2003 996 Turns Over But Will Not Start

[Auryan]

My 2003 996 C4 Cab has been running great. Car sat for about three weeks and now turns over, dash lights all go on but will not start. I did replace the fuel pump relay per a recommendation but had no effect. Almost seems to be electronically immobilized though the key remotely opens and locks car. Open for suggestions.

[judgejon]

battery? sounds like what happened to me a few years ago.

[PorscheTechnician]

What all have you checked? You didn't see if the battery was dead and just replaced the relay did you?

Edited June 9, 2010 by PorscheTechnician

[Auryan]

battery seems good, interior lights, head lights go on and top even goes up and down. engine turns over and over and over but just will not fire up

[Auryan]

also checked every fuse in the block, not sure how to check the big relays in the block above and to the right of the fuze block???

[txhokie4life]

check fuel pump, check for spark, jumper fuel pump relay and check for fuel pressure flow if you

know where the fuel lines are.

check for any codes even with out a cel.

check the battery voltage when you do crank -- should be above 12V.

m

[Auryan]

thanks M will give those a try. have access to a cel tomorrow hopefully something shows. Battery is from 2007 cranks strong and shows 12v but no more

mark

[PTEC]

Definitely check fuel pressure. By far the most common cause of a crank but no start is the fuel pump.

[*fill-up*]

Check your starter, had the same problem as you on my 01 911. It cranked and cranked, so I replaced the battery, the important relays, checked all fuses, and key. Took it to the shop, needed a new starter.

Try push starting it in reverse, see if it will fire up. I was able to do it with me girlfriend, and by doing that I knew it wasn't a fuel problem or anything

[jcan]

Excuse my ignorance, but why push start it in reverse? Does it make a difference?

[phillipj]

"Try push starting it in reverse, see if it will fire up. "

Expalin please......

[Auryan]

cel scan showed no errors today. Though for sure it would..... seems to have no spark. even took starting fluid and sprayed directly into intake. could smell it come through tail pipes....

My C4 has a tiptronic trans for the push start idea. Would like to be able and omit the starter. Great idea though! May have to just flat bed it to dealer 80 miles away...bummer.

[Auryan]

Not exactly sure where fuel lines run. Pretty sure I can here the fuel pump start but......not positive. Fuel pump relay feels like it "clicks".

Is there a really good way to check fuel pressure or just disconnect the feed at the intake?

Thanks,

[Loren]

Not exactly sure where fuel lines run. Pretty sure I can here the fuel pump start but......not positive. Fuel pump relay feels like it "clicks".

Is there a really good way to check fuel pressure or just disconnect the feed at the intake?

Thanks,

Well you can disconnect the feed and catch the gas in a container. That won't tell you if it is weak (no back pressure in an open line) - but it will tell you if you are getting gas.

[PTEC]

There is a test port on the passenger side of the engine compartment right on the fuel rail. Ideally you would have a fuel pressure gauge hooked up and you would measure the pressure when cranking. IIRC, the pressure should be around 4.4 bar.

Edited June 10, 2010 by PTEC

[1schoir]

"Try push starting it in reverse, see if it will fire up. "

Expalin please......

As Mark has said, it won't work in his case because he's got an automatic, but it might work to eliminate the starter as the culprit in a manual.

IIRC, the "reverse" idea is just because of the gearing...don't need to get it up to any fast roll to pop the clutch, although first would give a similar (but sometimes too sudden) result.

Regards, Maurice.

[*fill-up*]

"Try push starting it in reverse, see if it will fire up. "

Expalin please......

As Mark has said, it won't work in his case because he's got an automatic, but it might work to eliminate the starter as the culprit in a manual.

IIRC, the "reverse" idea is just because of the gearing...don't need to get it up to any fast roll to pop the clutch, although first would give a similar (but sometimes too sudden) result.

Regards, Maurice.

Thanks for explaining Maurice! I just didn't know his car was an automatic, I assumed it was a manual, so thats why I suggested it

[judgejon]

Definitely check fuel pressure. By far the most common cause of a crank but no start is the fuel pump.

sure sounds like a fuel pump issue. the batt should be at just over 12v when the key is turned on. when cranking the motor to life the batt will go down to 10 v or so due to the heavy draw from the ignition. upon start the voltmeter should show 14 v, or just under 14v. after the engine is running for about 10 seconds the auto a/c will cause the voltmeter to momentarily dip to about 13v. if this is happening the battery is probably ok and its the fuel pump, imho.

[Auryan]

Well the saga continues...... fuel pump was replaced and ran great for about 2 weeks and would not start again. Engine turned over and over and over but no go. Towed car back to dealership and they replaced the fuel pump again and it started again.....left the car there for 10 days and low and behold the 7th time the dealer when to start the car it wouldnt. They then hooked the car up like it had just gone through open heart surgery and decided to replace the fuel system module. We even checked the alcohol level of the fuel in the tank just in case (under 6% alcohol) battery tests out OK too. The car ran great for about two weeks then sat for about two weeks and will not start again....round three. Dealer is stumped even had Porsche on the phone. Summer is almost over and I would be very receptive to any ideas?

[Auryan]

someone else suggested pulling one of the injector connections to reduce the amount of current on the rail, supposedly should start if the fuel regulator is questionable. Didn't make any difference. Checking pressure again on rail......

[ninsei]

someone else suggested pulling one of the injector connections to reduce the amount of current on the rail, supposedly should start if the fuel regulator is questionable. Didn't make any difference. Checking pressure again on rail......

Was the fuel pressure ever checked? If so, was it low when the prob was happening?

[Auryan]

pressure was low prior to the dealer replacing the first two fuel pumps. I paid for one they paid for the second. Have not been able to check other than pressing the passenger side rail check valve post starting attempt. Rail is not holding pressure (if it is supposed to) just seconds after attempt. If I pour fuel into the intake the engine briefly makes an attempt to start but quits immediately. Going to replace battery (reads 12.19 volts w/ no load) just in case.

[ninsei]

well I may be facing a similar problem with my 2000 C2. I'm about to replace the fuel pump (for the first time) and hopefully that's it for me, we'll see. I re-read this thread and did not see a mention of the fuel filter being replaced? On my 2000 it's a separate item under the car. on yours it may be in the gas tank? Either way, could be something to look at.

[Auryan]

Good idea! Not sure anyone addressed that. Thanks

[Auryan]

Picked up an injection system pressure gauge today. Hoping to see 4.4 bar but have nothing..... looks like fuel pump number 3 on the way.