Engine only starts with AFM off...WTF
 

My freaking car will only stay running with the AFM off. If I install the AFM, the car will start but turn off.

http://www.redhavana.net/files/DSCF0077.JPG

S4 ECU, hybrid turbo

Any suggestions.

Bad AFM, might be reading 100% which makes car runs rich and dies.

Or, a vac leak. Try holding the flapper door open and seeing if you can get it to start/run by holding it open. If that doesn't work, check your grounds (coworker had the same issue and it was a bad ground)

I tried a different AFM, and had the same problem.

I'll try and hold it open to see what happens.

Anyone else have any tips before I go work on her?

bump

Do you have any idea of what kind of voltages you're getting at the ECU from the AFM? When connected, of course...I'm thinking wiring/ grounds also...

I did'nt get a chance to work on the car this weekend, but I'll check the grounds also.

with the AFM plugged in, does the car fire up, rev for a second and then just cut out and die?

If so, I suggest you replace the fuel pump relay that normally sits behind the passenger headlight area of the engine bay.. it's connected to teh same bracket as the injector resistor pack.. I had the same situation happen on a friend's engine swap.. it took forgever to trace it back to the relay (not to be mistaken for the FP relay under the dash).. The car would always fire right up, idle for a split second than jsut die ...

Exactly!!!

Was this on an FB though?

Actually, it sounds like the AFM is bad, or the fuel switch in the AFM isnt working.

Here is a test for you. Jumper the fuel pump test connector (I assume you have a stock ECU harness). Its a yellow plug normally located around the passenger strut tower. Install a jumper there, and the ECU will "IGNORE" the signal its supposed to get from the AFM.

Reasoning behind this...

The AFM has in "interlock". This interlock is bypassed when the key is in the "start" position, and allows the pump to run. Once you return the key to the "ON" position, the ECU needs a signal from the AFM stating that the motor is running. If the signal isnt present, it shuts the fuel pump back down. Hence why your car only starts for a second, then dies.

Rat

He said that he switched AFMs and it didnt' solve the problem..

The no run issue I had was on an FC.. You did an FC motor swap into your FB.. Did you swap out the entire FC wireharness as well?

If so, look at the injector resistor pack .. this is normally mounted behind the pass headlight on a bracket.. it has a large circular plug.. (actually there are 2 plugs) .. this bracket also holds the relay I am speaking about.. this unit is what allows the fuel pump to go from 9V at idle to 12V ..

thanks fellas

I'll try today and see what happens.

There is a chance that the other AFM I tried is also not working.

I'll borrow one from a friends T2, and see if it starts.

Luis

search up my name mang, i was at that same point about 3 or 4 weeks ago

Car starts now, and idle's. But with the tps dissconected. It has a ford type tps that is mostly used with haltech setups.

My plan is to use a 13B-RE throttle body with the stock tps.

How many wires does the FD TB use? I'm hoping it's 3