Unique SR issues. Any help is appreciated!

[hstylez]

Let me start with the details. 93’ 240 with an s13 redtop swap. A few months ago I had this thing fired up just fine only time find a leaky turbo gasket. Took all that noise apart and reassembled and am now having some issues with starting/running.

Here is what is happening currently:It will crank-fire-crank-fire-fire-crank-crank….and will not stay running on its own. One of the things I noticed when I turned the key on is that the fuel pump would turn on, and stay on until I turned the key off. I thought the fuel pump was only to run for a couple of seconds with the key turned on, and shut off automatically if the engine was not being cranked yet. Interestingly enough, a few months ago when I had it running, the fuel pump shut off on it’s own before a start.

So after I tried to start the car several times, I could smell unburnt fuel near the exhaust pipe. I figured the engine was flooding itself (somehow, with the fuel pump not shutting off at key “on”, and the fuel smell), and so I disconnected the fuel pump fuse, cranked the engine over a couple times, and then left the car for a bit. When I came back, I put the fuel pump fuse back in, and when I tried starting the car again, I went immediately from key “off” to “crank”, not giving the fuel pump time to run without the engine cranking. The car started up right away, and ran fine for a couple of seconds. It then started to run all stumbly like, and wouldn’t react at all to the throttle. I tried tapping on the fuel pressure regulator, and the injectors while it stumbled, but the tapping didn’t seem to cure the irregular idle.

When I say stumble, I mean the engine sounded like it was running on 2 cylinders, and violently shook about the soft motor mounts. While it ran rough, the engine would barely react to throttle changes—I could open half throttle, and the engine would hardly rev. I noticed also that the black smoke was puffing out of the exhaust while the engine stumbled. I attempted to start the car several times after this, and only got it to rough idle.

Things I would like to know are:-Doesn’t the fuel pump have some sort of timing mechanism when the key is turned on? Or does it pump until a desired fuel pressure? Or is it supposed to always run when the key is on?-Even if the pump did run nonstop, the fuel pressure regulator should keep the pressure at the injectors constant, and not create an over-fueling situation…would a bad FPR force the injectors to leak?-Could the injector(s) be stuck open?-What is a good way to test the injectors to see if they are leaky?

Any other suggestions to what might be going on would be great. Anyone else have this problem? Thanks for reading!

[IanS]

the fuel pump should prime for 3 to 5 seconds,

black smoke = too much fuel

if the fuel pressure regulator sticks then it will give a stupid amount of fuel pressure causeing the engine to run stupid rich (black smoke) you can use a fuel pressure gauge to check the fuel pressure, it should be 43 psi with the vacuum line unpluggedif the injectors are stuck open it would also cause stupid richness, you can use an ohm meter to test the resistance on the injectors to see if they are working

what fuel pump are you running?

how long did the car sit without running and did it have a stabilizer in it?

[hstylez]

Thanks for the reply man.

I forgot to add I am running a walbro pump.

The car sat for about 3 months in between starts. I did add some (2 gallons) of fuel right before the most recent start. Also, there was no stabalizer in the fuel when it was sitting.

As far as the injectors go, what exactly is the process for testing them. I do have a multimeter is that all i need?

Thanks again for the help so far man...

[S13FASTBACKSR]

if you are running rich then the easiest way to test if your injectors are the culprit and sticking open is to pull your spark plugs. If one or 2 of them are quite a bit blacker than the others (usually only one) then that spark plugs injectors is sticking open. Say you pull the spark plugs but the one from the #2 cylinder is really really black and the rest arent, then cylinder #2's injector is sticking open

[S13FASTBACKSR]

I just read your whooole post, the fuel pump should not prime that long just like stated above me...Obviously if the FP keeps pumping fuel 100% of time and never stops then your going to be running waaaay to rich and have the problems that you are having..Double check your FP wiring..if you are 100% sure its correct then I would look to your ecu. Now what you can do to test your ecu is get your car running for as long as possible..just go from off to cranking right away so the engine will run..but you have to be ready to look at the back of the ecu very quickly because the engine may not run for long..first of all take off your kick panel covering your ecu..now unbolt your ecu (not the blue plug, just the bolt(s) holding it up) now let it hang and go over to the drivers side or better yet have a buddy start the car..now look at the l.e.d. on the back of the ecu when the engine starts running and if that l.e.d. stays on then your ecu is bad and you need a new one

[IanS]

Thanks for the reply man.

I forgot to add I am running a walbro pump.

The car sat for about 3 months in between starts. I did add some (2 gallons) of fuel right before the most recent start. Also, there was no stabalizer in the fuel when it was sitting.

As far as the injectors go, what exactly is the process for testing them. I do have a multimeter is that all i need?

Thanks again for the help so far man...

use your multimeter to test the resistance between the two pins of the injector I cant remember what the ohms should be my FSM doesnt want to open (stupid computer)

[hstylez]

Ok well let me ask you guys a question on the wiring then. For the brown wire, O2, it says run it to any 12V switched. I soldered it with the fuel pump wire figuring it is 12V switched. What did you guys wire it to? I dont really see how this could effect it, especially when it didnt do it last start up and the wiring hasnt changed...

Also, as far as bad ecu, you are saying that if the led stays on while the car is runnign then the ecu is bad?

[IanS]

I just read your whooole post, the fuel pump should not prime that long just like stated above me...Obviously if the FP keeps pumping fuel 100% of time and never stops then your going to be running waaaay to rich and have the problems that you are having..Double check your FP wiring..if you are 100% sure its correct then I would look to your ecu. Now what you can do to test your ecu is get your car running for as long as possible..just go from off to cranking right away so the engine will run..but you have to be ready to look at the back of the ecu very quickly because the engine may not run for long..first of all take off your kick panel covering your ecu..now unbolt your ecu (not the blue plug, just the bolt(s) holding it up) now let it hang and go over to the drivers side or better yet have a buddy start the car..now look at the l.e.d. on the back of the ecu when the engine starts running and if that l.e.d. stays on then your ecu is bad and you need a new one

whether the fuel pump primes indeffinetly or not, the fuel pressure should never go above the specified value set by the fuel pressure regulator.

befor you do anything else, you need to check your fuel pressure, if it is above 43 PSI with the key on fuel pump priming your FPR is bad

if its good, check your spark plugs to see if any of your injectors are stuck open. If your plugs are all black you can unplug all the injectors and while cranking, use a test light on the injector plug to see if the injectors are pulsing or just staying open, if none of the injectors are pulsing and they are just staying open, then start looking into an ECU or wiring problem

[sicairos_2007]

cant this be an ecu problem becuase doesnt the ecu tell the pump when to shut off and when the injectors to shut?

[hstylez]

Ok thanks for the info guys.

Smiles: That makes the most sense. Ill have to do that. Anyone running a NISMO FPR? Can it be adjusted below stock pressure? Just curious.

[S13FASTBACKSR]

whether the fuel pump primes indeffinetly or not, the fuel pressure should never go above the specified value set by the fuel pressure regulator.

This is true but, you still have to consider that even if the FPR is bad that the FP is still not working correctly because it is constantly pumping. So whether or not the FPR is bad or not the FP is another problem within itself. And the reason I think you should check the ecu first before the FPR is because in order to check the fuel pressure you must purchase a gauge and take the time to install it. checking the ecu is simple and free, just walk out to your car and do the test i told you about

[IanS]

This is true but, you still have to consider that even if the FPR is bad that the FP is still not working correctly because it is constantly pumping. So whether or not the FPR is bad or not the FP is another problem within itself. And the reason I think you should check the ecu first before the FPR is because in order to check the fuel pressure you must purchase a gauge and take the time to install it. checking the ecu is simple and free, just walk out to your car and do the test i told you about

you dont need to buy a fuel pressure gauge, you can rent one from any good auto parts store, or you can go to any decent mechanic and they can test it, for a nominal fee (less than $20)

[S13FASTBACKSR]

good to know but not to sound like a d!ck or anything but im just trying to help him out by doing the simplest things first which would be turning the key and looking at the l.e.d. and if the ecu tests good then I would go ahead with renting a gauge just my 2 cents

[IanS]

good to know but not to sound like a d!ck or anything but im just trying to help him out by doing the simplest things first which would be turning the key and looking at the l.e.d. and if the ecu tests good then I would go ahead with renting a gauge just my 2 cents

sorry, somtimes I have a hard time looking at problems from the perspective of a normal person, Im a mechanic and have access to tools most people dont, Im already starting to forget what its like to ghetto rig everything and make my own tools Ive also found I dont go through nearly as many zip ties. Checking the ECU is the best way to start.

Ok thanks for the info guys.

Smiles: That makes the most sense. Ill have to do that. Anyone running a NISMO FPR? Can it be adjusted below stock pressure? Just curious.

yes the Nismo FPR is adjustable, you do need a fuel pressure tester thoughI run the nismo, and I know a lot of the SR guys on here do also because its a direct bolt in and its also the cheapest

[hstylez]

Ok so one final question. I guess the question that would answer it all: Is the fuel pump supposed to prime for a certain amount of time (3-5 seconds) OR does it prime to a certain fuel preassure? I feel that if it is on a timer there is an electrical issue. If it is a desired fuel pressure than fuel is leaking somewhere? Ideas?

[S13FASTBACKSR]

The fuel pump is only supposed to prime 3-5 seconds. One time I was trying to drain all of my fuel from my gas tank because it had been sitting for a very very long time without the engine even being started for months. So what I did was pull the fuel hose off that ran into the fuel rail and held it over a bucket. Then I had a buddy of mine turn the key on and the fuel would pump out for approxiamately 3-5 seconds and stop..and we kept repeating this process and everytime the fuel pumped for about 3-5 seconds and then stopped ( remember this was the fuel that was supposed to be going to the fuel rail) so therefore the rail never even saw pressure. So basically that is proof that the pump is supposed to only prime for 3-5 seconds and not prime until a certain fuel pressure is reached

[hstylez]

The fuel pump is only supposed to prime 3-5 seconds. One time I was trying to drain all of my fuel from my gas tank because it had been sitting for a very very long time without the engine even being started for months. So what I did was pull the fuel hose off that ran into the fuel rail and held it over a bucket. Then I had a buddy of mine turn the key on and the fuel would pump out for approxiamately 3-5 seconds and stop..and we kept repeating this process and everytime the fuel pumped for about 3-5 seconds and then stopped ( remember this was the fuel that was supposed to be going to the fuel rail) so therefore the rail never even saw pressure. So basically that is proof that the pump is supposed to only prime for 3-5 seconds and not prime until a certain fuel pressure is reached

Outstanding thanks for the info. Must be a electrical problem then, i hope my ecu isnt ****ed

[S13FASTBACKSR]

just do that test i told you about and you'll know if your ecu is bad or not

[NY S13 SR]

O2 power cannot be connected to Fuel Pump Signal wiring.

_________________Jeff HHeavy Throttle Performance Inchttp://www.heavythrottle.com

[hstylez]

It lives!

I want to say thank you to everyone that helped and took the time to read my long *** post. Jeff, thank you for pointing that out ( I knew i bought from you for a reason). Once I read that I headed outside with a friend and he noticed that the red wire from the O2 was actually frayed a bit. We believe that since the wire was exposed it was grounding out, and since i wired the O2 to the fuel pump wire and it also was being grounded out, hence the constant pumping.

Anyways for now it is running and i took it for a drive, awesome feeling.Ran really well and pulled hard.

One issues if anyone can chime in on:-Speedo wasnt working. Im going to assuming this is because I used the SR transmission harness? Any input on how I can get it working would be awesome. What wires can i switch around that will give me a signal?

Thanks again guys!!!

[leroiboy]

from what i understand, it is ok to use the sr transmission harness, but you have to use the ka speed sensor.