Satch.... You are the man... That was the piece of information i have been wondering about...

I will test the injectors spray next..
And we will see where that leads me..

 

No worky... Something is stopping the pulse from the ECU.. What could it be..

http://www.youtube.com/watch?v=lMJEOoB4DYs


http://www.youtube.com/watch?v=knqiqbFgRHU

 

You can remove the plug to the injector and test for voltage on the wire from the ECU to see if you get the 8 volts when starting. Also, w/the injector plug removed, set the meter to ohms and place one lead on the injector terminal and the other meter lead on the other injector terminal and see if you have low impedance injectors or high impedance injectors. Low would be about two to three ohms while high would be about 11 or twelve ohms. An "86 S4" is supposed to use "low impedance injectors" and this might be your problem.

 

They injectors are low impedance. They are 3 ohms.. all of this has been checked..

I am thinking that some thing like a part will tell the ECU not to send the signal.. Like my CAS for instance... If it had a bad wire.

 

I thought you tested the signal on the Green injector wires w/key to start and it read 8 volts which is what it is supposed to do to fire the injectors so its not the ECU. There is a Resistor Pack/Box located inbetween the Main relay and the injectors. If it is not working properly then the injectors will not fire. Should be hard to do but do you have the primary injector plugs on the secondaries by chance?

Before I mentioned the impedance of the injectors did you state that this aspect had already been checked and verified? Nope.

 

Since you now have access to the primary injector plugs, both pins in the plug will have 12 volts w/key to on and when cranking the voltage on one of the two pins will drop to 8 volts or so.

 

All of these thing have been checked...
Resistor Pack/Box = GOOD
injectors = GOOD
volts = GOOD 12v and 8v

The plugs from the Primary injectors can not reach the secondary injectors.. and the secondary injectors would have fired.. They are wire up also..

Here is the thing.. an injector is a coil. I posted a colored schematic... on my profile just in case to help me..

a coil.. is an electro magnet.. it uses positive and negative voltage to work. I should be getting a pulse from the ECU on pins 3E and 3C ... the other side of the voltage...

If i dont get it.. then the injectors will not fire..
So the ECU or somthing attached to it.. .. My guess is something attached to it has a broken wire.. and is telling the ECU not to work..

Or the ECU is crap.. But i have gotten 2 more and how many ECU's do you really go through..
1 ECU came out of a working car..
So what would tell the ECU not to fire the injectors..

Anyone???

 

You already stated that the ECU has the 8 volt signal which runs directly to the injectors as there is no connectors on the way to the injectors to interfere w/the signal. This is your ground signal, so the ECU is doing its job. Again, once the ground signal leaves the ECU, there is nothing in the way to prevent the signal from reaching the injectors unless the wires were damaged or the pins in the injector plug are pulled back or damaged which occurs quite often. I know you checked the ground signal at the ECU, but how about at the "primary injector plugs itself." The B/Y wire from the Main relay feeds voltage to the Resistor Pack which then passes it onto the injector to provide the battery voltage signal while the ECU's job is to provide the ground signal and as stated earlier this signal occurs so fast that the multimeter cannot possibly read this number for display purposes thus the voltage amount is indicated somewhere between 12 volts and 0 volts.



Also, the secondary injectors "only fire under load and this does not occur while the car is free reved in the driveway" unless you trick the car into thinking it were under load, which is done by disconnecting the vacuum hose to the Boost sensor, plugging said hose, and disconnecting the TPS. Doing this creates load.

EDIT: One thing you could do is to depin 3E and 3C and then switch over the wires from the secondary injectors which are pins 3H and 3F to where 3E and 3C go and then turn over the engine and see if the injectors connected up to these two wires will fire, either the secondary injectors connected to these two wires or switch them out for the primary injectors.

 

Another thing you could do is to remove the small plug from the ECU, jumper the fuel check connector, turn the key to on and then place a brief ground to either wire in the disconnected ECU plug that runs to the primary injectors and the injector should expell some fuel.

 

Does anyone know what the Inhibitor switch does... or looks like.. and where it is?

 

It's found on only autos or cars that were once autos but converted to a manual transmission. It is found on the passenger side of the transmission housing. It prevents a car w/auto from being started in gear.

 

Perhaps the voltage drop on the ECU injector wires is caused by the electrical drain from attempting to start the car and not because the ECU is sending a ground signal. If this is so, then you should remove the small ECU plug and put a ground to the injector wire w/the key to on to see if the injector spits out some fuel. This is my last advice to you.

 

So i have tested out my ECU.. Put it in another car.. It runs fine...
Thanks AC chillin.. RX7 guy here in town.. Who let me test it..

He said that i should get a under the hood harness.. Off a wrecked car.. That might not be a bad idea..

i have been tracing wires and voltage here and there.. nothing yet...
So I know now that i have a component or a wire that is messed up... I just have not found it ..lol Thanks every one and most of all Satch for the help...

 

And jumper the fuel check connector in addition to the info in my previous post and if fuel spits out then that specific wiring is good to go. Should take all of two minutes to checkif that.

 

I got the car started.. after a long test everything out.. I am not sure what the full issue was. Boy do I know more about my rotary though..

It seems that i have to floor the gas to get it to start though.. and it will stall until it gets warm.. But after its warm it is working fine..

So if anyone know what this issue is.. thanks for any help.

 

Does this problem occur after numerous times using the car or just the first time it started up after repeated attempts to start the car as it makes a difference? If it does it repeatedly then perhaps low compression or fuel amount at start up is the problem.