New year same problems...all 8 injectors firing two times per revolution

[ReneH]

Hi together! Happy new year at first!

So as I'm staring again today with a new distributor, the problems are the same.

I have also made a new wiring of the three shielded cables from the distributor to the ECU. Nothing changed.

I also have measured the ignition suppression resistor.. 21.8k, so also this part is ok.

I'm out of ideas...I have changed everything. Every part (ECU, distributor, MAP, O2 sensor) also the wiring routed outside the car directly to the ECU.

Still the same problem. The ECU switches both banks at the same time. Two times per revolution...

Is it possible That this is normal while staring? I always have disconnected the ignition coil from the distributor and the distributor cap off to see the position of the finger...

Thanks for all answers in advance...

[86 1/2 Brutus]

I'm not sure what you are working on, but this, to me, sounds to me like it is the multiplex computer that fires the injectors.  

[ReneH]

Hi, what do you mean with "multiplex computer"?

[86 1/2 Brutus]

The fuel injection computer.    did you change the pickup coil in the distributor?  If so, your problem is going to be with the computer, or the wireing from the computer to the injectors.  What year and what engine are we dealing with?

[ReneH]

I have changed the ECU and also the whole distributor without any effect.
We are talking about a 302/347 stroker. I have had the same problem with my original ECU and also with a new from a 351W. Is there another computer?
All cable from the distributor and the injectors connected with the ecu...

[86 1/2 Brutus]

what year?

[86 1/2 Brutus]

what about the wireing from the tfi module?

[ReneH]

1986
I have made a new wiring of the three shield  cable outside the truck, directly to the ecu. Also no change

[86 1/2 Brutus]

what about the tfi itself?

[ReneH]

My new distributor has also a new tfi module on it...

[86 1/2 Brutus]

go and unplug 2 of the wires that go to the injectors, wipe them off and send me a clear pic of the 2 wires

[ReneH]

I hope I have understood...this are the both cable the goes directly from the ECU (Pin 58 and 59) to the two injector banks ground.
Is there a relay between? I haven't found one...and the cable color is the same on the connector of the ECU.

[ReneH]

20230115_155523.jpg

[86 1/2 Brutus]

assumeing you have a volt/ohm meter.  Put the meter on ohms.  connect the black wire from the ohm meter to the minus - battery terminal.  Connect the red wire on the ohm meter to each of the black wires on each fuel injector plug.  the reading should be not more then 2 ohms.  Then disconnect the black wire from the battery.  On each injector connector there is a black wire and a different color wire.  start with the first connector.  connect the black wire from the ohm meter to the first injector's colored wire ( the wire thats not black)    Basically.  put the black wire from ohm meter on the wire that is not black, take the red wire from the ohm meter and touch it to all of the other injector wires that are not black.  The meter should read infinite.  Repeat this process with each injector connector.

[ReneH]

Ok...I don't really understand, what you mean.

My cable at the connectors are red, supplied with ignition 12 volts and 4 of the injectors have a tan/Red cable going to the ecu. The other 4 have a tan/orange cable that also goes to the ecu...two banks with 4 injectors. Every injector has 14 ohms. So 4 in parallel have 3.5 ohms, measured to the red supply cable...

I have made new connectors to the injectors...everyone with a single cable.
Combine on a good accessable point...

[ReneH]

20230115_163822.jpg
This is my wiring...

[86 1/2 Brutus]

Good, glad you have that.  The colors did not look correcft in the pic you sent.  so we will start here.
Put the ohm meter on volts, ground the ohm meter.  Take the red probe and touch it to the yellow wire on the eec relay.  This should read battery voltage.  Turn the ignition switch on, not accessory but on, touch the ohm meter to the red wire coming off the eec relay, you should have battery voltage.  Do that and we will work from there.

[86 1/2 Brutus]

Looking at the schematic, it looks like each injector is supposed to fire twice.  4 of the injectors are paralleled with the other 4.  from the sehematic 1 and 5 should fire at the same time, 2 and 6, then 3 and 7, then 4 and 8 are supposed to fire at the same time.  They are connected together and will fire at the same time.  This is probably a waste spark system.

what exactly is your truck doing?

[86 1/2 Brutus]

I looked again at your original message.  From the sechematic, they are supposed to fire twice.  2 injectors are supposed to fire at the same time.
Its hard wired this way.

so whats going on?  does it not start, not run, backfire?

[ReneH]

Ok. First the truck runs...but as rich as it can be...all 8 injectors fire the same time, twice per revolution. I have had some posts before...end of last year.
No backfire...it almost make sounds that it's drowning in fuel...also all 8 spark plugs are wet after some minutes of running the engine.

Gary and others have also mentioned, that this is wrong. As you said, it should be a sequential injection with two channels firing  at different times.

Regarding to your last measurement...yellow is SPOUT on my connector...this should have 12v all times hot, also with ignition off?

Here is my old connector...I also have changed it while searching the failure...
20230115_170750.jpg