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Red ECU Questions


8KRedRacer

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Hello Everyone,

I purchase about a year ago 1997 V8 US model that the previous owner installed a Lotus Red ECU from US MY1998-2004. The engine starts and idles fine with no issues, but upon acceleration it does not accelerate smoothly and the engine is running very rich. Also, when I purchased this car it ran like this and it had been serviced about 1,000 miles ago at a Lotus dealer for similar problem by the previous owner. The Lotus dealer found someone had removed the hoses to the wastegates and the EGR value. I have a CEL and the code is P0462. The P0462 is related to the wrong model year ECU and I know it is related to the ECU is looking to non-existent fuel pump relay. I am running straight pipes at this time and the acceration problem occurred with the catalytic convertors as well. I have calibrated the turbo wastegates per the Service Notes. I have checked the connection of all the vacuum holes and routing. I have the ability to scan (thanks Peter!!!) the engine operating parameters.

Does anyone know if the MY 1998-2004 Red ECU have different air to fuel map from that of 1997? With the Red ECU, it is running an open loop system in that it does not pay attention to the O2 sensors. How does the engine change the air to fuel ratio in open loop and adjust for changing operating conditions? What operating parameters should I be most concerned with when I am doing my data logging in order to improve the acceleration and rich air to fuel condition? If anyone has any other suggestion, I would be most interested.

Thank you in advance for your suggestions and any assistance you could provide!

Cheers,

Alan

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Where to Start!

1. The Red ECU does NOt run in open loop, it does run in closed loop. It does not pay attention to the post warm up CAT O2 sensor, however.

2. If the P.O. disconected the wastegate control hoses, that means the ECU would never LIMIT the boost and over boost would be occuring all the time (very bad and dangerous for the engine)!

3. I am not sure what you meant by the EGR hose was disconnected, but is you mean the path from the exhaust manifold port to the EGR valve was blocked or removed, thats OK with the red ECU as the EGR function is disabled in the red ECU.

4. The fuel mapping should be OK with the red ECU, for the engine if it is functioning correctly. But If it is running rich there may be another problem. A stock Lotus red ECU should have the correct fuel map.

5. How do you know it is running rich? Do you have an AFR sensor?

6. There is nothing you can easliy do to change the fuel map. Has someone installed a external fuel controller?

Wayne

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The Older I get the Faster I was

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Hi Wayne,

Thank you for the reply and the information! I completely understand that it is very difficult to impossible to troubleshoot at problem over the internet.

“1. That make sence, but does the Red ECU calculate the A/R ratio based on a nominal value for the post O2 sensor? What I am having a difficult picturing is how does the loop becomes closed without an actual value from the post O2 sensor.

"2. I would agree one hundred percent this was very stupid by the previous owner.

"3. What I was referring to is the clear hose that is located under the intake manifold (purge, EGR manifold to NRV hose) had been cut and spliced by the previous owner. It was disconnected at the splice.

"4.OK thank you for the information.

"5. You can smell the gas coming from the exhaust and the pre O2 sensors are reading around .900 mv. I do not have an A/F sensor.

"6. No one has installed an external fuel controller.

BTW, I have really interested in what you did with you intercooler project. I job very well done!

Thanks,

Alan

]

Edited by GKP
Tidy up post and remove multiquotes.
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1. All ECUs for fuel injected engines require the feedback from the pre CAT O2 sensor to determine the correct "clean cruise" stoichemetric ratio (14.7:1 for gasoline) for closed loop operation. When the throttle is opened near maximum the sysem goes into open loop and uses the stored fuel mappings.

5. You cannot "read" the O2 sensor voltage and acurately determine the AFR. The O2 sensors are constantly switching between lean and rich values to keep CAT and a higher temperature. The ratio of time between the lean voltage and rich voltage is a closer approximation of the mixture. Read the plugs or borrow a AFR sniffer.

Wayne

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The Older I get the Faster I was

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Alan,

You might check into Innovate Technologies AFR reader. I use it on my 83 turbo and it works great. Simple hook up and drive as it records your AFR or Lambda. Info is stored on a SD card you can later download to read. If you have a driver, you can watch it live in the passenger seat. A really invaluable tool for your current questions.

Best,

Jeff

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www.espritturbo.com

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1. All ECUs for fuel injected engines require the feedback from the pre CAT O2 sensor to determine the correct "clean cruise" stoichemetric ratio (14.7:1 for gasoline) for closed loop operation. When the throttle is opened near maximum the sysem goes into open loop and uses the stored fuel mappings.

5. You cannot "read" the O2 sensor voltage and acurately determine the AFR. The O2 sensors are constantly switching between lean and rich values to keep CAT and a higher temperature. The ratio of time between the lean voltage and rich voltage is a closer approximation of the mixture. Read the plugs or borrow a AFR sniffer.

Wayne

Wayne,

Thank you again for the information. That makes perfect sense!

Cheers,

Alan

Alan,

You might check into Innovate Technologies AFR reader. I use it on my 83 turbo and it works great. Simple hook up and drive as it records your AFR or Lambda. Info is stored on a SD card you can later download to read. If you have a driver, you can watch it live in the passenger seat. A really invaluable tool for your current questions.

Best,

Jeff

Hello Jeff,

I will look into the AFR reader suggested above and without accurate data I am just shooting in the dark!

Alan

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