DigDug

pimpin7

Yeah that was my face too. After the car wouldn't start, when I fixed the spark.

Well the wires weren't actually touching each other, I had put grey rtv stuff left over from the rebuild so they wouldn't touch. I figured since I went through all this trouble now I might as well redo them. I pretty much would be suprised if any FD doesn't have the same problem with the wiring harnesses, unless there still on their first engine.

pimpin7

Okay had some more time today to work on the injectors. And I am coming across some weird issues with the injectors.

I am now 100% sure that when I ground the F/P at the diagnosis connection, it is the injectors that are being activated, and they are infact spraying fuel. Weird right? I can now smell the fuel through the intake port, this is of course with the intake manifold off.

Well here is what is weirder, I followed the manual to test the injectors via the battery, grounding one pin and the other pin at B+, and the injectors do not spray any fuel.

It's almost like my injectors have done a 360 degree, where it injects fuel when its not supposed to ground to f/p, and doesn't inject fuel when it's supposed to.

All of the injectors are this way both primary and secondary.

This is beginning to be rediculous, what luck I have.

pimpin7

Are you guys 100% sure that the injectors should not spray when f/p is grounded, as what are the odds, that all injectors are doing this?

Mahjik

iTrader: (1)

Yes. If they did, you would flood the engine trying to pressure test the fuel system.

pimpin7

Oh yeah, I forgot to mention why I am so certain it is the fuel injectors I am hearing rather than fuel entering the fuel rail. I unplugged all the injector plugs and when I grounded the f/p there was no spraying noise. When I hooked up just one injector, meanwhile f/p grounded the noise came back, and this was for each injector, as I plugged back more the sound become more plural.

pimpin7

DigDug, you said to check voltage at the ECU directly, I am assuming this is with ignition on. But I don't understand if those wires are for grounding purposes, how will they produce voltage?

Anyhow I was thinking about the ECU and there is a little black and yellow wire, that is always not plugged there is no where to plug it to, it is seperate from the wiring harness plugs, but I really don't think that is it, I did a search and think someone said it was for a fan or something.

I will be checking the voltage regardless at those points (4W, 4Y, 4X, 4Z), and then continuity from injector plug to ecu, while I'm at it. I'm just so stumped.

DigDug

No, I meant to test on the harness connector pins. The diagram I attached shows the pinouts for the ECU connector. You should test the 4W, 4Y, 4X, and 4Z pins (refer to the pinout diagram) on the harness connector. Test voltage to ground on each pin with ignition turned to "ON".



I can look at the wiring diagram, but you'll have to be a bit more specific. Black w/ yellow stripe? Where is it located? Did you cut it off from one of the ECU connectors?



Continuity between the injector and the ECU (ground) is what I am suggesting that you test. For each pin I mentioned, hook the multimeter up between the harness connector pin and any ground, and set to voltage (at least 12V). Do this with the ignition turned to "ON", but do not ground F/P or it will flood the engine. Each pin should read ~12V.

DigDug

And that definitely doesn't sound right. Are you sure you're grounding the correct pin? Make sure you are only touching the F/P pin with the jumper wire.

pimpin7

Dig Dug thanks again,

Yep, those are the two terminals that are being jumped together, causing the injectors to spray. Perhaps the injectors just became bad and are now stuck on open.

The black w/yellow striped wire, is a seperate wire from the ecu harnesses. Its a single wire and has a male adapter on it, but it just hangs there with nothing I have seen to plug into. Honestly I don't really think it is an influence as it never says anything about it on the rebuild video. And I never remember having it plugged in the past, when the car was running.

DigDug

If they are spraying, you should be able to see/smell fuel through the spark plug holes. It's also very unlikely that both of your primaries failed at the same time. That makes me think it's a wiring problem that affects all of the injectors, or else you have no fuel pressure.


I'll take a look at the wiring diagram - I think I've seen the wire you're talking about.

Gadd

Eureka!!!!!!!!!!!...... (maybe..............)

I thought it was odd when you said you had 0 volts on the primary injector on the ecu side of the connector.. The wires inbetween the ecu and the pimary injector are shorted to ground somewere...... you going to have to trace them back and see if you can find a bare spot.

The black/yellow wire with the connector by the ecu is a fan test wire and does not connect to anything

pimpin7

Gadd & DD, You never cease to impress me, how do you guys know so much?

Well anyhow thanks again for your time guys.

I was able to work on the car for an hour today. And after all that 100% certainty about the noise, Unfortunately I was mistaken about that noise. I just thought since I had the injectors plugged and it sounded so much like spraying that it was the injectors. You guys were right it was something else, I unplugged all the injectors and the noise was still there. So that tells me the sound wasn't actually coming from the injectors. I'm guessing the noise I am hearing is fuel being pressurized. It must be when the fuel enters the fuel rail.

Whats more is when I unplugged the harnesses at the ecu, I noticed a black/white wire from the farthest top right managed to unplugg itself completely from the yellow plastic of the harness it is terminal 4a on the diagram dig dug attached .

Also I tested for continuity from the injector wires to the ecu harness, and all continuity for each set was there. Tommorrow I will be testing the positive side of each injector to double check voltage, and then voltage on the ecu harness.

pimpin7

Gadd,

So your saying that each wire on the injector has positive connection to it. One positive from the black and yellow wire, and one positive from the ecu side? Just like the rear secondary injector reading I had... hmm. I'm just having trouble comprehending that as the manual says to test the injector flow rate via the battery you connect one pin to ground and the other to positive. And not only that the ecu grounds those wires, doesn't it? So that would lead me to believe the ecu side of the wire would have no voltage. But both you and dig dug say that both wires should have juice. I hope that I'm wrong again, I really do?, lol.

So basically the primary injectors are the only ones activated upon startup. When do the secondaries come on line after a certain rpm range or boost pressure?

I'll do some hunting again today. Thanks for the help.

pimpin7

Gadd, I think we might be on to something. I checked the secondaries and the difference between the primaries is the secondaries (both front and rear) are producing voltage at both terminals in each plug. Whereas the primaries are only producing one voltage and that is on the black/yellow striped wire, and no voltage from the ecu side. There is continuity from the ecu terminal to the plug terminal @ the injector. So if the primaries should recieve two +voltage readings, I think you are right it must be grounding somewhere.

pimpin7

or its just not recieving juice @ the ecu side.

Gadd

OK.. All the injectors recieve pos. bat voltage via the EGI relay and the b/y wire anytime the ignition key is in the run position. the other wires from the injectors go directly to the ecu and it grounds them ( at the appropriate times) completing the circuit and opening the injectors. Now heres the odd thing, you should see voltage on both sides of the injectors when the circuit is open, the power is going thru the coils in the injector just like any wire. So when you thought the injectors sprayed fuel when the fuel pump was jumped, and you had 0 volts at the ecu side of the injector, this told me that something else was grounding the wire, ie a short to ground. Now with the key on, you can open the injectors by grounding the non- b/y wire, if you want the confirm the injectors are opening, you do not need to have the fuel pump running, because you'll here a "click". You can use a pin stuck into the wire at the injector connector and a test lead to ground the injector (ecu side).

pimpin7

Oh my freaking A! You are not going to believe were the problem is arising. After you confimed that both wires to each injector should be getting juice in your previous post. That lead me to test the front secondary injector to confirm that both secondaries did indeed recieve two positive reading. Which it did, confirming what both you and Dig Dug had stated.

Okay after that point I checked the ecu directly, you know how when you unplug the harness the ecu has several pins in there. Well I tested the 4z and 4x pin both secondaries which are the ones on the bottom tested 12v. Now the primaries are the top left two 4y and 4w and then I tested them, sure enough there was voltage there as well. So I was thinking to myself rather than tackle trying to remove the wiring harness locating the short and re-removing the medusa's head, why I'll just cut that wire and run a wire directly to the injector.

So I begun to take steps towards this goal. So I cut the top right wire light green and red (4w) the one that goes to the front primary. After cutting it I wanted to read the voltage from the wire. And guess what it read 0v. I was like what in the hell is going on. Thinking that one of the other wires might be creating the problems. Out of desperation to try and figure out what could possibly have caused the 12v with harness unplugged, to go to 0V with harness plugged, I pushed the harness in tightly with my hand. And the 0v changed to 12v. So with an assistant I pushed the harness tightly as possible with my fingers, and had the assistant go to the engine bay and check the primaries for voltage at the primary plugs. And both produced the 12v from the ecu wire.

Now the harness is totally locked in but must have gotten dirty or some how is not being pushed on the ecu pins quite all the way, hopefully the ecu hasn't shorted out somehow causing it to have this problem. So right now I'm in the process of letting the electrical cleaner solution see if it does the trick.

What a freak! Out of all the connections that would do that the two primaries injectors.

pimpin7

So I guess you were right from the very start a loose connection, how a simple problem can create such grief.

pimpin7

Ahhhhhh! Argghhhhhh!

I spoke too soon. There are these two sets of black with spotted grey wires with a circle connection on them near the ecu. One has no voltage it comes from the harness, and one which comes from a little box on the ecu labeled control unit has voltage. Originally when I installed the ecu I figured they were ground wires so I bolted them to ground. Well When I thought it was a loose harness I was wrong. I touched the wire that comes from the control unit with my fingers and apparently when I did that voltage went to the injector wires, like it conducted through my body or something and gave the 12v. Is there supposed to be voltage to these wires? Is the outside of the ecu supposed to have voltage pass through it, because that is exactly what this wire is doing.

When I unplug the wire harness above, and test the pin it reads 12v, when I plug the harness back in and read that wire it reads 0v. It's crazy once I think I solved the problem I really didn't.

mad_7tist

ok the injectors should only be getting battery voltage on the b/y wire. the ecu controls duty cycle through the ground side. seen as a series of flashes when you prob it with a good test light that is hooked to the batt pos terminal. you will need a good high impedence test light just clip it to the pos terminal and probe the lg/r,b,w, wire and you should see the light flicker when you crank the engine. careful cranking it with no surge tank on, diisconnect the coils to be safe. this test is done with the injector clip disconnected

pimpin7

Okay here is my confusion.

I had completed several tests today.

At the ecu, I tested the pins for the injector lg &lg/r/w/b. With wiring harness unplugged. The top two pins for the primary read 9.9 volts each. Then at the secondary pins each gave a 12v reading. Showing that the ecu is providing voltage to each wire.

So after that point I plugged the harness back in and probed the wires directly at the ecu. And suprisingly the voltage changed completely. The top two for the primary gave 0v. No matter how many times I probe them. And the bottom two for the secondary again gave 12v. I though it might be a loose or dirty plug, but that is not the case.

This is totally strange I am getting two different readings for each test, one of them must be wrong?? How could that voltage change just because its plugged or unplugged. So that trouble is happening right there at the ecu. Unless the ecu is channeling the power, or something. Or Unless each injector recieves the power differently. But the wiring diagram shows that the power comes to them the same. I imagine they should all give the same readings then?

pimpin7

mad 7tist

I'll give that a shot, and see what happens. I've tried just about everything, I think I'm gonna have to break down and let someone touch my baby's body.

wylie

Sorry I havent read all the previous posts so I dont know if this has been covered...


Make sure the wires are correct on the injector clip and not backwards.

Look through the manuals here.

http://www.iluvmyrx7.com/3rd_gen_manuals.htm

pimpin7

I did something really stupid out of my frustration. I went through all the trouble and pulled the primary injectors out to see if they were working visually. Mad7ist i read your email to late. Oh my god was it a nightmare. It's easy when the engine is out, but a disaster when the engine is in the car. Anyhow, something good did come out of it. I found out the injectors aren't being grounded out, like you guys had said all along. But how? Each injector will open when I ground them out directly at the battery. But when I tested through cranking the engine over, the injectors would not open. I did another test as suggested by Mad7ist.

What I did was cut one of the wires that come from the injector with 12v and probed the ecu at that terminal with a test light, and it would not light up the test light when I cranked the engine over. When I grounded that same wire to a local ground spot the injector sprayed. So here is what I know now with a 100% certainty the ecu is the problem.

Either I shorted the ecu out somehow, or a wire that controls ground is not connected, but I have connected everything. One thing that did seem strange to me however is That there are two circle connections that connect to a stud off the ecu, one has a positive voltage and one has a negative voltage I did put those together onto the ecu stud when reinstalling. To be honest with you I am not sure that is how it should have been.