LannyRX-7

my 86 n/a starts extremely easily but shuts off after about 4 seconds... In those 4 seconds the gas works and there are no buzzers or anything. when the four seconds ends the car dies and I can start it over (and over) again and it does the same thing.

The little electrical plug underneath the steering wheel used to unflood the car (fuel pump plug?) makes a clicking noise when I start the car....and then it clicks again and right after it does the car dies. I was thinking it's some kind of emergency shut off or something. Only had the car for like a month so I don't know much about it.

I've searched and someone said it was a vacuum leak, but it doesn't seem like I have one, I've looked at most of the lines and they are still good.

Any help would be appreciated. I want to get this thing going again tonight.

Bigretardhead

check for major vacuum leaks, not just cracked hoses. like check to make sure your intake tube isn't falling off or something. also, check to make sure your AFM is plugged in. and then just check for other loose/disconnected plugs.

Aaron Cake

iTrader: (1)

I'm betting it's a major vacuum leak. The reason the car runs for about 4 seconds is that the ECU ignores the signal from the air flow meter for the first few seconds after starting, so a big leak won't have an effect (much of one) until the ECU starts paying attention to airflow...

Also possible, but less likely, is a bad air flow meter (AFM). If the ECU does not see the proper signal from the AFM, the car will do EXACTLY what you have described.

LannyRX-7

I checked the AFM and it's plugged in and I tightened down the TB (it was already tight), I can't really hear any vacuum leaks or see any cracked hoses and non-connected hoses. Although there are alot of unconnected wires but they are the normal ones.

The plug under the dash (fuel pump relay?) is clicking right before the car shuts off and I checked out the plug and it is fine and looks as good as new. The car is getting adequate airflow but the fuel pump seems to be shutting off.

Rxmfn7

iTrader: (4)

Can you give the car gas immediately once the car starts, and hold it at ~5000rpm or so, without it shutting off? If you can do this, but it cuts out at lower rpms, its most likely a vaccum leak. Let us know if you can do this, then we can go from there..

Aaron Cake

iTrader: (1)

If there are no vacuum leaks, the problem is most likely the AFM. There are test procedures in the factory service manual (download at http://www.fc3s.org).

LannyRX-7

nope...during those 5 seconds I can rev it all I want, if I hold my foot at 5000 rpms or whatever it gets there like normal and whenever time runs out BOOM no matter whether my foots on the gas or not it shuts off.

LannyRX-7

bump

Aaron Cake

iTrader: (1)

So have you checked your AFM yet?

Pyrocloud

I have the same problem with my 86 n\a.

Please help to resolve this problem, its my only ride.
I'm going to check the AFM now.

Pyrocloud

Also if you keep the starter on the car will run forever.
At any RPM.

The FSM is alittle vague on the readings, so you guys are saying any reading between what the FSM says means that the AFM is ok.

Another point. At the same time all this started happening, I fried my ECU, unrelated, when I replaced my ECU the problem went away for about three days.
Then four days ago it started happening again, is this just a coincidence?

Pyrocloud

OK the AFM checks out, all the ohm readings are within FSM specs.

While looking at the Primary coil banging my head on the hood, I noticed a green plug that seemed to go nowhere, upon further inspection I found a little green fuse like plug in the end of a white plug.

It was sitting underneth the Pirmary coil. The green thing says 2.5 amps on it, that leads me to belive that its a fuse. It also has a loop on it and on that loop is the symbol for ground. Triangle w\ line in front of it.

Checked it with the meter and there is no ohm reading on it, is this normal?

Pyrocloud

I found it, I found it, I found it!!!!!

Yea, it turned out to be a bad fuel pump relay under the dash. It has five connection points and six wires going into it.

To check it I took off the black cover, held the relay closed (you'll have to take it apart to see what I mean) and the car stayed on, wow.

Check that out to see if you have the same problem.

Thanks a million to Dave at fc3s.com for the advice!