Honhel

Hi,

My Honda Jazz (Fit) has a blocked off EGR-valve (the previous owner had this done). Because the engine light was on and started to bother me, i brought it to a car shop and had a new EGR valve installed, that i bought online (at the car shop i learned that the old valve was blocked off with a metal plate). As soon as i drove off (the engine light was off) the car started to shudder and shake. I probably drove about 500/800 metres and drove back to the car shop. Because i didn't have time to have him investigate any further he blocked off the new valve and my car drove as "smooth" as it did before with the old blocked off valve and the engine light is "on" again.

I'm a noob but tried to inform myself by reading different threads. I've been reading about the ECU and resetting it after modifications. Should that have been done in order to reset and avoid shuddering? Maybe i sould have driven a little bit further in order to clear the passageways?

A friend of a friend repairs cars and i would like him to take a look. Could removing the plate and resetting the ECU resolve the problem? As a noob it seems so strange that it runs smooth with the plate on and causes problems without it. Any other possibilities?

I also find that the car has less mpg (kilometers in the Netherlands ;-) than could be expected of a car like this. Could this be related to the EGR situation?

Myxalplyx

I will try to answer this as best as possible with what little knowledge I have.

Resetting the ECU would have not done anything to resolve the code and light from coming up. Clearing the passageways would not have removed the check engine light or code. The EGR is looking for flow to go through it. If there is no airflow going through it, the code will pop up (EGR low flow). You will either have to reconnect the EGR piping to the exhaust so that exhaust flow goes from the exhaust to the EGR, disable the EGR somehow (Ex: ECU Tuning software) or intercept the signal going to the EGR and 'lie' to it and send it false flow numbers to satisfy it.

As to your car have less mpg, here is an interesting read that may be directly or indirectly related to that question. Let me know your thoughts --> EGR Removal - Performance Gains or Loss https://www.physicsforums.com/thread...r-loss.663150/

rit14623

Resetting the ECU is easy. Unbolt the battery cable connector nut and then lift the battery cable connector off the battery terminal. Wait a minute. Reconnect the battery cable to the battery and tighten the battery cable connector nut.

The check engine light can come on for a variety of reasons. You would need to get an engine code reader to find out the problems. If the engine is shuddering while driving, that's not good. When it is shuddering, it kind of sounds like your car is in a scenario where it is dumping more raw unburnt fuel into the exhaust manifold, which will damage your primary catalytic converter.

Is the EGR valve plugged in? It is an electronic valve.