powrdby13B

Aight.. Made some slight modifications to a S4 vert crossmember to fit a header, figured we should port the intake and do the tb mod at the same time, and now it won't start. ECU is not throwing a code, everything is hooked back up, and we are lost. Any ideas?

Andrizzanizz

iTrader: (1)

did you mess up the starter?

powrdby13B

car cranks, sparks but i have to jump the fuel pump and the injectors arent pulsing

powrdby13B

update- car started when i sprayed starting fluid in the throttle body, so i thinking its not getting fuel somehow. how do you check the fuel pump and injector relays and where are the located?

Andrizzanizz

iTrader: (1)

the fuel pump is in the fuel tank, an easy way to check it is to turn the key to accessory mode and listen if the fuel pump clicks on.

powrdby13B

it does not. but where is the relay

kenny senter

go to 1300cc.com I believe it is. They have a process to prime the fuel pump through a harness plug in the engine bay by way of a jumper. If the fuel pump isnt priming, look for a fuse and check that. I've never even looked so I'm not sure if there is a fuse for the pump or not, but its a good place to start.

misterstyx69

iTrader: (142)

Did you unhook the Fuel lines?.,.if so,you may have them on Backwards..try switching the lines..If not,go ahead and do a Deflooding Procedure and try that to see if it was just a simple case of being flooded.

powrdby13B

we already jumpered the fuel pump, lines are not on backwards, already deflooded it 10,000 times.. The fuel injectors are not pulsing.
There are scopes that can "hear" fuel injectors when they pulse. These are not pulsing. The fuel pump does not turn on UNLESS we jumper it. If we spray it with starting fluid, it will run while it burns off all the starting fluid.

kenny senter

is everything plugged up correctly? If you're positive it isnt your injectors, check their wiring and the signal from the ECU telling them to fire.

kenny senter

just read another thread where someone mentioned removing the air filter and moving the flap a few times to see if that triggers your fuel pump to pressurize the rail. After doing your throttle body mod, is your MAF situated properly?

powrdby13B

That is all definitely flamebait, sir.
But since I need the help,
Yes everything is hooked up correctly. I used my other three s4's as reference to make sure.
We checked the fuel pump and injector relays, all injector/pump/relay wires for continuity, and double checked resistance on the injectors.

pfsantos

iTrader: (1)

Andrizzanizz and others:
For the record, the fuel pump turns on only with ignition on and either (1) AFM flap not closed or (2) yellow fuel pump jumper terminals connected. I should also mention the above trigger the circuit opening relay (coil side), which itself needs to get power (ign on).

Make sure you didn't forget the ground wire under the rat's nest. BTW, the circuit opening relay is under the instrument panel, to the right of the steering shaft. Also, make sure the AFM is working right. Hope some of this helps.

powrdby13B

Cool thanks man. We regrounded that ground because it was dying.
We tested the AFM, too (I've had bad luck and I was like man, you got to)
Yeah, we checked the leading coil to make sure it had power.

Thanks for the help, man. It's nice to hear something useful. Checking relays as we speak.. And we will check for continuity on our new ground

DragonRx7

I was having trouble on mine after emissions/TBmod, too. It would crank and sputter with starting fluid but wouldn't run. I adjusted the idle screw on the throttle body to get it to hold a 1500rpm idle and loosened it from there to a good solid 900-950 idle.

Try cranking it all the way in (basically close to 2k) and see what happens.

powrdby13B

Okay, for those whose car won't start! My buddy works at Mazda and his master tech said that if your car has all the requirements for starting - that's air, gas, spark, timing and compression - and it won't start, for some reason the ECU is dumping way too much gas in and it's flooding out all the time. Pull out the trailing injectors and it will start. He was right.

And then we made it four miles before we got pulled over turning into his shop for driving with open headers

ilike2eatricers

trailing injectors? i dont see why that would fix your problem if your fuel pump isnt running unless you jumper the connector and your injectors arent clicking.

FCGizmo

Hooray it runs. Turns out the engine was incredible flooded, the throttle cable was too loose and the tp was way out. So I unplugged the fuel pump relay and the coil fuses, and the leading spark plugs and cranked on it for about 15 min. Put it back together and pulled the the idle adjust screw all the way out and tightened the throttle cable and it fired right up. After some minor adjustments of the tps and idle screw she purrs at a smooth 900 rpm. A little high i know but any lower and it shakes too much.