rpm bounce cause?

**ralph13** · May 20th, 2017 09:56 AM

rpm bounce cause? anu anu po kaya mga dapat i check dito.

lancer gti 1992 EFI

12v engine.

problem encountered: from cold start mababa masyado rpm nya pero habang tumatagal tumataas. but after nya ma reach ung stable idle bigla nlng siya ng up and down na idle. mas malakas ang rpm bounce pag ng headlight. kelangan pa adjust idle to 1k rpm para maging medyo stable. but 1k is too high for idle..

note: nka bypass na servo

salamat po

**lowslowbenz** · May 22nd, 2017 08:12 PM

12V engine? Ano yan?

Bypass ang servo? Why?

If its fluctuating idle, then there is something wrong in your idling circuit. Have your throttle body checked.

**rodetor** · May 22nd, 2017 08:29 PM

The 12V stands for 12 Valves, in a Mitsubishi engine for that model. 3 valves per piston cylinder, in a 4 in line cylinder engine.

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**lowslowbenz** · May 22nd, 2017 08:33 PM

Originally Posted by rodetor

The 12V stands for 12 Valves, in a Mitsubishi engine for that model. 3 valves per piston cylinder, in a 4 in line cylinder engine.

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Ah ok. thank you for enlightening me sir.

**rodetor** · May 22nd, 2017 10:31 PM

Originally Posted by ralph13

rpm bounce cause? anu anu po kaya mga dapat i check dito.

lancer gti 1992 EFI

12v engine.

problem encountered: from cold start mababa masyado rpm nya pero habang tumatagal tumataas. but after nya ma reach ung stable idle bigla nlng siya ng up and down na idle. mas malakas ang rpm bounce pag ng headlight. kelangan pa adjust idle to 1k rpm para maging medyo stable. but 1k is too high for idle..

note: nka bypass na servo

salamat po

Alisin mo yun pagkaka bypass, o ayusin mo yun servo. Mataas sa una, nasa range of 1300 ~ 1500 RPM mula sa cold start during idle. Habang tumatagal sa idle na warm up, saka lang bumababa ang RPM, malapit sa normal, stable idle na 800rpm. Mahihirapan yan ECU( computer box ) sa normal control and monitor, sa engine operation. Baka ma-damage pa yan ECU, at lagi kang may check engine light.
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**rodetor** · May 22nd, 2017 11:55 PM

Originally Posted by lowslowbenz

Ah ok. thank you for enlightening me sir.

[emoji106] walang anuman.

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**ralph13** · May 23rd, 2017 05:17 PM

Originally Posted by rodetor

Alisin mo yun pagkaka bypass, o ayusin mo yun servo. Mataas sa una, nasa range of 1300 ~ 1500 RPM mula sa cold start during idle. Habang tumatagal sa idle na warm up, saka lang bumababa ang RPM, malapit sa normal, stable idle na 800rpm. Mahihirapan yan ECU( computer box ) sa normal control and monitor, sa engine operation. Baka ma-damage pa yan ECU, at lagi kang may check engine light.
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actually sir sira na kasi servo ko and ung servo ko is very rare. kaya wala na dito masyado sa pinas nun. hndi ko ma gets kasi kng sa ignition ba or sa electrical na kasi tuwing gagamit ako ng headlight dun mas lumalakas ung rpm bounce nya

**barako ba ma** · May 23rd, 2017 05:58 PM

Your car has aged graciously. The pcm runs the engine in open loop when the engine has not reached normal operating temperature, meaning, it runs at preset parameters and will only make smart adjustments when it has warmed up. Have your TPS scoped for errors in signal. When the TPS and the MAP or MAF signals don't match longer than two seconds, the engine hunts or the idle speed is unstable because the PCM is confused whether to follow the TPS or follow the MAP/MAF. If the TPS is adjustable, it might be out of range or has glitches on the signal band. This is true with the '90's TPS

**rodetor** · May 23rd, 2017 06:59 PM

Originally Posted by barako ba ma

Your car has aged graciously. The pcm runs the engine in open loop when the engine has not reached normal operating temperature, meaning, it runs at preset parameters and will only make smart adjustments when it has warmed up. Have your TPS scoped for errors in signal. When the TPS and the MAP or MAF signals don't match longer than two seconds, the engine hunts or the idle speed is unstable because the PCM is confused whether to follow the TPS or follow the MAP/MAF. If the TPS is adjustable, it might be out of range or has glitches on the signal band. This is true with the '90's TPS

True, logically that is how the PCM works. He needs to calibrate its TPS, kung wala sa calibrated range in WCT (wide close throttle ). Palagi mag aadjust ang PCM ng idling speed.

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**barako ba ma** · May 24th, 2017 01:29 PM

He needs to calibrate its TPS, kung wala sa calibrated range in WCT (wide close throttle

?????

Are you referring to ranging the TPS from closed throttle (0.5 v) to wide open (4.5 v)?