1500rpm Idle And Tapping When Warm

[Maccer 0]

Hi all,

 

Firstly apologies for re-re-repeating some old questions but I'm a little stuck as to where to start!

I have a combination of problems on my '88 1.6 205 which I suspect will probably have about 20 different answers to but here goes.

 

Car starts, can sometimes be a little reluctant - second turn and some throttle usually gets it if the first long one won't. Idles irratically for a few seconds and can sometimes stall but I give it a few jabs on the throttle soon as it starts and then she's usually alright. If it has needed the second turn it blows an intial bit of blue smoke and smells of fuel but runs clean after. Once started it will idle high-ish 1200-1500 while cold then once warm will drop down to around the 900-1000 mark and sounds alright on tickover to me too.

 

Problem: When I take it out and really give it some welly, the idle sticks at 1500 and the engine sounds very tappety at the top when idling. If driven gently for a while after the tapping usually dies down a bit however the idle stays at 1500 as soon as it's been driven for a while, and won't drop back to normal if you give the throttle a jab as I've read some others will. The tapping is only really noticable when its warm and has just had some pedal to metal treatment as you cannot create the same amount of noise by holding it at 1500 when cold, although if you have the bonnet open you can hear the tappets working lightly.

 

From reading this site I know I'll need to clean out the air intake system, check vaccum hoses, set up the ignition timing and maybe check the valve clearances, but I'm not sure if these two problems are related and don't know where I should start! A point in the right direction would be great.

 

I'm also a little strapped for cash at the moment and need to sell my other car before I can spend anything more on the 205. I do very little mileage anyway but I'd like to know if I run it with the tapping am I doing any major damage to it??

 

For ref, car has done 61k, I've just had the manifold gaskets done by Peugeot and it's got new 10-40w semi synthetic in it. The oil pressure seems good - 2/3 dropping to 1/2 when warm and it has a fairly new cam cover oil hose too - although the pressure guage doesn't seem to respond to the throttle position.

To complicate matters further I'm not sure what fuel it used to run on but I'm now using Tesco Super 99 Octane and am going to stick with that.

[DamirGTI 342]

I've had something very similar , and it was the SAD ... try this , when the revs increase up to 1500rmp stop immediately open up the bonnet and squeeze the SAD pipe which goes to the main inlet pipe in between the TB and AFM , if the revs drops down when you fully squeeze the SAD pipe then it's the SAD not closing completely ..

 

This usually happens during the long driving on a flat road/motorway , because then the coolant temp. drops down below say 85-80C and if the SAD heater connector is unplugged or if the wiring on the connector is broken then the gap on the bimetallic disc inside the SAD will open up again and it'll start to increase the revs like on the cold starting ..

 

So first try this "squeezing" test and then check the SAD heater connector (black connector) if it's maybe unplugged , take the multimeter switch the ignition on and measure the voltage across the connector terminals , if it's fine you'll need to see approx 12v .

 

Hope this helps !

Damr

Edited June 13, 2008 by DamirGTI

[djinuk 2]

just sold a good working sad aswell

[Maccer 0]

Started taking all the intake hoses off yesterday and going mad with the carb cleaner when I found that the tiny little ignition advance hose from the distributor had fallen off the throttle body as the end had perished. So I chopped a bit off and popped it back on and now I'm down to about 1200. Cleaned the butterfly whilst I had the pipes off and that seems to be returning to the right position, didn't check the SAD tho - will check the SAD pipe later today. Cheers guys think I'm half way there!