Went out and looked, and I couldnt really find any larger grounds bolted to the engine.

 

On top of the engine and the location depends on if it is an S4 or S5. S4 it's toward the rear near the EGR and it is not accessible w/o the removal of certain items and the S5 is more towards the front of the engine.

 

hey sorry i havent posted on subject for a while, i figured it out. it ended up being the pulsation plug that comes on s4 harnesses, the s5 doesnt have them. on s4 harnesses there is only one wire out of the ecu that goes to this pulsation plug that is located in front of the passanger side tower, it takes the one injector wire and splits it into the 4 plug wires. on the s5 harness they actually did away with said plug and the wire is a hard wire all the way to the injectors. so all i did was take what was suppose to be output power from the harness and hard wired it into itself to create the correct flow of current for each injector.

 

S5 motor, I see a couple ground though.

 

What I meant was, I see a couple grounds. I do have a ground attached near the oil filter pedestal that has a little box on it, but its not attached to anything, and I cant find anything to attach it to. Has a single spade male connector.

 

If it looks like a small computer chip then it is a condenser and there are two in the engine bay, one for the oil pressure sensor and one for the coils. It's not imperative whether they are bolted to the car or not. These are not a true ground. Again, you cannot visually see the main engine ground as it is hidden.

Engine ground pic: http://www.aaroncake.net/rx-7/grounding.htm

 

OH! So does this ground actually run to the ECU itself? IE, through the EM harness to the actual ECU?

*EDIT* Also, do you happen to know which ground it is coming from the ecu itself? Just need to know which one on the EM plug it is. Youve got my hopes up the Cosmo will start soon!

 

Pins 3A, 3B, 3C and 3D.

 

I am an idiot as it says that right on the walkthrough you sent me. Thank you so much for the help though!

 

Turns out, all those grounds are still in order, almost zero resistance from the ecu to the engine, so I think they are fine. What else would stop the injectors from firing? The car will run using starting fluid, but not of its own power. I have fuel to the rail, and back out the return, so thats not the issue.

 

Is this an S4 or S5 (I forgot the exact deal here).

 

s5 engine and ecu, but in an 87 HB cosmo. the E harness is completely untouched, but I removed stuff from the EM harness, and... I think thats where I went wrong haha

 

Pin 2I (Brown/White wire) should have about 5 volts w/key to on. This is the Vref voltage which powers up certain engine sensors and it needs to read the proper voltage.

You could also have a CAS that is incorrectly stabbed and causing the timing to be out of whack which would cause the injectors to not work properly.

And are you sure you don't have the fuel lines (ingoing and outgoing) mixed up?

If you jumpered the fuel check connector and w/key to on and the return fuel hose removed and placed in a jug do you get fuel flow?

 

I for sure am getting fuel back out the return line, I think Ive checked to make sure they were put on the proper way a hundred times now haha.

as far as the CAS, it was my first thought to check that, but I have absolutely zero fuel on the plugs. We are talking bone dry. Not to mention, when I run it off of starting fluid, it actually idles fairly smooth, so I think the CAS is at least not the main problem.

So the 2I plug needs power to make the injectors fire/supply the engine sensors with power? Where does the stock ecu get the 5v source from?

 

Pin 2I needs the proper voltage to power certain engine sensors and if that voltage is shorted out then the engine won't start. If you checked the Br/W wire at the TPS or Boost Sensor w/key to on and found about 5 volts then it's good. If you found 0 volts then not so good. Secondly, the CAS sends a signal to the ECU to allow the injectors to fire so if the signal is not as it needs to be then of course you won't find fuel on the plugs. Thirdly, was this an early 87 model as they are equipped w/a resistor box that had low impedance injectors and you either would need this box to run low impedance injectors or if you don't have the box then you would need high impedance injectors or if you did not have the box but you had low impedance injectors then you would need resistors wired into the injector wires to work these low impedance injectors. I'll guess this is your issue.

 

Fell behind on this as a result of surgery and Fall matsuri. I found 5 volts on the TPS, but I couldn't find a br/w wire headed to the boost sensor. As far as the CAS, doesn't that also send the signal for the ignition? The car will run with ether, meaning the ignition is receiving signal, so shouldn't the injectors be seeing the same signal? The car was a 89 actually, S5 everything so far as I can tell.

 

Focus on what was asked in post #40 as far as the injector impedance (are they high or are they low) and the resistor box (is it incorporated in thto the wiring or not).

And have you checked the timing?

 

Well the car I pulled everything from was manufactured in 89, and it doesnt look like they changed a thing, so I would say they are the high impedance that came in series 5 fc's. How else could I tell? As far as timing, no I havent checked it yet, but the plugs are completely bone dry when I pull them out, and it never even sputters to fire. Could the timing be off enough to cause that?

 

What about the resistor box that might have come w/the 87? Is it installed or not? Check the timing and if it's good then it's one less thing to worry about.

 

There isnt a resistor box, but there shouldnt be. The car it all got swapped into is an HB cosmo, thats the only model year 87 in my situation haha. The engine, ecu, and wiring are all 1990/S5. I will check the timing when I wake up tomorrow.

 

Was just looking at the wiring diagram, and I noticed that when the Fuel Pump relay is on, it sends a ~5volt signal back to the ecu. I do not have a fuel pump relay wired in, as its in a totally different chassis. Could this be the issue? Does the ecu need that 5v signal to turn on the injectors?

 

Relay in the engine compartment or relay under dash? And which wire are you specifically talking about?

 

Honestly unsure of the relay's physical location. Looks like its pin 1K, should be a G/R wire.

 

The G/R wire you speak of is supposed to read 12 volts while cranking the engine and the voltage drops to around 2 volts after a couple of minutes of engine idling.

 

So if it werent, then the car wouldnt start? I guess the other question is how in the world Im gonna make that happen haha