2000 911 C4 just died
 

Was driving the car all day and was running like always..GREAT! Then I get home, shut it off for about 30 minutes, come back out and now it will not start. Turns over fine, but just wont fire. Read a bunch about the possibility of it being the CPS, so I replaced that, but still no life....any ideas?? HELP!! she's my daily driver!!

Fuel pump ? I'm not sure how you check fuel rail pressure in these cars - but relay should be easy to swap out / test ...do you hear pump priming in frunk when you turn ignition on before cranking ? How much fuel is in tank ?

I thought the same thing...when I turn the key all the lights come on and everything sounds okay....should the pump make sound I can hear from inside the car?? I did not notice any pump sound in the car....I'll open the hood and try again.

benclark - if the engine is nice and hot AND the car turns over fine but just seems like it isn't getting fuel AND it has been sitting an hour or so after being turned off, a likely candidate is the purge valve above the alternator. If so, the car will start fine in the morning (probably).

Check this link, there are a few more but knew where this one was. https://rennlist.com/forums/996-foru...l#post13137027

I left it overnight and still nothing this morning... going to replace the fuel relay and see if that does it...should the fuel pump make any sound when I turn the key on? It's clicks but that's it..when I crank it over it smells like gas from the tailpipe.

Guess we're not in the same timezone, it's still tonight here.

Unfortunately outside my knowledge area however I seem to remember that someone said that it makes noise for a very few seconds when you turn the key. If it smells like gas when you crank it, doubt it's the fuel pump or relay.

If it turns over fine but doesn't even sound like it's trying to start, CPS was a good guess. I can't really offer any help. Good luck and I hope someone with more knowledge pokes their head into your thread soon.

The fuel pump should prime for about 1 second when you turn the key to the last position before crank. You can try to jump the fuel pump relay.
If it's not the fuel pump, you will need to check for sparks.

Does the tach needle bounce for about 1/8" when cranking? I know you said you replaced the crank position sensor but wiring can also be an issue.

Same thing happen to me(2002 c4 cab), just after a Porsche service. Drove it around for the day, parked for dinner, and wouldn't start 1 hr later. It was the fuel relay. apparently not that uncommon according to the dealership. 15 pounds i think for the fix + the transport back to the service centre. Hopefully an easy repair for you at home.

I am picking up the fuel relay and will try to put it in after work this evening. I'll get back with you all and see if that does it....

Try a new relay. Be sure the fuse is good, too.

When the fuel pump on my Boxster was suspected of dying the tech connected 12V power directly to the fuel pump leads to eliminate any fuse, relay, or wiring problems. (I had of course checked the fuse at home in the driveway and the tech had loaned me his bypass relay to eliminate the relay as the problem.) The pump didn't even run with power connected directly to it.

Check for codes.

I had a similar problem like this and it was a simple fuel filter clogged up from low-grade gasoline. Replaced it and filled with premium and wah lah... it fired up.

What about the battery. When mine died, they went without any warning...

Battery is new, so don't suspect any issues there..fuel filter is a new suggestion, guess I can try that as well. No codes as of yet...YET....

If it turns out to be the fuel pump, there is good news: On a C4, DIY fuel pump replacement is a snap. That little square black plastic dome in the front trunk gives you direct access to the top of the fuel tank.

^^I'd take 5CHN3LL's advice!

Hey, and if you come back tomorrow and tell us the problem was just a simple empty gas tank, then you're in big trouble mister! haha!

While I like the vote of confidence, I'd change the fuel pump last (unless you test it)...start with the cheapest stuff (fuses, relay, filter)...hopefully you don't get to the pump - but if you do, at least you're better off than if you had a C2.

My money is on fuel pump.
L@@k here:

https://rennlist.com/forums/996-foru...5-minutes.html

changed the relay....no dice...opened the fuel tank, there is gas but I got the wrong friggin pump....so I can't change it until the new one comes in. going to do the filter right now and see if that does it...

Just replaced the fuel pump....still nothing! It turns over just fine, just will not fire!! Replaced the crank sensor, fuel relay and now the pump....I'm out of ideas right now....I thought for sure the pump would do it.

I would try to diagnose something before throwing parts at it, the parts approach gets expensive fast.

My usual way of tackling such a problem is:

Check for fuel
Check for spark
Check for compression

If you have all three something should happen:D

I would first check for fuel pressure (measure it if you can). Do you smell unburned gas when it turns over?

Sounds like you have done what is logical first. Check that the CPS is plugged in tight and that the wiring is not crimped anywhere. Unplug the engine bay wiring harness connections and use some electrical cleaner on both connectors. Make sure they are plugged in tight. Check the engine ground strap for corrosion, unbolt and clean the connections. It sounds like you have addressed the fuel delivery issues, so now you are going to have to address spark issues. Pull the most accessible spark plug and see if you have spark.

I assume you have already checked all fuses related to fuel and ignition/DME/ECU. There is a reason why you have a crank but no start condition. Just have to logically think through the process of locating the problem. Not that it would have much to do with present state, but are there any codes? A simple OBDII reader will tell you if there are any codes.

Working the same issue: started fine, minor stumble pulling out after 10 days of no activity. Drove to store, started up, died within 3 miles. Towed home.
Replaced the fuel pump relay, nuttin. tested the DME relay: nuttin. Jumped the FPR socket, got the fuel pump running fine. Tested the new FPR, operates fine. Put new FPR back in; No power to the pump. The wiring diagram can get pretty dense at this point, so I'll keep looking. Anybody with any ideas?

BTW, if you're interested, the symptoms that led me to look at fuel, rather than MAF, etc. was that when trying to crank, the motor would try to run (barely), but only with my foot off the accelerator. Soon as I put any pressure on the gas, it quit. Told me that I have spark, but insufficient fuel pressure/flow.

Fuel pressure regulator gone wacky? So many things have to align perfectly just to get the engine to start it is almost overwhelming. But you are saying you have no 12V to the fuel pump. That has to be either the fuse, relay, or maybe the ignition switch. Are you checking the fuel pump terminals directly and have no 12V on the connector?

I hate when someone post for help and then never returns to let the community know what the fix was!:icon107:

Yeah he only had 7 posts so not surprised he never graced us with the outcome.

Update: It appears that something in the DME isn't allowing the FPR solenoid to ground itself., thereby preventing the fuel pump operation. Short of a replacement dme, any ideas?
Had a P0102 code the I cleared with no effect, cleaned the MAF and have a new one coming soon. Using my durametric, I couldn't get any actual values while stopped or while cranking. I activated the fuel pump also with no change. I rang the wire between the FPR and the DME, so it's not a broken wire..

Get in touch with ECUDoctors and pick their brain on the DME problem. They might have some experience with the problem.

Good idea, I'll try that. Really, I suspect that one of the inputs to the dme has failed, telling the computer not to let the moter start. I'll keep looking, and will post the results.