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Location:
Vic
Registered:
May 2002
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4ag cold starting & poor spark
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Sun, 02 May 2004 06:50
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My 4ag always starts perfect when hot but can crank for a fair bit when cold & sometimes drains the battery.
It seems to have a very weak spark.
I checked the resistance of the coil & its within limits. Would a faulty ignitor cause a weaker spark?
Is there anything special about the 4ag coil? Can i just swap it for a spare i have?
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Banned user
Location:
ADELAIDE - The Drift City
Registered:
July 2002
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Re: 4ag cold starting & poor spark
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Sun, 02 May 2004 08:28
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try a different coil then, but a faulty coil would give overall poor starting and running anyway, not just when cold.
fwiw: i have a holden turbo piazza coil on my 4age, works great
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Club Member
Location:
sydney
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Sun, 02 May 2004 09:59
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are you running a cold start injector?? is the cold start injector getting signal? is the injector opening and fuel flowing?
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Location:
Vic
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Sun, 02 May 2004 11:05
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Yeah the cold start injector is now hooked up & working fine.
If i squirted fuel directly into the throttle body it usually doesnt make any difference anyway.
I tried a different coil today but it made no difference.
The spark still looked pretty weak & was no different when i triggered the coil manually. I may be just used to the strong spark of my old ke20.
So i'm pretty sure the coil/ignitor is ok now.
Leads are new, dizzy cap & rotor look pretty good.
Plugs are about the only other thing i can think of, altough they look perfect & always burn a perfect color.
Any suggestions?
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Location:
Montrose, VIC
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Sun, 02 May 2004 12:42
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Are you sure there's enough voltage coming to the coil??
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Location:
Vic
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Sun, 02 May 2004 12:51
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I did think of coil voltage & checked it.
It does drop when cranking but i tried a wire straight from the battery to the + side and it made no difference to spark output or help it start.
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Location:
Adelaide
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Mon, 03 May 2004 13:02
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How is your earth? see if there is any voltge drop between engine and chassis or -ve batt terminal
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Location:
Vic
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Tue, 04 May 2004 00:13
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Yeah earth is good.
I'm gunna put it down to spark plugs at the moment. When i ran bosch plugs in my race car it would not even think of firing on cold mornings so maybe its the same with these ND plugs.
I ordered some NGK iridiums from the US last night so we will see if that helps.
While i'm at it i may look at repl;acing dizzy cap & rotor even though they look ok.
Will my local parts place have a listing for a RWD cap & rotor? They did when i got new leads.
Or will i have to get them from toyota?
Whats the rough price?
Thanx for the help every1, i'll let you know how i go.
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Location:
Adelaide
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Tue, 04 May 2004 00:34
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Out of curiosity, why did you order the iridiums from the US? Are they any cheaper?
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Location:
Vic
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Tue, 04 May 2004 02:07
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Cause they want about $30 each here and i got 4 for $50US delivered.
I just went and ordered a rotor and cap. Early AE82 looked to be the same as whats on my RWD 4age so i hope they fit.
$18 for the cap & $7 for the rotor, cant argue with that
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Location:
Ipswich
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Tue, 04 May 2004 04:36
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Hmm, my 4AGE doesn't idle when it first starts up if the engine is cold, it will start up easy, but the moment I close the throttle it dies... So I have to keep it running for maybe 1 or 2 minutes, and then it's fine...
Maybe similar problem?
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Location:
Vic
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Tue, 04 May 2004 05:07
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Is your cold idle up system working correctly?
It should be sucking air for cold idle through that hole at the bottom near the throttle flap. As hot water flows through the throttle body revs should drop. Thats providing you have the hoses hooked up etc.
You might also have to play with the idle mixture a bit to get it running all perfect.
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Location:
Ipswich
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Tue, 04 May 2004 05:58
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Ah... that's probably it. I don't have my cold idle circuit working at all... The cold injector works, but not the circuit under the throttle body...
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Location:
Vic
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Tue, 04 May 2004 23:37
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Thats your problem then.
With the 4ag the throttle is closed at idle so it gets air from the cold idle circuit when warming up & then the idle circuit once warm.
You will need to compensate by either winding out the idle screw more until it idles when cold but this will also give a faster hot idle.
adjust the throttle flap so it open at idle, idle bleed screw will also need adjustment & so will throttle sensor.
If you have a spare idle up passage on the top of the throttle body you could hook this up to an air bleed solenoid(from most toyotas with pollution stuff) & a switch in the cabin that lets extra air in when you need it.
Or just put up with it stalling until warm.
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Location:
Ipswich
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Wed, 05 May 2004 00:10
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Hmm yes... I guess I'll have to put up with it for now... maybe I can get like a choke mechanism (mechanical) to hold the throttle partially open so that I don't have to keep my foot on the accelerator when it's cold (which makes hill starts kinda hard cause my handbrake doesn't work very well at all)
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Location:
Vic
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Wed, 05 May 2004 02:48
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Dont do anything dodgy like that.
The easiest way would be to hook up a pollution solenoid to a switch so you can bleed air into the throttle at start up.
Less dodgy & easier to set up
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Location:
Melbourne
Registered:
July 2002
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Re: 4ag cold starting & poor spark
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Wed, 05 May 2004 04:12
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bmak,
When ur car is cold, try cranking it over whilst pumping the throttle.. Mine was doing exactly the same thing. Cold starts it wouldn't kick , but when its warm it starts straght away. I checked every injector and piece of wiring. Couldnt' find an answer. But I found a work around, just pump the throttle on/off/on/off a few times while cranking the engine, should start straight away.
Cheers
Gaz
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Location:
Vic
Registered:
May 2002
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Re: 4ag cold starting & poor spark
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Wed, 05 May 2004 04:45
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Thanx
I'll give it a try next time i have trouble, i ve already tried all sorts of throttle positions but never pumped it
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Location:
Melbourne
Registered:
July 2002
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Re: 4ag cold starting & poor spark
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Wed, 05 May 2004 07:34
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yeh i did the same.. tried 1/4 throttle, 1/2 throttle, full throttle.. adn the only way to start it was pumping it ..  good luck man
Gaz
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