H2

I've never had one of my 928s not start (except for dead battery). This a.m. the S4 would crank over really well...and sputter like it was just about to start...then not. Almost for sure starving for gas. But it was getting some gas and certainly spark.

I replaced a gas hose on Sat. and immediately started the car up and revved it a few times to make sure there were no fuel leaks. It was a hot day. This morning was a bit chilly. I wonder if I might have introduced some air in the system? Or perhaps the Fuel Pump is getting weak but that would be coincidental.

Do I dare spray some starter fluid into the MAF to get it going? (I think not but I had to ask). Or dribble a little gas maybe? Can a little air in the system cause this? I dang near ran my battery flat cranking thinking that it was going to catch every time I tried.

Thank you,

Harvey

chaadster

It's probably the check valve on the fuel pump. IIRC, there's a crush ring that needs replacement after loosening. There is a lot written on this, so a search should be fruitful.

Mike Frye

Harvey,

I've heard some people have had success with the starting fluid technique. Some have blown parts of their intakes up into the hood with it. I wouldn't do it.

The car will run for quite a few minutes with just the gas that's in the lines before it runs dry. If you didn't idle it for more than a few minutes after replacing the fuel line, you might not have tested the entire system. Which line did you replace?

You had to depressurize the system before working on it right? How did you go about that?

You could try the fuel pump relay jumper technique to see if you hear the FP running, while trying to get the fuel into the system, then try it again.

the flyin' scotsman

I wouldn't put anything down the MAF but perhaps jumper the fuel pump relay, check for pressure/leaks and the pump is functional.

Which fuel hose(s) were replaced?

sharkmeister85

How long were you cranking it over for? Did you hold the throttle open? If it doesn't start after a few seconds, and you continue on, there's a good chance of flooding, especially on cold mornings. Next time you try to start it, hold the throttle wide open, but be prepared to back it off fast when it starts!
Glenn

Big Dave

My fuel lines had nothing but air in them (replaced them all). It took 5 seconds of cranking to pressurize the system, but it started.

You won't have problems w/ air in the system unless it's not being pushed out by fuel.

Mrmerlin

what Dave said,

JHowell37

These aren't diesels. Air in the system simply gets pushed through without issue. DON'T use starter fluid. I wouldn't even bother to jumper the fuel relay, just open the rear hatch. When you crank the car for a few seconds, you should hear the pump run for a second or two when you let go of the key. I have a stupid question. Does the car have gas in it?

H2

I replaced the 6" front gas hose only. Depressurize? I just unscrewed the old hose and caught the gas on a rag. Yep, 3/4 tank of gas. Maybe I did flood it. I don't usually press the gas pedal when starting but after a couple of tries I did this a.m. After work, I'll go over it again. Flooding makes sense.

Odd but my '85S pops into life almost instantly, no matter how long it sits. The S4 has always turned over a couple of times before catching. Nothing to be concerned about, just an observation.

I've not disturbed the crush ring on the FP check valve. I may have to go there to see if it might be sucking air.

Thanks, all.

Harvey

jpitman2

I replaced most of my lines last year, and to make sure it was purged of air I brdiged the relay and let the pump run for 10-15 mins, found one leak and fixed. After that it started first hit after sitting for many weeks in bits. Pump check valves do seem to start leaking down with age, and accumulator might be worth checking too.
jp 83 Euro S AT 50k

H2

After work yesterday, when it was warm, I tried starting my (new to me) S4. It started right up...but wouldn't start at all that morning when it was cool (but not cold). It's been starting easily ever since the beginning of Spring but the weather has always been warm (Maybe it's because this car was an Arizona car and it's sulking?)

This morning, again when it was cool, it started after three attempts (and I was careful to not flood the engine by pressing the gas). It barely started at first, acting like a carburetted car that needed a bit more gas pedal...then as it warmed at minute, all was fine and I drove it about 15 miles with no issues at all.

I had a similar problem with my 968 and thought it might be the fuel pressure gauge (I think that's what it is, sits up near the fuel rail) and was not holding gas up near the injectors...or the fuel pump/check valve. I replaced the fuel pump/check valve and it's started perfect ever since.

Therefore, I'm wondering if some 928s experience cold weather starting problems (my '85S doesn't), or perhaps the fuel pump is just getting weak and doesn't like cool weather? The car acts exactly like it's not getting enough gas. Do FPs get weak with age or just give out all at once? I have a spare used pump and new check valve but changing out the FP is just enough PITA I'd just as soon put a new one in and eliminate that as an issue...now and down the road.

Any other thoughts on this before I order a new FP?

Thanks, guys (and gal).

Harvey