[rohan_fonseca]

Is the corsa OBDII compliant? As far as my layman knowledge goes only OBDII compliant vehicles have a sensor in the catcon in addition to the sensor in the exhaust manifold. Experts please comment.

[rks]

Originally Posted by rohan_fonseca

Is the corsa OBDII compliant? As far as my layman knowledge goes only OBDII compliant vehicles have a sensor in the catcon in addition to the sensor in the exhaust manifold. Experts please comment.

Here is a very informative website on the Check Engine warning light:

EFI & Computerized Engine Troubleshooting

1996 and later vehicles will all use an OBD II compliant engine management system. (Some 1994 and 1995 models may also use OBD II.) OBD II is, in part, an attempt to standardize trouble codes and retrieval methods across all makes of vehicles. [...]

OBD II systems also perform a variety of other diagnostic checks not performed with most older systems, such as misfire detection, detection of leaks in the fuel evaporative system, and monitoring of catalytic converter efficiency. Therefore most OBD II vehicles have quite a few more possible trouble codes than pre-OBD II vehicles.

On an OBD II vehicle, when the computer detects a potential problem, it will flag it in its memory, but will generally not turn on the Check Engine light until the second or third trip (ignition cycle) in which the problem is detected. After this, the light will stay on solid until the diagnostic for that trouble code runs and passes on two or three ignition cycles. (For some codes, such as misfire codes, it must additionally run and pass under the same speed and load conditions which were experienced when the code originally set.) Finally, some codes may not turn on the Check Engine light at all - the light only has to come on when the problem indicated by the code could cause the vehicle's emissions to rise more than 50% above federal emissions standards.

One simple thing to check on an OBD II vehicle that has the Check Engine light on is that the gas cap is not loose. If it is, this may be detected as a leak in the fuel evaporative system. As stated above, after you fix the cap, it may take a few trips for the light to go off.

If the Check Engine light is flashing, this means that the computer has detected that your engine is misfiring (i.e. failing to ignite the fuel in the cylinders) badly enough to risk damage to the catalytic converter (misfiring pushes unburned fuel down the exhaust, which can overheat and damage the catalytic converter as it tries to burn it up). If the light is flashing, you should repair your vehicle as soon as possible. Misfiring problems are most commonly caused by such things as a bad spark plug, bad spark plug wire, or ignition coil/module problems.[...]

[adman77]

Thanks a lot dude. That was quite informative. Me thinks now it's a lot clearer why my check engine light flashes. No need for me to worry anymore.

[rks]

@adman77, if the Check Engine light stays on continuously (instead of flashing) here is what the website says:

"If you drive around with the Check Engine light on, it may be indicating that your vehicle is putting out more exhaust emissions, using more fuel, or not running as well as it should, so you should get it fixed."

In your case I think it stays on while idling at high rpm. I suspect it could be due to high emissions, since you have removed the catcon, but there are other possibilities as well.

If the Check Engine light flashes that could indicate engine misfiring as noted in the quote in my previous post.

[adman77]

It doesn't stay on continuously. Just comes on when I rev it high while idling. Then goes off after couple of minutes.

[hkanitkar]

I may be wrong here, but isnt the ECU to be reset - to adjust according to the modifications to the engine and altered inputs ?? ( dunno the exact term used )

Changes due to the mods - increased air intake, changes in the throttle body, Presence of the Fuel pressure regulator -- engine check light may be comin up because of these as the factory settings are totally changed.
( i hope you get my point - am just not able to put it in right technical words )

[adman77]

Originally Posted by hkanitkar

I may be wrong here, but isnt the ECU to be reset - to adjust according to the modifications to the engine and altered inputs ?? ( dunno the exact term used )

Changes due to the mods - increased air intake, changes in the throttle body, Presence of the Fuel pressure regulator -- engine check light may be comin up because of these as the factory settings are totally changed.
( i hope you get my point - am just not able to put it in right technical words )

Maybe, but AFAIK, ECU has to be flashed only after major mods, such as Turbocharging, supercharging etc (Guys, correct me if I'm wrong). Otherwise, the ECU compensates the extra air with fuel automatically. Anyways, am going to Bangalore (driving down) and getting a standalone ECU in a couple of months.

[sAP]

The question: What performance mods warrant an ECU change/ re-programming of the car's computer chip?

The answer:
"Items such as as K&N filters and intakes, cold air systems, underdrive pulleys and exhausts do not affect programming and do not require custom programming.

Superchargers, aftermarket intercoolers, headers, larger Mass Air-Flow sensors, nitrous oxide, performance cams, performance heads, boost underdrive pulleys (for Superchargers), larger fuel injectors, X/H-pipes and higher than stock fuel pressure require custom programming in order to supply the correct air/fuel ratios, ignition timing or prevent the check engine light from coming on."

Referred from Performance Chips Tuners PCM Research Guide

sAP