4G92 low idle RPM after changing alternator

jebatdex

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jebatdex

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Guys

I just had my alternator replaced. After that, I see my idle rpm is very low, around 500 (before this ok, around 1k). During alternator installation, I see the mechanic remove both terminals of the battery too.

Is it because of the ECU being reset? How to get it to normal idle rpm? Should I go to workshop, spend RM50 for them to properly set my ECU back (using that device which they plugged in it under the dashboard, I duno the name :confused:)? Appreciate all inputs. Thanks.
 

vr2turbo

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vr2turbo

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Guys

I just had my alternator replaced. After that, I see my idle rpm is very low, around 500 (before this ok, around 1k). During alternator installation, I see the mechanic remove both terminals of the battery too.

Is it because of the ECU being reset? How to get it to normal idle rpm? Should I go to workshop, spend RM50 for them to properly set my ECU back (using that device which they plugged in it under the dashboard, I duno the name :confused:)? Appreciate all inputs. Thanks.
As far as I know that is only for diagnostic when engine check lights comes on, and not for tuning.
4G92 I think can tune idling if same as my 4G63. Just turn the screw on throttle body....
 

john_unai

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john_unai

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i thought OBD can adjust rpm, they just adjust the rpm reading on the the OBD..:questionmark::questionmark::questionmark:
 

jebatdex

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jebatdex

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I think, i will clean the TB and see how. Is rpm still low, will adjust the screw on the TB a bit. Never touches that because before this, idle rpm is good. After remove the battery, ECU reset, than idle rpm drops.

Another question, on the TB, there is 3 vacuum hoses marked P E A. On mine, only P & E is connection, but A got nothing (no hoses connected to it). Is that normal?
 

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vr2turbo

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I think, i will clean the TB and see how. Is rpm still low, will adjust the screw on the TB a bit. Never touches that because before this, idle rpm is good. After remove the battery, ECU reset, than idle rpm drops.

Another question, on the TB, there is 3 vacuum hoses marked P E A. On mine, only P & E is connection, but A got nothing (no hoses connected to it). Is that normal?
I remember mine two are used and the one not used is plugged up with a cap
 

m a v [3] r i c k

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m a v [3] r i c k

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Try driving your car around for 1 week or so and then see if it gets better. I don't know what is going on at the ECU but based on my personal experience, after a battery disconnection (change), my car will consume more petrol for the first tank and gets better eventually. Engine idling too will be affected.

I would say you should just drive your car as how you used to for a week or so before you waste any unnecessary money.
 

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vr2turbo

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Means let the ecu learn back....:driver:

If that is the case, in future for any battery change, link a good battery on when removing old dead battery.....
 

jebatdex

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jebatdex

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m a v [3] r i c k;1064666228 said:
Try driving your car around for 1 week or so and then see if it gets better. I don't know what is going on at the ECU but based on my personal experience, after a battery disconnection (change), my car will consume more petrol for the first tank and gets better eventually. Engine idling too will be affected.

I would say you should just drive your car as how you used to for a week or so before you waste any unnecessary money.
OK then... will do. Thanks :burnout:
 

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jebatdex - your issue settled?
 

jebatdex

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I cleaned the tb (as much as I can becoz I didnt take out the tb, just remove the plastic hose from the air intake), and I adjust the screw on the tb a bit, rotate counter clockwise about 100deg. Now, idle is fine. I dont know whether this will make my fc worse or not, since this is regard as manual setting, not computerized. Hopefully the fc is not much affected. I usually get 11cents/km for highway, and 14cents/km for urban driving, with current RM1.70/l fuel price. Lets see during this raya, will travel from Johor to Perak :burnout:
 

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I cleaned the tb (as much as I can becoz I didnt take out the tb, just remove the plastic hose from the air intake), and I adjust the screw on the tb a bit, rotate counter clockwise about 100deg. Now, idle is fine. I dont know whether this will make my fc worse or not, since this is regard as manual setting, not computerized. Hopefully the fc is not much affected. I usually get 11cents/km for highway, and 14cents/km for urban driving, with current RM1.70/l fuel price. Lets see during this raya, will travel from Johor to Perak :burnout:
Should not affect your fc unless you tune idling very high and you idle most of the time in traffic....lol:biggrin:
 

Shinjite

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Shinjite

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OK then.. so I shouldn't be worried much. :proud: thanks
As long as your idling is all A-OK even with the air-conditioning turned on. Everything will be fine. Before going on a long trip back for Raya, do a regular service check up to make sure everything runs as intended :biggrin:
 

vr2turbo

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As long as your idling is all A-OK even with the air-conditioning turned on. Everything will be fine. Before going on a long trip back for Raya, do a regular service check up to make sure everything runs as intended :biggrin:
Mine the FICD a bit KO already, so without air con now higher a bit, then air con cut is just nice.....lol:biggrin: