EGR Blanking, is it recommended or not.

**Tediber Ang** · October 11th, 2016 06:37 PM

I noticed it was at 0% even at idle ..... Anyway i'll check it again. Don't like keeping the obd2 device connected always as it seems to heat up. And as i know the egr should be open at idle speeds and closes at higher revs.

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**oj88** · October 11th, 2016 07:03 PM

Originally Posted by Tediber Ang

I noticed it was at 0% even at idle ..... Anyway i'll check it again. Don't like keeping the obd2 device connected always as it seems to heat up. And as i know the egr should be open at idle speeds and closes at higher revs.

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It's usually closed at idle. In fact, one symptom of a stuck-open EGR valve is rough idling.

It only opens up under certain conditions (varies widely among different vehicles). But it should definitely be closed during idle and WOT.

**Tediber Ang** · October 11th, 2016 07:16 PM

Thanks .... Mine seems always at 0% no matter what i do.

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**oj88** · October 11th, 2016 07:31 PM

Originally Posted by Tediber Ang

Thanks .... Mine seems always at 0% no matter what i do.

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I'm guessing your OBD2 is either not picking up the correct sensor value or your vehicle has an all-mechanical EGR valve and the computer is not controlling it.

Also note that the 0% reading your reader is showing is the 'commanded' value requested by the computer to the EGR valve.

**aar0nix** · October 12th, 2016 04:40 AM

Originally Posted by oj88

It's usually closed at idle. In fact, one symptom of a stuck-open EGR valve is rough idling.

It only opens up under certain conditions (varies widely among different vehicles). But it should definitely be closed during idle and WOT.

Sir please let me correct this.

The EGR Valve is always open at varying degrees except during WOT.

It is usually at 26-30% open during idle at 25-32°C intake air temp (IAT), 35-40% open at 35°C+ IAT. 0% open at WOT. 40-50% open when cruising at 80km/h

Before I had my EGR blanked, I experienced puffs of black smoke whenever I floor the accelerator of my mux (12/2014, 2.5 4jk1-tc model) after idling or being stuck in daily traffic. After blanking, no more black smoke during the same conditions.

I had it blanked with a slotted (10mm hole) 3mm stainless plate and this is what I get now: EGR always at 100% open, turns closed whenever I step on the accelerator, even light stepping. Then turns back to 100% open gradually. 0% when cruising.

Attached is a graph using torque pro with bafx obd2 scanner. Shows how the egr operates after blanking. I'd rather have this than puff black smoke all the time whenever I'm done braving Manila traffic. ;)

**oj88** · October 12th, 2016 08:26 AM

Originally Posted by aar0nix

Sir please let me correct this.

The EGR Valve is always open at varying degrees except during WOT.

It is usually at 26-30% open during idle at 25-32°C intake air temp (IAT), 35-40% open at 35°C+ IAT. 0% open at WOT. 40-50% open when cruising at 80km/h

Before I had my EGR blanked, I experienced puffs of black smoke whenever I floor the accelerator of my mux (12/2014, 2.5 4jk1-tc model) after idling or being stuck in daily traffic. After blanking, no more black smoke during the same conditions.

I had it blanked with a slotted (10mm hole) 3mm stainless plate and this is what I get now: EGR always at 100% open, turns closed whenever I step on the accelerator, even light stepping. Then turns back to 100% open gradually. 0% when cruising.

Attached is a graph using torque pro with bafx obd2 scanner. Shows how the egr operates after blanking. I'd rather have this than puff black smoke all the time whenever I'm done braving Manila traffic. ;)

There may be exceptions to the rule but I can't imagine having the EGR cracked open during idle. In almost any documentation I've read, having the EGR valve open, even slightly during idle, will cause rough idling or cause the engine to stall. (P41 – Exhaust gas recirculation (EGR) system -insufficient flow detected – OBD2 Trouble Codes)

Your EGR mapping is weird. Either we're not interpreting it correctly or it's not operating in a traditional way.

But I agree with you, with that kind of mapping, you will definitely see black soot coming out the tail pipe if you didn't blank it.

Other references:
AGCO Automotive Repair Service - Baton Rouge, LA - Detailed Auto Topics - How Does an EGR Valve Work
Exhaust gas recirculation - Wikipedia, the free encyclopedia

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**aar0nix** · October 12th, 2016 12:10 PM

Originally Posted by oj88

There may be exceptions to the rule but I can't imagine having the EGR cracked open during idle. In almost any documentation I've read, having the EGR valve open, even slightly during idle, will cause rough idling or cause the engine to stall. (P41 – Exhaust gas recirculation (EGR) system -insufficient flow detected – OBD2 Trouble Codes)

Your EGR mapping is weird. Either we're not interpreting it correctly or it's not operating in a traditional way.

But I agree with you, with that kind of mapping, you will definitely see black soot coming out the tail pipe if you didn't blank it.

Other references:
AGCO Automotive Repair Service - Baton Rouge, LA - Detailed Auto Topics - How Does an EGR Valve Work
Exhaust gas recirculation - Wikipedia, the free encyclopedia

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You are talking about an EGR system installed in a gasoline engine.

It operates differently with diesel engines. Only off at WOT. Always partially open at idle and partial throttle.

I will record a similar graph on a non-egr blanked Isuzu MUX and post it here.

**oj88** · October 12th, 2016 12:48 PM

Originally Posted by aar0nix

You are talking about an EGR system installed in a gasoline engine.

It operates differently with diesel engines. Only off at WOT. Always partially open at idle and partial throttle.

I will record a similar graph on a non-egr blanked Isuzu MUX and post it here.

I won't argue with you. Thank you for that assertion.

**monty_GTV** · October 12th, 2016 01:05 PM

see video posted by bro zix888 (gtv2011 ph) 2 yrs ago regarding the actual behavior of egr valve of a montero diesel engine during idle and when gas pedal is pressed. its in normally closed position during ignition then around 8 secs of idling, it will open and stay in normally open position. it will closed and open as the gas pedal is press.

montero sport egr valve - YouTube

it's interesting to see those mappings and reference documents

**aar0nix** · October 12th, 2016 11:10 PM

Originally Posted by monty_GTV

see video posted by bro zix888 (gtv2011 ph) 2 yrs ago regarding the actual behavior of egr valve of a montero diesel engine during idle and when gas pedal is pressed. its in normally closed position during ignition then around 8 secs of idling, it will open and stay in normally open position. it will closed and open as the gas pedal is press.

montero sport egr valve - YouTube

it's interesting to see those mappings and reference documents

I guess I don't need to graph out a friend's mux then. The video shows how the egr operates on a diesel engine.