924Board.org

[j03k64]

I've got a fresh head in this car, new fuel pump, new fuel pump relay/DME, all the electrics are clean and wired for business.

While working on the fuel system, the Hot Start Valve (AKA: Supplementary Start Valve, or Electric Solenoid) makes this absolutely brutal 80s alarm clock buzzing, screaming, almost electric chair noise when the fuel system is energized.

It quieted down a bit once we sorted out the wiring mess from the previous owner; however, it now makes a toned down version of this sound when we attempted to make our first start and run in today. The car won't start, it just turns over.

There's lots of spark, fuel to the CIS distribution head and lots at the connections located back of the intake/head, but not much on the plugs - #1 didn't even smell like petrol.

I honestly didn't even notice the solenoid was there until we pulled the fuel system from this car during restoration; the one on my 79 has never made a noise. I reckon we either wired it incorrectly on re-assembly and or fried it when troubleshooting the fuel pump circuitry.

The Haynes manual says it MUST be replaced if it is dead; so I'm assuming it's rather important and likely the culprit of our fuel delivery issue.

I found some info here:
http://www.924board.org/viewtopic.php?t=34767&view=next&sid=71d74dddcf3e3d28692645964289dba7

Has anyone else encountered this?
Would this be correct diagnosis?
How do I determine what wire goes on what prong (to confirm its current wiring). There's a grounded side (brown and brown-white) and the hot side (red-yellow).

I'm going to order a fresh one... 99% sure it's fried (anyone know the part number considering it has three aliases?).

Cheers!
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1979 Porsche 924
1980 Porsche 924

[brian19600]

When I bought mine, the po had left it unplugged for some reason. He mentioned something about it not running right with it. I don't know if that's true or not, but the car was running with it unplugged.

From my understanding, that valve is supposed aid in hot starting and was a mid-78 add on. It would stand to reason then, that it isn't absolutely necessary for operation-especially cold.

Have you pulled the injectors to see if fuel is spraying out? Would it fire on ether?
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78 924

[j03k64]

Brian, that's good to know! Thanks for the prompt reply! I wasn't sure as I haven't had much experience with that portion of the fuel system. I thought it was a bit strange for it to not run due to the HSV. If it dies and is indeed hooked up I'm guessing it impacts the mixture depending on what position it's stuck in?

I did a bit of research, seems the HSV is marked NLA at Porsche.

Solenoid Valve, Stock Code, 477133525D ; 477-133-525-C; 477-133-539; 477-133-539-A; 477133539; 477133539A; 477133525C, Manufacturer N/A

I'll unplug it and see what happens.

Looks like I'll be pulling the injector lines and voiding them to be sure they're crystal clear. It has the steel lines, they're nice, unless they're stuffed up....
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1979 Porsche 924
1980 Porsche 924

[brian19600]

What guys usually do is pull the injectors and stick them in jars, then turn the fuel pump on-looking for a nice spray pattern and there should be an even amount of in each jar.
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78 924

[Ozzie]

The hot start solenoid should have no power as it runs from a thermo switch in the coolant line. Only activates if the coolant is hot and when cranking.
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[j03k64]

Thanks Ozzie! That is good to know!

I knew it was connected back there, it hadn't occurred to me that it is off until the car was BOTH hot and being cranked.My solenoid is most definitely dead; unplugged it for now.

Does the solenoid also provide some sort of altitude mixture adjustment then; as the coolant boiling point would change?

Brian, I'd test the injectors, but the line to the cylinders are very dry; the CIS was funky =/

I pulled the fuel lines and injectors, two of them were slightly obstructed and there was funk in one of the fuel distribution holes up top. Got it all cleaned up, it wasn't enough to explain why my plugs and lines are bone dry...

I pulled the fuel dist head and sure enough, the pin is stuck. Red, very sticky residue on the pin itself and in the lower section (does one lube the small roller?). I very gently cleaned it up, replaced the dist unit and fuel lines. Sea Foamed the pressure regulator bolt, it didn't want to come out, letting it sit over night. It's likely gummed up as well.

Trying for start again tomorrow!

Has anyone bought a HSV recently? Pelican is even showing it as NLA...

http://www.pelicanparts.com/More_Info/477133525D.htm?pn=477-133-525D-OEM#tab5
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1979 Porsche 924
1980 Porsche 924

[brian19600]

You can send an email to parts heaven. Include a copy of the parts drawing and the item number. They have 924's they are parting.
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78 924

[Ozzie]

solenoid only works on temp.
someone may have a whole working setup after changing to EFI.
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

[j03k64]

I'll keep that in mind Brian! I managed to find a spare unit upstairs in a box while looking for injectors; no idea if it's good or not.

The fuel dist head was half plugged up, it spent a few days in an ultra-sonic cleaning tank; working much better now.

I spent the last week trying to bring two of the injectors back to life. They're working, but the pattern is irregular/partial. Pretty sure they're stuffed up between the screen and nozzle. I surrendered ordered 4 new ones... everything else is new, might as well get on with it!
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1979 Porsche 924
1980 Porsche 924