924Board.org

[Johnny_Haywire]

Hey guys, bought my '81 N/A late last autumn and after changing jobs and moving to a new place, I'm finally getting some time to work on the car.

It hasn't run in at least a year or two (maybe more) and so I'm proceeding with caution. I changed the oil and also pulled the cam cover and gave the cam and lifters a liberal soaking with oil, and also fogged the combustion chamber before putting the new Bosch plugs in. I also changed the cap and rotor.

The fuel return line that goes to the barb on the tank is cracked and leaking, so I'm soaking the compression fitting in penetrating oil to get it apart so I can replace or repair the line. I did replace the "S" hose from the tank pump to the external pump, which was also cracked. They are likely all cracked and rotted, but I'm starting with the ones that leak when I put fuel in the tank.

In the meantime, I pulled off the intake boot and got her to fire up with some starting fluid while a friend cranked her over. Sounded fine, no loud knocks or major smoke.

So, I'm getting spark and the engine seems fairly sound, cam looked okay, nothing out of the ordinary in terms of funk on the valvetrain for a 98,000 mile car.

However, with the key in the "on" position, I am not hearing any noise or sound from the fuel pumps. Granted, the tank and lines are dry, but shouldn't I be hearing something, a bit of hum or whirring?
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1981 924 N/A 5-speed

[Ozzie]

Fuel pump relay runs off the tach signal so if its not cranking or running the pump stops.
Bypassing the relay works for testing.
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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

[Johnny_Haywire]

Thanks for the info, Ozzie. That's a pretty major relief to hear ; )
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1981 924 N/A 5-speed

[Brockoli]

when the key is in the ON position you can also flick the side mirror adjust button (thats what she said?). For some reason this turns the fuel pump on for a second. I use it to pressure up the fuel system when I havent started the car for awhile since I need to replace the fuel accumulator. I know this trick works on my '79 and '80 and hopefully your '81. If nothing happens than you know no power to the pump.
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'80 924 M471,Wideband O2, Full coilover susp,23/19 sways,Bilstiens,KLA Strut Brace,Roll Bar,Test Pipe,BBS RS, Willwood BBK

25% of a '87 944 Chumpcar http://straightpipe.ca/forums/showthread.php?t=2454

'79 924 Sebring Edition(Sitting)

[Johnny_Haywire]

Thanks for the tip, Brockoli! I'll give that a shot this evening if I can (or tomorrow afternoon) and report back on my findings.
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1981 924 N/A 5-speed

[Fasteddie313]

I'd...

Pull the injectors, Put them in 4 identical pop bottles, jump 30-87 on fuel pump relay to run the pump, Techron in the gas tank, push the metering plate on the fuel distributor to make the injectors spray into your pop bottles..

Go ahead and fill up the pop bottles a couple times to get that Techron through the system, running it is good for it, give it a chance to clean its self up..

Then empty your bottles and fill them about half way with the injectors, compare there levels, the bottles should have equal amounts of gas in them and you should observe a nice cone pattern spray from the injectors.. And it makes very cool sounds.. EEEEEEeeekkkk...

The injectors should stop when your not pushing on the metering plate, a good base setting for the mixture screw is to go rich just until the injectors spray by themselves and then back until they stop while you have the fuel pump running with the metering plate at rest...

If all the injectors don't stop spraying at the same time the ones that continue to spray or dribble while the others are off need to be replaced as they are leaking, give them a chance by running with the techron first..

If your fuel in the tank is questionable maybe you should drain the tank and add fresh fuel first..

If you have access to a CIS fuel pressure testing kit by all means use it, as before run the system with techron for a while first to give it a chance to clean itself up..

If your car has lambda or an O2 sensor system you can then tune the mixture screw by monitoring the lambda frequency valve duty cycle with a dwell meter...

My car is a turbo so small things may differ, dont take my word for gold..
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80 Turbo - Slightly Modified

[Johnny_Haywire]

Thanks a million for the tips, Fasteddie! I've tracked down some Techron (Advance carries it) and will be getting started on that and the injector test soon. Was hoping to do so tonight but work has gotten extra busy for the next week and I'm off to AHRMA racing this weekend. Thanks also for the heads-up on which pins to jump for the fuel pump, you've really made this a good bit easier on me.

The system on yours seems pretty similar on my '81. It has an O2 sensor, but I don't have a CIS tester. I used to have a dwell meter but it hasn't surfaced while unpacking from the move. But the manual way you pointed out should get me in the right direction.

The fuel tank is bone dry currently, so no old fuel in there that I could tell. I put some fresh fuel in and it leaked out through the rotted return line near the tank barb. That line is currently soaking in PB Blaster so I can disconnect it and repair it (the one high up in front of the fuel tank). Not the most convenient place to put a connection that requires two wrenches, though. Thanks, Porsche ; )

I did buy two new fuel filters so I can basically sacrifice the first one with the Techron and whatever crap is in the line.
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1981 924 N/A 5-speed

[Fasteddie313]

Also...

Fuel pump grounds between the tail lights under the vertical carpet on a crown of male spades... Clean em all and under the crown to chassis..

Fuel pump power is a wire that runs under the drivers door sill plastic cap thing, I dont recall what color but I put a 3 way switch in it.
OFF - OEM WIRING - 12V+
So I can turn it off, straight battery power, or OEM circuitry.. I dont even have power to it anymore so its more like 2 offs and OEM power..

Clean all the fuses contacts, I used a drill bit by hand to clean the fuse terminals and buffed the fuses on my jeans.. I think thats what fixed my fuel pump actually..

Clean all the grounds you can find, add a new one to the alternator and to the engine block, and make sure the battery to chassis ground or wherever it goes is good..

Just replace all the braided cloth covered vacuum lines in one shot and any others that seem even questionable...

Clean all the sunroof drains out, they exit under the hood on the outside bottom corners of the windshield, and under the rear end of the car, white hoses.. Use weed whip string or something, compressed air could blow the lines off there ports in the roof and then the sky falls (or so I'm told)..

Clean out the under hood drains!! they exit through the firewall right in front of the battery and the same on the other side, Inspect this wet drain area for rust and leaks into the interior floorboards..

These are some other things I'd do to a "new to me" 924..

Google search...

site:924board.org SEARCHTERMS

Replacing the caps with your search, is a much better way of searching the site IMO..
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80 Turbo - Slightly Modified

[Johnny_Haywire]

Thanks, Fasteddie. I'll definitely clean all the connections, and knowing where the fp ground is will make it even easier. I'll make sure to hit the drains as well. Just found a coil of weed whip wire in the basement here. The body is pretty clean and rust is minimal, but I know what you mean about it building up in that back end of the front fender when the passages are clogged.

I've got a pretty long list of things that I'm planning on doing to the car (belts, hoses, vacuum lines, tires, brakes, shocks/struts, weatherstripping/seals) but I wanted to make sure the fuel pumps are working and that I can fix the leaky fuel hoses back there first. I'm going to make sure she can go around the block without leaking fuel before she gets any of the fun stuff.

I just tried Brockoli's method of flicking the mirror selector on the console with the key "on" but to no avail. Even had a friend get under there to see if it made any sound, but nothing.

My Hayne's Manual arrived this afternoon and I will track down the relay so I can jump it. I was hoping get by with some wire and alligator clips, but I think it's probably time I made a proper jumper.

Also did a quick test of the electrical system tonight, the key warning buzzer sure works, and headlight and all other lamps are good (signals, hazards, running lights, headlamp motor). Wipers work but won't turn off in the off position (2nd up from the bottom), but that's a problem for another thread or likely a good cleaning of the switch. Washer pump works. Horn does not work. A few bulbs out on the dash. Power mirrors and windows work.

For the last thing of the night, I hit that return line fitting with penetrating oil again. Gonna soak it for a few days before messing with it.
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1981 924 N/A 5-speed

[Johnny_Haywire]

Sorry for the delayed update, gents. Work got pretty crazy for a few weeks and then nothing but heavy rains here in Chicago every free moment I had.

So, I fitted a jumper to the pins 30 and 87 in the fuse panel section for the fuel pump relay and it (they) work! I had the battery disconnected, but the main pump started running as soon as the battery was connected. Wasn't sure if it would need ignition power or not, but now I know. Not sure if the in-tank pump was running, but I think so.

I did clean the ground and all the electrical connectors for the fuel pump. Connectors seemed okay (I had cleaned the in-tank pump connectors last fall), but the ground in the hatch area was really rusty.

I then proceeded to work on removing the fuel hose that runs from the hard return line to the barb on the bottom of the tank, which has some cracks near the barb and leaks fuel. Wow, whoever engineered that area for a 2-wrench compression fitting is truly a cruel bas#*rd. Way high up in the hump above the diff.

Luckily my diligent applications of penetrating oil worked as I was able to loosen the bugger and disconnect it. Having coffee now and then I'll get it fished out of there and dissected so I can see what I'll need to do fit new hose on it.

Pics to come of the hose. Looking very forward to the next step of running some Techron through the system and testing the injectors. And then, fingers crossed, firing her up.

Thanks again for all your helpful posts and tips!
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1981 924 N/A 5-speed

[Johnny_Haywire]

Amigos, below are a few pics of the hose in question (hose from hard return line to the barb on the bottom of the tank). My plan for now is to Dremel off the outer crimp material, remove the rotted rubber hose and replace it with new high pressure FI hose and a high-quality clamp. I've attached a pic of what I think this style of crimp is. I'll need to cut pretty close to the top, and hopefully just like the last pic, the OEM fitting has a flare at the end to keep the hose on it.

If 924 ends up being sound (i.e. trans and clutch are not trashed, engine without sad noises), I'll re-do all the hoses back there with AN bits. But for now, this is just to get her going.

Went to swap in the sacrificial fuel filter today and could not fit either of the two I purchased from Rockauto (one Purolator and one Wix). Both have two different sized holes for the compression fittings, yet oddly on opposite ends. The inlet and outlet holes on the existing filter are the same size, and the one replacement that came with fittings has a much smaller outlet compression fitting in it. Not the end of the world (basically a trip to the hardware store), but kind of annoying as I wanted to get one step closer today to the Techron flush. And also annoying because I did order the correct parts.

Anyway, if any of you have any tips on putting new FI hose onto the original fitting, I'm all ears. Ye oulde Dremel comes out tomorrow...

And, yes, the rear bumper is off. Drivers side mount sheared off. It was held on with a ratchet strap when I bought it. The PO told me his parents took the car out and when they came back, they said the bumper "wasn't working right." Ha! Sure isn't... Anyone in the Chicago area with a spare they'd like to part with?












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1981 924 N/A 5-speed

[Johnny_Haywire]

Sorry for the delay in updates, amigos. Work has been crazy and I've been taking all I can get before it slows down.

I made some progress of repairing the rotted return hose. Some careful use of the Dremel and the crimp came right off to reveal a barbed compression fitting. I bought some 200psi fuel hose and will use a stainless clamp to hold it in place.








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1981 924 N/A 5-speed

[Johnny_Haywire]

I finally have a fuel filter that will fit (purchased from O'Reilly auto parts) after the two I bought from Rock Auto were incompatible. My fuel filter has two of the same size inlet/outlet openings (M14, I think). The filters from Rock Auto had M12 on one end and M14 on the other, but it was opposite on both filters (a Wix and a Purolator). And yes, I did make sure I had the flow correct. Weird.

I need to install the return hose and then I can start by flushing out the fuel line to the filter/engine with Techron. Then I plan to install the filter and clean out/test the injectors (injector seal kit is on its way).

Fasteddie, I have a question about doing this test - can I install a switch on my jumper for the fuel pump relay? Or, rather, is that safe? It's pretty tough to get in there and install/remove the jumper under the dash, and in case something goes wrong (another leaky hose, etc.), I was hoping to just use a switch on the relay jumper to kill it. I will reconnect the intake boots and will also pull the coil lead when I do the test.
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1981 924 N/A 5-speed

[Johnny_Haywire]

And lastly, here are a couple pics of her. Sorry, these should have been the first things I posted ; ). Interior pics to come. It's black and in decent shape, though the seat bottom seams at the side bolsters are splitting.










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1981 924 N/A 5-speed

[ideola]

Nice start to this project!

Where in Chicago land are you? I'm up in the NW burbs, Woodstock. We should get together.
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erstwhile owner of just about every 924 variant ever made