406oc.co.uk

Some of you may remember that i recently had a problem with my hdi in that it keeps holding back on power intermittantly. Had air-flow meter replaced but not cured.

Basically when the fault happens it feels like theres no turbo - The revs creep us really slowly then all of a sudden it clears and all is ok.

It did it from cold today for approx 5 miles then all was ok, - It does seem though to happen only in the higher gears 3rd and 4th / 5th.

Its baffling me any ideas??
ps its a 90bhp 2001

Perhaps your Vac Pump is worn out? This provides the Vac needed for the turbo actuator.

Could it be the EGR on the way out? If it is sticking open intermittently, the symptoms could feel like a loss of turbo boost.

Well i have just had the car put back on the diagnostic machine and it has come up with 'loss of signal air-mass' which was the same fault code as before when the mass meter was replaced.

One other interesting point is that the egr valve used to hum intermittantly but stopped if you turned the engine off and restarted - but it has not made the humming noise recently so i am wondering if this is the problem, but i would have thought that if it was the egr valve it would do the fault all the time and put the management light on?

Baffling!!

its most likely the engine ecu harness plug, the pins on it wear out and with the shaking of the engine you get a poor contact, though when you test the circuit it all seems to be fine

James so how do i go about rectifying this ? and where is the plug situated?

you need a new engine harness, you can repair it if you have A LOT of patience, as you open the bonnet, look to the left near the front, there is large black plastic box, the ecu is in there, take the cover off, and unclip the plug, turn it over and look at the pins, there are three rows of them and about 40 of them, using a watchmakers screwdriver set CAREFULLY bend the pins so they are closer together refit, clear the fault codes and test drive

Well just spoke to perrys peugeot, and interestingly they are saying they have had no problems with the connector going to the ecu, But they do suffer from broken down wires on the harness to the ecu where it bends in to the connector, so a starting point i guess and its booked in in a weeks time. Pleasure - i imagine its gonna cost a bomb!!

robconnors1977 wrote:its booked in in a weeks time. Pleasure - i imagine its gonna cost a bomb!!

Well don't let them at it then ?

If you don't want to look yourself, a decent Auto Electrician or garage will do a better job than Peugeot.

The dealers are not usually that good at finding intermitant faults (unless your lucky on the day and get the only guy there that knows his stuff)

im such a dick, you got an air mass meter fault and replaced it but the same fault was logged, the air mass meter on a HDi 90 is only there to see if the EGR is function, it clearly isnt and is flagging the air mass meter, my solution, pull the vacuum pipe off the EGR solenoid and blank it off

James it sounds like your a star - but can you explain in a bit more detail what to do!!.

Thanks

you need to locate the EGR valve solenoid, im not sure whereabouts it is on a 406, but if you have a haynes manual it should tell you, there will be two small rubber pipes on it, take both of and blank them off, and thats it, go for a drive and it should be fine, you may notice a small increase in fuel economy

i got this from one of the guys on pug306.net

its a guide for a 306 HDi 90 EGR

www.pug306.net wrote:ok ill keep this short! take one hdi engine bay!



If you look at the top left corner the EGR valve is placed just out of sight...

it looks like this



you can see the blue clip at the back. this is the part you need to remove... i used a screw drive to press back against the egr valve on the blue clip and it just pops off. like so



For me, it frees up the revs and will hopefully improve mpg!

instead of taking the plug off, take the vacuum pipes as i said, as im sure it will put the K light on

Many Thanks james will give it a go tommorrow. The valves are on the baulkhead.

Just out of interest how is the flow meter connected to the egr valve. Does this mean that the probable cause of all this is the egr valve is shot?

Thanks again. Your advice is very usefull.

Oh and when you say block of the pipes i take it you mean the actual pipes and not the solenoid connections?

the air flow meter measures rate of air flow, the rate of air flow will decrease when EGR is used and the engine managent will look for this decrease when EGR is requested, if however the flow is too low all the time as the EGR is stuck, it will think the air mass meter is at fault, when the actuall EGR valve is stuck, or the solenoid is, but if the solenoid was stuck it would log a fault like EGR solenoid short circuit internal fault, the reason i say to take the vacuum pipes off is because if the solenoid is faulty then the EGR will still be working when it shouldnt and you will still have the problem