Idle speed cold engine - QP4 3.2 Evo

Arvid

Member
Messages
158
225/45 is the correct front tire. The fronts are 1% larger than rear. If you use 225/40 then there is a 3% difference the other way. I use 225/40/18 and 265/35/18 on mine which is also 1% difference like the original.
 

mab

New Member
Messages
13
Well,more fiddling going on. The idle air valves are working fine - no more hunting idle during warm up stage so they did like a good clean. But,the engine will not tolerate TPS set at 0.5v - it will start with with a 2000 rpm cold idle and idle unevenly when warm between 1000-1200. I have set it to 0.30-0.35v and that seems to calm things down with 1400-1500 cold idle and rock steady warm idle at 1000 rpm. The cold idle still seems too high - what rpm other members cars have when cold/warm ? I don't know if tacho is reading correct or not but at least it's steady. I think I'll leave it like this for a while and see how things progress.

Regarding high idle, I recall that i experienced something similar. Maybe you have already looked in to it, but there is a provedure, where you unplug the valves and set the idle to a certain speed (maybe 700 or 800, I do not remember exactly). This cured the problem for me.
 

Arvid

Member
Messages
158
Regarding high idle, I recall that i experienced something similar. Maybe you have already looked in to it, but there is a provedure, where you unplug the valves and set the idle to a certain speed (maybe 700 or 800, I do not remember exactly). This cured the problem for me.

Thanks for the tip - I will try that for sure. The engine now idles nicely but still at 1000rpm. If the taco is correct I still believe this is a bit high. I haven't had the chance yet to search for any false air leaks but it sure isn't the intake runners as all seals are new. Could be in the small rubber hoses at the back of plenum maybe. I've noticed that the hoses to the Amal valve are rock hard - could a leak here create increased idle ?
 

Arvid

Member
Messages
158
Update : The problem was resolved in the "Air Condition control unit ECU" thread.
 
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