Smallport idling very high

[panda_dan]

OK guys

Any advice you may have

I have just finished my smallport 4age conversion in my ae85.

Engine: Originally smallport 4age automatic, retained automatic ecu now running with w55. We bridged the auto ecu park function

It starts fine but idles between 2000rpm and 2500rpm. it does not throb or hunt for air, it just evenly revs high.

Moffat and I have checked everything and are stumped at this stage

Inlet manifold vacuum
Crank case vent
No 'sucking' noses indicating any vacuum leaks
All gaskets seem to be in order
Checked everything we could think of

TPS is looking like it's where it should be. In the middle, not left or right skew

Only thing we haven't checked is ignition timing

And one other thing to not is that if you put your hand over the throttle body and stop it sucking so much air in, it calms down to about 1500revs, which is an imporbement, but still too high.

Thanks for any help - Danny

[2LTR Rona]

1 check idle screw position

2 possible faulty thermostat

3 possible faulty cold by pass valve (if small port have it, can someone confirm)

with my bluetop I had the same issue you described, after replacing both the thermostat & cold by pass valve the idle settled down, before that it was up around 2500

[panda_dan]

Cheers for that

Yep we checked idle screw - that wasn't it

Thermo & o-ring both brand spanking

Cold by pass-valve? not too sure about that 1. Do you mean cold start injector thing on the bottom of the throttle body?

Thanks for your help

Keep it coming 4age crew...

[postfach]

Do these have vac lines going to the power steering? Mine came off at the PS end and I couldn't hear it sucking, same symptoms as yours. Just a thought.

[2LTR Rona]

throw it in to DIA mode and see if you get any codes

[panda_dan]

No power steeering on the old ae85

will try running DIA mode

[slighty_sykotic]

No power steeering on the old ae85

will try running DIA mode

Power steering lines he said, from the motor. Did you block them if the donor car had p/s?

and is this when its cold or warm? (the high idling)

[panda_dan]

Sweet as sorry Postfach i read you wrong

aaah Sykotic it's when it's cold

and i let it warm up and it didnt deviate

[gepsk8]

spray brake clean around all ur gaket joins, if motor changes sounds ur probably in the right area,
u blocked off, all un used hole in manifold?
check map sensor airline for breaks or damage

[rollaholic]

smallports do have the cold idle speed bypass valve under the throttle body, (the cold start injector is on the side of the manifold, with a small fuel line running from the fuel rail) however a problem with the bypass valve usually results in surging idle

[rollaholic]

heres a handy diagram i pinched from a thread on here ages ago

[jondee86]

To check if the cold start idle up air valve is stuck open, when you have
the air intake ducting off, just stick your finger over the hole where it
takes its air from. That's the hole inside the throttle body on your side
of the butterfly. It's about 6 mm in dia. The engine should drop about
1000 rpm if the valve is wide open. Only maybe 100 rpm if the engine
is warmed up, and the valve is working properly.

Check the throttle butterfly is closing completely. Even a millimetre gap
will let enough air pass to push your idle way up !!!

Disconnect the cam cover vent hose from the intake manifold and
block the tube into the manifold with you finger. Does the engine speed
drop lower than it was with the hose connected ??

Check for any open tubes or holes that could let air into the manifold
or throttle body. If you find any, block them off. The only thing that can
cause an idle above 2000 rpm is air leaking into the inlet manifold.

Cheers... jondee86

[no_8wire]

Does it idle high all the time or only till the engine is warmed up?

[panda_dan]

ok thanks for all your help guys

I got home last night and took the TB off, and took the cold idle bypass valve off and made a plate to blank it off

but my gasket goo takes a day to cure properly so i didnt start it right away to see if that has made a difference. I will start it when i get home tonight

if it does work - stoked. If it doesnt - i'm screwed because i'v tried everything else people have suggested to date

no_8wire...it idles high all the time. cold, warm, all the time

Danny

[gepsk8]

throttle cable to tight?

[l1ttle_d3vil]

^^^make sure the butterfly is 100% closed too, even if the cable is sweet.
i've had this problem before, it was like the accerlator got stuck partially open but it was actually the bolt on the end of the butterfly, inside the TPS. it had vibrated completely off which allowed the butterfly to have sideways movement, hence not shutting properly. it had to be forced shut by hand before the idle dropped.

[panda_dan]

Ok thats pretty much sorted now. Blanking off cold idle valve seemed to work

Took it for a quick drive yesterday, and now and again it would start loping/hunting.. so probably a air leak?

I checked the timing without bridging anything on the diagnostic plug and it was a solid 10deg. is this low for smallport?

Which ones are you supposed to bridge to set the timing?

Also does anyone know on AE85's what colour the wire for the taco is?

And where an easy place to connect onto it is (does it come thru with the ignition and starter wire and other stuff that sit on the firewall?)

And also the check engine light. (Do 85's have them?) and the water temp gauge?

Thanks for your help

[panda_dan]

Ok thats pretty much sorted now. Blanking off cold idle valve seemed to work

Took it for a quick drive yesterday, and now and again it would start loping/hunting.. so probably a air leak?

I checked the timing without bridging anything on the diagnostic plug and it was a solid 10deg. Is this low for smallport?

Which ones are you supposed to bridge to set the timing?

Also does anyone know on AE85's what colour the wire for the taco is?

And where an easy place to connect onto it is (does it come thru with the ignition and starter wire and other stuff that sit on the firewall?)

And also the check engine light. (Do 85's have them?) and the water temp gauge?

Thanks for your help

[panda_dan]

bump

need help!