"Check Engine" Light Turns On When Driving Past 70

**jut703** · April 23rd, 2013 03:42 PM

I've been using an old '95 Lancer GLXi (itlog) from my dad's office for the past few days, and I've been bothered by the fact that the check engine light keeps turning on.

Upon closer observation, it happens whenever I go past ~70 kph, no matter how low I keep my revs (i.e. 5th at 1.8k rpm).

The light only vanishes when I turn the engine off. Even after starting the engine again, the light doesn't turn on, at least until I hit 70 kph again.

I've had my engine fluids checked (oil, brake, power steering, etc) and all where within normal levels. Temps were fine too.

I plan to have the car checked soon, but I'd like to hear the thoughts of seasoned troubleshooters on this case, just so I know what to expect when I send it over for repairs. Thanks!

**JohnM** · April 23rd, 2013 03:53 PM

The Itlog has a very minimal number of sensors. Ang most likely CEL culprit is a loose MAF sensor plug pero weird kasi speed-based. The speedo is a simple cable affair.

**ghosthunter** · April 23rd, 2013 04:11 PM

Originally Posted by jut703

I've been using an old '95 Lancer GLXi (itlog) from my dad's office for the past few days, and I've been bothered by the fact that the check engine light keeps turning on.

Upon closer observation, it happens whenever I go past ~70 kph, no matter how low I keep my revs (i.e. 5th at 1.8k rpm).

The light only vanishes when I turn the engine off. Even after starting the engine again, the light doesn't turn on, at least until I hit 70 kph again.

I've had my engine fluids checked (oil, brake, power steering, etc) and all where within normal levels. Temps were fine too.

I plan to have the car checked soon, but I'd like to hear the thoughts of seasoned troubleshooters on this case, just so I know what to expect when I send it over for repairs. Thanks!

Maybe it has to do with the air-fuel mixture? ... a clogged fuel filter or clogged fuel line can result in leaning out the fuel mixture in to the cylinders.

**JohnM** · April 23rd, 2013 04:14 PM

A resident gearhead who owned two CBs (both turbo) said there's a sensor in the gauge assembly that sends a speed signal to the ECU. You might want to start there.

The crank angle sensor can also trip a CEL but it looks like it's not related.

**basti08** · April 23rd, 2013 04:52 PM

Originally Posted by ghosthunter

Maybe it has to do with the air-fuel mixture? ... a clogged fuel filter or clogged fuel line can result in leaning out the fuel mixture in to the cylinders.

Dirty MAF/throttle body?

**jut703** · April 23rd, 2013 07:43 PM

Thanks for the advice guys. Might be a simple case of a dirty filter or sensor, I'd look into that

**Martz1977** · April 25th, 2013 12:12 AM

most probably the filter. why not simply have it scanned?

**basti08** · April 25th, 2013 12:16 AM

Our employee's Accent CRDi CEL also turned on once because of clogged and very dirty filter.

**LN106G** · April 25th, 2013 09:11 PM

The most common sensor to light up the malfunction indicator lamp (MIL) aka "CHECK ENG" is the mass airflow (MAF) sensor. Try cleaning its probe first with electronic contact cleaner as well as its connection. If after cleaning and the MIL still lights up, have your car undergo an engine scan to pinpoint which sensor is at fault (eg, oxygen sensor, TPS, CTS, EGR, etc)...