pimpin7

Damn! Who **** on my parade.
Just got the engine rebuilt, and reinstalled.

Well so far I have had every possible problem known to this motor. Rebuilt the engine because of compression, with help of other members was able to diagnose no spark, and now finally I get no fuel entering the housings. I'm not sure exactly what it is this time. Possibly a bad connection on the primary fuel rail. I know the fuel pump and egi relays work because when the fuel hoses are unplugged they are doing the job pumping the fuel out. I'm not too savy on fuel injectors, but I imagine if somehow there was a bad connection or got unplugged somehow, it would not allow absolutely any fuel out, correct. So basically what I'm asking is if the fuel pump is pumping the fuel through the lines then the injectors must be whats stopping the fuel from entering the rotor housings, by not having power to them possibly? I've checked computer codes and none are given for any fuel injector problem.

I don't think I could have got the fuel lines mixed up since they have the dots on them to which goes to which, and on top of that were labeled when removed.

I know for sure no fuel is entering the housings because the plugs are not wet with fuel, and when I spun the rotors with the ignition no fuel was shot out, it smells absolutely dry of fuel.

Thanks,

pimpin7

bump

quicksilver_rx7

free one ^

pimpin7

Thanks for the free bump man ('_')

Well just wanted to follow up.

I'm desperately needing some suggestions, as I have done almost everything I possibly can to figure this out. I have recently rebuilt my 13b rotary. Before removal of said engine, everything was working, only that the engine was becoming tired, so I had to do something about it.

I have got nearly 120psi compression now on each face of the rotor after the rebuild. I have spark. But for some damn reason the fuel does not want to enter the housing. And before I start ripping of the top half of the engine I figured I could talk to anyone that might have a suggestion as to what could be going on.

At first I might have done the most stupidest thing I could think of. I thought the engine since it was starting had become flooded, so I threw some atf fluid in there. It almost started but was rough and died out, I believe the ATF ignited and that is what happened. Thank god I didn't blow the motor because of it. I don't think I'll ever put atf in my engine again.

Here is what I have found out:
1)Fuel pump is good, I have listened to it turn on and tested continuity.
2)Fuel lines are installed correctly, I have visually seen fuel entering from the left pipe via fuel filter, and exiting from the right pipe, top pipe for charcoal canister, which my FD has none.
3)when I ground the fuel pump via diagnosis connector I can here the injectors coming online and it sounds like it is spraying and I visualize no leakage.
4) when I crank the engine with spark plugs removed, I see and smell no fuel coming out, it is virtually dry of fuel.
5) Engine cranks over but does not turn on.

So my only conclusion is something is going on with the injectors.

Any suggestions? Anybody have a similiar experience.
Thanks again,

DigDug

Sorry about that!


Correct - the injectors won't be opening if they don't get power. Otherwise, when you turn the car off, fuel would be dumped until the residual pressure in the fuel system is relieved.


Have you hooked up a fuel pressure gauge to make sure you really do have adequate pressure? If you do, then I would start looking at the injectors.

DigDug

This may seem trivial, but here's the FSM page about testing fuel system pressure.

DigDug

Hmmm, just noticed this part - it's early!

So you're grounding the F/P diagnosis terminal, and you can hear the injectors when you turn the key to "ON"? That's not right - only the fuel pump is run when you do this, not the injectors...

Once again, I would first verify that you're getting pressure, then look at the injectors. It could be a wiring issue with the injectors, or it could be something extremely simple that you're just overlooking.

pimpin7

First off Thanks for the information and help, that has given me a better idea about the fuel system operation.

Yes, when I ground F/P and turn the ignition to on- at the fuel pump I hear it turn on- and at the intake manifold to lim I hear the injectors turn on as well, but I'm not sure that they are spraying fuel or if it is just air as weird as it sounds. Because with the EGI fuse and relay, and circuit relay installed and engine cranked absolutely no fuel is spitting out of the spark plug holes, and on the spark plug I can smell no fuel, just the engine assembly lube I put in there. Indeed sounds like it might be a wiring issue, which I wouldn't doubt I had a wiring issue with the CAS's. The wiring is so worn out on the FD's its dangerous.

I guess there is really only one sure way to see if the injectors are working, by pulling them out and visually see if they are spraying fuel. There such a pain in the butt to get to.

Hyperite

Yeah, you definitely shouldn't hear the injectors unless you have an AEM computer....and I'd guess they're not spraying fuel if your engine is bone dry. I would probably NOT just yank the injectors and see if fuel sprays out when you try to start the car....test the wiring instead, and test the resistance along the injector. That should be plenty to let you know if they SHOULD work (which I'm gonna guess you'll find a problem with the wires, probably NOT that all the injectors froze closed)

pimpin7

[QUOTE=DigDug]Sorry about that!




Correct - the injectors won't be opening if they don't get power. Otherwise, when you turn the car off, fuel would be dumped until the residual pressure in the fuel system is relieved.
QUOTE]

So even if power was not being recieved by the injectors, fuel could still enter the housing because of residual pressure relief, after the igntion is turn off. So I would imagine with at least some fuel in the housings the engine would try to turn on.

Hyperite

No, that's what he's saying. Car off = injectors closed. If that weren't true, a normally functioning car would flood every time it's turned off as gas just spews past the injectors.

Gadd

Sorry to here you havent got you car running yet. I saw your previous thread about the crank angle sensor, It sounds like your wiring harness is crispy and that can cause all sorts of problems. This is what I would do:

Ck. for fuel pressure at the inlet pipe, ( the line at the left standing at the drivers fender) you should have more than 20lbs with the key on and a jumper in the F/P terminal.

Ck for battery voltage at the +B terminal in the diagnosis connector with the key on.

recheck the connectors on the ecu make sure there fully seated.

If those ck out, carfully add a small amount of fuel in to a vacuum nipple on the uim.

If the engine fires for a sec then dies you going to have to pull the uim and ck for battery voltage at the black/yellow wires at the injectors with the key on.

pimpin7

lol, your right. I read through it too fast and got all backwards.

pimpin7

Hi Gadd, thanks for your help as usual, I am in debt to you. Yeah pretty much nothing is going to give that easy for me and this car, so close to taking a bat to it, to end all the madness,lol. But I know I would really regret the car getting the best of me. Perhaps it is just a good thing that I am having to go through all this trouble, so the engine wont be a running fire hazard. Plus I get to meet cool selfless guys like you all. You are exactly right about the wiring harness it is a crispy one. I just didn't want to mess with it because everything was working fine before I removed the engine, and plus I got all pumped up about the engine being put together I became impatient and didn't spend the time to redo most of the wiring, like I should have at least at the terminals anyway, now I might have no choice. I guess all the movement of the wiring harness created some problems. The problem is now If I have to get to the primary injectors, its buried underneath medusa's head it is going to be a real problem. I could bearly get my multimeter pins in there to test out voltage, and continuity. I know it can be done just wanted to spare all the grief.

Thanks very much for the suggestions, I'm going to start with the simple things first, like you guys have mentioned. At least now I have a focus of where to start.

lopedl

iTrader: (1)

The wiring harness is so old and subject so much heat it becomes frail. The sad part of it is it can also make or break your engine.

pimpin7

Gadd,

I checked everything you said and it turned out that everything above the Intake manifold checked out okay. Since I couldn't figure a way to get fuel through the small nipple on the manifold I just skipped that and headed straight for removing the manifold again.

Here is what I found out.

You know how when you touch the two pins of a multimeter under ohms it will give you perfect continuity of 0, meaning that there is 100% contact.
Well all of the fuel injectors had 100% continuity as the multimeter red 0 ohms, no resistance.

After that I checked the male plugs, and here is what is weird.

The two primaries tested 12.2volts on the Black and yellow wire,
and 0v on the misc. colored wire(I believe these ones are the ground?)

The rear secondary produced 12.2v on the Black and yellow wire, but then when I went to test the misc. colored wire(I believe for the rear secondary the color is Light Green) it read 11.6v. That's strange shouldn't this be a ground wire? If so that means it is probably getting juice somewhere. Anyhow if that is the case I still don't understand how that would affect the primary injectors from spraying fuel on startup? Any ideas guys. And I still don't understand how when the F/P is grounded the injectors come on, I can only guess something is causing a short.

I didn't have a chance to test out the front secondary injector as it was getting to dark, will be doing this tommorrow.

It sounds like I have good injectors.

Gadd

Hmmmmmm..... I'm not clear on what you mean by "when the F/P is grounded the injectors come on," If that were true, the motor would be WAY flooded. The misc colored wires go to the ecu, and the ecu grounds the injector and opens them. But the ecu will not open an injector untill the motor is cranked over. When you say you cked for continuity on the injectors, was that with the wiring harness disconected? You should have about 14ohms across the injectors. But I dont think that they could have all gone bad at once............. So.. You'll need to ck for conutinuity from the injectors, to the pins on the ecu. Do you have a wiring diagram? (disconnect the neg cable on the battery before messing with the ecu)

Sorry I'm not sure I'm helping much, but stick with it buddy you'll get this baby running!!!!!!!!!

pimpin7

Gadd, your helping more than you could imagine.

Well regarding the F/P pin at the diagnosis connector when I ground it with the ground pin to test for fuel pump operation, I can always hear the injectors spraying at the uim, when I remove the connection the injectors stop of course. I thought that was part of the process until others had mentioned that this is not normal, and that you should only be hearing the fuel pump activated. The weird thing is I had thought that well since they are spraying that should at least dump some fuel in the housings and allow the engine to at least attemp to turn on, and that I would see and smell fuel exiting the spark plug holes, but to no avail.

Yes, I checked the pins of each injector with the plug removed. The multimeter indicated that there was continuity between both pins of each injector. The wires are pretty tore up on the plug side. I am really thinking the injectors are okay, and that there must be a short somewhere.

Good idea I'll begin to check for continuity from the ecu and plug, using the wiring diagram. I'll cross my fingers and hope to not cry.

pimpin7

Thats what might be messed up on the secondary plug because I have two positive readings. And according to that information I should only be having one positive and one 0v reading.

DigDug

Are you sure you aren't hearing something else when F/P is grounded? You ground the terminal and then turn the key to "ON", correct? And at this point you hear something from the engine bay? Is it a continuous noise, or does it happen briefly and then stop? Could it be the ABS actuator cycling? That always happens when you turn the key to "ON", but it is not a continuous noise.

Have you checked fuel pressure yet? You should make sure that you are getting proper fuel pressure before diagnosing the injectors...

If you know you have pressure, try hooking up 12V to the individual injectors to "manually" open them. You'll be able to hear them opening if they're working. You might want to release the residual fuel system pressure before doing this, or you'll end up flooding the motor.

DigDug

Here is the section of the wiring diagram dealing with the injectors. As you can see, the ECU switches ground. Simply test voltage at the ECU pins (4W, 4Y, 4X, 4Z).

Gadd

Ya I'd feel better if you could eliminate a fuel pressure problem. I'd lend you my fuel pressure tester if that would help. btw, I gave you the wrong min fuel pressure in a past posts. FSM says 36 to 38 psi

pimpin7

Thanks again guys, really appreciate your time. Fuel pressure could be a problem, honestly I am just inspecting it visually when I have someone crank the engine I can see fuel spraying out of the hose into my jar. Well maybe I forgot to leave an important piece of the puzzle, I drained the fuel from the tank via a bolt on under the tank, because the fuel previously was old, and I wanted fresh fuel. I did not depressurize anything, is it possible I did something wrong in that instance. I will go and buy a fuel pressure gauge from the auto parts just to make sure.

My next step is to clean up the harness because there were a couple of bare spots on the wires, which can't be helping matters.

I am almost 99% sure what I'm hearing when I ground the f/p is the injectors, it sounds distinctive as spraying and its coming from the exact area the injectors were installed on the uim. It is only activated when the f/p is grounded, regardless of the ignition being turned to the on position, when the ground is removed from the f/p the spray noise stops. But I want to be a 100% sure so I will put ground and power to each injector just to make sure they are at least functioning.

pimpin7

Would low fuel pressure prevent the injectors from opening. I would think it would at least allow some fuel to be permitted.

Gadd

The injector would even if you had no pressure but it would limit the amount of fuel the injectors put out. I dont think fuel pressure is the prob, but like Digdug said it would be nice to eliminate it as a problem. You must be hearing the fuel flowing thru the fuel rail, there is a constant flow thru the rail when the pump is running. Draining the tank was a good idea.