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-   -   Hot Wire/Jump a fuel pump? (https://www.toyota-4runner.org/3rd-gen-t4rs/308752-hot-wire-jump-fuel-pump.html)

aa010175 01-01-2023 12:38 AM
Hot Wire/Jump a fuel pump?
 
I have fuel leakage from the injectors to the fuel railings. 4 or 5 of them are leaking. I would like to replace the bad O-rings and then test out the fuel railings and pressure prior to putting the whole upper engine back together and again finding out it’s still leaking. Is there anyway to activate the fuel pump without the engine running? Thanks Dave

rcvxl24 01-01-2023 02:44 AM
Quote:
Originally Posted by aa010175 (Post 3777235)
I have fuel leakage from the injectors to the fuel railings. 4 or 5 of them are leaking. I would like to replace the bad O-rings and then test out the fuel railings and pressure prior to putting the whole upper engine back together and again finding out it’s still leaking. Is there anyway to activate the fuel pump without the engine running? Thanks Dave

Yes, if you have an extra battery laying around (car, lawnmower, etc) you can hook the leads up to the fuel pump and jump it.


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gamefreakgc 01-01-2023 08:28 PM
There is a way from the diagnostic port but it has been a very long time since I have done it on a Toyota. +B is the fuel pump power wire you just have to ground it and I don't know which is the diagnostic port ground. Be sure to have some spare fuses on hand as if you get it wrong the fuse will blow.

aa010175 01-01-2023 08:57 PM
Do you mean the test port that it’s under the hood? I found B+. Are saying to just ground it out and the fuel pump will run? Thanks Dave

gamefreakgc 01-01-2023 09:34 PM
Quote:
Originally Posted by aa010175 (Post 3777344)
Do you mean the test port that it’s under the hood? I found B+. Are saying to just ground it out and the fuel pump will run? Thanks Dave
Yes the Test/Diagnostic port under the hood. I just don't remember which is ground. You'll hear it run if it works. Like I said though, don't strand yourself and make sure you have replacement fuses. E2 used to be the ground on old Toyotas but I didn't see one labelled as such last I checked. You'll ground it by running a paper clip or small section of wire from +B to the ground wire on the diagnostic port. I suppose you could try just connecting it to the ground right there on the side of the intake and see if that does it.

Once you have the correct ground turn the key to "On" but don't start the engine. You should hear the pump run if it works.

aa010175 01-01-2023 09:47 PM
Quote:
Originally Posted by gamefreakgc (Post 3777350)
Yes the Test/Diagnostic port under the hood. I just don't remember which is ground. You'll hear it run if it works. Like I said though, don't strand yourself and make sure you have replacement fuses. E2 used to be the ground on old Toyotas but I didn't see one labelled as such last I checked. You'll ground it by running a paper clip or small section of wire from +B to the ground wire on the diagnostic port. I suppose you could try just connecting it to the ground right there on the side of the intake and see if that does it.

Once you have the correct ground turn the key to "On" but don't start the engine. You should hear the pump run if it works.
Thanks so much for the information. I will give it a try and report back. Dave

aa010175 01-01-2023 11:24 PM
1 Attachment(s)
Here’s the photo I found to use’s.

gamefreakgc 01-03-2023 03:20 PM
Quote:
Originally Posted by aa010175 (Post 3777371)
Here’s the photo I found to use’s.
Did jumping those terminals work? Toyota must have changed their diagnostic procedures at some point.

phattyduck 01-03-2023 05:53 PM
On OBD-I Toyotas, jumpering Fp and B+ in the diagnostic port (same connector still used on the gen3 4Runner on the intake manifold) would power the fuel pump with the key ON. I'm not sure if the connections are still there in the connector on the 4Runner. Otherwise the fuel pump will only be powered with the key in START or the engine is actually running.

-Charlie

loneshepherd 04-16-2023 07:01 PM
1 Attachment(s)
Did that work? my 97 5VZ 4R doesn't have a pin to use in the Fp slot.


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