no adjustments and replce the new one later.

Thanks for Every AL experties for keeping this forum upto date and its really helpfull us to get the work done in a proper way with good machanics rather going in to Makabass.

[Rumesh88]

Did your ECO test fail at idle speed or at 2500 RPM? If it fails at idle speed I'm afraid you would have to wait for the TPS to come. You may have to pay a small surcharge when your renewal is delayed. Meanwhile you would have to manage your driving for a few days somehow. How bad is your ECO test result anyway?

Edited December 16, 2014 by Rumesh88

[IceBurg]

Both the ways it failed.

See the results below,

HC Co Lambda O2 Co2

Idle 0 7.85 0.96 4.46 10.1

2500Rpm 44 6.59 0.96 3.68 11.4

Edited December 16, 2014 by IceBurg

[Rumesh88]

Both the ways it failed.

See the results below,

HC Co Lambda O2 Co2

Idle 0 7.85 0.96 4.46 10.1

2500Rpm 44 6.59 0.96 3.68 11.4

Considering the above readings I wouldn't advise you to go for a partial tune up before replacing the TPS which was already found faulty. Clean up of the throttle body, MAF sensor, IACV, PCV, and replacement of plugs, air cleaner, etc., may solve your ECO reading problem but if the issue goes beyond these simple things ie if the likes of injectors, MAF and/or O2 sensor need replacement then you must have the proper TPS in place first.

[IceBurg]

@Rumesh

Recently I have replaced my TPS sensor and did the full engine tune up and after that i didn't get the check engine light issue. Fuel efficiency is also increased after the repair.but morning start it still RPM goes upto 2000 and quickly its comes back to 1800 stable the RPM no shakes like earlier and after engine comes to working temp it goes down to 750. so feels like its normal.

Finally Sorry for the late reply. Thanks for your valuable feedback s and really appreciate you guys expert comments and keep up the good work.

Thanks