Finding a leak

[DIYheadache]

Hi Forum,

My wife's car has returned to form and has a high idle (2800) when started from cold and idle fluctuates when coming to a stop.

Y reg 206 1.4 Auto

The consensus on the forum is it is a vacuum leak, somewhere. How best to find the leak? I've heard that you should spray carb cleaner around the manifold and listen for changes in idle. Is this the best method and will it find the leak?

p.s - A bit hessitant to spray highly flammable liquid on an engine, how should I be sure not to cause a fire?

Many thanks

Pete

 

[wotan]

Have you checked the erg valve?
It could be gummed up or stuck open, also check and clean the mass air flow meter.

Wotan

 

[gblades]

If you want to spray carb cleaner make 100% sure that you dont spray it around the air intake in you have a MAF (mass air flow sensor) as it can damage them and you will be looking at a fairly expensive repair bill.

 

[DIYheadache]

FOUND IT!

It's one of the inlet manifold seals. On the others the manifold sits flat with the head but on the fourth inlet there is a small 1.5mm gap and you can see the seal. I hope this is not a warped inlet manifold!?

I don't want to remove the manifold myself, so could anyone on here give me an estimate on how much it will cost to replace the seals (I think they maybe damaged)?

I also discovered that the back box has rusted through at the joint, dripping constantly. How much will this cost to replace?

Many Thanks

Peter

 

[DIYheadache]

Hmmm, not sure about the gasket.

Could any of the old-school mechs help here?

I've placed a vacuum gauge on the engine when warmed up. Vacuum is roughly 18 inchs but is not steady, waves up and down by plus or minus 1 mark. Does this point to anything?

http://www.secondchancegarage.com/public/186.cfm

Scenario 11 - This is the closest to what I'm getting, but centred at 18". Says retarded ignition!! Why would the ignition be retarded?

Thank you

Peter

 

[DIYheadache]

Took car to Peugeot specialist. He had a good look at the intake system and all sensors and could not find anything wrong. He changed the exhaust and put in a bottle of Forte Gas treatment. He said this should help clean up the engine inc lambda sensors.

Was out the other day, everything running smoothly, was waiting for ages in traffic and the engine starts reving up and down! Engine temp was around 94 and no engine management light. It can't be the purge valve again?

have searched around and on lambdapower site it said this sort of beheviour,including the high idle, could be caused by a sluggish lambda sensor. Does anyone agree with this? I have a replacement temperature sensor, which I will swap over asap.

I would really like any help with this please.

Peter

 

[Belle427]

does not sound like a lambda problem to me. What was the outcome on the gasket you said looked as if it had failed

 

[DIYheadache]

The guy at the garage checked it and said he did not think it was leaking, if it was he'd expect it to idle rough all the time.

Looking at the MOT test results, I would say the lambda sensor was fine too. I'm going to change the temperature sensor in the hope that this will sort it out.

Thanks

 

[DIYheadache]

Why is this problem only happening at 94 degress, which is also the point when the cooling fan turns on? Once the engine has cooled down a bit it stops. Could the fault be related to the cooling fan coming on? My thought is turning back to the Idle control valve again!

Peter