4AGZE Injectors Not Firing

sirdeuce
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Re: 4AGZE Injectors Not Firing

Postby sirdeuce » Fri Jun 21, 2019 10:30 am

jondee86 wrote:
jondee86 wrote:The resistor pack does not need to be grounded. It is just 12V in and 12V out
and there is no reason for grounding.

OK, so I was shooting from the lip there. When the circuit is not active it is 12V in and
12V out, but when it is active it is more like 12V in and 3V out due to voltage drop across
the resistor pack. The injector resistor pack itself will likely contain two ceramic encased
wire wound resistors something like these...

Image

The resistors are sized to provide the required "dropping" resistance, and to dissipate
the heat generated in the resistor without overheating. The metal case holds and protects
the electrical components without forming any part of the circuit. Unlike the metal cased
igniter, the resistor pack does not require the outer casing to be grounded.

Cheers... jondee86



I did not say the 'pack' needed grounding. The resistors need the pigtail coming from the pack to be grounded to complete the circuit. The 'pack' cover is a heat sink to help with heat dissipation and needs to be secured to the chassis to protect the wires from their load and vibration. Maybe we are both misunderstanding each other.
One shot, one kill.

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sirdeuce
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Re: 4AGZE Injectors Not Firing

Postby sirdeuce » Fri Jun 21, 2019 10:35 am

Alex170984 wrote:From memory on my car before I changed the engine to 4AGZE, the resister pack bracket was bolted underneath the ignition coil bracket so they were earthed at the same time.


I have seen that, I have also seen the resistors grounded with their own bolt. Basically any place you can access a bolt to ground to the chassis would work.
One shot, one kill.

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jondee86
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Re: 4AGZE Injectors Not Firing

Postby jondee86 » Fri Jun 21, 2019 3:51 pm

sirdeuce wrote:Maybe we are both misunderstanding each other.

Such things are possible :) And of course, you are correct in saying that if 12V is
supplied to a component, that 12V must eventually be grounded to complete the
circuit and activate the component.

However, there are a couple of misconceptions that come up from time to time
and need clearing up. Plus a few points about grounds and good grounding practice
that are worth repeating...

- Not every electrical component that is bolted down is actually bolted down for
the purposes of grounding. Some are just bolted down to keep them in place.
- While having clean bare metal under a ground connection is nice, it is not
always essential to making a good ground in a well maintained vehicle. The
action of tightening the securing bolt down on the ring connector will remove
surface corrosion and ensure a good contact between the head of the bolt and
the connector. The threads of the bolt will do the same thing to make sure
there is a solid path to ground via the bolt.
- A wired ground connection to the battery negative is always preferable to
using the chassis as part of the ground path.
- The ECU does not ground thru the metal case (for the above reason) and is only
bolted down to hold it securely in place. The ECU has multiple ground wires and
these must be securely bolted down to the head or block at the end of the engine
furtherest away from the alternator.
- A good ground connection that has not been disturbed for 20 years can become
bad due to corrosion forming between the contact surfaces. Usually, all that is
needed is to loosen the bolt a little until you can just twist the ring connector back
and forth by hand. Do that a couple of times to break down the corrosion and then
tighten. Nine times out of ten that ground will be working fine again.
- You can never have too many ground wires. Too few often causes problems.
- Despite what grandpa told you, never run your engine with the battery disconnected.

Common sense will indicate that you cannot make a good ground path thru badly
rusted, dirt encrusted or heavily painted metal, so that is the time to break out
the wire brush and sandpaper. Use your multimeter to check that your ground
connections have zero resistance.

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

Alex170984
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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Tue Jun 25, 2019 5:15 am

Hi all,

Had a recommended mechanic round and checked through everything. The cam and ignition timing is all okay. Checked HT leads, dizzy, dizzy cap, injectors, AFM etc

It runs on easystart and even when the spray is taken away, but dies after 30 seconds or so.

Cannot pinpoint the cause of why it will not run and idle. My loom is a mess since i've stripped it back. Definitely a fuelling issue somewhere.

I've got a spare GZE loom which requires my knock sensor plug, dizzy, fan and O2 plugs to be spliced onto. Whilst that is being spliced properly where I work by the electrical department I shall clean every single earth point, sensor and pin to ensure clean connections are made when it's plugged back in.

So, basically i'm starting again. There is something I have missed when installing the loom when I installed the engine and hopefully being more meticulous I'll find what I missed.

How do I check fuel pressure?

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sirdeuce
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Re: 4AGZE Injectors Not Firing

Postby sirdeuce » Tue Jun 25, 2019 8:12 am

Aw man, I hate these problems. To be honest I've been doing the same with my 1990 Toyota pickup. Different issues though, the thing runs but has CELs. Pain it the tailpipe! I feel for ya.
Could it be a fuel issue? Good pressure until the engine runs? Like a restriction, fuel filter, pinched line, weak fuel pump, pump pick-up sock gunked up, y'know, things like that.
One shot, one kill.

Alex170984
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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Tue Jun 25, 2019 8:32 am

I've bought a replacement COR but I doubt that'll be it.

We checked to make sure I was geting fuel through by undoing the nut on the fuel filter and obviously fuel went everywhere when I cranked it, so it shows the pump is pumping.

The fuel lines are hardlined and there are no kinks so it cannot be that. I'll double check and redo all the vacuum and fuel hoses, as if I've connected one wrong this may be a problem?

Feels like the injectors are still not firing and the 5th injector was flooding the engine which allowed it to run for a few seconds and with the easy start that made me think it's still the injectors. I'll replace all the fuse and relays - these are parts which don't cost much anyway so it won't be bad in terms of money. The injector wiring on the new loom is uncut and unmolested so that should be all good.

Or could it be down to the transistors in the ECU?

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jondee86
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Re: 4AGZE Injectors Not Firing

Postby jondee86 » Tue Jun 25, 2019 2:28 pm

Best place to test for fuel flow/pressure is at the outlet hose from the fuel
pressure regulator. Take the return hose off and fit a spare piece of hose so
that you can run the open end into a clear container. Turn the ignition ON and
force the pump to run by jumping the fuel pump test plug or opening the flap
in the AFM (if you have one).

When the pump runs there should be a strong jet of fuel into the container.
If there is only a weak flow or a dribble, then you have a blockage in the fuel
rail or FPR.

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

Alex170984
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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Tue Jun 25, 2019 4:51 pm

I'll have to do that once I've got the loom back on as now it's all off.

Just one thing though...my fuse box cover from the engine bay fuse box, has '10a INJ' shown, but in the fuse panel itself there is no connector for a fuse in the casing.

I do hope this is not the reason why it hasn't been working...although I have definitely not gone to the ardious task of changing that fuse box - I did have to take it off of it's mounting so I can reinstal a replacement 60amp fuse but I don't remember disturbing any of the connectors in the casing.

Do you guys have this '10a INJ' fuse? I'll post the photo up in the morning.

Image.

Image

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jondee86
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Re: 4AGZE Injectors Not Firing

Postby jondee86 » Thu Jun 27, 2019 1:24 am

The wiring diagrams that I have don't show any fuse in the injector power
supply. The relay gets power directly from the battery (via one of the fusible
links) and the relay is energised by 12V from the ignition switch. So basically
if 12V appears at the injectors when you turn the key ON you are good to go.

It is not unusual in old Corollas for Toyota to use the same basic fuse box
design for several different versions of the same car. For example the 4AC
powered AE86 has the same fuse box as the 4AGE powered AE86, but the EFI
related slots are empty. Also certain markets have different requirements
for safety systems and interlocks, so EU and US and JDM versions of the AW11
may all have slightly different versions for the ECU and fusebox.

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

Davegt27
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Re: 4AGZE Injectors Not Firing

Postby Davegt27 » Thu Jun 27, 2019 9:10 am

the top cover flagged for some reason so I went and looked, both my 88 an 89 GZEs are green

88gze

Image
Davegt27 Code One Racing

Alex170984
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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Fri Jun 28, 2019 1:41 am

Davegt27 wrote:the top cover flagged for some reason so I went and looked, both my 88 an 89 GZEs are green

88gze

Image


It's interesting that it's on the GZEs but my fuse box is from my car which is originally N/A.

Very strange.

But thank you all for your comment - I shall not worry about it.

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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Thu Aug 01, 2019 4:22 am

Hi all,

It's been a while and I've had no motivation to do anything with the car.

I have the loom off and decided to trace the injector lead grounds back through the loom.

Seems I have them grounded in pairs and not as the multi-meter stated of having 3 on one ground and 1 on the other ground.

The loom is now a mess as I had to cut all the protective covers, but I've ordered some specific tape for wiring looms so I can put it back together properly so it is usuable. I've purchased 4 new injector clips so I plan to refresh all four clips. There was no obvious damage to any of the wires in the loom.

I am going to chase back E01, E02 and E1 as well, as these are all very relevant grounds in the circuit to make sure they are okay.

Other than that, i'm assuming it's the grounds themselves inside the ECU and/or a mechanical issue.

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