406 sri engine idling to high?!

[nobbie]

I fitted the 205 1.9 gti inlet manifold while I was waiting on my new coil pack to arrive, After I fitted the coil pack and inlet I started it up and it idles just below 2000 revs. Can anyone tell me what the problem could be as I have tried everything! Idle control valve is fine.

Thanks

[mjb]

Have you unplugged the throttle pot?

[nobbie]

what you mean? is that one of the plugs on the throttle body? I have taken them out and they are fine, took it out for abit and the downpipe was glowing red and I wasnt driving fast?!

[mjb]

You want to fiddle with the plug to the beige squareish lump mounted on the side of the throttle body opposite where the linkage turns

Try unplugging it and see if it makes a difference to anything. It should make a huge difference for the worse. If it doesn't, you've likely found your culprit.

[steve_earwig]

Sounds to me like an air leak on the manifold, is that possible? I could be thinking carb here...

[Welly]

For the manifold to be glowing red hot means the mixture is very weak - don't drive it like this.

It could indeed be sucking air in somewhere. If you were to spray a bit of WD40 on the joints whilst the engine was running you should hear the tone change when it sucks some through helping you to find it - I'm sure it's ok to do this, right guys?

[jasper5]

For the manifold to be glowing red hot means the mixture is very weak - don't drive it like this.

It could indeed be sucking air in somewhere. If you were to spray a bit of WD40 on the joints whilst the engine was running you should hear the tone change when it sucks some through helping you to find it - I'm sure it's ok to do this, right guys?

Yes, you are correct, if you suspect an air leak, spray WD 40 around the inlet manifold joints, but don't spray the WD 40 anywhere near the glowing manifold.

[nobbie]

You want to fiddle with the plug to the beige squareish lump mounted on the side of the throttle body opposite where the linkage turns

Try unplugging it and see if it makes a difference to anything. It should make a huge difference for the worse. If it doesn't, you've likely found your culprit.

I have unplugged it and nothing happened?!(this is the yellow coloured one) This is the only plug that I didnt actually have to lengthen to recah the new throttle body position, what do i need now? I have a spare throttle body that I could fit if that would help?

Thanks for all the help guys. You wont believe how much I appreciate it!

[mjb]

I have unplugged it and nothing happened?!(this is the yellow coloured one) This is the only plug that I didnt actually have to lengthen to recah the new throttle body position, what do i need now? I have a spare throttle body that I could fit if that would help?

The one you need to unplug is the bottom one in this picture (The one above it is a temperature sensor iirc, and the one on the other side attached to the yellow plastic is a heater)



It's the bottom right one in this view:



If unplugging it makes no difference, try the one from your other throttle body.

If I'm right about the cause, it could also be the idle control valve as shown here just behind the radiator:


Unplug it, pull the clips off, yank it out, give it a good old clean with carb cleaner (it'll be FILTHY inside) and put it back using jubilee clips as you won't be able to replace the stupid peugeot ones

For the manifold to be glowing red hot means the mixture is very weak - don't drive it like this.

It could indeed be sucking air in somewhere.

If the throttle pot is disconnected/broken, if memory serves it'll just open the idle control valve fully and try to guess how much fuel to put in using some air pressure sensor or something, causing lean operation and iffy idling around 2000rpm on the tubby

If you were to spray a bit of WD40 on the joints whilst the engine was running you should hear the tone change when it sucks some through helping you to find it - I'm sure it's ok to do this, right guys?

As Jasper said, keep it away from anything hot if you want to keep your hair+eyebrows That also goes for blasting compressed air about - it's rather easy to create a mildly explosive atmosphere

[nobbie]

Okay I checked th plugs etc and they are fine, so I squirted wd40 on the inlet and there was a leak at the throttlebody. so took the conversion plate I made up back off and resealed it and bolted it all back up and it is now running better. It does sometimes idle a little high, but if i turn it on and off then it is okay again?! Not to bothered about it as it is definately better than it was.

Now for the next problem! I am pretty sure the dump valve spring is to weak, as when I lay off the throttle at lower revs I hear a chudder through the idnuction kit? It does dump higher up the revs but with a slight chudder still. Am i correct on it being the dump valve?

[jason1987]

from what ive been reading thats the turbo not building up enough pressure on low revs to open the dump valve so it just goes back through the turbo, nothing to worry about on small turbod cars like ours lol

[mjcook1984]

how have you matched the inlet ports are the sri ports are like a light bulb shap and the 205 gti ports are rectangular surely going from rectangular to circular must be playing havoc with the air flow

[no2lurch]

i'm keeping an eye on this... what gains are there with the gti inlet manifold? sorry to hyjack the thread.