Fire: GZE-swap problem - need ideas

[ThaChemist]

The good news is that, after lots of work, great help from you, rewiring and the lot, I've got my 4A-GZE into my AE-92 Corolla GT-S and all fitted up nicely. The wiring went ok - I followed the wiring diagram as much as I could, since the engine is a little bit of a hybrid of the GZE and the old 4A-GE.

Anyway, I turned the key today, and an interesting troubleshooting issue came up. I have to take it down to a different shop to get the piping custom-fit, so I ran it without the supercharger pipes connected, essentially with no intake, since I figured it would still start, even if it idled badly, and if there were any major issues, I could still deal with them there.

What I didn't expect was what I got. It cranked like a champion and the fuel was there, but it wouldn't start. So a friend grounded a spark plug and we tried it again, and the spark was there, too! It's bizarre. Fuel + spark + air.... yet it just didn't catch.

Then, when I persisted, a flame shot out the intake! And again, after a bit, when I tried it again. So there's spark and fuel, but it just won't go like it's supposed to.

Troubleshooting isn't doing me much good, either. The timing is fine - I did the timing belt and distributor at the same time, and that's all in perfectly. Although the G- wire (spark retarder?) isn't connected since I'm still using the old igniter, the sparks do go. The #10 wire goes to injectors 1 and 3, the #20 to 2 and 4, just like GZE wiring diagrams and harness indicated. I'm using the GZE ECU, all the necessary pins fit...

Any ideas? I'd really appreciate the help.

Cheers.

[oldcorollas]

is the throttle body before or after the SC?

maybe you are trying to start with effectively WOT?

[wilbo666]

Is it an airflow metered GZE?

If so it won't run with the AFM not connected...

This comment is no help if it uses a map sensor tho!

Cheers
Wilbo

[TooF]

yup thorttle body is before the sc so unless youve done something odd you are runnig at full throttle. otherwise id be pointing my finger at a timing issue.

[ThaChemist]

Yeah, it's AFM... so... that kinda makes sense. I'm flooding it so badly that it doesn't even sound flooded. I'll give it a go and let you know!

[turbo_gze]

Flames and bangs shooting out of the intake sounds like a timming issue I had on a Smallport 4age when the timming was out a bit. Kept trying to crank it over and over then it then a bang come out of the intake.

Ended up being the dizzy being out.

[Mos]

The wiring went ok - I followed the wiring diagram as much as I could, since the engine is a little bit of a hybrid of the GZE and the old 4A-GE.

Exactly which components are you using from which engine? And which GZE did you get? Are you using coil packs and a crank angle sensor or a dissy? Since you're using the GE ignitor ("old ignitor") it would imply you're using a dissy and single coil.

The timing is fine - I did the timing belt and distributor at the same time, and that's all in perfectly.

I'm not trying to be a pric, but it doesn't matter who did it - you need to check it again as part of the diagnostic process.
You also need to check to make sure the rotor button (assuming you're using a dissy) lines up with the correct cylinder's TDC - because it's spitting flames out the intake, it suggests the timing is out - so you MUST check this and not make assumptions about previous assembly.

Although the G- wire (spark retarder?) isn't connected since I'm still using the old igniter, the sparks do go.

? G-? Which wire is this exactly?
There are a number of pickup/ecu/ignitor setups in the 4A range. You need to explain your layout.
For instance MR2 4AGEs had the pickup connected to the ignitor as well as the ECU. Most other versions of 4AGEs and 4AGZEs has the pickup going only to the ECU. I think there was a dissy GZE version but my memory is very hazy on that.
Working from memory the only G- that springs to mind is the return signal on a pickup sensor, and if that's not hooked up there will be no signal being sent to the ECU or ignitor for that particular pickup.

If you're using a coilpack GZE ECU with a GE dissy and single coil you might have problems depending on what the setup is.
The coilpack GZE ecu needs two TDC pickups, iirc in the form of G1 and G2 pickups and a (mostly) single lobe rotor, in order to fire the correct coils.
Newer 4AGEs had the same pickup strategy as a coilpack GZE.
The older single coil 4AGE pickups had a single G pickup with a 4 lobe rotor, which each lobe corresponding to each cylinder's TDC or thereabouts.
The MR2 4AGE with the pickup connected through the ignitor, as far as i remember, is identical to the 4 lobe 4AGE setup other than the ignitor having "start up" control over the coil rather than the ECU.

If you have used a coilpack GZE ECU with the pickups off the GZE then at least the ECU should be seeing the engine position correctly. It should then be able to supply the correct IGT and IGD (or whatever that pin was called). In theory if you hooked the IGT up to a single output ignitor and a single coil, using a dissy, it should still be able to fire the correct cylinder.

My memory on the exact details is a bit rusty as it's been quite a few years since I've had anything to do with 4As.. so bear with me, but most of the info should be accurate enough to work from.

The #10 wire goes to injectors 1 and 3, the #20 to 2 and 4, just like GZE wiring diagrams and harness indicated. I'm using the GZE ECU, all the necessary pins fit...

The batching of the injectors is not critical - they'll supply fuel even if batched incorrectly.

HTH.
Mos.