peug 2.1 td revs going up and down when idling

zxb29 · Post by **zxb29** » 04 Sep 2006, 23:50

Hi guys

i seem to be having a problem sometimes when i start the car up. The engine seems to be revving up and down and sometimes just goes up so i have to switch off the engine quickly. Its quite random but switching the car on and off a few times cures the problem until it re-occurs

any ideas what the problem could be

peug 406 2.1td P reg
seems to be a electronic pump where the accelarator cable goes into a box near the battery.

Thanks.

Zab.

JohnD · Post by **JohnD** » 05 Sep 2006, 09:07

Could be air in the fuel system.

AndersDK · Post by **AndersDK** » 05 Sep 2006, 10:02

Agree on the air problem.
It is by far the most common problem on diesel engines.

The rotary diesel fuel distributor pump does not accept even the slightest amount of air in the incoming fuel. It upsets the volumetric regulation of the fuel.

Look for any suspect fuel line : surface hairline cracks on rubber hoses, split hoses at studs, especially the overrun hoses at the injectors.
And its both the feed & return lines to/fro the tank.
The filter/heater bowl is also to be suspected.

A good trick is to replace the very last run of fuel hose going into the pump with a clear hose. This way you can instantly see if you have sorted the problem, as any air will be visible as bubbles.

I urge you to do this before you invest in any replacement components or garage labour.

JohnD · Post by **JohnD** » 05 Sep 2006, 15:48

Since it's a 2.1, a lot of the under-bonnet fuel line is clear plastic.

zxb29 · Post by **zxb29** » 06 Sep 2006, 11:24

thanks for the replies guys il have a look today if i can il get back to ya all

OwenP · Post by **OwenP** » 06 Sep 2006, 12:28

Does anyone know where I could get clear plastic fuel line from?
Cause I'm having a very similar problem.
So far have used silicon but that won't last forever, and has already changed it bore, upwards thankfully.

AndersDK · Post by **AndersDK** » 06 Sep 2006, 23:47

Its PVC hosing -

Used everyhwere you have to move fluid any kind :
1) campers & boats for drinking water and waste water
2) cars for fuel & vacuum sensing in general
3) industri for oils and air supply
4) home & garden for garden hoses and laundry machines

Available in almost any thinkable diameter and wall thickness.

zxb29 · Post by **zxb29** » 07 Sep 2006, 15:29

ive taken a look at mine it is clear plastic which is covered in dirt but cant seem to see any air gaps yet i suppose il have to take a look when the problem occurs.

as per the thread by the chap with the 306 mines different as if blip the throttle the revs just go higher and still jump up and down

JohnD · Post by **JohnD** » 07 Sep 2006, 15:52

If air is getting in, you'll see the air bubbles passing through the pipe when the engine is running - or even if you squeeze the primer bulb without the engine running. Don't rule out the primer bulb from having a slight leak.

zxb29 · Post by **zxb29** » 12 Oct 2006, 15:15

hi guys this is still happening but not only when i start up nw last 2 mornings when ive started car has been fine as soon as i got to the bottom of the road and stood still in traffic it would start idling erraticaly either a switch off/on would cure or pressing rev pedal a few times would help

ive read somewhere it could be the idle air control valve ?

anybody know where this would be on the 21.td engine ?

JohnD · Post by **JohnD** » 12 Oct 2006, 16:03

Sounds like air getting into the fuel.

davethewheel · Post by **davethewheel** » 14 Oct 2006, 00:43

could be the engine temp sensor it's a green sensor on the right hand side of the cylinder head, i've heard of a few of these packing up and causing the revs to fluctuate, it's worth a try and the sensor is only around £8.00 from the dealers

AndersDK · Post by **AndersDK** » 14 Oct 2006, 18:38

davethewheel wrote:could be the engine temp sensor it's a green sensor on the right hand side of the cylinder head, i've heard of a few of these packing up and causing the revs to fluctuate, it's worth a try and the sensor is only around £8.00 from the dealers

On a good old TD ? 8)

davethewheel · Post by **davethewheel** » 14 Oct 2006, 21:01

AndersDK wrote:
davethewheel wrote:could be the engine temp sensor it's a green sensor on the right hand side of the cylinder head, i've heard of a few of these packing up and causing the revs to fluctuate, it's worth a try and the sensor is only around £8.00 from the dealers
On a good old TD ? 8)

yes all the peugeot 2.1td's and xantia 2.1td's have this sensor.

regards dave

AndersDK · Post by **AndersDK** » 15 Oct 2006, 00:18

I stand corrected

Thanks Dave !