Mondeo Tdci Hesitating After Egr Blank

[edwardwilcox1981]

I have had a blanking plate with a hole in on my EGR for the last year or so, I recently found out that the car is a euro 3 which means I can use a full blanking plate without the car showing the EML light.

Last night the car was running fine until changed the blanking plate and now I have hesitation when driving/accelerating under 2500rpm, when above there is no hesitation.

The car seems faster when above 2500rpm also.

The blanking plate with a hole that was taken was dirty, now it's blanked surely it doesn't matter?

Please help!

[stevegtuk]

Might be worth checking the hoses for splits first.

The blank won't make any difference above about 2000 rpm as the egr would be normal closed anyway if it is working.

I have never seen the point of having a hole in the blank in the first place as it defeats the object of a blank by allowing the gases through that you are trying to stop, also, in most cases, with euro4 cars, it still brings on the EML light.

[edwardwilcox1981]

Thanks for replying, I changed the egr pipe to a silicone one a few months back.

The car ran perfectly before I changed the plate to a blank, it was dirty though, would that make a difference even though it's now blanked?

Cheers

[stevegtuk]

Did you check all the other hoses too when you changed the egr hose?

Did you clean the egr and manifold before putting the original blank in? if not there could have been a large build up of carbon and changing blanks may have loosened a chunk.

There is a possibility it could be something unrelated to the blank and just a coincidence.

Id suggest you take the egr and manifold off and clean them, sometimes the simple (although very messy) jobs can solve the problem. See if that cures it and go from there.

[FOCA]

I agree with steve and add that i have never heard of a solid EGR blanking plate increasing hesitation - onlly reducing it

As steve has said - if you clean out the the inlet manifold it may sort it, i recommend you fit a new air filter (if not done in the last 6months/6k) and reset the ECU (not the trip computer) for the ECU to "relearn"

Maximum torque is just below 2500rpm and there is often a "step" in the power delevery arond here, the egr can "soften" this power delivery by increasing turbo lag (as some energy that would utherwise go to the turbo is lost through the EGR

So the power delivery below 2500 is similar pre and post (solid EGR) blanking plate, but above 2500 the blanked motor pulls stronger as there is more boost available this may be more noticable in some gears than others ( so the extra power/ torque above 2500 is percieved as less under 2500)

look at the extreme step in the torque curve - with very little torque below 2k- then peak torque about 2.3-2.5k, and the remap increases the torque above 2k/2.5k - but not below 2k - the plate can have a similar (but a bit less extreeme) effect -

http://www.mybluefin.co.uk/curves/mondeotdci130bhp-d.pdf

although the EGR has a specific operating range (ie- under 2k on some engines) it can affect the engine throughout the enire rev range, as the energy lost through the EGR opening is never fully recovered (as the engine revs through the power band- the turbo has to "catch up" with the engine)

Just to point out the standard boost control system(s) are still in place (actuator/ VNT etc) and it just boosts quicker (but not more peak boost) with the solid EGR blank - so its safe/ will not cause exesive stress on the engine

Let us know how you get on