possible EGR total bypass.

2246 Views 5 Replies 3 Participants Last post by SRH990, Mar 16, 2010

winterheating

Discussion Starter · Mar 15, 2010

i just need to check a few things, my mondeo is an 04 130ps tdci.
the EGR is at front of engine with position sensor on EGR valve.
i also have a Maf sensor fitted(i here some TDCi's dont?????)
when removing vac pipe or blanking, or reinstating the engine light takes a while to come on or extinguish, but it knows either way.

basically my pcm can tell via the Maf and Map sensors aswell as position sensor on EGR if anything is fiddled with,
what i need to know is what euro stage is my tdci,as i may have a total bypass for EGR that totally eliminates exhaust gas re-entering, as not to dilute fresh oxygen, does not lower or raise boost levels, keeps the pcm happy with no fault codes or engine light coming on. so totally eliminating EGR valve problems and intake build up of gunk.

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SRH990

· #2 · Mar 15, 2010

If you have a sensor on your EGR then you have a Euro 4 model. It senses more than just open and closed as live diagnostic data shows EGR flow as a % figure which changes according to driving conditions. AFAIK it's only TDDi models that don't have a MAF but even so, I'm sure all Euro 4 models have a MAF.

Be interested to see how you are proposing to bypass the EGR, I used a blanking plate and drilled larger & larger holes until the engine warning light didn't come on and ended up with a hole so large it wasn't worth having the blanking plate fitted!

I do know that I've just cleaned my EGR valve out after only 6,000 miles since last cleaning it and had a fair amount of sooty crud to remove, I'd certainly like to bypass mine permnanently.

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mondeotdci130

· #3 · Mar 15, 2010

blanking a Euro4 EGR (i.e. sensored) gets the engine management light on but no side issues, i.e. no limp mode?

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SRH990

· #4 · Mar 15, 2010

No limp mode, just the warning light. I found that with the EGR totally blanked off it took up to 2 days for the light to come on, with a 10mm hole I didn't get a warning light but plugging in the diagnostics showed an 'insufficient EGR flow' DTC.

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winterheating

Discussion Starter · #5 · Mar 15, 2010

yeah, ive always thought blanking(or not) with a plate with a hole in is a waste of time, as any exhaust gases re-entering is bad, also like you say if its big enough to not bring light on then its enough flow as if EGR was connected and working normally.????

so going from what you say the pcm will bring light on if it EGR flow percentage gets to a certain point, but if flow restricted slightly light will not come on but log a dtc.

the light being on apart from annoying means it wont show any other fault that the light my show, and possibly the pcm will not give full potential power????

i have managed to totally bypass the exhaust gas from entering,(blanked of at exhaust manifold and small exhaust pipe removed alltogether) and basically fooled the Map sensor, so the light is not on at the minute(for last 4 weeks) but i guess that it would come up with a maf sensor dtc.if i check fault codes.
the next stage will be to fool the Maf sensor.

this car actually had a passing egr valve even when fully closed so the result was this in the intake and head.

dont look as bad on pic but i couldnt fit my fingers in some of the inlet ports!!

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SRH990

· #6 · Mar 16, 2010

winterheating said:
yeah, ive always thought blanking(or not) with a plate with a hole in is a waste of time, as any exhaust gases re-entering is bad, also like you say if its big enough to not bring light on then its enough flow as if EGR was connected and working normally.????

so going from what you say the pcm will bring light on if it EGR flow percentage gets to a certain point, but if flow restricted slightly light will not come on but log a dtc.

the light being on apart from annoying means it wont show any other fault that the light my show, and possibly the pcm will not give full potential power????

Thats my experience, with reduced flow a DTC was recorded but no engine light. Even with it totally blocked and the light on, there wasn't any reduction in power, almost the reverse in fact.

I'm not quite clear how you bypassed the EGR - with no flow, either exhaust or clean air, the senor will throw up the light & DTC. If the EGR is still opening and you haven't got exhaust pressure as the connecting pipe is open, you will loose boost pressure in the manifold and power.

There have been discussions about modifying the electric connection to the EGR to fool it into sensing the valve is open when it's actually closed but no-one has come up with any actual suggestions how to do it yet.

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