405 GTX TD emission problems

garage is talking 'swap the pump, it's

First thing, take it out on a quiet road and floor it in second. Keep this for at least 10 seconds, and you will see the cloud of smoke reduce, and eventually go completely. Do this again, and then take it back immediately for a retest. Mine (93 1.9 TD with 140,000) got a score of 0.5 after this trick. There could be a fault in the pump, but try this first. There is also an adjustment on the top of the Bosch pump , under the cover where the turbo diaphragm lives, where you can, if you know what to do, reduce the overfuelling on turbo boost. If you get it wrong, however, you end up with reduced power. Basically, if you take the cover off and remove the diaphragm, you will see a spring. Put a washer, or thin packing under this spring, no more than 1mm thick, and it will reduce the over fuelling on turbo boost. DON'T turn any of the spindles. Have you checked all the glow plugs are OK? One down and you will have this sort of problem when starting. Also on the TD the glow plugs remain on for about 2 or 3 minutes after starting. They go off when the temp is up, or the throttle has been open enough to activate the little micro switch on the top of the pump for more that a certain time.

If the engine runs ok then ignore this. You may have an air leak on the pipe from the tank to the pump. It goes via a fuel preheater in the back of the water pump on mine. You might also have a perished rubber pump. I did change mine a year or so back.

Hello Brian,

The garage tried that - the levels came down a bit (from 5.3 to 4.3), but it wasn't enough.

I'll try that!

Cna these be checked without removing them? Sorry to be such a novice :o)

OK ... the Haynes manual refers to that switch, but I haven't discovered it yet.

OK -

Cheers - thanks for the reply.

Phil Andrews

Philip

I had the same problem this month on my 406 1.9TD. Smoke reading 5.6. The local dealer recommended filling with Forex an injector cleaner and then giving the car a good burn up the motorway. This cures 90% of problem engines. This cured the problem and brought the reading down to 2.5 upper limit is 3. They now recommend using an injector cleaner at each service. Mike

Hi Mike, I saw your previous post about forex. I've had a look and can't seem to find it anywhere. Where did you manage to get hold of it, and how much was it, roughly. I've tried wynn's oil additive and 3 bottles of redex, but I still seem to get smoke,

Neil

Hi Mike,

Thanks for that - I used injector cleaner, and that brought the levels down a bit (but not enough - 4.3). I took another look under the bonnet yesterday after hearing other advice and found that the fuel filter housing appears to be leaking slightly (down near the inlet pipe) when I prime the system with the squeeze-bulb - could this have any bearing on my problems?

Cheers,

Phil Andrews

There's a star washer holding a filter/one way valve assembly. The 'o' ring is probably leaking. I left mine to sort itself out. It's a very expensive part to replace. Cheaper to just get a 2nd hand filter pot.

The later 93 on cars don't have the microswitch. Later vehicles using this engine just leave the heater plugs on for a few minutes.

Hiya,

OK ... I've found out that it's £63 inc VAT + postage for the filter unit assembly. I didn't realise that that part of it might be repairable - I'll attempt that, thank-you kindly for the info.

Cheers,

Phil

Hiya,

Right! Thanks for that - as usual, the Haynes and the hardware don't match.

((:o)x