Hi,

 

Been a long time since I have posted here but once again we have a Fabia!

 

Anyway, I picked up a 51 plate 101HP with a EGR fault (P0402 Excessive Gas Flow) but it's a bit resistant to be fixed. Now I'm doing my best but I'm much happier in the land for breaker points but finding the electronics facinating and keen to learn.  So far I have:

 

Checked all hoses are connected and in good condition (not smoke tested), reset fault code.

 

Cleaned throttle body and pipe to EGR, reset throttle alignment and fault code.

 

Swapped EGR Valve for known good unit, reset throttle alignment and fault code.

 

Just been out and hooked up VCDS, cleared the fault code, and took it for a drive, started to get some odd results:

 

When diving along at light throttle everything looks normal but as I accelerate and start to load the engine up manifold pressure increases to over 980mb and drops to 120mb on closing the throttle off.

 

I also noticed that timing was advancing to over 38degrees, is this normal. Does seem a bit steep, at tickover it was between 0 and 6 degrees ATDC not sure if this is related but seems odd, where is this reading coming from, camshaft sensor? Are these readings normal?

 

What I'm thinking is the MAP sensor is shot and giving false high readings leading the ECU to belive the EGR is letting too much flow back to the manifold or am I mile off?

 

Any comments appreciated.

 

Your MAP sensor seems to be reading normally, I'd expect a vacuum with the throttle shut and 0.12 bar is indeed a vacuum, I'd expect atmospheric pressure with WOT and 0.98 bar is indeed atmospheric pressure.

 

The ignition advance looks fine as well.

 

You mention throttle body adaptation but don't mention EGR valve adaptation, have you done this for both valves?

Have you checked other pipes, like the servo one for instance, that is after you have performed adaption on the substitute EGR valve for good measure?

Thanks for the replies,

 

I have reset the ECU code 00 and run an adaptation on the EGR 074,075 and the throttle body 060. Switched ignition off and waited for 30 secs. Back on and drove it till it settled down.

 

Have checked the condition and that all pipes are secured to where they should be. I suppose the next step is to try to do a smoke test but not that easy at this time of year outside... And yes did check the servo vac hose as well. Nothing looks loose, split etc.

 

One odd thing is when I reset the code this morning I noticed it'd switched from Excessive Flow to Insufficient Flow.

 

I'd like to actually fix it but coding it out has to be an option.

Your MAP sensor seems to be reading normally, I'd expect a vacuum with the throttle shut and 0.12 bar is indeed a vacuum, I'd expect atmospheric pressure with WOT and 0.98 bar is indeed atmospheric pressure.

 

The ignition advance looks fine as well.

 

You mention throttle body adaptation but don't mention EGR valve adaptation, have you done this for both valves?

 

 

Have just noticed you said both valves, Have done the Throttle Body and EGR, are there any others?

Swapped EGR Valve for known good unit, reset throttle alignment and fault code.

 

The two valves in question are your original EGR valve and the 'known good' EGR valve. That is all.

If you are now getting reports of insufficient flow now, maybe have another look at where the EGR valve pipe enters the inlet manifold, you might just find that the port is gunged up and needs clearing.

Finally got the time to get back into this and it is exactly as rum4mo said.

 

Pulled the top off the throttle body and cleaned the pipe that links the EGR to the throttle body, all seemed clean but had a blockage further down. Poked it clear and dumped some cleaner down it. Reset of the throttle body and hey presto.

 

For reference  the AUB motors have a rubber seal between manifold and throttle body so you can pull it for maintenance without needing a new gasket.

 

 

Thanks all.