'07 LC cranks but won't start after fuel pump replacement

B

BB3551

Joined
Nov 24, 2021
Messages
4
Location
North Texas
First of all, just wanted to say thank you to everyone who's contributed to the great content on here. I've been a lurker for years, but haven't needed to post until now.

I'm the proud owner of a 2007 LC with ~263k miles. Today, I decided to proactively replace the fuel pump with the Denso 950-0210 kit. No issues removing the old one, and both pumps were identical. I dropped the new one into the plastic cage, connected the small power plug that goes directly into the pump, connected the rubber hose, and put the entire assembly back into the tank (making sure to position it so that the sender float moves freely). I then connected the main larger power plug and two fuel lines at the top.

I reconnected the negative battery terminal and attempted to start it--the first red flag was that I couldn't hear the new pump priming. Tried cranking 5-6 times, but it wouldn't start. I used my OBD2 reader and there were no codes.

Some info that might be helpful:
- Immediately after the starter stops trying to crank, there's a buzzing sound for 1-2 seconds (I believe this is the fuel pump--so good to know that it's not entirely dead/faulty).
- During removal of the old pump, I did the following to remove pressure from the lines: Unplug the main electrical connection at the top of the pump and attempt to start the engine several times until it no longer gets fuel. Didn't touch any fuses, relays, etc. (I suspect this was not the right way to do it...)
- Had to reuse the old fuel pump filter sock since my new one didn't fit
- Did not use the small O-ring that came with the new Denso pump because there was no O-ring on the old setup. I've heard that this part is important, but don't see why its absence would cause my new pump to act like it's not getting power.
- Just put my battery on the tender to make sure everything's getting full power

What have I done, folks?
 
fjc-man

fjc-man

SILVER Star
Joined
Mar 21, 2014
Messages
1,143
Location
Commerce City, Colorado
Where the pump discharge line connects to the pump it has to have an o-ring. The picture is of my FJ Cruiser oem pump, I’m pretty sure yours is real similar or the same. Otherwise there won’t be sufficient fuel ring pressure.

7E29AD7E 91D4 4C86 B9F2 EC427876A5BE


20FCAC7C D43C 44C0 8FE9 CAC7118B3D85
 
OEMGUY0720

OEMGUY0720

“Der liebe Gott steckt im detail”
SILVER Star
Joined
May 20, 2019
Messages
1,647
Location
Las Vegas
Did you by chance transferred the rubber o-ring seal from the old to the new fuel pump?
430A45A3 BBDE 4305 A97A D4E7A6806811
 
B

BB3551

Joined
Nov 24, 2021
Messages
4
Location
North Texas
I didn't notice any rubber O-ring on the old pump to transfer to the new pump. I did receive a new O-ring with the Denso kit, but didn't install it. I'll try that in the morning.

Any chance that my fuel pump relay or EFI relay went bad during this install? Is there a way to bypass those and force power to the respective systems?

Thanks for the quick replies.
 
jerryb

jerryb

Supporting Vendor
Joined
Jul 30, 2016
Messages
2,555
Location
pensacola fl.
it should run without the oring. But it needs to be installed. it prevents backflow on the pressure line-- on paper. ha.
you can't hear the fuel pump at all with the engine running or during cranking and it doesn't run with the key turned to the first click.
You can use techstream to make it run, then you can hear it, without the engine running.

fuses
correct key - security light goes out
battery terminals, adequate voltage, load accessories off.
yellow fuel line clips on top of the pump cover plate
cranking voltage at the connector at the same plate
park or neutral.
 

Users who are viewing this thread

Top Bottom