Mechanics

ENGINE RPM DROPS-COLD IDLE

2006 Daewoo Matiz • Manual • 68,000 miles

Hello!
I own a 2006 daewoo matiz, euro III, 68.000 km.
I have an issue with this car wich so far I was not able to fix my self or at service.
The problem starts at the first engine start of the after a long parking(minimum 8 hours). The engine starts fine, but after a few seconds it starts to choke, drops rpm(even stops sometimes).
NO error codes are stored in PCM memory, wich makes this very tricky fix.
So far I've tried:
-replacing spark plugs and wires
-replacing PCV valve
-cleaned IAC valve(with Idle Lear procedure)
-cleaned EEGR valve from deposits
-cleaned oxigen sensor from deposits
-tested TPS voltage
-tested car with Daewoo Tools Scan 100(nothing is wrong for the PCM)
and that's were I runed out of ideas here, so if you have any advice on this matter I woul appreciate it. Have a good day!
Avatar
Lucianskyes
August 23, 2011.



Start by checking the fuel pressure if its within specs

Rasmataz
Aug 23, 2011.
Thanks for the answer and sorry for the delay in answering. I have tested my car with a new fuel pump, and nothing. Same problem. I also have replaced IAC unit with new one and added BG44K in the fuel tank, and no fix. Again back to the drawing board. Could this be alternator or battery related?

Tiny
Lucianskyes
Sep 1, 2011.
http://www.2carpros.com/articles/engine-hesitates

Could be caused by one of the following below

Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Crankshaft position sensor
Knock sensor
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note:If it doesn't apply disregard it and keep testing.

Rasmataz
Sep 2, 2011.