got stranded .... |
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got stranded .... |
dax1969 |
Apr 17 2023, 09:13 AM
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#1
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Member Group: Members Posts: 372 Joined: 10-March 14 From: belgium Member No.: 17,103 Region Association: None |
Hi guys,
Got stranded yesterday with my 1974 2.0 fi... no buzz fm the fuel pump. Saturday the car started and ran great, only thing I did to the car that day is that I took my steering wheel off as it was a few teeth off center. Used a impact gun to remove and install the big nut (no idea if this has something to do with my issue). Perhaps I had to be more gentle ... Before I left on sunday morning I turned the key and heard no buzz fm the fuel pump... tried again and there was the buzz and the car started right up. Went to fill up the car and no issues with starting. After a 50 km drive I parked the car and when I came back again no start/no buzz fm the fuel pump. Started switching the relays, even with the ones fm the headlights... no buzz/no start. Switched fuses on the relay board (that's why you see the white in the position of the blue and vice versa)... still nothing. Called roadassistance and luckily an older gentlemen showed up. He took his voltmeter and said he could get the car started if he jumpered the relays - see picture. The car indeed started right up and I headed the 50 km back home with no issue. Disconnected the jumper ofcourse as the pump otherwise kept working. So where to start fm here... I have the file "porsche 914 fuel pump troubleshooting" but did not go through yet. I just keep wondering what could cause my issue. The questions I have are the following : 1. Can the removal/reinstalling of the steeringwheel cause this issue (perhaps the connection of the switch came loose ? Pinched a wire so no ground ? 2. Ignition switch was replaced about a year ago (Porsche one, not chinese crap). If an ignition switch fails, does the car crank or nothing at all ? Trying to figure out if I have a switch failure. 3. My fuel pump has a slight "humm" for a while (assumed it was resonance with the bottom plate (fuel pump is located near the rack) but can a fuel pump go bad "half" ? I mean can she fail on giving the familiar buzz at start up but still run when relays are jumpered ? 4. Relay board itself was replaced a year ago with a rebuild one fm Bruce Stone Some advice I received on facebook 1. splitting/widening the relay pins (did this in the past but perhaps have to do it again) - fyi ordered new relays anyway 2. bad CHT sensor ? But once the car starts with the jumpered relays, the car runs fine. Overruled by other members in the meantime Any suggestions are welcome... thks Krgds Dax |
StarBear |
Apr 17 2023, 09:17 AM
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#2
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Advanced Member Group: Members Posts: 2,054 Joined: 2-September 09 From: NJ Member No.: 10,753 Region Association: North East States |
Ah, the joy of adventure and mystery with 50-year old cars. Glad you made it back home and got a knowledgeable roadside assistant!
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SirAndy |
Apr 17 2023, 09:20 AM
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#3
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Resident German Group: Admin Posts: 41,815 Joined: 21-January 03 From: Oakland, Kalifornia Member No.: 179 Region Association: Northern California |
Glad you made it back home and got a knowledgeable roadside assistant! I second that, that has to be about as rare as a winning lottery ticket! (IMG:style_emoticons/default/beerchug.gif) |
930cabman |
Apr 17 2023, 09:49 AM
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#4
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Advanced Member Group: Members Posts: 3,545 Joined: 12-November 20 From: Buffalo Member No.: 24,877 Region Association: North East States |
Ah, the joy of adventure and mystery with 50-year old cars. Glad you made it back home and got a knowledgeable roadside assistant! (IMG:style_emoticons/default/agree.gif) My bet would be it's something simple and the older chap knew how to diagnose? what a rarity is that. Keep us apprised, can you wire the fuel pump direct to the battery and listen for the usual "hum"? |
Superhawk996 |
Apr 17 2023, 09:52 AM
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#5
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914 Guru Group: Members Posts: 6,469 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
Don’t get distracted with all the other stuff.
Since it runs with the power relay and the fuel pump relay jumpered, you know where the issue is. Bench test the relays - you’ll probably find they are OK since swapping other relays didn’t help but jumpers did. If those relays bench test OK, you now know the issue is that the relay pins weren’t making contact to the relay board sockets. The pins to the relays can be expanded slightly, and, the relay board sockets can be tightened slightly. That will likely fix your issue. |
87m491 |
Apr 17 2023, 09:57 AM
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#6
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Member Group: Members Posts: 295 Joined: 29-July 12 From: Portland, the original! Member No.: 14,731 Region Association: North East States |
I think your answers are right in your post. To play on words, I think
your steering wheel swap is a red herring or "Post Hoc" fallacy, i.e. "after the the fact, there for because of the fact". I'd bet highly unrelated UNLESS you messed with the ignition switch as well in the process. Ignition on, no fuel pump buzz means either the switch signal is not getting to the relay, or the relay is bad (or possibly the lead from the relay to the pump is suspect). The fact that the repair fellow jumpered the relays (amazing he knew which ones. I'd have to consult a manual) and you were on your way points to bad relays or bag ignition switch trigger. (but might have also been coincident with a wonky ignition switch playing nice for a moment. You need to do what roadside repair did and grab a DVM and find the weak link. Hopefully easy like the switch or the relay and not a bad wire or relay board etc, but any should be pretty straight forward to pin down. Hi guys, Got stranded yesterday with my 1974 2.0 fi... no buzz fm the fuel pump. Before I left on sunday morning I turned the key and heard no buzz fm the fuel pump... tried again and there was the buzz Called roadassistance and luckily an older gentlemen showed up. He took his voltmeter and said he could get the car started if he jumpered the relays - see picture. So where to start fm here... I have the file "porsche 914 fuel pump troubleshooting" but did not go through yet. I just keep wondering what could cause my issue. The questions I have are the following : 1. Can the removal/reinstalling of the steeringwheel cause this issue (perhaps the connection of the switch came loose ? Pinched a wire so no ground ? Any suggestions are welcome... thks Krgds Dax |
Superhawk996 |
Apr 17 2023, 10:03 AM
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#7
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914 Guru Group: Members Posts: 6,469 Joined: 25-August 18 From: Woods of N. Idaho Member No.: 22,428 Region Association: Galt's Gulch |
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DRPHIL914 |
Apr 17 2023, 10:09 AM
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#8
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Dr. Phil Group: Members Posts: 5,808 Joined: 9-December 09 From: Bluffton, SC Member No.: 11,106 Region Association: South East States |
that is amazing he did know how to do that! i bet we would get that in the US!
i had this happen 2 years ago but unfortunately for me jumping the relay didn’t work because it was a short in the board itself. i now have 2 new boards one from Bruce as my spare ans one from 914sixer that’s in the car now. note to self, keep a spare board on board! Phil |
Spoke |
Apr 17 2023, 11:36 AM
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#9
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Jerry Group: Members Posts: 7,052 Joined: 29-October 04 From: Allentown, PA Member No.: 3,031 Region Association: None |
Here's another schematic view of the relay board. Your guy jumped relay K74 (ECU power supply) and K75 relay (Fuel pump). So 2 relays were jumped. K74 provides 12V power to the ECU on Pin 1 of the FI power connector also power to K75 on pin 85.
Follow K74 pin 85 back to the connector to cabin and you see it connects to pin 8 which is from the ignition switch. w/o 12V on pin 8, the power supply relay doesn't work and neither will the fuel pump. Since your car didn't start up, you don't know if the power supply relay didn't get power from the ignition switch, or it's contacts were not making good connections, or if just the fuel pump relay didn't pull in or has bad contacts. When the problem happens the only audible feedback you get is the fuel pump not running. You can't hear the ECU running or not. Since your guy shorted 2 relays, you don't know which relay was causing the issue. Likely only one relay caused the issue. You can try bending the relay leads out a bit but if the issue is in the wiring or ignition switch, you still have an issue. Until you solve the issue, you should carry those little jumpers with you and your voltmeter. If it happens again, check for voltage from the ignition switch by measuring from the 8A fuse (which also is connected to the cabin connector pin 8) to chassis. If you have voltage on the 8A fuse, then try jumping just one of the relays at a time to see which one is not functioning. You may also want to reseat the cabin connector (make sure not to get off by one pin) and the FI power connector. About the impact tool on the steering column, it may not have done anything or it did. Large vibrations anywhere near wiring/connectors/fuses is not good. Attached thumbnail(s) |
Montreal914 |
Apr 17 2023, 11:37 AM
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#10
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Senior Member Group: Members Posts: 1,675 Joined: 8-August 10 From: Claremont, CA Member No.: 12,023 Region Association: Southern California |
Isn’t there something about the D-Jet controller that can cut off the fuel pump in certain conditions?
Could that function be acting up? (IMG:style_emoticons/default/confused24.gif) |
GregAmy |
Apr 17 2023, 11:57 AM
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#11
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Advanced Member Group: Members Posts: 2,385 Joined: 22-February 13 From: Middletown CT Member No.: 15,565 Region Association: North East States |
The pins to the relays can be expanded slightly, and, the relay board sockets can be tightened slightly. That will likely fix your issue. (IMG:style_emoticons/default/agree.gif) |
GregAmy |
Apr 17 2023, 12:02 PM
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#12
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Advanced Member Group: Members Posts: 2,385 Joined: 22-February 13 From: Middletown CT Member No.: 15,565 Region Association: North East States |
Isn’t there something about the D-Jet controller that can cut off the fuel pump in certain conditions? Could that function be acting up? (IMG:style_emoticons/default/confused24.gif) D-Jet computer grounds the fuel pump relay solenoid any time it detects ignition/spark sequences. Opens the circuit when there's no sparky. It also closes the fuel pump solenoid circuit when the key is in the "start" position. It's pretty basic. |
dax1969 |
Apr 17 2023, 01:14 PM
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#13
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Member Group: Members Posts: 372 Joined: 10-March 14 From: belgium Member No.: 17,103 Region Association: None |
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friethmiller |
Apr 17 2023, 02:11 PM
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#14
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Senior Member Group: Members Posts: 634 Joined: 10-February 19 From: Austin, TX Member No.: 22,863 Region Association: Southwest Region |
I had a similar problem last year. It was my hot wire at the battery terminal. I'd start there first. If the connection isn't rock solid, it can cause this behavior. It's a super easy fix, of course. Best of Luck!
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r_towle |
Apr 17 2023, 02:42 PM
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#15
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Custom Member Group: Members Posts: 24,624 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
you removed the two jumpers after it was running?
if yes, its the fuel pump relay you need to focus on. It may be a simple as examining the relay and figuring out how to widen it...meaning open up the pins just a bit more. I also found itsy bitsy wire brushes at a store that sells firearms. Those, on a drill...do wonders for the sockets. Get a few, they don't last once on a drill. Rich |
Mikey914 |
Apr 17 2023, 03:09 PM
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#16
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The rubber man Group: Members Posts: 12,711 Joined: 27-December 04 From: Hillsboro, OR Member No.: 3,348 Region Association: None |
It's obviously in the fuel pump relay area. If you have tested (which you can do with a swap on a headlight relay) relay, you should be able to make it work. Then it should be just the relay. If not, it's on the board. probably at the sockets as some suggested.
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Type 47 |
Apr 17 2023, 07:07 PM
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#17
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Senior Member Group: Members Posts: 784 Joined: 1-June 10 From: St. Louis, MO Member No.: 11,790 Region Association: None |
Thks yr feedback… will dive into it as soon as possible. Will report back. Just saw the youtube vid of George going through the relayboard…. THE guy… he was happy he could help (and I was happy to get home. Rgds Dax Dax, thanks so much for posting this and your picture. It really helps to put us in your shoes. I too got stranded for a short bit after we had installed a new e-distributor, this weekend. Car died in a round-about and I diverted for a low traffic lane but in the middle of a middle each/way turn lane. Luckily, some yuts stopped and help push us to the low traffic spur on the round-about, then downhill and out of the way. After several uncomfortable moments, my son found one of his crimped connections failed, so the e-distributor shut down, he got it patched up and we were immediately headed home. clean your contacts on the relay board, and you maybe good. again, thanks for posting the pic |
second wind |
Apr 17 2023, 10:42 PM
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#18
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Senior Member Group: Members Posts: 860 Joined: 30-December 10 From: Los Angeles, California Member No.: 12,543 Region Association: Southern California |
Hello...I feel your pain....my car was down for six months last year with identical issue....I ended up changing 13 different components and wala it works perfect now....I think the root cause was the 50 year old wire harness but a wonderful world guy walked me through a million tests and they were all correct. Even when I thought I knew what was wrong. he would say "test it first"....he was right. After getting the car running great my fuel lines rotted ad now back up on the stands. One day this war will be over....NOT!
gg |
dax1969 |
Apr 18 2023, 01:43 AM
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#19
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Member Group: Members Posts: 372 Joined: 10-March 14 From: belgium Member No.: 17,103 Region Association: None |
Thank you all for your feedback. To be on the safe side I have some new relays on the way fm 914 rubber (hurry up Fedex !) as I heard they are better than the Chinese aftermarket ones. Looking for small wirebrushes to clean the sockets but more difficult then I thought... fire arm stores are not so common here in Europe (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif) I'll let you know what I'll find rgds Dax |
dax1969 |
Apr 18 2023, 12:20 PM
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#20
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Member Group: Members Posts: 372 Joined: 10-March 14 From: belgium Member No.: 17,103 Region Association: None |
UPDATE: up and running …
Cleaned sockets with some sandpaper wrapped around a toothpick… spread the pins slightly and bam… The familiar buzz of the fuelpump is back… Anyway, once the new relays are in fm 914rubber I will put those in and carry the wehrles as spare… @spoke … thks yr drawing and explanation. That one is much simpler to understand for a non electrician Happy it was not more than that (although I feel stupid as I could have fixed it myself on the road… anyway first time I used roadassistance and their service has been tested now (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif) Thank you all Dax |
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