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Discussion Starter · #1 · (Edited)
While doing some work on my car in preparation for the track season starting up again in the spring, I find that I'd really like to get rid of the EGR plumbing since the heat from this is not favorable to some of the extra plumbing I have installed for my intercooler setup.

There seems to be conflicting information about whether capping the end at the exhaust manifold and capping the end at the EGR valve under the plenum and removing the plumbing (but leaving the EGR valve connected to the ECU) will or will not cause a CEL condition on the V8 cars. I'm running the Lotus yellow high-torque ECU code on my car.

Is there definitive information one way or the other on whether leaving the EGR valve hooked up but having the stuff capped and removed in between will or will not trip a CEL condition? I have heard some folks doing this with no code thrown. I also know that there is the supposition that the sensor on the EGR valve is a temperature sensor used to confirm exhaust gas circulation, but on most other EGR valves the sensor is a valve position sensor used by the system to PWM control the valve position, and leaving all this stuff hooked up will result in the valve position indeed moving as expected by the ECU.

So what's the definitive word on whether capping this will throw the CEL? If this does indeed throw the CEL, will a firmware change to the red ECU code from the yellow I'm running now avoid this issue (I understand the red code doesn't use EGR) and is there any issue with the red code passing the emissions test (in Oregon they just plug into the OBD-II port and check for codes).

Thanks for the team's advice, and Happy New year.

Knut
 

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Capping the EGR as you described does not cause a CEL to be thrown by the "Red" ECU code. Mine has been capped for some time now. However, I do have half the plumbing still in place. The part arriving from the valve under the plenum. Capped at the flex joint. Also, I passed the emission test in Georgia. They just plug into the OBD; after I showed them it's location. Also, as you're probably aware, the Red code ignores the post oxy sensors.
 

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Discussion Starter · #3 ·
Thanks Irox for the info on the red race ECU not throwing a CEL with EGR capped and also passing emissions in your state. So that addresses half of my question and gives me a fall-back of switching to that code if necessary.

For the first half of the question, does anyone know if the non-red Lotus V8 ECU codes (yellow high-torque in my case, but I think that has same EGR behavior as the standard ECU code) will or will not throw a code with the EGR port capped?

Worst case, I suppose I could just go ahead and cap it and remove the plumbing and see what happens, and if it gives me CEL problems that threaten to hamper me passing inspection switch to the red code then if needed, but it would be nice to know what to expect beforehand.

Knut
 

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The H.T. Firmware upgrade to the standard ECU, will generate a EGR error code, P0401 "insufficient flow detected", as the thermistor embedded in the EGR body will not indicate any heat (>136.4 * F.) as it is not getting any heat from the exhaust manifold. However since the EGR rediness test runs very infrequently it will take a while to show up.
 

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Discussion Starter · #5 ·
The H.T. Firmware upgrade to the standard ECU, will generate a EGR error code, P0401 "insufficient flow detected", as the thermistor embedded in the EGR body will not indicate any heat (>136.4 * F.) as it is not getting any heat from the exhaust manifold. However since the EGR rediness test runs very infrequently it will take a while to show up.
Great info and might give me a lead on what I might need to work around this. I presume the readiness flag indicator would not be set until after this test is run and the local inspection would require all the readiness flags to be set in order to pass, Right?

So is the only thing the ECU needs is a temperature reading on the thermistor that exceeds 136.4F? So all I would need to do to cheat this is to determine the resistance at that temperature and bypass the thermistor with a resistor that corresponds to a temperature higher than 136.4F?

Knut
 
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