Blanking the EGR valve

[dbjazz]

2007 GD1: 1.3 L L13A i-DSI

I have blanked it and now, predictably I suppose, the valve is throwing OBD2 codes and putting the EML on.

Can I stop that happening, maybe by fitting a thick gasket between the valve and the blanking plate so the valve doesn't touch the plate on opening?  Or drilling the plate (when removed of course) with a small hole to allow some pressure relief to the valve?

[Jocko]

Attach the EGR valve to its cable and tie it up out of the way.

[embee]

I don't know about the Jazz system of that era, but some EGR diagnostic systems use a temperature sensor to decide if the EGR is actually flowing gas, if the temp doesn't change between on/off then it's probably faulty. If yours has this type of diagnostics then it will be an issue when blanking it off. If other owners have done it without such issues then it's obviously possible to get round it.
It might use a valve displacement/position measurement.

[dbjazz]

Attach the EGR valve to its cable and tie it up out of the way.

Thanks I did consider that.  My concern was that I think it may need to be pressing on the blanking plate to keep an all round seal.  Anyway would that stop the OBD2 codes and EML light?  If so my solution in following post should work too.

[dbjazz]

I don't know about the Jazz system of that era, but some EGR diagnostic systems use a temperature sensor to decide if the EGR is actually flowing gas...

Interesting, I couldn't seem to pin down how they check themselves.   

Anyway I took the aluminium blanking plate off and there was a clear mark, almost a dent, where the valve had been hitting it.   Bit annoyed with the plate seller who should have known that and should have done what I have now done..

Which is to drill a large hole in the plate, bigger than the valve, so it can open all it likes into the exhaust but any gas it lets in won't be going anywhere as the air intake port remains blocked. I had to fit a new gasket between the plate and the valve (with the old one still between the plate and the iron exhaust circulation body.)

I had assumed that the EGR was throwing codes because it was hitting the plate (i.e. the "valve displacement/position measurement" you mention) but it may be the temperature thing.  Either way that should fix it.  Long journey tomorrow, if I don't say otherwise assume it did fix it.

[Jocko]

As far as I am aware you remove the erg valve, fit the blank in its place, and leave the electrics connected so that the ECM sees the correct signals. AFAIK there is no temperature sensor on the Jazz.

[dbjazz]

OK, when the valve was hitting the blanking plate the OBD2 code I was getting was:

P0404  EGR "A" control circuit range/performance

Now after I drilled a hole to allow the valve to fully open I am getting a new code instead:

P0401 EGR "A" flow insufficient detected

So it looks like the valve is clever enough to know both when its movement is restricted by an obstruction and when it opens OK but there isn't the expected gas flow.

I would expect the insufficient gas flow code to also be thrown if I remove the valve from the exhaust body but left it plugged in.

Has anyone here sucessfully blanked their EGR without re-configuring the ECU in some way?

All I can think of now is to drill a second small hole to let some gas flow but less than before the blanking plate. Not really what I was originally aiming for.

[dbjazz]

I have now drilled a 5mm second hole in the blanking plate to avoid  OBD2 code "P0401 EGR "A" flow insufficient detected".  Recommended hole size seems to be 8mm but at that size I can't see much point in having a blanking plate at all - I suspect the valve itself restricts to less than an 8mm diameter hole.

All a bit of a waste of time really as exhaust and carbon is re-entering my air intake again.

[Lewo]

Out of interest have you tried what Jocko suggested yet?

[E27006]

I don't know about the Jazz system of that era, but some EGR diagnostic systems use a temperature sensor to decide if the EGR is actually flowing gas, if the temp doesn't change between on/off then it's probably faulty. If yours has this type of diagnostics then it will be an issue when blanking it off. If other owners have done it without such issues then it's obviously possible to get round it.
It might use a valve displacement/position measurement.

The Jazz EGR is basically an electrically-operated  solenoid with a  valve position / displacement  device, the latter  a 5000 ohm potentiometer with a wiper,  the ECU measures the position of the EGR "penny on a stick" valve  by reading a voltage returned from the potentiometer and wiper,  The EGR does not simply open or close, the position can be anywhere between 0 and 100% depending on the control demands  of the ECU  and driving conditions.
Has anyone tried a Chinese aftermarket Jazz ECU? They are about £40 to £50 to buy, a fraction of the OEM part,  £400?