4AGZE Injectors Not Firing

Alex170984
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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Sun Jun 02, 2019 4:57 pm

My ecu plug also does not have a pin for E1 earth - is that odd?

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jondee86
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Re: 4AGZE Injectors Not Firing

Postby jondee86 » Sun Jun 02, 2019 6:18 pm

E1 would normally be the third brown wire on the ring connecter. The 88 and 89 AW11
wiring diagrams show that the pin should be in the same plug as the E01 and E02 pins.

Cheers... jondee86
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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Mon Jun 03, 2019 1:02 am

My E1 is definitely not there..

However, I've got a photo of another set of ECU - 4AGZE AFM plugs which shows E1 being vacant as well.

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Re: 4AGZE Injectors Not Firing

Postby jondee86 » Mon Jun 03, 2019 2:43 am

It is not that unusual for some wires to be missing if the same ECU is
used for different versions of the of a vehicle. Since E1, E01 and E02 are
all shown as running to the same ground point, it might be that E1 has
been joined to one of the other grounds inside the ECU.

If the engine has run with that ECU before, then it should be OK.

Cheers... jondee86
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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Fri Jun 07, 2019 8:13 am

Just an update for you all, I have an earth problem.

More ecu earth problem.

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Re: 4AGZE Injectors Not Firing

Postby sirdeuce » Fri Jun 07, 2019 11:10 am

Any hair left on your head?
One shot, one kill.

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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Fri Jun 07, 2019 1:39 pm

Yeah lol it's going grey though due to my twin boys. I have wiring issues though through the reasons I cannot explain.

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Re: 4AGZE Injectors Not Firing

Postby sirdeuce » Fri Jun 07, 2019 1:47 pm

Twin boys are no problem, boys in general, girls on the other hand.....
One shot, one kill.

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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Mon Jun 17, 2019 3:17 pm

It now fires up! It was an earth problem and I fixed it in a different way but won't go into that. So thank you for everyones help and advice and apologies if I did not seem gracious because I am!

Now, the next problem! It runs for 5 secs then dies- i'm assuming this is the AFM?

I don't have my throttle cable attached, would that make any difference?

Cheers

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Re: 4AGZE Injectors Not Firing

Postby sirdeuce » Mon Jun 17, 2019 6:35 pm

Sounds like an issue I had with one of my AE86s. Check the fuel circuit in the AFM. Try jumping the fuel test circuit at the diagnostic port. If the engine runs by jumping the fuel circuit then check the ground at the AFM plug. This is the ground bolted to the manifold, top of the runners under the plenum, a lot of people miss this one. If the ground is good check the AFM to see if the circuit in the AFM is working. I fixed my 86 by running a new ground from the AFM plug to the intake manifold.
One shot, one kill.

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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Tue Jun 18, 2019 2:06 am

sirdeuce wrote:Sounds like an issue I had with one of my AE86s. Check the fuel circuit in the AFM. Try jumping the fuel test circuit at the diagnostic port. If the engine runs by jumping the fuel circuit then check the ground at the AFM plug. This is the ground bolted to the manifold, top of the runners under the plenum, a lot of people miss this one. If the ground is good check the AFM to see if the circuit in the AFM is working. I fixed my 86 by running a new ground from the AFM plug to the intake manifold.


You mean this one?

Image

If so, this is working, as it's my E1 ground.

Jumping the FP & +B is my next port of call so i'm hoping it'll show it as the AFM.

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Re: 4AGZE Injectors Not Firing

Postby sirdeuce » Tue Jun 18, 2019 2:57 pm

Pins and needles, pins and needles.
One shot, one kill.

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Re: 4AGZE Injectors Not Firing

Postby UNLIMITED 86 » Tue Jun 18, 2019 7:21 pm

Alex170984 wrote:It now fires up! It was an earth problem and I fixed it in a different way but won't go into that.


Please explain what you found the exact cause to be and how you ultimately fixed it so that other members encountering this issue in the future know what to look at.

Conrats!
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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Wed Jun 19, 2019 2:33 am

It's pretty stupid to be honest.

I tested for continuity between E02, E01 and E1 on the chassis and found I had an open loop. At the time i determined there must have been an issue with the wires in the loom. As I had already put the rail back on again I couldn't be bothered to strip it all again, so I cut the wires at the ECU plug on E01 and E02 and attached new earth wire and bolted this onto the cylinder head, going through the bulkhead. This then gave me good earths for E01 and E02.

I then discovered that I'm an absolute idiot because I sprayed the intake manifold with silver hammerite and did not sand back the earth point that all three earths terminate too.

As I did not relocate E1 earth, I decided to rebolt down the ring connector in the fuel rail loom and hey presto I had E1 again! (after sanding back the paint)

I didn't check the cleaniness of that earth point at the start because an 'accomplished sparky' had determined that I had another problem as the earths were all attached when my car was at his house. This is only reason I did not check that originally as I went by someone's opinion. So this could have been avoided if I had of cleaned the intake earth and a competent person could and should have found it.

But ultimately, clean up your earth points to bare metal before installing.

However, 3 of my injectors do earth back to pin10 and the other pin20 but they are wired in pairs on the power from the resister pack.

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Re: 4AGZE Injectors Not Firing

Postby sirdeuce » Wed Jun 19, 2019 9:17 am

Ooohh, cutting the earth wires and just jumping the ECU to the block is BAD. The ECU is grounded to the block, but along the way from the block/manifold there are tap points for the various sensors for their grounds. You'll need to splice your harness back together.
As for the painting of the earth points and not getting continuity? Don't feel alone, it's been done many times. A few bald peeps out there because of it.
Glad ya got it ironed out!
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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Wed Jun 19, 2019 2:08 pm

Hi,

This is not at all sorted.

I reattached the wires on the ecu plug and the car didn't attempt to turn over. Put new earths back on and it fired up then died.

Bridged the ports in the diag box and the car ran for longer but then spluttered and died. So is that AFM, COR and fuel pump?

Took TPS off it ran for longer. Took cold start injector off, didn't attempt to start. Guessing injectors are not firing and it's running off the cold start injector?

I also tried to test for fault codes and the check light just constantly flashed- no break. Took AM2 out to reset, just flashed constantly.

Any ideas? lol

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Re: 4AGZE Injectors Not Firing

Postby jondee86 » Wed Jun 19, 2019 5:49 pm

Alex170984 wrote:However, 3 of my injectors do earth back to pin10 and the other pin20 but they
are wired in pairs on the power from the resister pack.

Had a think about this and it is not ideal. The one injector will be getting a bit more
current, and the three will be getting a bit less. Doubt if it is enough to stop them firing
but you should try and transfer one over so that there are two on each ECU pin.

Running on the cold start injector is quite common. The injector only squirts while cranking
and cuts out as soon as you let go of the key when the engine fires. It will run on for a couple
of seconds then fade and die. Check that you don't have any broken wires inside or just outside
of the distributor, and make sure that the EFI fuse is not blown.

Cheers... jondee86
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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Thu Jun 20, 2019 1:06 am

Hi all,

How bright should the noid light flash on the injectors? When I tested 1&2 there was a little flash but nothing like the whole bulb illuminating.

I do have a replacement wiring loom now, but due to it's cost I have to splice my alternator, starter, knock sensor and dizzy plugs onto it, as it was running different gear as it came from a track car. Rest of it is in excellent condition.

When I connected the old E01 and E02 wires back onto the harness it did make a clicking noise but it didn't want to turn over at all, just cranked, like before.

I took a video but I don't have anything I can upload it to...

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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Thu Jun 20, 2019 1:09 am

jondee86 wrote:
Alex170984 wrote:However, 3 of my injectors do earth back to pin10 and the other pin20 but they
are wired in pairs on the power from the resister pack.

Had a think about this and it is not ideal. The one injector will be getting a bit more
current, and the three will be getting a bit less. Doubt if it is enough to stop them firing
but you should try and transfer one over so that there are two on each ECU pin.

Running on the cold start injector is quite common. The injector only squirts while cranking
and cuts out as soon as you let go of the key when the engine fires. It will run on for a couple
of seconds then fade and die. Check that you don't have any broken wires inside or just outside
of the distributor, and make sure that the EFI fuse is not blown.

Cheers... jondee86


EFI fuse is fine and i'll check the dizzy later.

It's getting to a point where I'm going just going to get someone to do it for me. Found a chap near to me who does electrics for VW Camper vans, so the age of wiring and simplicity/technology is from the same era ish. Rather than go to a main dealer where they give it to an apprentice who would have no idea!

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Re: 4AGZE Injectors Not Firing

Postby jondee86 » Thu Jun 20, 2019 4:24 am

The fuel injector pulse is only a few milliseconds, so the noid light will only
show a very brief flicker of light while cranking. After a extended period of
cranking your plugs should be wet with fuel when you check them. If they are
wet swap them for a fresh dry set or dry them out over a gas burner.

Basically, if the engine fires up on the cold start injector, you must have spark
at more or less the right time. So fuel is the logical problem area. If the injectors
have 12V and the ECU has grounds, then the injectors should be squirting unless
there is some loss of rpm or crank position signal from the distributor to the ECU.

Cheers... jondee86
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persists in trying to adapt the world to himself. Therefore, all progress
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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Thu Jun 20, 2019 5:02 am

Regarding my relocation of my E01 and E02 onto the intake ground point...I connected the original wires back up last night and I heard it click but it wouldn't turn over. It's odd as my E1 is connected via the original ground point on the inlet manifold, but the E01 and E02 won't let me fire the engine. Swapping back to new earths did. Must be a problem with the E01 and E02 wires.

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Re: 4AGZE Injectors Not Firing

Postby sirdeuce » Thu Jun 20, 2019 7:43 am

Our engines injectors are a 'batch fire' type of injection, it's why there are 2 injectors per ECU out. Typically cylinder 1 and 3 fire together then 2 and 4, since those are the cylinders that fire close together. So, when the injectors ground leads go to the resistor, which is 2 resistors in parallel, injector 1 and 4 should go to one resistor and injector 2 and 3 should go to the other. This arrangement allows each injector to be grounded separately without having 4 separate resistors. If they're wired incorrectly the only thing that won't be happy is the resistor really, current through the injectors won't change, just the current through the resistor.
Speaking of resistors and grounds, how is the grounding point for the resistors? The point where the resistor pack meets the chassis can be corroded or insulated with paint. Another issue that has popped up in the past.
What are the resistance values across the resistors? Might consider replacing that piece. I'm sure someone has a good one you could get cheaply enough.
jondee mentioned a noid light, it would be a good idea to get one of those. Make sure it is an LED type, the flash is brighter(yes they were made with incandescent bulbs, dull and slow). Or you could make an LED test light, I made one with a 10mm led and a 285 ohm 1/4 watt resistor. For the terminals you could flatten some solid copper wire to fit in the injector plug slides.
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Re: 4AGZE Injectors Not Firing

Postby sirdeuce » Thu Jun 20, 2019 7:52 am

Another thought, I had a similar issue with a VW squareback I had a long time ago, long time ago, the transistors burned out. That took a long time to figure out. Open the ECU and inspect the components, look for anything obvious like blown capacitors or melted transistors or resistors. Look for corrosion and dark spots in the circuit board. I don't know if you have any experience there so I won't suggest any more than a visual inspection.
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Re: 4AGZE Injectors Not Firing

Postby sirdeuce » Thu Jun 20, 2019 7:58 am

What about the ground wire that goes from the front of the engine to the chassis? So many people forget that one. Black wire with a yellow tracer with a black plug. Typically bolted to the front engine lifting hook.
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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Thu Jun 20, 2019 2:10 pm

Hello,

I've replaced the square plug that goes from the engine hook to the strut tower, as I found it didn't do anything. At the time I didn't realise my intake earth wasn't working, so I replaced it with a ring connector on some 4mm cable and put that straight to the strut tower nut.

It probably wasn't working as the intake had current going through it due to the earth not working as I had a painted surface.

Yes the ignition coil and resistor pack are awkwardly earthed as the stud that is held it in place, moulded into the rear inner arch came away and spun so I couldn't tighten it's nut up properly. It's currently secured via another stud that I've secured to the chassis with 'super steel'. I've tested that and it's okay.

Jondee has told me that 1&2 are paired and 3&4 are paired- a lot of mis-information out there. I did the noid light test and found I had a light on injectors 1 and 2 - I didnt get round to checking 3 or 4.

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Re: 4AGZE Injectors Not Firing

Postby jondee86 » Thu Jun 20, 2019 4:01 pm

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

Image

As the injectors are batch fired and not sequential, it really does not matter
how they are paired up. But the circuit is designed to have two injectors in
parallel on each resistor pack output to balance the current flow, so having
three injectors on one side is not ideal. Only one cylinder is likely to have the
injector squirt at the correct timing, ther other three will always be at the
wrong timing, but fuel still gets into the cylinders and the engine runs fine.

If you have 12V at all four injectors and the noid light flashes on all four, then
the injector circuits are working. If you want to be sure, unplug the cold start
injector and crank the engine for 15-20 seconds. Pull the plugs and check if
they are wet with fuel. If they are, while the plugs are out test each one for
spark when grounded against the head (dry the plugs with a propane torch).
Spark is sequential with a distributor so it has to occur at the correct time.

Cheers... jondee86
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Re: 4AGZE Injectors Not Firing

Postby sirdeuce » Thu Jun 20, 2019 6:56 pm

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.

Image



That makes absolutely no sense. The ECU is grounded to the chassis and the injectors, in order to complete the circuit, must be grounded to the chassis. 12v in and 12v to ground/chassis.
One shot, one kill.

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Re: 4AGZE Injectors Not Firing

Postby jondee86 » Thu Jun 20, 2019 7:55 pm

Image
The reasonable man adapts himself to the world; the unreasonable one
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Re: 4AGZE Injectors Not Firing

Postby jondee86 » Fri Jun 21, 2019 12:16 am

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
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Re: 4AGZE Injectors Not Firing

Postby Alex170984 » Fri Jun 21, 2019 8:33 am

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.

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