4AGE 20V Injectors not firing.

**70XIN** · 22-04-2011, 04:29 PM

Hi guys,

Okay, a little bit about the motor - basically a standardish 20V, standard BT ecu, and individual coils.

I can't get the car to start - it definitely has compression, spark, correct cam timing, possibly correct ignition/dizzy timing, and fuel pressure (worked that out by undoing the fuel filter a tiny bit..). The fuel injectors don't appear to be ticking (or working!) when the engine is cranking. I pulled out the spark plugs, and they're as dry as a bone. The injectors were cleaned a week ago, and i saw them running perfectly in the machine.

I have followed the 20V service manual, and checked all the voltages between #1-#4 and E01 and E02, they all check out. I have checked the 20V injector plugs themselves, and they are also registering 12 volts (i think all share the same common 12V wire?). I have checked the fuses in the engine bay, and in the drivers' side kick panel, none seem to be blown. I have checked the two main fuses on the

I have tried a spare ECU as well.

I am only suspect about things, but then again i don't that much about these things:
1) I only have one main grounding wire from the engine to the body - i haven't made/couldn't find the grounding wire from the gearbox to the body
2) The EFI main relay in the engine bay is hot enough that it would probably burn you if you held your finger on it.

I have also done some rewiring to the loom (tidying up and lengthening/shortening some stuff), but i'm positive i did everything right, i really took my time.

That's basically it, i hope you guys have some ideas, cause i'm all out

i will try to answer any questions as best i can

**70XIN** · 22-04-2011, 05:40 PM

Just to clarify, i have power to ONE side of each of the injector plugs with the ignition switch on - the side that has shared power (black/white wire).

The four 'signal' wires, for want of a better word, have nothing.

**BLK_20v** · 22-04-2011, 09:10 PM

You don't have an auto loom on a manual ecu or vice versa? Try pulling codes from the ecu. Usually you just apply 12v to the 2 white/black wires, connect the FC to your FOC relay earth (green / red wire) and it'll start. You are correct in the 4 injectors are powered off the same wire.

The fact you have spark but no injector pulse is weird, probably not going to make much diff, but whenever i wire one up i check the following...

* Brown wires are bolted tightly to the head (near thermostat housing / heater hoses)
* ECU has +B, BATT 12v
* Coil has 12v
* Ignitor has 12v
* Injectors each have 12v to the black / white wire

If you want to check the injector pulse you'll need a led light as a standard multimeter / test light isn't quick enough to see it.

As for the earths, i make sure the ignitor is earthed to the engine, alternator bracket to chasis, battery to chasis + gearbox. The efi relay getting hot is concerning... Check your joints and that none are loose.

Hope this helps somewhat, i'd be focusing on electrical as if the timing was out you'd still expect the injectors to fire.

**70XIN** · 22-04-2011, 09:35 PM

Cheers man, i'll check all of that. I unfortunately can't pull the diagnostic codes.

One thing i've noticed from other people's threads around the internet, is that BOTH wires going into each injector should have 12V with the ignition switch on, and then one of the wires is grounded by the ECU to make it open/close - is this right? Because if so, that's basically my problem right there haha.

But yeah, i'll check everything you've mentioned.

**70XIN** · 22-04-2011, 10:40 PM

Okay, i just had another check - all of my brown grounds are bolted onto the head, i have +B and BATT 12V, coil and ignitor have 12V. And as far as i know, it's a manual loom with manual ECU.

To confirm the other stuff:

With ignition switch on, ECU plugs in, injector plugs in, i have power at all of the injector 'signal' wires at the ecu pins - i can't/don't know how to check the power at the injector plugs with them plugged in

HOWEVER, with ignition switch on, ECU plugs in, but injectors unplugged .. i no longer have any power at the injector 'signal' wires at the ecu pins, and also at the injector end. I have power at the shared 12V that all the injectors use (black/white wire on all injectors).

I'm sorry if this is a ridiculously easy problem that a 3 year-old could work out, i'm just sick as fark and can't think too well. Thanks, Seamus.

**BLK_20v** · 22-04-2011, 10:51 PM

Originally Posted by 70XIN

Cheers man, i'll check all of that. I unfortunately can't pull the diagnostic codes.

One thing i've noticed from other people's threads around the internet, is that BOTH wires going into each injector should have 12V with the ignition switch on, and then one of the wires is grounded by the ECU to make it open/close - is this right? Because if so, that's basically my problem right there haha.

But yeah, i'll check everything you've mentioned.

Yep that is correct.... Ecu earths the injectors and makes them fire...

**Hen** · 23-04-2011, 07:48 AM

Having read about your dilemma on AE86dc it may be because the ECU is missing IGf and so shutting off the injectors.

More knowledgable people can confirm/deny, but I think that when a factory ECU "sees" IGf missing for several ignition firings in a row it thinks something is wrong and so stops injecting. Rig up a IGf faking circuit and see if anything improves (read here)

Hen

**BLK_20v** · 23-04-2011, 08:16 AM

Originally Posted by 70XIN

Cheers man, i'll check all of that. I unfortunately can't pull the diagnostic codes.
But yeah, i'll check everything you've mentioned.

Why can't you pull codes. Rig a 12v light up with ign power, and connect what would be the earth to the W pin on the 3rd ecu plug. If your diag box wiring has been totalled, earth out the TE1 pin on the ecu and bamm you're pulling codes. In my opinion this is the most important part of doing the wiring conversion.