Rathmar

iTrader: (8)

I went to start my car today after getting the intake manifolds reassembled and the first thing that happened when I started it was the car started to rev up, when it reached 4000 rpm I quickly shut it off, I went to turn it back on same thing.

I check the throttle cable to make sure that the throttle isn't at WOT, the cable is on correctly so I search for something else out of place.

Next I find that my AFM was unplugged, okay, found the problem.

I go to start the car, it fires up to ~1500rpm and then dies, and continues to do this.

Anyone have any idea what this is? I know the first 10 posts will be telling me that I have a vaccum leak however I checked over all the hoses before I came and made this post.

Any help is appreciated.

RotaryEvolution

iTrader: (30)

large vacuum leak, i would probably start by checking the BAC feed line and the booster vacuum lines to make sure they are plugged in.

classicauto

iTrader: (3)

Also,

Try jumpering the fuel pump test connector (a yellow, two prong plug that has a rubber boot around it) located on the passenger side near the strut tower.

If the fuel pump resistor has burnt out, the pump will get it cranking voltage then receive no voltage after about 2 seconds. By passing the resistor with the test connector should verify whether this is the problem or not.

91verty

i will lean towards the small hose that runs underneath the AFM. Same thing happened to me not long ago and this was the prob. MAke sure all your vaccuum hoses are connected.

Rathmar

iTrader: (8)

I checked the vacuum lines again, they are not the problem.

I also jumpered the fuel pump resistor and the car also failed to stay running.

Does this mean that perhaps my AFM is damaged or has a bad ground?

classicauto

iTrader: (3)

Firstly I would try checking the voltage to the fuel pump with a digital multi-meter when you start the car.

Put the key on, check for priming voltage. Then crank it and watch for voltage, and when it fires see if it gets voltage and then goes flat...or if the voltage stays constant while the engine shuts off.

That will at least rule out a couple of things...

Its possible though that the AFM could simply be bad, if you have another, try it. If not I have an S4 AFM and an S5 AFM that I could send with your surround if you like (couldn't recall which one you'd need)

Rathmar

iTrader: (8)

Okay, a little more diagnosing and hopefully a little more help from the rotor heads.

I hooked up a timing light to find out what cut out first, fuel or spark. I found out that I had spark until the very end so this is a fuel issue of some sort. I took my air filter off and watched the AFM while the engine was cranked and it appears to be working correctly, this leads me to believe that it is not a vacuum leak.

Any suggestions on what to check next? is my afm done?

Rathmar

iTrader: (8)

alright I monitored the power going to the fuel pump while cranking and the fule pump was getting 6v from the one wire and about half that from the other, the voltage did not zero when cranking and did not zero as the engine died.

are all signs pointing to afm?

junito1

will the car stay on if you give it gas? or does it die anyways?

Rathmar

iTrader: (8)

The car will rev up some if I give it gas while it starts but it still dies regardless.

I had removed the cold start fluid tank and saw that it was in the fuel pump wire diagram so I plugged it back in, however the engine still did not stay on.

classicauto

iTrader: (3)

Have you checked for voltage at the pump?

It really sounds like its dieing.....are you sure you got the right plug jumpered? There's about 4 that are in that vicinity but only one thats yellow, two pronged, and covered by a rubber boot.

And IIRC, having the connector jumpered should bypass the AFM's input into the ECU (meaning even if the AFM is pooched it should still work), but I could be wrong there.

junito1

i messed up my cold start somehow and now my car doesnt idle when started cold. So i have to hold the rpms at like 2000 till it warms up then it finally will idle on its own..

Rathmar

iTrader: (8)

I stated in post #8 that I was getting voltage at the pump, however it seemed low at only 6V, however it did not drop to zero.

I was jumpering the yellow plug also, perhaps I didn't have the jumped in correctly, I think I'll make an actual jumper with pronged connectors and try again.

fidelity101

iTrader: (11)

step on your brake pedal and hold it down while starting the car.

if it falls to the floor with easy, your booster line is leaking

I know you said its not a vacuum problem but its an easy check, cause I didn't tighten down the part on the intake manifold where the brake booster gets its suction from and I had a similar problem.

Rathmar

iTrader: (8)

just tried the jumper again and still wouldn't run.

Rathmar

iTrader: (8)

the only thing I can think of is that I'm not running the air hose to the main cat as I currently don't have it installed, infact my exhaust at the moment consists of a header.

Rathmar

iTrader: (8)

I'm calling it quits for today, I'll take another look at things tomorrow when it's light out, thanks for all the help so far guys.

Rathmar

iTrader: (8)

Alright, I think I found what my problem is.

I tested the AFM against the specifications in the FSM, however when moving the cone from closed to open the ohm jump to about 1800 and also at points hit 1, my guess is that when the cone hits these spots where the ohms are 1 the engine things that there is no flow or no AFM at which point the fuel is cut.

Also when I tried to chek the thermosensor I kept getting an ohm reading of 1 also, I thnk that my AFM is toast.