1999 S70 AWD fuel pump replacement

deano1 · Post by **deano1** » 17 Dec 2021, 04:34

Hey abscate
I noticed you just did a fuel pump on silver 99 awd s70... Welp! I have the same car with 121k original kms (75k mles) and looks like i have the same job staring at me.
A little back story,, I bought that s70 years ago in Sarnia Ont, from a gentleman that said he bought it from a dealer that took it in on trade from original owner with less than 100k kms.
Gave it to his son for a college car.
By the time i go it it was still immaculate looking but driving impression was different story. Yes, front to rear drive shaft was loaded thru ski hole. and I needed to buy a rebuilt one from "Colorado driveshaft"
Okay so i brought it back to serviceable condition and started driving it and was happy,,, but by this time the P2 chassis was in my fleet and i liked the p2 handling characteristics better, so when my Father in law took interest in the s70 well naturally I sold it to him.
So! just as many romcom's go, the FIL passed away shortly after taking delivery of beautiful low kms AWD s70 and I'm left wondering who was lucky enough to be mentioned in the will as new owner of this sweet ride.(pic me!)
And again as things go the s70 sits stationary for a couple years getting the odd drive around the block by a variety of family members all singing the praise's of sweet silver sedan and family Matriarch has yet to make a decision as fate of silver beauty.
Fast forward to last week? The s70 is finally up for grabs! Only now it no longer starts and gets diagnosed at friend of family garage as the dreaded FUEL PUMP and local garages all reject the project saying the "car is not worth it" or "we're to busy for a job like that".
So now it's mine, that beautiful silver s70 awd that i lusted after is now beached in my garage awaiting surgery.
What do you think? Cut the access port? or go whole hog and drop suspension?
I know dropping rear sub-frame is the proper way, but me being without access to a lift it makes cutting access port more desirable option.
Okay sorry this got a little long winded,,,I'm just procrastinating what i know has to happen.
Cheers

Post by **abscate** » 17 Dec 2021, 06:08

Without a lift, cutting the hole is probably best. The six bolts holding the subframe on bond to the Al in nasty climates, I used a 1500 ft lb nasty boy impact to get those out.

You might have a mess on top of the fuel tank if the car has sat, like rusted fuel lines and emission lines. You have to drop the tank to deal with those

Post by **scot850** » 17 Dec 2021, 12:40

If you have a decent sized garage, I did the fuel pumps as part of a sub-frame swap. Before you decide to tackle this, as you live in the rust belt of Canada, I would carefully check the rear sub-frame condition. Here in Calgary the sub-frame rust through and cracks usually near the rear frame bolts on the lower inner fender. I have seen several like mine here in Calgary at Pick and Pull all failed.

I did a how-to type thread on that process that I did in my garage with floor jack and axle stands. Access to a hoist is great if you can get that. Most repair shops shy away from it due to lack of info on how to do it. It is not too bad a job, but just a long one. If the fuel gauge is reading correctly, then only swap the pump on the passenger side. Some think there is one on the driver's side but it is just a pressure equaling transfer valve and not a pump.

The biggest issue is as abscate says, if the car has been sitting, there are a bunch of pipes on the top of the sub-frame and tank for the emission system that can rot out. They are NLA as abscate found out but he being the genius he is, found ways around that.

The hardest part is emptying the tank of fuel and getting those probably rusted sub-frame bolts out.

Neil.

deano1 · Post by **deano1** » 17 Dec 2021, 17:38

Scot, Is there a link to that thread?
There were reports that fuel gauge had failed about a year prior to fuel pump failure if that provides any clues? Apparently stopped working after driving over rough road construction.
I've yet to do a recon mission under the car yet.. But if i remember correctly this car is reasonably rust free under there. But i will update as the project moves forward.
Cheers

Post by **abscate** » 17 Dec 2021, 19:14

Some pictures and diagrams here

viewtopic.php?f=1&t=95586

Post by **scot850** » 18 Dec 2021, 16:16

This may help:

viewtopic.php?f=1&t=69287&hilit=V70R+fuel+system

Neil.

Post by **scot850** » 18 Dec 2021, 16:22

This may also help on the fuel system:

viewtopic.php?f=1&t=69887&p=366867&hili ... em#p366867

If you have lost the fuel gauge yo may have issues either with the wiring or the they level sensors. There are 2 sensors in the AWD fuel tanks, one in the fuel pump unit and one in the ejector on the LHS of the tank. The car averages the 2 levels and gives you the overall level in the fuel tank.

You may have critter issues with wiring but like abscate says, until you get into there you won't really know.

Neil.

deano1 · Post by **deano1** » 19 Dec 2021, 08:27

Had a little time yesterday and tried unsuccessfully to get power directly to pump with jumper at 87&15. swing and a miss. strike 1
Decided to spray fuel in pipe just ahead of etm and engine coughed to life briefly.. foul ball,, and strike 2
plugged in diagnostics with live data and it says "fuel pump relay OFF" with key in run position
Hmmm?
Checked resistance at fuel pump relay socket and get around 6 Ohms.. Strike 3 and done for the day.
cheers

deano1 · Post by **deano1** » 28 Dec 2021, 06:30

Hey
I've confirmed original in tank fuel pump is dead and doesn't seem like any amount of beating the tank with rubber mallet is bringing it back.
Now someone I was talking to the other day mentioned to me that I should just splice in an inline pump so as to not have to drop the tank... Any reason why this will not work?
Just fishing for options.
cheers

Post by **abscate** » 28 Dec 2021, 10:32

You have to splice it in upstream of the fuel Pressure regulator so that 50 psi is delivered to the fuel rail. That’s going to be problematic with an inline unit