Chevrolet Enjoy Petrol Engine Idle Issue

[karthik_r]

Hi folks, I have a Petrol Chevy Enjoy and off late facing an issue with the engine idle speed.

On cold start the engine idle rises all by itself upto 4-5k revs when parked (ie no load). Also the engine revs increase in between gear changes but does settle very late to what one would consider normal.

All of this disappears when the engine is in operating temps.

Has anyone seen such an issue with their rides ? I am thinking MAF or the IAV, but any pointers are welcome

Cheers!
Karthik R

 

[VISHNUCARCRAZY]

Thermostat can also be faulty . ( Which regulates the engine temperature )

 

[bhvm]

Check these-
MAF sensor Near Air filter. Most likely the culprit.
EGR valve might be stuck open (If Your petrol has one, But unlikely)
O2 sensor Near cat cons
Check wiring going to injectors, This might be bit by rats.
If it has Idling valve, check that also.

Thermotstat is unlikely, as it comes into play later in the game and not just at crank. And faulty thermostat if Stuck closed will cause overheating but no RPM issue.

 

[VISHNUCARCRAZY]

Just clarifying BHVM sir , what if thermostat has an issue and it misjudges for preheating the ride ?

 

[bhvm]

Just clarifying BHVM sir , what if thermostat has an issue and it misjudges for preheating the ride ?

There are 2 scenarios-

1 Thermostat Stuck closed-
The engine will quickly overheat and if ignored, Will seize and permanently ruin it. One has to have a quick eye on the Temp gauge if disaster is to be averted. On Modern ECU controlled engine, Often the ECU will throw the car into LIMP mode to prevent damage as much as possible.

2. Thermostat Stuck open-
The car will take long to heat to its normal temperature and will run poorly until It does so. FE also takes a hit. Sometimes RPM variations (Small ones) and white smoke can be seen. But generally in warm weather like India, Cars with stuck open thermo can be driven around quite a lot before you face any problems. Generally, Thermos are desiged to fail in an Open position in most of the cases.