car won't start/idle.
 

Car has been running beautiful the last year that I've had it. Done excellent regular maintenance, and taken great care of it. Recently I swapped out my radiator, and hoses (cooling properties only). When I was all done I went to start it and it wouldn't start. It turns over, gets spark and fuel, and revs up but then immediately dies. Won't idle at all. I just changed my spark plugs and my MAF and still nothing. My friend thinks it might be my safc, but all the settings are the same as they were when the car ran....the only thing that someone suggested is maybe a vacuum leak but i dono how to check that... Otherwise I'm stumped...please help. Its a 1989 GTUS non turbo btw.

Not sure why this is in the PowerFC section. Are you using a PFC on your S5 or the stock ecu? The reason I ask is you mention the MAF (AFM). Which ECU (model #) are you using if its stock? N350?

Yeah, the reason I posted here is because I'm running a safc right now. The car seems to die right as the SAFC turns on. My friend told me the safc might be killing the car. Since we are pretty positive its getting spark and fuel, the air might be the problem. Also why I switched my maf. But yeah, the car has a stock ecu and mostly stock internals.

You should post this issue in the 2nd generation section!..

Cool thanks.

Sounds to me like the SAFC isn't configured or wired correctly.

Here's the skinny:

On a S4 car, the AFM has a manual switch that controls the FP relay.
On a S5 car, this 'relay' is controlled by the AFM signal in the ECU itself. If the ECU doesn't see AFM signal when the RPM's start moving, it kills the pump.

SAFC splices into the AFM thus being the source of your potential problem. Verify all of your wiring again and be absolutely sure it's correct then reinitialize the SAFC and reconfigure all of the settings for a S5 car.

I did a bit of googling on that, but couldn't find a good link. Any chance you know of any good resources? I'm kinda new, but I'm learning lol.

There's a REALLY old write-up on my site:

1300cc 2nd gen S-afc

Make sure your SAFC harness matches the tutorial, otherwise you'll need to dig up the manual for your particular unit.

So I got it disconnected, and the car runs!! Sorta rough though. It won't really idle on its own, but it will rev up and sounds healthy. Do I need to do something to tell the car it no longer has the safc? My friend thinks its dirty bad fuel from three months ago. Adding a fuel additive now. But any thoughts?

If the fuel is really that old, it could be the cause. If the car hasn't run in that long, check your plugs, check for vacuum leaks, and perform normal basic maintenance.

Yeah I cleaned all my plugs earlier and they are brand new. I'm about to drain the fuel now. But nothing needs to happen when unplugging an safc for it to run normal?

So long as you reconnected the wires that the SAFC disconnects.

For a situation like yours, "You screwed the pooch."!
Perfect car, messed with cooling system, now car is crap.
That means you screwed something up while working on it.
You have to examine ALL areas where there are electrical and vacuum/boost lines involved
around where you worked.

Have heard this story so many times. Then the person remembers, that they did something else which is where the problem is.

At night when in your bed (not having sex) but trying to sleep, slowly think over all that you did when working on the car. Also think about other parts of the car. Maybe it will come back.

Most times the people never tell us what they found because they are embarrassed.