Andrew Beattie
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| posted on 12/1/08 at 06:08 PM |
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4age fast idle
Hi,
I have just tried starting my 4age for the first time but am having problems with idling.
When I start it it idles at 2100rpm which then drops to about 1800rpm after a couple of minutes.
By covering the three nozzles in the picture (2 on the left, one on the right) the rpm drops to 1500.
It was oscillating up and down as well but I've stopped this by screwing the screw on at the bottom right (side on in the picture) fully in.
I've also put up a picture of the vacum hoses from the fuel pressure regulator, as I wasn't sure if these were correct either.
Any info or advice would be much apprieciated.
Thanks
Andrew
p.s. Its from a 1990 corrola (ae92 i think)
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flak monkey
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| posted on 12/1/08 at 06:49 PM |
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For a start, its normal for the 4age to idle at about 2000rpm for several minutes when its cold due to the wax stat letting extra air into the
throttle body.
Theres 2 reasons for the problems you are having though:
1. the wax stat is stuck open, solution: a manual choke conversion. http://mr2oc.co.uk/Knowledge_Base/op=show/kid=265.html
2. Theres air in the cooling system which is fooling the temperature sensor.
David 
[Edited on 12/1/08 by flak monkey]
Sera
http://www.motosera.com
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t.j.
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| posted on 12/1/08 at 06:49 PM |
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Make a picture from bigger distance.
First: clean the intake 
Then: I see a lot of "open" holes! Are there no vacuum-leaks?
Grtz
Please feel free to correct my bad English, i'm still learning. Your Dutch is awfull! :-)
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t.j.
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| posted on 12/1/08 at 06:52 PM |
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quote:
Originally posted by flak monkey
For a start, its normal for the 4age to idle at about 2000rpm for several minutes when its cold due to the wax stat letting extra air into the
throttle body.
Theres 2 reasons for the problems you are having though:
1. the wax stat is stuck open, solution: a manual choke conversion. http://mr2oc.co.uk/Knowledge_Base/op=show/kid=265.html
2. Theres air in the cooling system which is fooling the temperature sensor.
David
[Edited on 12/1/08 by flak monkey]
Damn, David is faster....
You could be right as that isn't connected and prob. stuck. Why isn't the system connected like toyota mented?
Please feel free to correct my bad English, i'm still learning. Your Dutch is awfull! :-)
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COREdevelopments
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| posted on 12/1/08 at 08:01 PM |
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andrew i recognise that inlet manifold!!! did you buy it off ebay? from Robevs383??? im sure thats my old manifold!!!
Rob
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Findlay234
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| posted on 12/1/08 at 08:39 PM |
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Youll want to either properly connect up your vacuum hoses to the throttle body or at least block them all up. One of the issues that causes the
loping idle is a small leak from either the vacuum hoses or elsewhere. Have you sealed the throttle body onto the intake properly as well?
The you should have one of the vacuum tubes connected to an idle up valve. This works with a signal from the ecu basically opening a valve so that the
vacuum tube is open to atmosphere, thereby increasing the idle speed. This is used when you are chewing a lot of amps from the battery with lights,
heaters and fans. It idles up to let the alternator provide enough charge.
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thomas4age
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| posted on 13/1/08 at 09:21 AM |
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There's a few faults in the pictures that will cause the High idle.
I don't know whether the pictures represent the way you tested the engine but here goes anyway.
theres a Auxilary Air Valve (cold idle aid) underneath the throttle body (on your manifold at the side facing the engine) you must attach 2 coolant
lines from the engine to it otherwise the thermostat in the valve will stay open letting extra air in the engine. I had this also and my Idle switch
on the TPS then offcourse tells the ECU that the engine is running to fast for Idle and starts altering the ignition timing to get the Revs around
900rpm. this result in the engine jojoing up and down in revs when warm. a new cleaning of the valve made it work without problems again.
So either no coolant or a broken valve results in a higher than normal Idle when warm. if it gets really high the ECU will try and get revs down, if
that doesn't happen you should also check the Idle switch in the TPS because most 4age do jojo around, and if the switch doesn't work it
won't idle nice.
Also there's the positive cranckcase ventilation plug on the manifold that isn't attached or blocked of leaving an open hole after the TB,
which also makes the engine run very high on idle.
it's however not uncommon for these engine to retain a rather high idle when not fully warmed up. my old 16 did about 1400rpm when stone cold,
after 6 seconds cold start injector stops pouring fuel then the revs dropped to about 1200rpm, and only after the gauge read 70degrees coolant Idle
would slowly drop to 850/900 rpm.
I'll put up some piccies to help you out.
edit piccies
 
4age throttle body
 
4age manifold vacuum connect
here's how the TPS should read
 
4age TPS pinout
good luck any questions please ask.
Grtz thomas
[Edited on 13/1/08 by thomas4age]
[Edited on 13/1/08 by thomas4age]
If Lucas made guns, Wars wouldn't start either.
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Andrew Beattie
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| posted on 14/1/08 at 09:03 AM |
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Thanks for all the great responses, I recon I can cure the problem now. Unfortunately have gone back to uni, so cant change things and check but I
think I have all the info I need.
Yep think its your old manifold Rob!
Thanks again,
Andrew
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