Ok, so, a while ago I was driving home in the rain and I hit a pretty big puddle. A few blocks later I noticed my voltage drop to 12(ish). I let it sit for a couple days while I looked around for a new alternator. When the time came I to change it the weather was still bad (really heavy rain), but I had to get to work the next day, there was nothing I could do! So I grabbed an umbrella and a pack of zip-ties and changed my alt in the rain.

So everything was in, wired up correctly, ready to go. Crank crank crank, nothing. I noticed my 40amp 'ENG INJ' fuse was blown, so I replaced it. Same thing, cranking but no starting. De-flooded twice. Still nothing.

Checked the spark and replaced the plugs while I was at it. Good spark, should start right? No. So now I'm thinking "fuel". I jumped the yellow test connector and the rails are getting fuel so maybe the injectors aren't opening?



So here I am now. I believe the motor is not getting fuel because: A. the injectors are bad or B. the ECU isn't opening the injectors.

How do I test to see which is which? I'm so frustrated I can't even keep my mind on track. It better not be a wiring issue.

 

Get a set of "Noid Lights" to test the ECU... They plug into the injector connectors and will blink when the injector is supposed to fire.

Report back.

 

check the fuse underneath the dash that says engine, it should be a blue 15 amp

 

Can i just wire up some LEDs? And good idea, thanks.

Checked, its red, but 15amp and complete. Thanks

 

I just picked up some noid lights and a can of carb cleaner. Lights didn't light, but the carb cleaner got the car to sputter. I guess I need an ECU.

 

Hold on there...Before you go buying parts you might not need yet, check your wiring back from the injectors to the ECU with a DMM.
Also check to make sure that one of the wires at the injector has +12 volts on it from the EGI INJ fuse.

 

When you say "From the egi fuse" you mean check the fuse electrodes? I don't really know what runs off that fuse or where it goes

 

Battery Positive goes to the fuse box.
EGI Injector fuse sends positive battery power to one pin on the injector connectors.
Other pin on the injector connectors goes to the ECU. Ecu switches on and off the Ground side of the circuit.

 

Exactly what I needed to know, thanks.

 

does the rpm needle bounce when you try to crank it? if not, try replacing your main relay behind the trailing coil. if that doesnt work, then you have a bad ecu. i had the same problem and i took out the ecu and examined it, it was fried!

 

Something shorted your electronic Fuel Injection circuit(EGI fuse)that controls the Pulse to your injectors.
that made the EGI fuse Blow..
Now I can tell ya that the Egi fuse also holds the emissions **** on it too.Search the wiring harness for a short.IF that water made the car run Funny then you know that the problem is most likely under the car,somewhere.
..what you CAN try,rather easily,without jackin the car up, is just try another 40 map EGI fuse..IF that blows,then check the wiring.

 

Here's a quick update:

I replaced every fuse. I also took the alt off just to look around. Turns out a wire (B/Y) got smashed in between the alt and the nut holding the alt. So i cut that out and replaced it AND IT STARTED! I let it run a bit, gave it a little bit of gas (from inside the car) and then called my buddy to brag about it. I was under the hood and i gave it a little gas from the TB and the car just died. 100% cut out. It didn't sputter and rev down, just instantly off. Now it won't start again.

All fusees are good, fuel is good. I'm lost once more.

 

Also, the needle is bouncing.

Edit: I checked the voltage at the fuse (12.5v or so) and at the injector (0.0v @ both pins)

 

check to see if the coils are both reading proper ohms. should be around .5 to 2.0. also, check your tps, mass air flow meter, etc. something could have shorted due to that pinched wire. check everything according to the haynes manual specs. you should come out winning soon.

 

check the fuse under the dash again.

 

take out the ecu. unscrew the covers and inspect the internals (resistors, ic's, etc.) to make sure non are fried or brownish or rusted.

 

I replaced the AFM and I tried my ECU in another S4 Na. They both work. Like i said the car was running fine until i moved the TB flapper. All fuses are still good.

Would a bad TPS keep the car from even starting?? I thought it'd just **** up the idle really bad.