406oc.co.uk

OK, so. Went and bought a few spaniards. Tinkered with the fuel pump for two hours. But buggered, buggered if I could get the idle to come down.

First I adjusted the one on the back, pressing up against a spring and bellows kind of arrangement. On reflection, this turned out to be the damper ( )

Next I found one wedged right down the back, almost impossible to access in-situ. It was stopping the lever moving any further down, so I figured it must be the idle. Managed to unlock the nut on this and wound it right down... idle speed never moved. On consideration, now believe this to be the anti-stall adjustment.

So eventually I gave in and dug out the Haynes BoL. It suggested, via the medium of a very cryptic line drawing, that there were two vertical screws representing idle and fast idle control. Wound both of these up and down and neither made a jot of difference.

Threw book on the road in frustration. Put everything back the way I found it an drank tea and smoked until I felt better.

O wise and omniscient 406 forum, how does one adjust the idle speed on a 1.9 Bosch pump?

No idea but are you sure the cable isn't holding it open? Try disonnecting it perhaps.

Do as Steve suggested, then if that isn't causing the problem, using your Haynes manual, follow the instructions in the section that covers the diesel engine annual service. All pump adjustments, including tickover are usually listed in this section.
If your pump has a cable fitted for the fast idle, make sure there is a little clearance on that.
Also check that the anti stall adjustment is correct.
Idle speed is 800 rpm without aircon, 850 with.

Thanks guys. If it stops raining, I'll take another look.

[EDIT] Sun's come out. I'm going back in! *dons safety helmet and radiation suit*

Right, well still no joy. Thus, I went and had a poke around on the French car forum and found this.

Armed with this new information, I wandered back out in to the bright sunshine but freezing bloody wind and took some pictures:




Now, to me this looks like a PT100 with a bowden cable running under the air ducts to the back of the pump. There was a wee small bit of play in the inner cable, and it looked a little rusty on the inside. However when I started the engine and tried to move the cable in hand-o-matic mode it didn't seem to affect the revs. Admittedly there's little point in trying to fix this when it's so cold as it's not supposed to lower the revs until the enjin's warmed up

So, the questions:

• Is this the cold idle controller the fellow was talking about?
  How would I fix it/replace it? I can remove the bracket from its mounting and peel back the gaiter but otherwise can't see how it would come apart
  If it's not the cold idle control, what is it?

Also, while I was out there melding with things I don't yet understand, I discovered the stop lever. My question here: what effect does turning the screw on this up and down have? I realise if I screw it too far down it cuts off the engine/makes it struggle to start. Is there a point to this screw?

Right, once again I have been talking out of my arse.

What it actually is is a vacuum-operated diaphragm, acting on the cable which in turn acts on the fast idle lever.

The problem: there's no bloody vacuum hose attached to the diaphragm housing. There's the wee stub of pipe where the hose is evidently supposed to go, but no hose.

So, if I were to buy a length of hose - where would the other end go? Haynes is a bit mysterious on this subject. I gather there's some sort of temperature sensor, and possibly a solenoid on the other end which routes vacuum to the diaphragm when cold. Could someone with a working 1.9 have a look and find out where this hose is supposed to go?

Cheers, off to play wi' me steering wheel.

Tom

Well the 'other end' will have to plug into the vac pump arrangement somewhere as there's no throttle pot/butterfly/vacuumy bit on Diesels.

Just thought, yours is a 1.9'er right? you can frigg the pump on those for ubber extra go go - have you looked into this? the guys on the 306 1.9Dturbo forumz all go on about it.

Swissy - you really could do with a small written reminder of when your cambelt was changed, you wouldn't want to overlook that

Indeed, ramping up the pump and turbo are on the list of things to do come the summer, pay raise and garage.

Will have a look at the vac pump. One question, though - where's the vac pump?

Oh, and the cambelt change note is a big, fat, steaming lie

You are assuming the fault with your idle is the cable from the vacuum valve highlighted in your photo, have you tried disconnecting the cable from the pump side to see if the problem goes away with that disconnected?

With the cable disconnected, you can manually move the fast idle lever, this way you know for certain if the idle can be lowered or raised, according to where you move the lever.

Well yes I am Jasper as there is no hose connected to the valve. Therefore it's not getting any vacuum signal and appears to default to fast idle (unless maybe the lever is stuck in place or something, entirely possible I suppose). Even if I reduce the speed down to 800, it means I'll lose the cold-start protection. Then again maybe now it's warm enough that that won't matter until I can get the pump out and have a proper look.

I was trying to work the lever manually today. But it's wedged between the back of the pump and the engine block

Praps if I get it up on the ramps, I'll be able to disconnect enough of the ducting to get a better grip on it...

Another attempt either tomorrow afternoon or this weekend, methinks

Thanks for the advice, peeps

Right, I have commenced performing my impersonation of a dog at the base of the correct arboreal specimen.

Found a small hose dangling from the vacuum gubbinz. This turned out to be just right length to connect to the diaphragm. It had a split in the end, explaining why it had come off (whether from wear or from heavy-handed 'maintenance', I may never know). Chopped off the split length and dunked the end in boiling water. With some brute force, ignorance and swearing it finally went on. Well, a bit. Will need to find a wickle jub clip or something to keep it there methinks.

Anyway, just a moment or two after, the white 406 a few doors down from me turned up. Accosted the driver and guessed as to the car's 1.9ish nature. She was suitably impressed I could tell just from the sound Anyway, got her to pop her bonnet so I could have a look underneath ( ) and w00t! Long story short, I'd plugged the right hose in to the right place

Now, just got back from the shops. Although the car got up in to the high seventies, the idle still didn't come down. If anything I think it's a little higher this evening, a whisker shy of 1200. So now the whole thing is re-assembled I guess I need to fiddle with the pump settings... or maybe indeed the system is cream crackered.

So, what could be wrong? So far I have

• No vacuum - guess I should have run the engine before I re-connected the hose to see if it was pulling
  Bad diaphragm
  Bad thermostat - guessing not as the water temp is otherwise fine
  Cable sticking
  Fast idle lever stuck
  Idle and/or fast idle speed settings out

Tomorrow will try and get at the FI lever, no luck with this so far but I've not really tried very hard.

Thanks again for the continued advice and support

I'm thinking you need to work through th fuel pump adjustments in Haynes and see if that helps (not that I can work uot what it's saying but I don't have the right fuel pump to look at...)

Success! Um, kind of. Not really...

OK, well the idle is now down to ~950. Not perfect, but an improvement. I achieved this by slacking the damper and anti-stall all the way off and loosening the fast idle cable at the diaphragm bracket. Then I unlocked the fast idle screw and wound it in the reduce the speed.

Found that the fast idle screw tightened up, requiring the idle screw to be screwed out. This allowed the fast idle to be screwed further in.

Ended up with the fast idle screwed pretty much flush with the locknut - not good practice. Still, though, the idle wouldn't go below 950. So I fiddled with the cable control at the diaphragm bracket and found that tightening it up (i.e. screwing it in) further reduced the speed.

Problems, though - when it approached 900, it began to chug as though it was on the verge of stalling. Ended up setting it at 950 and calling it a draw until a complete overhaul is possible.


Now for the bad news

Started out by asking wifey to come depress the accelerator so's I could see if the cable was adjusted correctly. She popped her dainty hoof on the pedal and PING - yon brass bit on the end of the cable, mounted in the armature, disappeared somewhere in to the depths of the bay. Sigh.

To the scrappy!

Oh gawd, these things are sent to try us Tom!

Okay, well, scrappy trip proved disappointing - only one 406 with a cable present and everything else looked way too short. Wasn't able to get it out as they close early on a Sunday (and I slept late ^^).

Now off to B&Q to obtain bits for a 'temporary' bodge.

Question, then: how does one get the cable out through the bulkhead? Managed to get it d/c at both ends but it seemed to be held fast in the middle...

On the plus side, ****ing nice weather out today



[EDIT] Why is it vibrating more at lower speed?