Lack of TD5 power

Couldn't be arsed to fight with the cover bolt so pulled and plugged the pipes and modulator ports.

Now that has made a difference. Took about 10 miles to settle down but now it'll bowl along at 45mph in 5th very happily, it didn't really like that before. It'll actually pull without complaint or a great deal of throttle(*) from 30mph (about 1200rpm) in 5th. Wouldn't have done that before even with your foot flat on the floor, it would have just made labouring noises and stayed at the same speed.

I'll let a couple of tanks full go through and see what MPG I get. I'll then put the EGR pipe back (leaving the ILT one off) on for a couple of more tanks.

(*) Of course the fly by wire nature of the TD5 means that throttle position may not indicate how much fuel the engine is actually being given.

On or around Fri, 20 Mar 2009 23:19:00 +0000 (GMT), "Dave Liquorice" enlightened us thusly:

Mine was over 27 mpg average for the first time in my ownership, this last tank. That was the one with the blue redex in. Will see what it does on the next tank, with no redex.

It's still a touch on the low side, I'd say. Done all the servicing things, now, bar for cleaning the intercooler... which is not a service thing but would probably be a good idea.

AIUI the TD5 doesn't have tappets to adjust...

I pulled the pipe of the EGR, blanked the pipe off and went for a day out in the truck today. What a difference that makes!!. I'll monitor the MPG as well and see what happens.

Dom

On or around Sat, 21 Mar 2009 11:26:19 -0700 (PDT), Dom J enlightened us thusly:

I've never thought EGR was a good idea, nor does it do a lot. If EGR would solve the engine pollution problems, then they wouldn't have faffed around with all the rest of the stuff in euro 3, 4 and 5.

So all it really does is feed exhaust gases back into the inlet.

The have to add a butterfly valve in the inlet to draw even more exhaust gases in to get the TD5 to Euro 3 spec.

Reducing the temperature of the burn and the amount of oxygen available for the fuel. This is supposed to reduce the level of nitrogen oxides in the exhuast. TBH I'd rather burn less fuel, produce less CO2 and a little more NO than burn more fuel, produce more CO2 and a tad less NO.

On or around Sat, 21 Mar 2009 22:27:51 +0000 (GMT), "Dave Liquorice" enlightened us thusly:

exactly... I'm not convinced about reducing temperature, either: exhaust gases tend to be hot...

The ford TDi with EPIC has one of those butterfly valves, luckily, unplugging the electrics from the controller for the vacuum prevents it from operating :-) On non-turbos, you have to remove a link and wire the valve open... first time I drove one with such an abortion I thought "WTF?". throttle response is way down.

At least the EPIC system disables it electrically when you press the throttle. The mechanical one has variable butterfly opening depending on how much boot you've applied.

I'm guessing the later TD5 works like the EPIC, butterfly only active when it decides to do EGR.

On models with the ILT (EU3) there is an exhuast gas cooler fitted between the manifold and the EGR inlet...

Gawd knows, The modulators are fed independantly from the ECU, I did briefly toy with the idea of hooking up a couple of LEDs to show when either was active but that seems like an awful faff for no real gain other than interest.

I can't decide if these things are analogue ie. the amount either is open is variable or if they are just bang bang open or closed and if they are just open/closed how frequently they open/close.

On or around Sun, 22 Mar 2009 10:27:11 +0000 (GMT), "Dave Liquorice" enlightened us thusly:

I believe it's analog, it decides how much EG to R based on a mass airflow meter in the inlet, IIRC, that and throttle position and engine speed data.

Had a dig through RAVE. The ECU outputs are listed as "digital" 0 - 12v. The modulators are fed 12v from an engine compartment fuse and the ECU provides the earth path. There is no direct feedback to the ECM from the valves themselves or from the modulators. I'd expect an analogue system to have that so it knows where it is. OK there is feed back via other engine sensors but how does the system know if they are changing due to the EGR or for some other reason?

RAVE mentions the Mass Air Flow, Ambient Air Pressure, Manifold Inlet Air Temp, Coolant Temp, Engine Speeed & Fuel Delivered as all being used for the EGR sub-system.

On or around Sun, 22 Mar 2009 23:25:30 +0000 (GMT), "Dave Liquorice" enlightened us thusly:

they're all used to provide input. However, as you say, there's no feedback from the EGR devices themselves.