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> What'd I do now? New clutch, no fuel pump running
914bub
post Aug 31 2014, 12:13 PM
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Hey guys I need some help.

I got my 914 9 months ago. I traded it straight across for a car that a friend of mine wanted. The deal was we would both get each car running before the trade. The 914 needed a fuel pump and some tuning. It arrived running but needed a clutch and a master cylinder.

I got the clutch done and now the car won't start. I've got power to two of the pins at the fuel pump relay but no power down to the pump. I "think" the relay os clicking but need to get an extra pair of hands over here to crank is as I can't find my remote starter. If I understand correctly the ECU grounds the pump to make it run? If that's the case should I always have power at the pump with the key on? The car runs on starting fluid so the ignition is working fine.

Here's the rest of the story,(and yeah I feel stupid about this part). In my haste to button everything up I accidently plugged the 12 pin plug onto the relay board incorrectly. I plugged it in 1 pin off. Imagine if the #1 and 2 pins were plugged into 3 & 4 instead. I corrected that but just hope I didn't smoke something in the mean time. My dad also hooked the positive wire up to the negative side of the coil. ....That was good for a new set of points.

Any input would be greatly appreciated. I have the diagram of the relay board that was posted in another thread.
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Bartlett 914
post Aug 31 2014, 01:34 PM
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The fuel pump will only run for a few seconds after turning the key. Once the car starts, the pump will run continuously
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914bub
post Aug 31 2014, 01:39 PM
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QUOTE(Bartlett 914 @ Aug 31 2014, 12:34 PM) *

The fuel pump will only run for a few seconds after turning the key. Once the car starts, the pump will run continuously


Thanks. Is the ECU in fact grounding the pump as opposed to it energizing the fuel pump relay?

I've also been told that every car, (no matter the make), that has D jet injection uses the same ecu? Do you know if that's true? I have an ECU out of a D jet injected 72 Volvo. I haven't checked any part numbers yet. Thanks for the input.
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bdstone914
post Aug 31 2014, 01:57 PM
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QUOTE(914bub @ Aug 31 2014, 12:39 PM) *

QUOTE(Bartlett 914 @ Aug 31 2014, 12:34 PM) *

The fuel pump will only run for a few seconds after turning the key. Once the car starts, the pump will run continuously


Thanks. Is the ECU in fact grounding the pump as opposed to it energizing the fuel pump relay?

I've also been told that every car, (no matter the make), that has D jet injection uses the same ecu? Do you know if that's true? I have an ECU out of a D jet injected 72 Volvo. I haven't checked any part numbers yet. Thanks for the input.


Not all d jet cars do not use the same ecu.
Pull the fuel pump relay. Turn the ignition on.
Plug in the fuel pump relay. You should hear it click. If you have power and no click the relay could be bad. Pull the cover off the relay. Plug in relay and push down on the points. The fuel pump should run briefly. Swap it with a headlight relay which is behind the plastic cover in the front trunk. Try the fuel pump relay in the headlight. Check the fuse on the relay board for the fuel pump. Clean the fuse contacts.
If you plugged on the 12 pin connector one pin off and turned on the ignition you would typically fry the coil wire. If it runs on starter fluid it is probably ok.
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914bub
post Aug 31 2014, 02:24 PM
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QUOTE(bdstone914 @ Aug 31 2014, 12:57 PM) *

QUOTE(914bub @ Aug 31 2014, 12:39 PM) *

QUOTE(Bartlett 914 @ Aug 31 2014, 12:34 PM) *

The fuel pump will only run for a few seconds after turning the key. Once the car starts, the pump will run continuously


Thanks. Is the ECU in fact grounding the pump as opposed to it energizing the fuel pump relay?

I've also been told that every car, (no matter the make), that has D jet injection uses the same ecu? Do you know if that's true? I have an ECU out of a D jet injected 72 Volvo. I haven't checked any part numbers yet. Thanks for the input.


Not all d jet cars do not use the same ecu.
Pull the fuel pump relay. Turn the ignition on.
Plug in the fuel pump relay. You should hear it click. If you have power and no click the relay could be bad. Pull the cover off the relay. Plug in relay and push down on the points. The fuel pump should run briefly. Swap it with a headlight relay which is behind the plastic cover in the front trunk. Try the fuel pump relay in the headlight. Check the fuse on the relay board for the fuel pump. Clean the fuse contacts.
If you plugged on the 12 pin connector one pin off and turned on the ignition you would typically fry the coil wire. If it runs on starter fluid it is probably ok.


I did fry to coil wire,just haven't replaced it yet. When I close the contacts manually on the relay I still get no fuel pump. If I could determine weather the ecu supplied ground or fired up the fuel pump relay I could at least know which I should have full time at the pump. Right now I think I have neither.

Thanks for the ecu info. Good to know.
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bdstone914
post Aug 31 2014, 03:04 PM
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QUOTE(914bub @ Aug 31 2014, 01:24 PM) *

QUOTE(bdstone914 @ Aug 31 2014, 12:57 PM) *

QUOTE(914bub @ Aug 31 2014, 12:39 PM) *

QUOTE(Bartlett 914 @ Aug 31 2014, 12:34 PM) *

The fuel pump will only run for a few seconds after turning the key. Once the car starts, the pump will run continuously


Thanks. Is the ECU in fact grounding the pump as opposed to it energizing the fuel pump relay?

I've also been told that every car, (no matter the make), that has D jet injection uses the same ecu? Do you know if that's true? I have an ECU out of a D jet injected 72 Volvo. I haven't checked any part numbers yet. Thanks for the input.


Not all d jet cars do not use the same ecu.
Pull the fuel pump relay. Turn the ignition on.
Plug in the fuel pump relay. You should hear it click. If you have power and no click the relay could be bad. Pull the cover off the relay. Plug in relay and push down on the points. The fuel pump should run briefly. Swap it with a headlight relay which is behind the plastic cover in the front trunk. Try the fuel pump relay in the headlight. Check the fuse on the relay board for the fuel pump. Clean the fuse contacts.
If you plugged on the 12 pin connector one pin off and turned on the ignition you would typically fry the coil wire. If it runs on starter fluid it is probably ok.


I did fry to coil wire,just haven't replaced it yet. When I close the contacts manually on the relay I still get no fuel pump. If I could determine weather the ecu supplied ground or fired up the fuel pump relay I could at least know which I should have full time at the pump. Right now I think I have neither.

Thanks for the ecu info. Good to know.



You may have fried more than the coil wire. Friend of mine did the same thing connecting the 12 pin wrong. We spliced a wire from the board to the coil and still would not start. Replaced the engine harness. Found that the coil wire melted into other wires. You will probably need to pull the engine harness and cut it open to see the damage. Not that hard to do.
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Old Yella
post Aug 31 2014, 03:34 PM
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Did you check the fuse in the engine compartment before you pull the whole friggin car apart.

QUOTE(bdstone914 @ Aug 31 2014, 02:04 PM) *

QUOTE(914bub @ Aug 31 2014, 01:24 PM) *

QUOTE(bdstone914 @ Aug 31 2014, 12:57 PM) *

QUOTE(914bub @ Aug 31 2014, 12:39 PM) *

QUOTE(Bartlett 914 @ Aug 31 2014, 12:34 PM) *

The fuel pump will only run for a few seconds after turning the key. Once the car starts, the pump will run continuously


Thanks. Is the ECU in fact grounding the pump as opposed to it energizing the fuel pump relay?

I've also been told that every car, (no matter the make), that has D jet injection uses the same ecu? Do you know if that's true? I have an ECU out of a D jet injected 72 Volvo. I haven't checked any part numbers yet. Thanks for the input.


Not all d jet cars do not use the same ecu.
Pull the fuel pump relay. Turn the ignition on.
Plug in the fuel pump relay. You should hear it click. If you have power and no click the relay could be bad. Pull the cover off the relay. Plug in relay and push down on the points. The fuel pump should run briefly. Swap it with a headlight relay which is behind the plastic cover in the front trunk. Try the fuel pump relay in the headlight. Check the fuse on the relay board for the fuel pump. Clean the fuse contacts.
If you plugged on the 12 pin connector one pin off and turned on the ignition you would typically fry the coil wire. If it runs on starter fluid it is probably ok.


I did fry to coil wire,just haven't replaced it yet. When I close the contacts manually on the relay I still get no fuel pump. If I could determine weather the ecu supplied ground or fired up the fuel pump relay I could at least know which I should have full time at the pump. Right now I think I have neither.

Thanks for the ecu info. Good to know.



You may have fried more than the coil wire. Friend of mine did the same thing connecting the 12 pin wrong. We spliced a wire from the board to the coil and still would not start. Replaced the engine harness. Found that the coil wire melted into other wires. You will probably need to pull the engine harness and cut it open to see the damage. Not that hard to do.

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914bub
post Aug 31 2014, 05:48 PM
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Yeah, I checked both fuses on the relay board. They are both good. I'm still wondering weather the ECU provides ground to the pump or activates the relay? If it does supply ground what does activate the relay? Ignition switch?

I also assume I should hear/feel the injectors ticking when I crank it?

Thanks for the all in input so far.
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Dave_Darling
post Aug 31 2014, 10:18 PM
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The fuel pump is grounded full time. The ECU grounds one of the pins of the fuel pump relay, which then sends power to the pump.

--DD
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914bub
post Aug 31 2014, 10:32 PM
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QUOTE(Dave_Darling @ Aug 31 2014, 09:18 PM) *

The fuel pump is grounded full time. The ECU grounds one of the pins of the fuel pump relay, which then sends power to the pump.

--DD


Dave
Thank you. I should be able to move forward from here. I'm embarrassed to admit that i'm an ASE master tech and that we screwed up in our haste. I'm gonna dig into it tomorrow....
Thanks, Erik
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Tom
post Sep 1 2014, 08:26 AM
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Hooking the 12 pin up one set of contacts off will put 12 Volts switched to the tach wire and coil negative. Whenever the key is turned to on, if the points are closed, well, smoke will escape. It may not have been your father's error after all! Should be tach wire (black/purple) and dizzy (green)to 1, positive (black) to 15. Melting a wire in a harness like this will damage other wires in the harness. Not hard at all to replace/repair the bad wires.
The ECU provides a negative to the fuel pump when ever one of three conditions are met.
1- when key is turned to on - pump will run 1-2 seconds,
2- whenever the starter is turning engine over
3- whenever the engine is running over XXX RPM's
There is a link on this site to Brad Anders D-jet info. look under 914 info at the top of the page. As an ASE master tech, you will probably understand a lot of it.
Tom
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MikeM
post Sep 1 2014, 09:14 AM
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FYI....I have never heard any injectors clicking on my 74 with Djet, and the car fires up instantly.
Mike
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914bub
post Sep 1 2014, 09:07 PM
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Can anybody tell me which pin the ground signal,(for the fuel pump relay) from the ecu is supposed to be coming in to the fuse board on? I have the picture of the fuse board diagram but when I enlarge it enough to make the letters big enough to read they are too blurry.

I also tried to look at the flow charts on Brad Anders site but it will only show the initial page and I can't go to any of the actual diagrams.

Thanks,Bub
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Dave_Darling
post Sep 2 2014, 04:14 PM
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Four-pin connector (T-IV), front-left pin (III). When that is grounded, the pump should run--assuming the rest of the stuff is correct.

--DD
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