Whats Making My 1.9 8V Idle So High? :s

[johnhenry 20]

update!

 

fitted good used SAD this morning, tested everything for air leaks (easy start method) - verified NO AIR LEAKS

 

It still idles high, and hesitant under about 2500 rpm.

 

Any ideas? Coil/ignition amp??

> I'm going to switch my AFM over to another used one I've got to see if it makes any difference at all, I'm reaching now

[welshpug 1,661]

Igniton amp has nothing to do with idle speed!

 

If you really dont have any air leaks, the throttle cable is free, then it can only be throttle initial settings.

[johnhenry 20]

Igniton amp has nothing to do with idle speed!

 

If you really dont have any air leaks, the throttle cable is free, then it can only be throttle initial settings.

 

I know I'm just struggling to make sense of it :s

 

> no air leaks - I've gone over literally everything with easy start, no increase (other than over the air filter, to make sure it had the desired effect)

> when warm, pinched the SAD pipe, no change in idle, so i know that it's working.

> the idle screw is still fully screwed in - it should stall, and it doesn't.

 

i know I'm being stupid, i know I'm not doing something right. :/

[welshpug 1,661]

if the air bypass screw on the throttle body is screwed all the way in you need to back off the throttle stop, before doing this you need to slacken off the TPS screws or the Throttle spindle will stop against the TPS not the throttle stop.

[johnhenry 20]

will do the above, i have followed the haynes manual setup process on a throttle body that i have fitted and its made no difference, but ill have another stab, its probably me somewhere along the lines.

 

swapped over arm's too to an older one i had, no change.

 

A thought i had just out on my run was:

 

would a wire that's broken down cause it to run a high idle?

[johnhenry 20]

loosened the Throttle Position Sensor so it was free to move, and backed the Throttle stop screw off completely, so i knew the butterfly was completely shut.

 

it still idling high, up to 2000±

 

I've then moved the TPS on and off, to simulate the 'click' when the throttle shuts normally. There is a moment when the engine speed drops, then it climbs back to its usual idle.

 

I then changed over to another TPS I have, and the same issue happened, so its not the TPS.

I have also wound the AFM out 7 turns as standard, which is the amount you're supposed to, Ive used different (same numbers) AFM on it yesterday and it made no change.

 

SO by my logic, the components don't seem to be the issue, Its

>how I'm using them, I've cocked something up

>Wiring maybe?

 

I'm getting the feeling I'm only making things worse too, the bay is now looking really messy and unorganised :/

 

Welshpug - kind of why i got in touch with James, I don't mind parting with beer money/cash to have somebody who knows exactly what to do looking over it as I'm pretty much out of ideas, was out of my depth at least 2 weeks ago :/

 

Cheers

John

[DamirGTI 342]

May be a long shot , but try to retard the dizzy a little bit ...

 

If it's freshly rebuilt dizzy , and if you've adjusted it just by the markings which you've made when removing it prior to sending to be rebuilt the timing might be a bit more on advance side (will cause higher idle) due to the renewed dizzy internals (new springs particularly) .. or did you actually adjust the dizzy/timing properly when it arrived back rebuilt ?

 

Thing is , the springs inside the dizzy really do wear/stretch throwing the timing all around which affects idle speed quality and general engine performance .. i remember when i got mine recurved by the H&H boys , after fitting it and adjusting the timing idle is now rock solid just as on my Motronic 205 , also the engine performance gains are like day/night difference now with so much more power and torque .. though mine was modified engine and needed different advance curve , but i also had problems with unstable idle before so i'm sure that all the engines would certainly benefit from rebuilt dizzy .

 

D

[johnhenry 20]

update!

 

good news. A Mate came round and had a good look over everything with me, went through setup as per haynes again, seems to work nicely now! idles at about 1000, happy days! think i just go so used to seeing it a new set of eyes helped massively.

 

still seems a little bit high but I'm hoping with some tweaking it'll drop abit more.

 

potential though for us was a fuel pressure regulator, maybe fuelling too much causing it idle a little too high maybe? :S

either way - PROGRESS!