406HDi boost loss

Sebastijan · Post by **Sebastijan** » Thu Jun 14, 2007 11:21 am

Hi guys, I went trough the forum a bit and found a couple of topics that might or might not be the same problem as mine, but noone seems to describe their problem all that precisely, so I decided for a new topic.

I drive a Peugeot 406 HDi, and lately the engine started doing some odd things. The turbo normally kicks in at some 2000rpm, but now, when I strech it's legs on the motorway it won't spin up until 3000rpm, the odd thing is that if I let it fall under 2000 it'll boost up at 2000 again, or if I lift off for a couple of seconds (between 2k and 3k) it'll usually run normally again untill I go over 3k, than if I let it fall to say 2500 it won't pull untill exactly 3000. It does this in all gears at all speeds. I don't think it does that when it's cold, but I don't really know since I never let it revv heigh when it's cold. The car has done 180000+km so I guess it's time for the turbo to go, but other than that, it runs perfect, doesn't burn oil (as I would expect with a worn turbo), doesn't smoke, no problems at all, so I suspect some issue with the electronics.

I don't know all that much about these engnies, so thanks in advance for your advice

Sebastijan

Post by **Welly** » Thu Jun 14, 2007 12:00 pm

Hi, your Turbo will not have failed here (they seem to last forever).

I would suspect maybe the VAC Pump, an air leak in the Vacuum lines somewhere, or a problem with the boost control solenoid. Maybe also the intercooler hoses may have a leak.

Electronically, it could be Air flow Meter (rare) throttle position sensor (common) there might be others on here who will add more ideas so hang around a while too.

Welton.

robconnors1977 · Post by **robconnors1977** » Thu Jun 14, 2007 2:07 pm

sounds very similar to my problem that i have, so dont go replacing the air -mass meter just yet as i did as it probably wont be that. Mines booked in again tommorrow and we think it may be fuel pressure related so maybe and hopefully the LP pump as its done 144k on the original one so well over due.

Keep you posted!!

Sebastijan · Post by **Sebastijan** » Thu Jun 14, 2007 6:33 pm

I wouldn't even think of the air mass flow meter, since I don't see how that could wear out.

Sorry, but I'm not at home with the termology (I'm not form England), the LP pump is the pump at the fuel tank? A VAC pupm is a vacume pump? If so, where? The boost control solenoid would actuate the bow off valve right.

Thanks for the input

robconnors1977 · Post by **robconnors1977** » Thu Jun 14, 2007 8:37 pm

Yes thats the one in the tank and can cause all sorts of problems.

Could be your turbo solenoid valve, but that normally puts the K light on. Try disconnecting the egr valve solenoid to rule the egr valve out.

Sebastijan · Post by **Sebastijan** » Fri Jun 15, 2007 11:21 am

OK, so the car's off to the garage (it's time for a service anyway), and I described the problem to the mechanik, the first thing he thought of was the air mass flow sensor, so I also mentioned the LP pump, aparantly it's a miracle that it lasted this long anyway, so he'll have a look at that too, and I guess I'll just have to wait and see what he comes up with.

robconnors1977 · Post by **robconnors1977** » Sun Jun 24, 2007 4:48 pm

Did you fix the problem?