How do you get a 4age bluetop into diagnostics mode?

[cosi]

I dont have a diagnostics plug in the loom. Is there any way to get the ecu into diagnostics mode without it? I read on the net you need to short out two terminals in that plug but cant figure out which wires that would be.

Im asking because Im putting a 4AGE from a rwd trueno into a starlet. I think I realise why people go with twin carbs, heh.

[Ae92typeX]

To put early non-diagnostic box 4ages into diagnostic you need to bridge / insert 'service wire' into one of the round plugs on the loom. I cant recall which side of the engine bay it is and my diagnosis manual does not say sorry, but Im sure someone here will be able to say.

[l1ttle_d3vil]

hey dude, forgot to tell you lastnight in your other thread.

your diagnostics plug will be a yellow round two pin plug, with one brown wire and one blue/white I think. its the only yellow two-pin plug on the loom I think. i just got a wire about 3" long with two spade terminals on each end and stick that into each terminal to short them out.

but have you got a diagnostics light set up too?

[2LTR Rona]

l1ttle_d3vil - you mean like the one in the lower right hand corner of this pic ?

[l1ttle_d3vil]

yea thats where it is on my loom, but that plug looks like its bigger - maybe its the 3-pin plug for the dizzy or something?
but yes, thats pretty much what it looks like and it is located on that end of my ae86 loom so should be on yours too, unless its been cut up.

[matt dunn]

l1ttle_d3vil - you mean like the one in the lower right hand corner of this pic ?

If that is a RWD loom it should be behind your catch can.

Matt

[crnkin]

mine was by the starter motor plug matt, so i dont know if all the rwd's are the same

[l1ttle_d3vil]

yeah I've got two ae86 looms and they're both in the same place, and thats what he's using. yours is a corona so might be different. they may have changed it between 86's though...

[2LTR Rona]

If that is a RWD loom it should be behind your catch can.
Matt

Not 100% sure on the history of the engine or loom so will take a close look when up working on it next

Cheers for that Matt

[KinLoud]

Yeah - my AA63 Carina had a factory bluetop 4age. The diagnostic plug hung off the loom in the same area sort of below/between the dizzy and the ignitor.

Ken
Ham
021 408 863

[matt dunn]

Ok, I was refering to the RWD AE86 looms,

which it is near the wiper motor where the loom comes through the firewall.

The llom in the picture to me looks to have the Firewall connector that the
AE85 and AE86 have that connect the ign wires and temp/oil gauges etc
which made me think that looks to be one of them.

Matt

[cosi]

Wicked, thanks for the info

This afternoon I figured that if its going to just sit there and not go it might as well be shiny. So I took the manifolds and covers off again and started polishing everything with silvo. Once I had the loom off again I found no less than three dodgy connections in the wiring. The blue wire from the injectors into the computer was pretty wasted. I suppose I shouldve checked everything carefully when the engine was out - especially considering the wiring is 20 years old.

Im pretty confident its going to start once I get it back together

[JT]

Wicked, thanks for the info

Im pretty confident its going to start once I get it back together

You will want to know how to get it into diagnostic mode to set the timing correctly. Its just one pin on the ecu that needs earthing.

Find the link for your ECU from the list in this page http://www.club4ag.com/technical_main.h ... and%20Data

Find out which wire is the check connector/check light on the ECU pinout then earth it and you should see the check light flash slowly when you've earthed it.

[KinLoud]

If you are checking the timing on a bluetop 4age..Make very sure the throttle is closed fully (push it closed) as if it is just off the stop the timing will not go to the "base" timing and you won't be able to set the timing... Been there done that, confused the hell out of me.
A lot of toyotas have a little throttle damper thing and these can stick so that the throttle position sensor/switch sees that the throttle is open and spoils your ignition timing mission.
End of rave.

Ken
Ham
021 408 863

[Truenotch]

Hey Ken, Did this make your timing seem WAAY to far advanced? we can't get the timing on the 86 right, to get decent power (Up high but now low) the mark has to be way to far advanced (nearly underneath the crank pulley). Someone suggested the cam timing might be out on the exhaust cam making it go crazy but I don't think so.

The TPS is out or broken from what the diag codes have said so I might try swapping the throttle body to the one off our spare inlet manifold then see if that works.

Cheers.