Fuel pump bypass Switches

[scottfab]

So over the years I've experienced several fuel related issues mostly related to fuel pumps. Each time getting at the test pig tail for energizing the pumps to test them has been a pain.

Recently I had reason to believe I again had pressure problems and had to find the test pig tail and apply 12v to measure the pressure.
Well this time I installed a switch. No change that. I installed two switches to help with this issue.(turns out fuel was not the issue but now I have two helpful switches)

The first switch is wired between 12V and the "test pig tail" near the ECM.
The second actually goes from the FP2 fuse on the Auxiliary fuse box to a 12v source that is active with the ignition key. This second switch was an idea I had last year when the primary fuel pump stopped working. What I wanted to be able to do was kick in the secondary fuel pump to be able to drive home. Instead I had to get a flatbed out there and have it towed. How embarrassing.

Here is were I added the connector into the test pig tail.
http://zr1.net/forum/album.php?album...pictureid=1444


Here is the switch that goes to the "test pig tail":
http://zr1.net/forum/album.php?album...pictureid=1443


Here is the emergency bypass for the secondary fuel pump should the primary fail. (sorry the image is BIG. You have to scroll over to the right to see the switch and it's label)
http://zr1.net/forum/album.php?album...pictureid=1442


Now when/if the primary fuel pump fails I can reach over into the passenger side and pull the switch on.
I chose a pull type switch to keep accidental enabling from happening.


I noticed that I did not post a pic of the change I made on the schematic. Here it is. Note it is in the Section 8A manual as is shown by the page number.
[IMG][/IMG]

[scottfab]

Hmmm look at this. A new post that does not show up in the search for "New Posts".
Isn't that interesting.

[Pete]

I like the idea of the secondary pump switch.

Nice.
Pete

[Scrrem]

Now this is a cool idea. I need to find my pump test lead. Most of the ones I have seen, its sticking out of the wire loom near the ECM, but not mine. Maybe it got pulled out of the loom and back to the batterey, need to pull the battery and check.
Rich

[scottfab]

Originally Posted by Scrrem

Now this is a cool idea. I need to find my pump test lead. Most of the ones I have seen, its sticking out of the wire loom near the ECM, but not mine. Maybe it got pulled out of the loom and back to the batterey, need to pull the battery and check.
Rich

On a 90 it's between the battery and the engine. This is it with an added lead to go to the switch. Remember though this one only works with the ignition switched off because of how the 12v is routed through the FP1 relay. As the relay is engaged when the ignition key is turn on the 12v via the test lead is pulled away from the fuel pump.

[scorp508]

I realize this is 12 years old, but just wanted to say the knowledge is still helpful.

My primary pump left me stranded yesterday and I had to pull the C21 pin from the ECM to limp home on the secondary, but this gives me some ideas to implement.

[Subfixer]

I have one of the "emergency" harnesses that the Wazoo group makes. Plugs in between the tank and tank harness when needed. Switches primary pup power to the secondary pump.

Sent from my Pixel 4a (5G) using ZR-1 Net Registry mobile app

[Mystic ZR-1]

Originally Posted by Subfixer

I have one of the "emergency" harnesses that the Wazoo group makes. Plugs in between the tank and tank harness when needed. Switches primary pup power to the secondary pump.

Sent from my Pixel 4a (5G) using ZR-1 Net Registry mobile app

Makes a great troubleshooting tool too....

[scorp508]

Originally Posted by Subfixer

I have one of the "emergency" harnesses that the Wazoo group makes. Plugs in between the tank and tank harness when needed. Switches primary pup power to the secondary pump.

Anyone still have one, or know who in the WAZOO (see what I did there) to reach out to? I wouldn't mind throwing a few bucks their way. I'd rather muck with a switch on the side of the road than de-pinning my ECM.

[AndrewL]

Originally Posted by scorp508

Anyone still have one, or know who in the WAZOO (see what I did there) to reach out to? I wouldn't mind throwing a few bucks their way. I'd rather muck with a switch on the side of the road than de-pinning my ECM.

This thread is by the gentleman I bought my bypass harness from:

https://www.zr1.net/forum/showthread.php?t=25149