Peugeot 406 errant revs. - cholin
Have just acquired a P reg. Peugeot 406 2.1 TD. The previous owner had occasional trouble with the engine revs cycling and engine slow to rev down when foot off throttle. The local agent ran a diagnostic check which reported no faults but he did clean contacts on the ecu (quote). This cured it 'til the next time. Back to the agent same result with disappearance of fault.
It has now happened to me. Pulled up, into neutral, foot off, engine did 3 or 4 cycles between (approx.) 1500 and 2500 rpm then settled down and now seems ok. The car has done 63,000 and has shown this tendency for some time but at very long intervals (months) and was ignored but now appears to be becoming more frequent. I was aware of this history and have no axe to grind with the prev. owner, we are both interested in getting to the bottom of it.
Any ideas?
Peugeot 406 errant revs. - leerichmond21
try the shock absorber on the fuel pump throttle linkage because it maybe rubbing preventing a smooth return
Peugeot 406 errant revs. - DL
Yes, I'd check the throttle linkage firstly - it could also be air in the fuel system....that can cause rev cycling.
Peugeot 406 errant revs. - RichardW
IIRC the 2.1 TD has an ECU and uses drive-by-wire. The cycling of the revs indicates to me that there might be a problem with the throttle position sensor, or the engine speed sensor or something. Not sure how it sets the idle speed, as there won't be an idle air valve as there would on a petrol.

I would suggest a trip to a Lucas Diesel injection specialist who may be better placed to diagnose any errant sensors.

BTW what sort of MPG are you getting (on what sort of driving?). I was thinking about getting a 2.1TD Xantia if I can find one as a stop gap between my current (underpowered!) 1.9 TD and an HDi 110 (out of my price range at the moment!).


RichardW

Is it illogical? It must be Citroen....
Peugeot 406 errant revs. - cholin
Thank you all for your responses much appreciated. I haven't had the car long enough to establish a mpg pattern the prev. owner reckoned about 50/g on a trip and I don't think he is a dawdler. I will ask if he has a feel for shorter runs. Similarly with this fault I will see if it has any pattern and then follow your advices.

cheers
Peugeot 406 errant revs. - GolfR_Caravelle_S-Max
I know this looks "Anoraky" but I have had to keep consumption figures for tax reasons. I have done over 700,000 miles in cars in the last 9 years - 50% personal Mileage. MPG does cost me a lot! Did have an Alfa GTV 3.0 V6 but was costing £160+ per week.. Fun though.. Pug at 800m/week is around £60.
I'm currently in a 406 2.1 TD with 170k on it.. Still a great car.

Peugeot 406 2.1TD GLX 1998 R-Reg.
Daily Commute around 120 to 150 miles. (back route/M-way)
M-way: 14 mins @ 30mph, 60 mins @ 80 mph, 8 mins @ 35mph.
Back Route: 14 mins@30mph, 20 mins@75mph, 30 mins@40-30-20mph
Service every 6000m, "fuel saver" device is fitted.
Original Engine, injectors, glowplugs, Gearbox and Clutch.
New Radiator, Rear Link arms, Exhaust.

I also have table figures for a Pug 106 1.5D (1995 M) and a Punto JTD 80 (2000 W)

Table Shows Date, Miles per Tank, Total ODO, Tank Cost, Litres put to brim, Gallons, Pence/Litre and final mpg.

Date Tank M Total M Cost Litres Gallon p/litr MPG
29/1/02 725 128403 £51.22 73.3 16.11 72.9 44.99
6/2/02 688 129091 £55.69 79.7 17.52 71.9 39.26
21/2/02 619 130596 £50.79 69.7 15.33 72.9 40.41
25/2/02 462 131058 £38.31 52.5 11.55 72.9 40.02
5/3/02 717 131775 £52.57 72.1 15.86 72.9 45.22
13/3/02 596 132371 £45.45 62.3 13.71 72.9 43.46
19/3/02 844 133215 £50.38 67.3 14.80 74.9 57.05
24/3/02 505 133720 £37.52 50.1 11.03 74.9 45.80
30/3/02 616 134336 £40.52 53.4 11.74 75.9 52.45
7/4/02 565 134901 £49.36 64.8 14.25 75.9 39.66
15/4/02 579 135470 £50.54 66.6 14.65 75.9 39.53
21/4/02 609 136079 £52.01 68.6 15.09 75.9 40.37
26/4/02 548 136627 £40.95 54.0 11.87 75.9 46.21
28/4/02 381 137008 £40.95 53.9 11.87 75.9 32.11
2/5/02 416 137424 £33.72 45.1 9.93 74.7 41.91
1/6/02 626 138050 £53.34 70.3 15.46 75.9 40.48
12/6/02 622 138672 £49.48 66.4 14.61 74.5 42.59
24/6/02 674 139346 £49.27 67.1 14.77 74.9 45.66
11/7/02 1530 140876 £99.00 130.0 28.60 54.2 53.50
22/7/02 606 141482 £51.38 70.0 15.40 73.4 39.34
2/8/02 424 142543 £42.67 56.2 12.37 75.9 34.29
8/8/02 692 143235 £55.82 75.5 16.61 73.9 41.64
26/8/02 568 144537 £47.09 64.2 14.11 73.4 40.22
3/9/02 649 145187 £51.32 69.9 15.38 73.4 42.21
12/9/02 565 145752 £50.77 69.2 15.22 73.4 37.13
19/9/02 552 146304 £46.76 62.4 13.73 74.9 40.20
22/9/02 491 146796 £37.74 50.4 11.08 74.9 44.31
27/2/02 723 147520 £54.36 73.6 16.18 73.9 44.69
8/10/02 679 148198 £50.08 67.8 14.91 73.9 45.54
12/10/02549 148748 £42.49 57.9 12.73 73.4 43.14
19/10/02660 149407 £54.84 70.4 15.49 77.9 42.59
24/10/02645 150053 £55.26 74.8 16.45 73.9 39.22
31/10/02555 150608 £46.75 63.3 13.92 73.9 39.88
12/11/02571 151179 £49.54 67.0 14.75 73.9 38.73
1/12/02 557 151736 £46.03 62.3 13.70 73.9 40.66
9/12/02 633 152368 £53.18 72.4 15.92 73.5 39.78
15/12/02499 152868 £40.50 54.8 12.06 73.9 41.41
19/12/02603 153471 £43.76 59.2 13.02 73.9 46.29
27/12/02523 153994 £43.33 57.1 12.56 75.9 41.63
30/12/02741 154736 £57.17 77.3 17.01 73.9 43.56
31/12/02636 154799 £5.29 67.9 14.94 77.9 42.58
5/1/03 562 155361 £46.17 61.2 13.45 75.5 41.79
11/1/03 495 155857 £37.42 50.2 11.05 74.5 44.80
17/1/03 732 156588 £60.29 78.5 17.27 76.9 42.38
14/2/03 619 157208 £52.22 66.2 14.56 78.9 42.55
16/2/03 662 157870 £52.91 77.9 17.14 77.9 38.61
26/7/03 695 158564 £55.02 71.0 15.62 77.5 44.47
27/2/03 273 158837 £20.12 25.8 5.68 77.5 48.07
9/3/03 629 159544 £51.63 64.6 14.21 79.9 44.26
14/3/03 651 160116 £49.93 60.7 13.35 81.9 48.78
18/3/03 480 160596 £40.07 50.1 11.03 79.9 43.49
20/3/03 440 161035 £37.08 46.4 10.21 79.9 43.10
22/3/03 637 161672 £54.28 67.9 14.94 77.5 42.63
6/4/03 700 162372 £56.77 70.2 15.44 80.9 45.35
12/4/03 573 162945 £46.19 57.8 12.72 79.9 45.06
28/4/03 563 163508 £48.73 62.6 13.76 77.9 40.92
3/5/03 467 164976 £39.70 51.0 11.21 77.9 41.66
7/5/03 649 164625 £56.75 72.8 16.00 76.9 40.55
11/5/03 623 165247 £48.86 62.7 13.80 77.5 45.16
14/5/03 611 165858 £54.97 72.4 15.93 75.9 38.38
21/5/03 698 166556 £56.52 74.5 16.38 77.5 42.60
30/5/03 698 167254 £55.04 70.7 15.54 77.9 44.93
6/6/03 731 167985 £60.28 76.4 16.80 78.9 43.51
12/6/03 801 168786 £60.04 76.1 16.74 78.9 47.86
26/6/03 883 169669 £58.56 78.2 17.20 72.9 51.32
30/6/03 775 170444 £55.45 74.0 16.28 74.9 47.60
7/7/03 779 171223 £51.46 68.7 15.11 73.9 51.51
Peugeot 406 errant revs. - Reggie
Cholin, sorry for the late reply, but I have just got back from my hols last night.

I know of another 406 2.1td that has had a fault sounding almost identical to yours, and it turned out to be the water temperature sensor i.e. the one to the ECU, not the guage sensor.It is screwed into the thermostat housing with the green electrical connector on it. This was not identified by the main dealer when the diagnostic check was done.

Reggie
Peugeot 406 errant revs. - cholin
Thank you Reggie, will get it checked out when the time comes.
Neddless to say after posting the problem here it immediately happened again and then hasn't happened since.
Peugeot 406 errant revs. - cholin
RichardW.

Previous owner kept a record very similar to Alfa Pug's, reckons it worked out at an average of 48/g for general purpose motoring.
Peugeot 406 errant revs. - Reggie
My 406 2.1td that I have owned since it was 6 months old and now has the low milage of 50,200 miles does 38mpg for around town use to 47 mpg on a longer run type use.
Reggie
Peugeot 406 errant revs. - Mapsimus
By chance I am currently doing a mileage check on my 2.1 406

On a recent 350 mile m/way trip it managed 55mpg (70mph+), and over the last 1700 miles, mainly town use & towing (only a couple of long trips) it has returned 46mpg.

As yet I am unable to get a direct comparison with the a/c in operation.

Mapsimus
 

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