'78 928 Euro, won't start

[ozzieandstormy]

Hi,
I have a '78 928 Euro 5-spped, with only 43,000 miles. Now the problem is, when I took her out of storage this year she wouldn't start. However, this NOT all of the time, sometimes she'll start right up, and then there are others when the only way that she wil start is to spray a shot of starting fluid into the intake! Once she is started, she runs and drives AWESOME!! I figure that it must be something simple because it does not happen all of the time! I was thinking maybe fuel pump? Please help!
Scott

[devilinblack]

I'd start by checking the fuel pump relay, the pump(s) itself and maybe the fuel accumulator. The CIS fuel injection system is also known for not liking to sit so there could be something wrong with the fuel distributor as well.

[Danglerb]

If it was fuel pump why would it run after getting started with starting fluid?

I suspect cold start or something related if you don't have cold start. Take a look at some of the recent threads on the WUR and AAV.

[devilinblack]

Originally Posted by Danglerb

If it was fuel pump why would it run after getting started with starting fluid?

I suspect cold start or something related if you don't have cold start. Take a look at some of the recent threads on the WUR and AAV.

Ah, good point.

[Danglerb]

Starting fluid bypasses a lot of problems, so it isn't a good thing diagnostically or in general.

Not disagreeing with you Stephen, just typed at the same time.

Best to not use starting fluid and test each of the basics, spark, fuel, and compression.

[redrider044]

Isn't there a check valve at the fuel pump that is usually troublesome? They tend to stick at times in the open position. I read about this in this forum a while back. Just a thought, hope it helps.

[ozzieandstormy]

the fuel pump is on top of the gas tank inside the rear compartment right? I ordered a brand new fuel pump relay just to see! And the reason that I said maybe the fuel pump, was because when I click the key over, I do NOT hear the pump come on! Any suggestions?

[ozzieandstormy]

Oh, and it DOES start right up some of the time, I just NEVER know when she is going to be stubborn!

[devilinblack]

You may have two pumps. One in tank and one in the right rear wheel well. As for the pump running when you turn the key, mine generally does not run until I've engaged the starter and I've confirmed this with a second relay. The reason I suggested it could be the accumulator is because I know that mine when hard to start when cold when I first got it. After discovering that the accumulator diaphragm was bad and fuel was leaking out of the top I replaced it and it starts much more reliably now.

Before you start throwing parts at it, I'd check the pump for pressure and flow and confirm that the accumulator is good. It's possible that the starter fluid is getting it started even though the pressure in the fuel lines may be low after sitting for a while. Once started and running everything is fine.

If it's been running for a while and you shut it off, does it fire right back up?

[Rupesy]

Does this happen (the times when it won't start) only when the engine is cold or does this also happen when the engine is warmed up?

[ozzieandstormy]

the check valve would be in the back of the car when I lift up the rear carpet, correct?

[Danglerb]

Originally Posted by ozzieandstormy

the check valve would be in the back of the car when I lift up the rear carpet, correct?

No, the thing under the carpet is the return line and fuel level sender, the pump is on the bottom of the tank under a removable panel. I don't know anything about the check valve specifically though.

[MountainShark]

Most 78's had two pumps as Stephen described. The check valve is on the discharge of the first pump under the tank sometimes part of the banjo bolt on the hose connection. Check valve is problem can stick either open or closed. There is an optional pump with built-in check but not likely that you have since it came later. Your starting problem sounds a little like one I just conquered (finally). Voltage activating cold start valve flows thru cold start valve and therm-time switch, both tested good just corroded connections making voltage to low to open cold start valve. Just an idea. Check switch and cold start and clean connections all the way back to the start relay. Disconnect cold start valve and check voltage while someone hit starter, voltage need to be over 11 to insure cold start valve works.


Butch
78 928 Sometimes runs.

[DPW928]

If the pump is OEM Bosch, it will have the check valve which is integrated into the long hex outlet from the pump and is not individually replaceable. That's the bad news. The good news is that most leakdowns are due to dirty injectors or leaking fuel accumulators.

[Rixter]

78's, especially the early Euros, were a single pump & fuel accumulator in the right rear wheel well... double pump setup wasn't normal until 79MY (though there are plenty of 78's that have been converted to 2 pump setup for various reasons)
more info is needed to assist IMHO
you say it starts sometimes but not always... when does it NOT start? cold? hot? both?
since the car runs fine when started I would not look at the fuel distributor as the culprit
either the pump has issues, or the accumulator may not be holding pressure for one reason or another

[DPW928]

Originally Posted by Rixter

78's, especially the early Euros, were a single pump & fuel accumulator in the right rear wheel well... double pump setup wasn't normal until 79MY (though there are plenty of 78's that have been converted to 2 pump setup for various reasons)
more info is needed to assist IMHO

Correct! The references I have read indicate that Porsche only used two pumps in the vehicles destined for hot climates to prevent vapor lock.

[MPDano]

Yeah, my 81 Euro has two pumps. One under the rear removable plate next to fuel filter and one in-tank. I ended up removing the in-tank insides, so it just flows free. so I am running a single pump and it's fine. No vapor lock, but I do make sure it's always at least 1/2 full of fuel.