D4 Cold start - no power and throttle weirdness

[SuperMono]

Well a bit weird for me anyway.

Have had my 2010 D4 S for a few months and yesterday I had strange behavior on 2 seperate cold starts (on the way to work, again on the way home).

Started normally but had a very 'long' throttle with little or no power and then a decent surge as the revs built up.
Felt as though it was in one of the special program modes where the car is trying not to break traction.
Went back to normal as the temperature settled down.

When I got home I cycled the car through the program modes then turned it off.
Today, no issues, started, drove off, felt normal.

Any ideas?

[SuperMono]

No one else, so it must be just me?

Has done this one more time over the weekend past, again from cold start.
Cycled the program modes, stopped/started, seems OK.
Today, no issue.

[rufusking]

Is the sensation you're getting similar to the effect you get when you happen to get the left foot braking / right foot accelerator timing out? You know that pregnant pause then it takes off like a wife with your credit card.

Could be the brake light switch is getting a bit temperamental.

[SuperMono]

No, it is more the very long travel throttle effect.

I haven't managed/bothered to get the Nanocom plugged in yet.

[Catmatt]

Well a bit weird for me anyway.

Have had my 2010 D4 S for a few months and yesterday I had strange behavior on 2 seperate cold starts (on the way to work, again on the way home).

Started normally but had a very 'long' throttle with little or no power and then a decent surge as the revs built up.
Felt as though it was in one of the special program modes where the car is trying not to break traction.
Went back to normal as the temperature settled down.

When I got home I cycled the car through the program modes then turned it off.
Today, no issues, started, drove off, felt normal.

Any ideas?

My 2010 D4 2.7l did the same. Investigation revealed that either 1 of both EGR valves are remaining open (They should close when you shutdown) hence initial boost is being diverted on start up resulting in the big surge of acceleration once the revs built up.......sound similar?

This could be a range of reasons......Carbon has built up on the actuating rods, carbon has built up under the valve flap or worse case scenario, the valve/s are US so you'll need to replace them which is VERY expensive! ($3K plus!!)

Once cold, the valves will generally slowly close so it shows as an intermittent problem - here one day and back again the next. It can get so bad that you won't be able to drive over 15kph or the car will go into 'limp-home' mode....Just what you need 4WDing 150K's from help!!!

I elected to get the ECU remapped with a software 'fix' that permanently closes the EGR's and does not raise a MIL fault. Problem has never happened again and as a bonus, the D4 has much better performance for towing the camper trailer and better fuel economy.

[rar110]

If it's carbon build up, I would try Revive.

[sniegy]

Any smoke from the rear, Turbo hose split ??

[SuperMono]

Any smoke from the rear, Turbo hose split ??

Nope :)

[SuperMono]

My 2010 D4 2.7l did the same. Investigation revealed that either 1 of both EGR valves are remaining open (They should close when you shutdown) hence initial boost is being diverted on start up resulting in the big surge of acceleration once the revs built up.......sound similar?

This sounds like a possibility, thanks ;-)
Talking about EGRs with Dad 2 weekends back, an obvious jinx.......

I managed to get my Nanocom to work briefly and didn't notice anything immediately on fault codes for EGR flow, but it makes sense.

BTW, which remap?

[SuperMono]

OK fault code seems to support EGR, thanks for the input and advice.
Further investigation time I guess.

ECU: Engine Management
CODE:P045C
Exhaust gas recirculation B control circuit - Low
(HISTORIC)

Managed to get the Nanocom to talk to the D4 at cold start this morning, then wouldn't reconnect......