Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

 
 Reply to this topicStart new topic
> power to fuel pump, for carbs
rmital
post Jul 2 2012, 11:34 AM
Post #1


Northeast optimist
***

Group: Members
Posts: 1,947
Joined: 12-December 05
From: Park Ridge, NJ
Member No.: 5,268
why would I get power to the "Last resort unfused private swiched +12v" connection, but nothing at the "Pin 12 - Connector T12"?

I wrapped a wire around the pin designated by Andy's description and circled in yellow. Reinstalled the pin in the plastic connector and plugged it back in the relay board.
started the car and check the newly installed wire with volt meter and got nothin'.

....anything simple I should consider? (IMG:style_emoticons/default/confused24.gif)


Attached image(s)
Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
markb
post Jul 2 2012, 11:56 AM
Post #2


914less :(
*****

Group: Members
Posts: 5,449
Joined: 22-January 03
From: Nipomo, CA
Member No.: 180
Region Association: Central California
Why not just use the stock wiring? I did for my carbed 1.7, and it worked fine.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
rmital
post Jul 2 2012, 12:10 PM
Post #3


Northeast optimist
***

Group: Members
Posts: 1,947
Joined: 12-December 05
From: Park Ridge, NJ
Member No.: 5,268
QUOTE(markb @ Jul 2 2012, 01:56 PM) *

Why not just use the stock wiring? I did for my carbed 1.7, and it worked fine.

...first thing I tried...nothing there either....so I went to the other options without much investigation.

If no simple/quick fix and I have to trouble shoot, I'll just start there again and hopefully find the problem....or maybe they are related?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
r_towle
post Jul 2 2012, 12:19 PM
Post #4


Custom Member
***************

Group: Members
Posts: 24,574
Joined: 9-January 03
From: Taxachusetts
Member No.: 124
Region Association: North East States
try a different relay board.

rich
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
rmital
post Jul 2 2012, 12:41 PM
Post #5


Northeast optimist
***

Group: Members
Posts: 1,947
Joined: 12-December 05
From: Park Ridge, NJ
Member No.: 5,268
QUOTE(r_towle @ Jul 2 2012, 02:19 PM) *

try a different relay board.

rich

the one I'm using is in pretty tip top condition....one of the best ones off my shelf.
...I'm not to happy with the harness...but like I said, getting 12+v to the last resort connection.... (IMG:style_emoticons/default/confused24.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Tom
post Jul 2 2012, 01:04 PM
Post #6


Advanced Member
****

Group: Members
Posts: 2,139
Joined: 21-August 05
From: Port Orchard, WA 98367
Member No.: 4,626
Region Association: None
rmital,
Because the ECU is not being used the fuel pump relay doesn't have a ground signal to pin 86 and will not operate. You can wire a ground from the 4 pin connector pin #3 to a ground point and it will allow the fuel pump relay to operate.
Then you will have 12 volts at pin #12 of the 12 pin and pin #13 of the 14 pin.
Power for the "last resort 12 volts switched" comes from pin #87 of the power relay, seperate circuits.
Tom
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
rmital
post Jul 2 2012, 01:09 PM
Post #7


Northeast optimist
***

Group: Members
Posts: 1,947
Joined: 12-December 05
From: Park Ridge, NJ
Member No.: 5,268
QUOTE(Tom @ Jul 2 2012, 03:04 PM) *

rmital,
Because the ECU is not being used the fuel pump relay doesn't have a ground signal to pin 86 and will not operate. You can wire from the 4 pin connector pin #3 and it will allow the fuel pump relay to operate.
Then you will have 12 volts at pin #12 of the 12 pin and pin #13 of the 14 pin.
Power for the "last resort 12 volts switched" comes from pin #87 of the power relay, seperate circuits.
Tom

...I did this step depicted below:


Attached image(s)
Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
rmital
post Jul 2 2012, 01:12 PM
Post #8


Northeast optimist
***

Group: Members
Posts: 1,947
Joined: 12-December 05
From: Park Ridge, NJ
Member No.: 5,268
QUOTE(rmital @ Jul 2 2012, 03:09 PM) *

QUOTE(Tom @ Jul 2 2012, 03:04 PM) *

rmital,
Because the ECU is not being used the fuel pump relay doesn't have a ground signal to pin 86 and will not operate. You can wire from the 4 pin connector pin #3 and it will allow the fuel pump relay to operate.
Then you will have 12 volts at pin #12 of the 12 pin and pin #13 of the 14 pin.
Power for the "last resort 12 volts switched" comes from pin #87 of the power relay, seperate circuits.
Tom

...I did this step depicted below:

I do question that one green wire loose on the 14 pin connection. should that be done?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
ape914
post Jul 2 2012, 01:15 PM
Post #9


red locktite
**

Group: Retired Members
Posts: 240
Joined: 7-February 11
From: In front of a computer
Member No.: 12,676
Region Association: None
what are you trying to do? What is the "Last resort unfused private switched +12v" that you want access to? I dont understand the term "private switched" in regards to the 914 electrical system.

i dont understand what your trying to do by "replying to power to the fuel pump". The fuel pump needs no reply to its power. the pump simply needs 12 volts positive and negative to run. There is no reply to power or any signal feedback from the pump.

more data please.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
rmital
post Jul 2 2012, 01:18 PM
Post #10


Northeast optimist
***

Group: Members
Posts: 1,947
Joined: 12-December 05
From: Park Ridge, NJ
Member No.: 5,268
QUOTE(ape914 @ Jul 2 2012, 03:15 PM) *

what are you trying to do? What is the "Last resort unfused private switched +12v" that you want access to? I dont understand the term "private switched" in regards to the 914 electrical system.

i dont understand what your trying to do by "replying to power to the fuel pump". The fuel pump needs no reply to its power. the pump simply needs 12 volts positive and negative to run. There is no reply to power or any signal feedback from the pump.

more data please.

following the procedure on this site:
LINK
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
SirAndy
post Jul 2 2012, 01:29 PM
Post #11


Resident German
*************************

Group: Admin
Posts: 41,636
Joined: 21-January 03
From: Oakland, Kalifornia
Member No.: 179
Region Association: Northern California
I'm not sure i understand your problem. With the procedure outlined in my how-to, there is no need for anything but ONE wire on the now empty FI connector to GROUND.

This will give you 12V on the stock fuel pump connector right next to where the stock FI fuel pump used to be.

No other wires needed. No need to fiddle with any of the other plugs on the relay board. Nothing. Nada. Zilch.

(IMG:style_emoticons/default/confused24.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Tom
post Jul 2 2012, 01:37 PM
Post #12


Advanced Member
****

Group: Members
Posts: 2,139
Joined: 21-August 05
From: Port Orchard, WA 98367
Member No.: 4,626
Region Association: None
That should work. Maybe try replacing the fuel pump realy or at least test it to make sure it is working. Spread the male pins slightly to ensure good contact in the socket.
The green wire is for the heater fan. Should be pin 11 in the 12 pin conn.
Tom
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
rmital
post Jul 2 2012, 01:41 PM
Post #13


Northeast optimist
***

Group: Members
Posts: 1,947
Joined: 12-December 05
From: Park Ridge, NJ
Member No.: 5,268
QUOTE(SirAndy @ Jul 2 2012, 03:29 PM) *

......
No other wires needed. No need to fiddle with any of the other plugs on the relay board. Nothing. Nada. Zilch.

(IMG:style_emoticons/default/confused24.gif)

I figured as much....just didn't work out for me. I must have an issue with the harness somewhere....that why I tried the other options (points on the relay board) layed out in your article.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
SirAndy
post Jul 2 2012, 01:58 PM
Post #14


Resident German
*************************

Group: Admin
Posts: 41,636
Joined: 21-January 03
From: Oakland, Kalifornia
Member No.: 179
Region Association: Northern California
QUOTE(Tom @ Jul 2 2012, 12:37 PM) *
The green wire is for the heater fan. Should be pin 11 in the 12 pin conn.

Ignore the green wire in my picture. I had mixed matched years main harness and engine (D-Jet) harness at the time.
The green wire has no effect on the fuel-pump circuit.

(IMG:style_emoticons/default/shades.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
anderssj
post Jul 2 2012, 02:48 PM
Post #15


Dog is my copilot...
***

Group: Members
Posts: 1,656
Joined: 28-January 03
From: VA
Member No.: 207
Region Association: MidAtlantic Region
Just a thought--check that the 2 fuses on the board are good (use a volt/ohm meter). I can't remember which one is linked to the fuel pump, but I've found that if the heater blower doesn't work, chances are the fuel pump won't either . . . .

Hope this helps!

Steve A-
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
rmital
post Jul 2 2012, 03:01 PM
Post #16


Northeast optimist
***

Group: Members
Posts: 1,947
Joined: 12-December 05
From: Park Ridge, NJ
Member No.: 5,268
QUOTE(anderssj @ Jul 2 2012, 04:48 PM) *

Just a thought--check that the 2 fuses on the board are good (use a volt/ohm meter). I can't remember which one is linked to the fuel pump, but I've found that if the heater blower doesn't work, chances are the fuel pump won't either . . . .

Hope this helps!

Steve A-

yes...thanks. replaced them with new ones.

was really hoping this would have been easy....for a change.... (IMG:style_emoticons/default/huh.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
r_towle
post Jul 2 2012, 04:09 PM
Post #17


Custom Member
***************

Group: Members
Posts: 24,574
Joined: 9-January 03
From: Taxachusetts
Member No.: 124
Region Association: North East States
I just added that one wire, done
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
« Next Oldest · 914World Garage · Next Newest »
 

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 

Display Mode: Standard · Switch to: Linear+ · Switch to: Outline

Track this topic · Email this topic · Print this topic · Subscribe to this forum

- Lo-Fi Version Time is now: 14th May 2024 - 05:01 PM
Invision Power Board v9.1.4 © 2024  IPS, Inc.
All rights reserved 914World.com © since 2002
914World.com is the fastest growing online 914 community!
We have it all, classifieds, events, forums, vendors, parts, autocross, racing, technical articles, events calendar, newsletter, restoration, gallery, archives, history and more for your Porsche 914 ...