bmwrx7man

iTrader: (2)

im trying to get my buddys fresh rebuilt s5 turbo 2 all stock running.everything is hooked up car starts real quick and dies after 2 seconds of running. i checked for voltage at the injectors and i get 12 on the secondarys and 0 on the bottoms primarys . is the car suppose to have 12 all around? on the on position? maf is connected emssions still on . fuel pump works when i jump it out front. im lost on wat else to check

satch

iTrader: (1)

Did you measure for voltage at the ECU pins? The car should not start unless the primaries were working since the secondaries do not work in starting the car.

bmwrx7man

iTrader: (2)

no i didnt . mesure at the ecu. i gotta find out wat pins are wat. but either way . if they got no voltage how does it start only the secondarys had voltage . i cranked it over got it strarted like 3 times and it died right out . then it did not wat to start after that .

Furb

iTrader: (2)

Fresh rebuild, dies after first start, doesnt want to start after that...

Sounds like flooding to me, at first glance

satch

iTrader: (1)

The primary injectors are hidden under the upper manifold so how did you measure their voltage? If you measure the ECU pins for these injectors then you are measuring the wire that supplies the ground trigger for these injectors and not the voltage wire, but the ground wire will pull the voltage off of the voltage wire w/key to on. So pins 3C (Light Green/Black wire) and 3E (Light Green) would then have 12 volts w/key to on.

bmwrx7man

iTrader: (2)

its not flodding doesnt get enough fuel to start u can tell its not getting fuel the way it starts. i measured righjt at the injectors . yes i know the primarys are the lower ones lol i do have a s4 t2 i did myself . s5 is a lil more complicated . so am i suppose to see voltage at teh injecters is my question?

satch

iTrader: (1)

Right, but how were you able to get to the injectors if they are not accessible? And did you test for voltage w/the injector clip/plug connected to the injectors or not. And are you sure you measured voltage off of the correct wire. If the clip was not connected to the injector then only one of the two wires would have voltage w/the key to on and that would be the Black/Yellow wire and not the Light Green based wires. Also, did you try starting the car w/the fuel check connector jumpered? And I'm not poking fun at you that would indicate that you're not familiar w/the setup it is just that I have never heard of someone testing for voltage on the primaries before with everything in place. Never.

And the ECU pins for the S5 would be 3W and 3Y. Earlier I fed you the pin locations for an S4.

MIDNFauciUSN

iTrader: (8)

Yes, you're supposed to see voltage at all 4 injectors - one 12+ wire per injector. Though... trying to understand what you're typing is making me want to stab myself in the eyeball.

I'm with the guy that is skeptical that you already checked for voltage. Something strange would have to happen for you to have voltage at the secondaries, but not at the primaries.

bmwrx7man

iTrader: (2)

sorry i checked them with the top half off of manifold off . with each plug disconnected off the injectors . 2 secondarys had 12 volts . primarys none... so i put everything back together tried to start it and it did 3 times thats about it . ill try it with the jumper for the fuel pump on all the time

RotaryEvolution

iTrader: (30)

they HAVE to have voltage for the car to even attempt to start, you're obviously doing something incorrectly.

vacuum leaks are the primary cause of starting and stalling issues on an AFM based system.

bmwrx7man

iTrader: (2)

well i gotta figure why only 2 of them dont have voltage . i didnt do anything to this car besides trying to fix his mistakes . im gonna restab the cas . check the ecu connections then idk were togo from there . all the injectors ohmed out the same too . car was running perfect before the rebuild

satch

iTrader: (1)

Did you check the secondaries in the same way you measured the primaries, that is w/the plugs off of the injectors? If the plugs are off then only one of the two wires to each injector would have voltage and that would be the Black/Yellow wire. If the plugs are connected then both wires to each injector would have voltage w/key to on.

bmwrx7man

iTrader: (2)

yes like i said i checked all 4 connecters . 1 wire off each one had voltage . on the secondarys . the primarys had NONE wat so ever

satch

iTrader: (1)

Were you able to tell the color of the wire being probed for voltage?

RotaryEvolution

iTrader: (30)

your car is magical, it doesn't need voltage to fire the primaries!

bmwrx7man

iTrader: (2)

honeslty thats wats ******* with me right now lol . no voltage and it started real quick. and im gonna go check it out in about 1hr let u guys know more

RotaryEvolution

iTrader: (30)

you're looking in the wrong place though, check your fuel pressure, TPS setting, timing, make sure all your manifolds are sealed up and no vacuum lines disconnected.

i just spent 2 full days fixing this exact issue on a customer car, EVERY SINGLE MANIFOLD CONNECTION had gasket debris on them, so they ALL were leaking. car would shoot up to 4k then shut right off.