My idle keeps trying to drop lower and lower when the car is idle. I resetted my ECU because I threw on an exhaust and have a short-ram under the hood. But it persists to do this sometimes. Whatsup with this? Anyone else have this problem? I know that the RPM's jump high when you start the engine in cold weather blah blah, yeah I know that, but check this...When I start up my engine again...at the red light..the RPM's jump really high after I stall...And no, I can drive stick correctly. Please, somebody, help! Hot chicks at stake here at red light!



--- Kei

 

I only have a remote clue what could be happening here, but I would suggest that you start with a more diagnostic approach to the problem so that the technically able members on the forum can help you.

A suggestion would be to post some more specific info:

Did you put on your intake and exhaust at the same time, then reset the ECU? Or did you put on the intake alone first, left exhaust stock and ran with no problems? What procedure did you follow to reset the ECU? When was the last time the car didn't do this declining idle to stall behavior? Does the car do this when hot? cold? all the time? Is the check engine light on?

In other words, break this whole "thing" down into the action and reaction "components." There's a failure point in the chain somewhere.

If you've got the patience, time, and all the original parts, the easiest routine may be to put the car back as stock and let a dealer troubleshoot it.

If that's not an option keep reading................

Did you handle the MAS (mass airflow sensor) in a rough fashion when you installed your intake - they're real sensitive beasts.

If your MIL (check engine light) is already on, unplug the MAS and start the car. Does the car run (roughly) without stalling? Most EFI / ECU controlled vehicles have a limp mode that if the MAS dies, the ECU will set a fixed air/fuel ratio that will let the car run poorly to let you "limp" to the dealer. If the car doesn't stall, the MAS is most likely the culprit.

If it still stalls keep reading ..........

Another unlikely possibility...were any vacuum lines / hoses disturbed when the intake was installed..excess vacuum can cause a lower than normal idle.

Sorry that I cannot provide more conclusive help, I'm sure some other forum members will chime in here.

 

That was helpful info diesel, but I am still have a similar problem. When it rains or it's humid out, my Lancer likes to try to idle around 500rpms, almost stalling out. This started after I installed my RMR intake. I checked everything and all the vacuum lines look fine. Also I don't remember handling the MAS roughly. I made sure not to do that.

 

So the car sometimes idles ok, meaning that there are days when the car runs without a problem? Does the check engine / MIL lamp ever come on / has been on?

What needed to be unplugged underhood for the RMR intake installation? Was it only the MAS? Or did other connectors need to be unplugged? If you've got an issue on only a wet or humid day, it comes across to me that there is moisture getting into somewhere - like an electrical connector.

If you've rechecked all these things already, you may want to consider taking the car into either Autozone, the dealer, or anywhere you know there is a competent mechanic with an OBDII tool to plug in and check for fault codes in the ECU.

I think Autozone will pull DTC codes for free or a very low fee. I can't guarantee this will give results, but I think you've got to eliminate this angle.

I take it the idea of putting the stock intake back in and letting the dealer diagnose is not an option?

 

Damn diesel you are good. The only thing I had to disconnect for the RMR install was the MAS and the negitive battery terminal. I might take my car to Mitsu and let them check it. As for reinstalling the the original air box, I not going to do it. 2 reasons. 1 The MAS is a pain in the *** to remove from the original box, so there is no way I am reinstalling just to do it all over again. 2 The dealership I go to is the one that sold me the intake. They already know I got it. Thanks again for the help.

 

guys, HKL seems to be running fine, kei is in trouble. My car has dipped down to 5 and sounded like it may die on idle but never once has it stalled, I would actually prefer if it idled closer to 5 all the time. Is that what yours is doing HKL? Kei, Diesel's info is very helpful, troubleshoot the problem a little more in depth and please let us know what you find.

 

Pimpson, mine only idles at 500 when it is raining or really humid, otherwise it idles just fine.

 

HKL, good luck and let us know what you find out, you've got me curious as to what the problem is, esp since I was thinking about buying the RMR intake.

As an OT to this thread - Unless you could actually read what your oil pressure is during a 500rpm idle, you may not want such a low idle rpm. The top end of the engine, especially around the cam / rocker arms / and hydraulic lash adjusters need really good oil pressure for lubrication.

The pressure between these parts tends to force the liquid oil film out from between these parts which means you go from fluid based (hydrodynamic) lubricatrion to boundary layer lubrication from additives in the oil that coat the metal parts. Engines don't last very long on boundary lubrication.......

The engineers specify the stock idle RPM for certain reasons, I'm guessing that this would be one of them.

 

Alright, after I clean my brakes tomorrow... It's Kragen's or Autozone... Which do you think I should goto?

--- Kei

 

Dear guys if somebody can help me about the mas sensor problem if I take my car to a mitsu dealer if this can be fix or adjust back in normal position or I have to buy a new one, my problem was I take out the black box where the filter go and take out the the small cover on the sensor where the fins are so I can make a adapter but I think when I put this cover back a few days later it fell out its place, right now my car is running around 2000 rpm so I ask somebody out there what can I do.
also I take out the plug for the mas sensor the car work perfect but smell very bad,

zilfrith

 

vk - it's probably a toss up (we don't have Kragen's here in the NE) Call both to confirm that they can plug into your OBD-II plug and download any stored codes. If they both can, choose whichever is closer.

 

Zil.

1) The dealer can always fix problems, but they'll charge you if they think you were tinkering with the MAS.

2) Did you take apart the MAS itself? or only the airbox (where the air filter is) ?

3) If the MAS is plugged in does the car run? If it doesn't, then the MAS is probably toast.

4) The stink you smell when the car is running with MAS unplugged is because the ECU sets a limp mode air to fuel mixture, and it's one on the rich side. Since the mixture is rich, there's a lot of unburned fuel going into the catalytic converters, causing the smell.

If you can put things back as they were (stock), you could try to take it to the dealer that way and see if they notice that you had touched the mas and/or airbox.

 

Dear diesel, thank you for the information about the mas sensor, 2. I only take out the black airbox out, 3. the car run good when the mas is plug in and also when I have the airco on but when I turn off the airco it stay around 1200 rpm.
I think I will bring it to a dealer.

any comments if I have to buy a new one could please check one for me in the states how much it will cost me

again thank you very muck

Zilfrith

 

Zil - If the car runs good with the MAS plugged in (as you just replied), then I doubt the MAS is the problem. Take it to the dealer and see what they say. Good luck.

 

Dear guys if you have problem with the mas sensor run the car for 2 days with the plug out and after that plug it back than after that you have run it again for aprox 4 days( pacient ) so the sensor can adjust it self in normal position it happend to me and it works now the car is running good so now you can try it too, so when you work the mas sensor you have to be very carefuly with it

also I like ask somebody out there how I can time the car I know I need a timelight so after what I have to do, my car is lancer glxi 2000 1600 cc automatic transmition

Zilfrith