Where to begin. 911sc problems
 

Occasionally, my car turns over but will not start, especially if it sits too long. No loss in battery power, and the turn over is consistent. Now once it is running everything seems fine to the best of my knowledge, (though I don't exactly know what IS normal while running, other than obvious such as temp. Oh and the odometer has ceased. Other than that, I'm loving it when it's running, lol.

Since the problem happens after sitting for a while, it could be loss of fuel pressure caused by a bad check valve or bad fuel accumulator. You can check these easily by using a fuel pressure gauge set to see if your system holds pressure after shut down.

You could also have an intermittent ignition problem, very easy to check. Next time your symptoms occur, remove a plug wire, connect a spare plug to it and ground to the engine. Have someone crank the starter and see if you get a spark.

Hello,
I'm just down the road in Eudora....might be the check valve...these cars do not like to sit for long periods. You might want to start it and just let it run ever now and then. The odometer is a typical problem. Here is a link as to how to fix it yourself :) Hope I've helped some..

Alan


http://forums.pelicanparts.com/porsche-911-technical-forum/196987-odometer-gear-replacement-electronic-speedometers-long.html

What year? is it cis? try to prime the system by pushing up the arm atatched to plate in your air box. If it starts then i would think pressure loss at fuel accum (most likely) or leakdown at injectors? No expert just from experiance!

Ok I figured out this won't start thing. It could be because of this extreme heat, but the car starts right up every morning no problem. After driving though and sitting out somewhere, after a while I do lose pressure in my gas line, and so there's no gas running into the engine (hope this makes sense). The remedy for now is to turn the vehicle on and off a few times and let the pump fill the line back up. I've cut my start up time down from 20 or 30 minutes to about 2 min. Still I think this is something that needs to be handled. I think this is what Mikesride is talking about if I understood him right. I'll give that suggestion a try as well.

1980 sc

Residual fuel pressure.......
 

Tony F.,

Turning the ignition switch to ON/OFF won't make your FP run!!!!! Unless it is wired differently. So by doing what you think is priming the line is correct provided you could make the FP run which I doubt. Your car is exhibiting a symptom typical for low residual pressure. Two (2) things come to mind. A leaky fuel accumulator or FP check valve. I would suggest that you hook up a fuel pressure gauge and check your residual pressure. Take some readings after 5, 10 and 15 mins. (FP stopped). A gradual loss of pressure is normal (see spec) but zero pressure after 15 mins. is undesirable. Keep us posted of your findings.

Tony D.

Of course it could be a little simpler like leaking Injectors. Spray a little Oil around the injectors and pull them out . They are only held in place by large rubber "0" RIngs. If you have metal lines be careful and either put a plastic cup from a Brake cleaner spary can under each of them and watch for the leaking. You will want to have your heater fan / ducting from the fan out of the way and this has to be done after the car has started and turned off.

If the Injectors are OK, then check the Accumulator by first breaking the lines loose so that when you check it is easy! What you want to do is after the engine was running and just turned off, Break the line loose and see just how much pressure it has. The restart and the next time wait for about 20 minutes. If you lose pressure then it is either the Accumulator or the Check valve at the Fuel Pump. I had hot start problems with my 1976 and put on a Huge 924 Accumulator and finally got a Banjo Bolt that had a check valve / Spring and Added it to the system and no more Hot start! I eventually bought gauges and hooked things up to be there while driving the car.

My worse problem was it stopped while driving it! This turned out to simply be Shell Gasoline!

Yeah, you guys are right. It's the fuel accumulator. $461.00 for part, plus $160.00 Labor. Nothing I'm not used to being a bimmer/benz owner all these years.

P.S. thanx for the input, you beautiful people. :)

Fuel accumulator fix........
 

Tony F.,

Have you brought the car to the mechanic yet? It's a shame I'm away from home and could help you with your problem for less than 1/5 the estimated cost ($$$). If you could wait 2 weeks, we could fix this problem under $70. PM me if you still need assistance. BTW, why is the FA so expensive? Did you order it from Germany?

Tony D.

Haven't taken it yet, and I've already considered an alternative to taking it to the mech. I'd definitely like to take you up on the offer. Currently looking online to finding a lower price on that part.

TonyFlaco,

How do you know it's the Accumulator?
Could very well be a faulty check valve on the fuel pump.

How old is the pump?
If old or lots of Mileage, consider a new pump with internal check valve.

Accumulators seldom fail and last longer than the check valve - pump.

Go with Tony's advise, you're lucky for him to offer help.

$160.- labor to open 3 lines and install an accumulator? Hm.............don't go back there. :)

I'd get a good used one and depending on condition/age/Mileage, a new pump.