924Board.org

LeeXIX · Joined: 09 Feb 2006 Posts: 19 Location: Cleveland, Ohio

I need a bit of help. I have been working on my 924 for a few months now. The problem is that the car will start and run until it warms up and then quits and restarts but runs for about 5 seconds and then quits again.
I pulled off the Aux air regulator and found that it had a piece of carbon wedged inside of it. I cleaned it out. Oh by the way... should you be able to take the inside of the unit apart? It comes apart showing how the wiring is wound around the metal piece that deforms when you have power going to it for 5 minutes. If it is not supposed to come apart I guess that I will need a new one.
I put it back together and checked the ohms resistance which, according to my Haynes, said that it should be 30 ohms. Well....it tested at a consistant 49.1 Ohms (should I replace it?). I put the part back on and started the car up and it ran for a half an hour. So I thought it was finally fixed.
But when I revved up the engine my headlights would go up and then when I would rev it again the headlights would go down. I took it for a spin and the car was great........for about 10 minutes. With the exception of the headlights going up and down (a possible ground problem???) that is. Then the car quit. I wiggled the fuel pump relay and the car worked great for another 10 minutes. I did notice that the fuel pump relay was very very warm to the touch. A possible ground issue?
Do any of you have an idea what it could be? I am guessing that I should replace the Aux air valve (since it comes apart) and should add another ground somewhere. But what place would be the most effective place to add another ground?
Any ideas would be a great help

Thanks\

Lee

my e-mail is heb13.6@juno.com
_________________
I have a 924 (yellow) Porsche since I lost my 1971 914 in my divorce. She threw out everything except the shell of the body.

Stu2j · Posted: Sat Jun 17, 2006 7:26 am Post subject:

>>>But when I revved up the engine my headlights would go up and then when I would rev it again the headlights would go down.

Talk about a gremlin... I have no idea but I got a good laugh from it

Hope you track it down.
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-Stu
924 owner since 1988
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Paul · Posted: Sat Jun 17, 2006 8:34 am Post subject:

I'd try another fuel pump relay, most of us keep a spare in the glove box.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Eturbo924 · Joined: 09 Nov 2002 Posts: 2212 Location: Londonderry NH

Definately replace the fuel pump relay... but I have heard that when the relay is getting hot like it can be that the fuel pump is on its way out... and drawing to much current.

Eric
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1982 924
1992 968
2003 C4S
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LeeXIX · Joined: 09 Feb 2006 Posts: 19 Location: Cleveland, Ohio

Just to let you know....the fuel pump relay is new. I tested the fuel pump and it does not draw more than 7.5 amps and it does not get hot. But the fuel pump relay does. I removed the relay and installed a jumper wire with a 10amp fuse and the fuse got very warm and then popped. I even unhooked the warm-up reg and the aux air valve and the same thing happened. I believe that there is nothing else in the circuit.
The previous owner and he had replaced the fuel pump and had the same problem. The only thing is that he had the old fuel pump relay installed that had blown the fuse originally but replaced the fuse.
Am I missing something????? I am to the point of just removing the whole system and going with carburation. By the way...does anyone have a manifold and carbs that would fit? Or what could I use? I have gone over and over the system with no luck.
I just want to be able to drive the car for more than 10 minutes.
_________________
I have a 924 (yellow) Porsche since I lost my 1971 914 in my divorce. She threw out everything except the shell of the body.

Lizard · Posted: Tue Jul 04, 2006 11:00 am Post subject:

what gauge of wire did you use to jumper the circuit?

if the wire was not a big enough of a gauge and it got to hot it would pop the fuse, however if the wire was big enough to handle the current and the wire got hot and popped the fuse then you know that there is ALOT of corrosion on the female plugs inside the fusebox, or on the other pieces and then need to be cleaned/replaced.

with the other gremlins that you have mentioned I think that something is probably messed up in your fusebox and you should replace it regardless and check for burnt pins on the backside of it.
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Eturbo924 · Joined: 09 Nov 2002 Posts: 2212 Location: Londonderry NH

what other work... if any was done on the car by the PO?

Was the clutch replaced? Big jobs like that. The reason I would like to know is that it sounds like you might have a short in the system some where. Frequently when doing a clutch job some of the wires get caught in the bell housing when things are buttoned back up. This causes a dirrect short and can reek all kinds of havock.

The line going to the WUR is frequently the one that gets caught. Trace it and make sure it is not cut in any way or caught in some assembly.

Eric
_________________
1982 924
1992 968
2003 C4S
Parts Parts Parts and More parts.
E-mail me for parts you need!
Drive Fast!

LeeXIX · Joined: 09 Feb 2006 Posts: 19 Location: Cleveland, Ohio

I checked the wire on the jumper and it was a 14 guage wire. I did find out the problem with my headlight doors going up and down though. One of the wires to my instrument panel lights had broken and was grounding on the back of the dash panel causing the problem.
Nothing has been done to the clutch or anything other that a set of Splitfire spark plugs having installed by the previous owner.
Also, my wipers quit working and I checked the motor and found that I have no power to it either. I have traced back to the wiper switch and I have no current there either. So now I am considering the fue panel as the problem. I have pulled a few of the connectors off and have found no corrosion. Where would the corrosion build up on the fuse panel?
I finally removed the drivers seat and now I can lay down to work on the problem. I have found a hot wire that runs from the relay by the fuel pump relay that goes nowhere. I have found a large red wire as well as a yellow/white wire that are just hanging by the fuse panel as well.
The guy I bought it from said that it ran great for about 3 to 4 months and then this problem I have inherited began so he just quit driving it.
I have removed the fuel pump and cleaned the connections and added another ground to the intake manifold.
Do the fuse panels go bad on these that often?

Thanks
_________________
I have a 924 (yellow) Porsche since I lost my 1971 914 in my divorce. She threw out everything except the shell of the body.

Eturbo924 · Joined: 09 Nov 2002 Posts: 2212 Location: Londonderry NH

The blocks can go bad.

I have a 1977 924 (for sale) that had a fuel pump issue. Sorry I should have thought of this.. but it it is not entirely similar.

When I purchased the car the PO had jumped the fuel pump relay. So I figured he had a bad relay and got a new one. Buzzz thanks for playing...nope was not it. So I tired a couple other tricks until I decided to be logical about it and start at the back of the relay block. Bingo... found that the fuel pump relay ground wire had pushed out the back. I fixed the terminal, snapped it back in place and the car runs better than ever. So definately check to make sure the fuel pump relay has a good ground.

Next... on my 1982. I had an issue where the car would run great for a short period of time and then quit. It would quickly start back up... at first. Then over time it got to the point where it would not start back up. So I it was down in Conn (I lived in Mass) and a dealer suggested I replace the fuel pump relay. So I did. The car was perfect for about 1 month. Then it just died and would not restart no matter how long I let it sit. So my mechanic (before I did all my own work) said it is one of three things. The fuel pump relay... which was previouly replaced... the coil... or the black box that control the ignition functions (silver on the older cars). So he said we could experiment and replace on at a time... or do all three (figured I had damaged the relay) so I did all three. That was about 10 years ago now and I have never had a problem again.

So after you trace all the wires in behind the dash make sure you run the Haynes manual tests on the coil and box. Make sure you run them before you run the car and after it dies to see if the readings change.

Oh and expect to find some wires that go nowhere ... some of the options equiptment and such likely was never hooked up.

Eric
_________________
1982 924
1992 968
2003 C4S
Parts Parts Parts and More parts.
E-mail me for parts you need!
Drive Fast!

Jaf · Joined: 08 Jun 2006 Posts: 194 Location: Oria. Spain

This is probably not going to help but...could it be to do with the air meter? I found yesterday that because my air sensor plate was out of adjustment it was causing the relay to get very hot as it was clicking madly.

The poor old fuseboxes are not in the best position under the battery like that. All that water and battery acid makes for holes in the bodywork so the fusebox gets wet.

Jaf
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1978 924na

Lizard · Posted: Sat Jul 08, 2006 10:39 am Post subject:

all of the 924s/931s that I have seen or worked on have had alot of corrosion on the inside of the box, and some of the pins were broken on the inside, and replacing the box corrected the intermittant issues as the pins were no longer getting contact and loosing it.

I still say that unless the PO has told you it has been replaced or you have NO electric issues then I would be replacing the box.
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LeeXIX · Joined: 09 Feb 2006 Posts: 19 Location: Cleveland, Ohio

Thanks for the guidance.
I pulled down the fusebox and rechecked the connections. I deceided to try starting it again to see what happens. While it was running I noticed the green/black wire (which runs to the fuel pump) was getting very warm to the touch. I noticed that it had a red/white wire spliced into it as well (it runs to the warm-up reg as well as the air control valve). That wire (red/white) did not get warm, besides, I had unhooked them anyway. Only the wire (green/black) that runs to the fuel pump did. And then after a while the same...it quit running and then retarts okay started again.
What baffles me is that I have checked and rechecked the fuel pump and it only shows a 7.3 to 7.5 amp draw. Is there something else between the fuel pump and the connection at the relay? Do you think I should add another ground to the one that is on the back of the relay?
If I need a fuel pump should I get the Bosch one (664.00 USD) or is there a reasonable replacement available? I have an early '77.

Thanks in advance

Lee
_________________
I have a 924 (yellow) Porsche since I lost my 1971 914 in my divorce. She threw out everything except the shell of the body.

Slam · Posted: Sat Jul 22, 2006 11:13 am Post subject:

Don't pretend to know a whole lot about these cars, but isn't there an in-tank fuel pump as well? Maybe the big draw is there.
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'84 944 - kid blew motor
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'87 944 - sideswiped by trucker
'80 924 - gone
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'77 924 - rusting comfortably

Ozzie · Posted: Sat Jul 22, 2006 2:12 pm Post subject:

The '77 was too early for the intank pump.
May have been added later.
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Paul · Posted: Sat Jul 22, 2006 2:25 pm Post subject:

http://www.partsamerica.com/ProductList.aspx?PartType=52&PTSet=A&SearchFor=Fuel+Pump
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.