MA61 7MGE swap

[deacs]

almost nearing the end of my 7m swap
have switched power to STA, IGN and constant power to BATT on the ecu, also have power to the igniter and injectors
car turns over and sounds like its starting for half a second before losing injector pulse and power to the fuel pump relay from the AFM
any ideas of what i may have missed that may be stopping the engine from starting?
Cheers

[madmont]

The switch in the AFM earths the coil in the circuit opening relay.It does not supply power

[deacs]

sorry i meant that the afm activated coil in the circuit opening relay is working

[Hen]

Shooting from the hip, is the IGF signal from the ignitor getting back to the ECU? From memory, if it does not see this feedback it cuts the injectors after a second or two.

[jondee86]

Yusss... so I'll chuck these in as well Generic old toyota comments and I don't know for sure if they apply to the 7MGE or not... but they might. The STA (start) pin usually only gets 12V while the engine is cranking. And the COR usually has two coils; one only activated during cranking to start the fuel pump and the other activated by the AFM to keep the pump running once the engine has fired.

May not be any help, but something to check anyway.

Cheers... jondee86

[deacs]

Checked continuity between igniter and ecu and all good, not getting any signal with a test light though, it's not 5v ls it?
Sorry Jondee I meant the STA pin is hooked up to the starter signal while the IG pin is hooked up to the ignition

Cheers

[madmont]

Is the igniter properly earthed?

[Hen]

I'm also just going on generic 90s Toyota info here. There should be a few wires between ECU and ignitor. IGT is the trigger signal, a 5V square wave I think. Can probe it on a CRO. IGF is a feedback signal, the "ringing" of the primary side of the coil, showing that there has been a spark. It should also be visible on a CRO, just a bit of a pulse with every spark event. If the ECU doesn't see this it assumes there's been no spark and it may be spraying raw fuel everywhere, so cuts the injector pulse. From memory there is a Haltech?? (or other piggyback ECU) article about it.


The reason this sprang to mind is that you say you're losing injector pulse. If the fuel pump wasn't running then you should still be seeing injector pulses. Though hard wiring the fuel pump is an easy check too.

Just considered that maybe there is something getting power from STA, which should be getting IG+. So when you release the key something dies.

[deacs]

Igniter is definitely earthed, gave it and the body a quick sand just to make sure.
The key doesn't leave the start position between in almost starting then dying, also tried starting with the fuel pump hotwired and no luck, any vacuum hoses that may be stopping it from running?

[jondee86]

So you have something like this...



This link... http://www.turboninjas.com/mk3supra/...ndiv/10_IG.pdf ... seems to show a fairly standard Toyota ignition setup for the 7MGE. All the wires that conect to the ECU are important, and you should try and test them all end to end for continuity. In particular, the wires from the distributor can fail where they are subject to the greatest amount of flexing. An open circuit on any of those wires will probably stop the engine from starting.

The ECU grounds (usually multiple grounds crimped onto a single ring connector) also need to be securely bolted down.

Are the plugs wet with fuel after a few crank but no start attempts ?

Can you get the engine to fire if you give it a squirt of "Start ya Bastard" ? If it does, then you know that the ignition system is generating an Igf signal.

Cheers... jondee86

[deacs]

Car starts and runs with aerostart
Injectors pulse twice and that's it even when running on aerostart
Anything else that determines injector pulse besides the pickup coils in the distributor?