Acceleration Issues / EGR?

[tonyredz]

2003 406 S Hdi 90 hp

As per my previous post in December – the car was very sluggish and for a period I could not accelerate over 20 / 30 mph. I left the car off the road & did not it for a month. When I went to use it again a couple of weeks ago it would not start, (not a battery issue). Called out the AA he found there was air bubbles in the fuel line. He sprayed some brake cleaner into the air intake which fixed it and the car started.
He did an OBD scan which came up with the following codes:

P0401 – EGR Amount out of range
P1351 – Glow Plug main relay Short circuit or defective

I had a couple of Glow plugs replaced only last summer.
Does the EGR amount out of range may explain the lack of power / acceleration?

The AA guy noticed that the accelerator pedal was very low, close to the floor, (when car stationary!) On closer inspection It is about 2 & ¾ inches off the floor (7 cm). There seems to be about ¾ inch (2 cm) of play in the pedal.

His advice was to just use the car, not to bother about doing anything about the EGR. I checked a few websites regarding P0401 code – some say it is not a major issue others the opposite.
Have taken the car out it starts and runs OK and OK upto to motorway speeds. It seems OK.

Does anything need to be done about the EGR or the accelerator pedal?

Also, the air in the fuel line any insight as to what may have happened there?

Any advice / insight much appreciated.
Thanks.

[GingerMagic]

Firstly I would adjust the throttle cable, there should be a clip holding it in place but if it's pinged off then you'll have limited throttle - a clothes peg will do for the time being to keep the cable in place.

The EGR valve may be stuck open so your air pressure is being diverted out of the exhaust full time rather than on the over run - blanking plates are available online cheaply and just screw into place.

Try these out and then report back

[GingerMagic]

Sorry, just to clarify...
I mean the peg should hold the ribbed part in place once you have pulled the cable towards the bulkhead to take up the slack..... Don't make it too tight though as this sometimes causes error messages.

If there is slack in the cable then you will never have enough throttle to get the car moving.

[tonyredz]

Hi Gingermagic,

many thanks for your reply, would slack in the throttle cable explain the situation with the accelerator pedal? With it being close to the floor - 7cm off from the floor of the car, and there is a bit of play in the pedal as well about 2cm.

Cheers.

[GingerMagic]

To be honest I can't remember how my pedal behaved when the cable was slack - but 2cm free play is 2cm less throttle.....

You can take up the slack from under the bonnet, you can even see how it works and how it's affecting the performance, it's a simple design but it's flawed by a simple clip that often goes astray.

Try this first, if you are local to me I'm happy to pop by and have a look.

Also, take a peek here for an EGR blank
https://www.ebay.co.uk/itm/111125022659 ... media=COPY

[WillNZ]

+1 for blanking off the EGR. You dont need to buy a blanking plate, I have done all of my MANY 406's using thin tin (tin can works) which can be cut with a pair of scissors. There is not any real pressure in the egr system. When you do it, have a look into the intake manifold and see how gummed up it is. If severely gummed up, it will pay you to remove the intake manifold and clean it out.

Accelerator pedal should have minimum slack, I set mine at no more than 2mm.

Another thing to check is the integrity of the vacuum lines from the vacuum pump to the brake booster and the control solenoids for the egr and turbo. If there are leaks, the turbo will not open fully or at all (which would explain the lack of any power.) Pull the line off the vacuum pump and suck on it or use a syringe to draw a vacuum and see if it holds vacuum. If not, check for splits in the rubber connectors. If you dont find splits, check the brake booster holds vacuum as this can be a major leak source if the internal seals/diaphragm have failed. Also test if the solenoids are closing properly, they do fail occasionally.

[GingerMagic]

Hdi 90 is a mechanical wastegate - only the 110 and 2.2Hdi are vacuum controlled

However the EGR is vacuum controlled by the solenoids ( which are interchangeable) but I'm sure there is only one on your cars bulkhead - no harm in checking the vacuum lines.

If you were to have a fully functioning EGR valve that wasn't jammed open or obstructed in any way then you could just pop off the vacuum pipe and block the end so the EGR will never open....

In your case I would blank it off, yes you can use whatever is lying around to fabricate one if you prefer