check engine light at idle after throttle body cleaning

**harimon21** · September 8th, 2007 11:54 PM

my ride is lancer 91 efi. i cleaned the throttle body and the throttle valve. but after replacing everything after cleaning, check engine light appears during idle. resetting the ecu does not help either. it seemed na parang tumaas din and idel setting, because the car moves as soon as i released the clutch without stepping on the gas. this has been going on for 2 weeks now. what could be the cause? have i damaged anything during cleaning? any ideas?

**kinyo** · September 9th, 2007 12:15 AM

make sure you returned all sensor connections properly, especially the MAP and MAF sensors

**harimon21** · September 15th, 2007 07:37 PM

thanks for the reply. yung bang sensors e yung nakakabit malapit sa throttle body?

**speedyfix** · September 16th, 2007 10:18 PM

yup, check the sensors muna. malamang dun lang problem... or else baka a vacuum line na mali kabit.

**norrissee** · September 21st, 2007 03:29 AM

Try to have a shop read your CEL code. Chances are this will help you a lot in tracking down what's wrong.

Or check if your car has one of these:

If you have that you can use a DC tester to connect to the OBD output terminal (usually pin 1 sa ECU) and count the "waves" (voltage) it makes. Connect the positive sa tester mo to the pin and ground the ground. Long "waves" is counted as 10s and short "waves" as 1s.

Example: (L - Long, S - Short)
L, L, S, S, S, S = 24

Here are the CEL codes for a OBDI 1991 Mitsu Engine:

11 Heated oxygen sensor.
12 Air Flow Sensor.
13 Intake Air Temperature Sensor.
14 Throttle Position Sensor.
21 Engine Coolant Temperature Sensor.
22 Crankshaft Position Sensor.
23 Camshaft Position Sensor.
24 Vehicle Speed Sensor.
25 Barometric Pressure Sensor.
41 Injector.
42 Fuel Pump.
43 EGR (California only).
44 Ignition coil/Power transistor unit.

This helped me enormously in tracking down the CEL I had with my mitsu. Hope it can help you as well.

**harimon21** · September 22nd, 2007 09:36 AM

thanks norrissee, will check try your instructions this weekend... hope it works

**harimon21** · September 29th, 2007 09:38 AM

i have found this terminal under the steering wheel. is this the obd output terminal we are talking about? Seems a little different from the image posted. Anyway sinubok ko connect dc tester sa upper extreme right at lower extreme left. (tama po ba?). Then turned on the ignition switch. Wala naman madetect n a voltage. Tama po ba ginawa ko?

**speedyfix** · September 30th, 2007 02:17 PM

91 lancers will not have an obd port yet.

**norrissee** · October 1st, 2007 04:48 PM

Originally Posted by speedyfix

91 lancers will not have an obd port yet.

baka pwede rin pin 1 sa ECU instead of the diagnostic port... wala din ako diag port... I just used the pin 1 sa ECU ko (referred also to ECU pinout diagram, 1990s 4G63T kasi yung sa akin).

im not very sure anong engine/ecu yung sa 91 lancer... so I can't really say what pin yung diag port... baka may mga pinout diagram din para sa engine/ecu model mo. Pero usually meron naman mga ODBI readers mga shops, you can have the code read there nalang para sigurado.