RPM Limiter question

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Aug 24, 2020 | 12:55 AM

#11

CathedralCub

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From: Earth

CathedralCub is a splendid one to behold

Quote:

Originally Posted by kimdongs90

I heard(from an American engineer) that due to torque limit it can shut down Ignition plugs. So i wanted to double check if that was correct.

I've never heard of this as intended behavior.

Quote:

Originally Posted by kimdongs90

because my ignition plugs where shut down but not the injectors.

This would not happen by normal programming. This would be a recipe for melting catalytic converters and blowing up the muffler.

Quote:

Originally Posted by kimdongs90

The engine was on a dyno

So it is not in a Chevy Express G4500 Cutaway? Now we need to know what is connected to it and what is programmed.

Quote:

Originally Posted by kimdongs90

we were at about 4000rpm

Power pull or just revving? Did the PCM think it is in gear? Is there a transmission connected? . . . or wheel sensors? . . . or wheels?

Quote:

Originally Posted by kimdongs90

when suddenly there was "POP POP POP" sound coming from the converter and the converter was HOT RED

From your description of injectors on spark off I'd say you melted (the) catalytic converter(*) depending on what is connected. The "POP POP POP" would be unburned fuel burning in the exhaust system.

Quote:

Originally Posted by kimdongs90

so we went back to idle but still had the noise. We turned of the engine off wait few minutes and cranked back. we still had that noise even at idle

Makes sense, fuel injected into cylinder, not burned, released into exhaust that still has fire in it, BOOM, repeat.

Quote:

Originally Posted by kimdongs90

So we checked everything and noticed that the sensor 1 and 2(I think they called it ho2s sensor) on the bank 2 side converter were dead. We changed the sensors and crank back. But this time the engine was not making the same noise as usual. So with the engine still running we did fuse, wiring check but everything was okay but all of the bank 2 side ignition plugs were not working. So we double checked fuse and wiring, everything still good. But when we did the O2 sensor relearn the ignition plugs were working back straight away.
So we think that it was due to torque limit the ignition plugs were shut down as the engineer told us. But we don’t understand why it didn’t work back until we did the O2sensor relearn.

We need a lot more information in order to be able to help you. You'll need to volunteer a bunch of information that we don't even think to ask you about. This started as a 6.0 in a newish G4500 cutaway, then turned into an engine on a dyno, then turned into an engine on a dyno that has the whole exhaust system including catalytic converters and oxygen sensors. In three more posts will it be upside down and in space and fueled by hair spray and pickle juice?

We're not going to be able to help you until you tell us the entire configuration with details. Maybe some pictures would be a good idea as well. Remember, we're helping from the far side of the internet with a picture of the configuration painted by your words.

Last edited by CathedralCub; Aug 24, 2020 at 12:55 AM. Reason: Fixed a quote

Aug 24, 2020 | 09:39 AM

#12

Mike

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From: Dark Side, AZ

I wonder if its some engineer in Korea trying to reverse engineer GM'* handy work. When I was there in 97-98, I never seen any american production vehicles.

Makes me wonder if they are trying to duplicate US emissions systems.

Aug 25, 2020 | 01:07 AM

#13

CathedralCub

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From: Earth

Hmmmm . . . I hadn't thought of that.

Well, either way, we can't help him if he'* not giving us the whole picture.

It did think it was weird that one of those ended up in Korea.

Hopefully kimdongs90 comes back and fills in the blanks.