Ok now, so .. i've been at the 'start up' stage for about 3 days now (actually only about 6 hours of work https://www.nopistons.com/forums/pub...IR ) and there has been a problem that im stuck on.



Well, ive tracked it down through the fuel pump and open relay to be a ground problem. Ive been looking and all my grounds i can see are grounded. Perhaps something isnt connected right? Anyways..



Here is the problem. Fuel pump wont turn on, injectors wont fire.

When we jump the fuel pump, fuel obviously flows :-p Goes right up to the injectors then right back to the fuel tank! Reason being, the injectors wont fire. None of them. So me and my friend went through everything looking for this ground that was missed. We were curious about these also, so i included a picture. Can anyone tell me what they belong to? Thanks for the help

does no one know?!

You must have a series 5, cuz on my 4, ive neever seen those plugs, or i havent seen them yet....lol...



No idea man...sorry

the one on the right is the aws or air supply plug. i cant see the one on the left.



the ecu should be firing the injectors if it sees an rpm signal

You know where the rpm sensor is? :( I feel like a n00b .. haha

front left of the motor, crank angle sensor, looks like the bottom of a distributor

oh, so the CAS sends the rpm signal?

yep

well thats working i know that, cause when we started it up off of carb cleaner, the rpm's showed on the tach, so thats gotta be working. You know where there is a diagram that shows the complete s5 harness? I mean, whatever ground is grounding the open relay (basically all the wiring going to the fuel pump) has a bad ground and i cant seem to find it anywhere. :(

have you tried manually grounding it?

the fuel pump jumpper in the engine bay is what i tried. It starts the fuel pump right up. And looking at the wiring diagram its apparent it completes the ground that should already be completed. So i went out with some nice electrical testing equipment and tracked to down to being a ground for sure. Only thing is, the injectors still dont turn on. Which is really weird. That leads me to believe thats SOMETHING is not plugged in correctly and grounded.



Everything was working fine when i took the engine out. No electrical problems at all. I dont see why something would just up and go bad like that after a month of non usage. I mean, it could happen but unlikely.



Only thing is everyone i know with 7's around here have s4 and im not sure if the wiring harness is the same. I know they have some differences, but not sure what. And i cant find any diagram that shows in atleast semi-detail the wiring harness. :(



this problem is getting to me! ITS EATING MY BRAIN!! https://www.nopistons.com/forums/pub...O_DIR

I had a problem similar to this in my S4, but the car would start and run like ass, I went through the thoughts of a blown motor, 0-60 times were timed in minutes, turned out to be the injector resistor (yours is located by the right front headlight in the silver panel by the fuel pump relay) in mine the resistor was bad and was only firing one primary injector for the front rotor. Test the unit, it may have gone bad

i hate this car :(

you moved the harness when you took it apart, fd's always have harness problems after a motor swap



s5 is different but that circuit is prolly not

today im gonna redo all the harness. Take it all off and put it back on. Maybe i missed something that im just not seeing when its hooked up. What kind of problems do you see teh FD's having when you mess with the harness?

this is your 7's way of saying it wants to cuddle.



kevin

cuddle? its about to catch a baseball bat to a headlight if it doesnt knock this **** off!

usually the cas wires go bad, but they are routed totally different on the fc. its the bending the harness that does it

yea i discovered this the hard way "hey we'll just move this o2 sensor wire over he........*snap*.....SUNUVABITCH 14 YEAR OLD ******* WIRES"



kevin.

I just thought of something .. im not sure, so im asking.



If there the ecu doesnt pick up there being any coolant in the system will the car not turn on?

nope. the ecu will fore the injectors if it has power and an rpm signal

damn this problem is ******* with me! Ok, i unhooked the wiring harness again. Gonna reconnect everything up. I still dont get why the car wouldnt atleast start, if i jump the fuel pump and turn the car over. Obviously the injectors arent firing, correct? I havent tested them with an injector tester yet.



im usually good with this stuff, but damn.. this one is making me go insane! everything is working but the damn fuel system. Ive read the entire fuel section in the service manual, and the entire electrical section too! To see what relates to what. And still ... cant find thise problem. Im thinking its something really really easy too :(

im about to cry :(



ive been out there all day trying to figure it out.. redid hooked up the harness, checked the ecu to see if it was all plugged in right, etc.. and i cant find it. had ANYONE had a problem like this? everything works fun except the ******* fuel. Im going insane! good god

Have you tried a different ECU. Did you just do a new engine swap or what were you doing ot the car that made it do this?



C

the last engine blew. Everything electrical was working top notch when i took out the old engine. It is the same s5 13bt engine that is in now. Everything hooks up perfect. Havent tried a different ecu because (1) i dont have an extra t2 s5 ecu and (2) i dont think anything is wrong with it. Everything else electrical works. :(



im going to my buddys shop to pick up his injector tester, so hopefully i can see whats going on with the injectors. There isnt much to the fuel system. Only 2 relays!



ok quick question. If the jumpper wire is in the test connector for the fuel pump, will the injectors fire?



perhaps the injectors wont fire unless the circuit relay is activated? Since the jumpper bypasses the whole relay, that would explain the injector problem. Then i would be back to square one with just the fuel pump problem. Possibly?



i appreciate the help, sorry if i seem all moddy and pissed off, ive been at it for 3 days and ive never had a problem so difficult (yet probably so easy of a solution).

My 87 TII did that. it only ran on either/starter fluid but i had fuel, spark, comp, air. The part of the ecu that controlled there injectors was shot. I got the car like that so i don't know what hapened.



Have you welded anything on the body or anything?

Only the fuel pump will turn on when you jump the test connector.



A few questions, does the tach jump when starting the engine??

nope havent welded anything on. I just did an injector pulse test and i have no power to the injectors. :(



So, no power to the injectors, and no power to the fuel pump. Everything else, has power.



Any ideas of what might be causing this? Not the ecu.



yup, tach jumps, so im getting rpm signals. And yes, the fuel pump is what turns on when i jump the connector. I tried to check to see if any codes would come up and got nothing. Im pretty boggled as to what exactly is causing it.



There has got to be a short, or ground somewhere, and i need to find out what runs both the pump and injectors that may have gone bad.

if the afm isnt getting a signal, would that cute power to the pump and injectors?

Have you done a resistance check on the fuses? sounds like you have a bad fuse or ground at this point

i switched around my fuses in the engine bay to make sure they were all good. Everything seems to point to a ground not being grounded. Only thing is, i dont know where this magical ground is :(



every ground that is on the harness in the engine bay is grounded to a nice ground. Any other grounds i should check?

no the ecu will fire the injectors if it has power and sees rpm. the ecu grounds the injectors. if the injectors do not have power then there is a problem on the power side. try the main fuse, main relay etc

Engine should start and die right away with the flow meter unplugged and you not even getting that.



And you got the ground that is near the injetors on the engine block right, what year is this car again?



C

its a 91 t2, i will take some pictures and video.. 1 sec, brb..

well ****.. i would take pictures and movie but my cameras batteries died. After taking 3 pictures, the ******* BRAND NEW batteries died. This camera is going out the ******* window. Jesus.. everything i own is turning into **** piles!

Hmm I thougth my reply went thru.



If you got the ground on the fuel injector side to the engine block and then the one probably by the shock tower, check and see if you get voltage at the egu fuse. Test it with and with out the egi fuse, you may need someone to crack the car while wihle u do this.



C

Check the mass air flow (MAF) sensor. It has a switch that shuts off fuel (I don't know about the injectors) when no air flow is detected.



Also, you didn't reverse the primary & secondary harness did you? It's not easy but it can be done. (trust me here).



The fuel flow & injector problem are most likely related. Take your time. Start at the beginning with a good wiring diagram. Start at the fuel pump relay and work your way back to the ECU. Chances are, it will be something simple since it was working when you took the motor out.