Fuel Pressure problem

larryh · Post by **larryh** » 22 Feb 2007, 18:38

right on mij!

greasefingerss · Post by **greasefingerss** » 22 Feb 2007, 20:29

If the engine backfires each time before it dies, then my experience with this is fuel delivery. So either it is being cut off for some external reason (like MIJ suggested

carl · Post by **carl** » 27 Apr 2007, 14:30

Below is my original posting I am about to attempt to replace the fuel pump on my 850 series this weekend....I need your help what direction will I be turning to take off the plastic retainer? Also what tool would you guys recommend to take it off? And last question does the wiring on top come off?

Please help! Thanks

I am planning on replacing a fuel pump on a 1993 850 series volvo, I am pretty handy with doing mechanic work that isn't a problem but, i have never replaced a fuel pump before. Can anyone tell me before I tackle this project what tools are needed? And what will I be encountering?

Thanks for your replies...

Post by **Ozark Lee** » 27 Apr 2007, 17:49

I am planning on replacing a fuel pump on a 1993 850 series volvo, I am pretty handy with doing mechanic work that isn't a problem but, i have never replaced a fuel pump before. Can anyone tell me before I tackle this project what tools are needed? And what will I be encountering?

Thanks for your replies...

As the thread you bumped shows, it is kind of a "run what ya brung" project. Be nimble and dig deep into the tool chest. I've used a big hurkin pair of Channel Lock pliers, an oil filter wrench, and the hammer and a screwdriver to do the tap method on various other cars. It largely depends on what tool you have and how much clearance you have to get the tool in place.

As far as what you will be encountering:

The plastic fuel line "quick release" clips can be a challenge. The two screwdriver method seems to work. Release the fuel pressure first so that you don't spray yourself with gasoline and also so that you don't fight the fuel pressure working against you on the quick release connector. Just relieve it at the schrader valve at the end of the fuel rail.

Are you replacing with an OEM pump or a Walbro or other aftermarket pump? You need to fit the lines into the assembly if it isn't an OEM.

Clean the pickup screen at the bottom of the assembly.

You are asking the correct questions. Be patient and it will go fine for you.

...Lee

indnajns · Post by **indnajns** » 30 Apr 2007, 17:51

Not to change the subject, but what type of documentation did the nifty pictures and text come from and where does one get such?

Post by **Ozark Lee** » 30 Apr 2007, 19:02

Not to change the subject, but what type of documentation did the nifty pictures and text come from and where does one get such?

VADIS

It depends on where you are, the Brits seem to get a better deal than us USA guys for a stolen copy, but eBay will get it for you every time.

The learning curve for the software is steep and unintuitive but there is a lot of information there.

...Lee

Tornado Bait · Post by **Tornado Bait** » 06 Oct 2007, 11:41

1994 850T with about 1/4 million miles. I was experiencing long cranking time before start, sluggish response and random loss of power at constant speeds. Finally it just quit leaving my oldest daughter stranded. After towing it home I diagnosed the problem by checking fuel pressure at the fuel rail; none. I then checked voltage at the fuel pump power connector in the trunk; none. After I pulled the relay #103 as mentioned in another thread I re-soldered some connections which restored power to the pump, but still no fuel delivery.

Now if you've read this far in the thread you already know how to remove the pump assembly as shown earlier. Here is how to save yourself some money and disassemble the assembly to get at the pump motor. In the first 3 pics you'll note the steel tubing above the hose is shiny. That's how it was when I removed the assembly from the tank. Over time the hose shrank pulling itself and the clamp to the end of the tubing. Upon further inspection I discoverd it was barely touching the end of the steel tubing. That could explain the slow starting and sluggish response due to lack of fuel pressure.

In this pic I lightly touched the hose and slid it to the side to better illistrate how the ends barely meet.

Here you'll see the inner motor housing removed from the main assembly. There are two ramp style clips on the motor housing that slot into the outer assembly sleeve. A little pressure from a small screwdriver is enough to release them.

The inside of the motor housing showing where the red (+) and black (-) leads connect.

The housing is like a clam shell with snap connectors holding both halves together. Once again a little pressure from a small screwdriver is enough to release them

Housing in two pieces exposing the motor.

I did get the motor to run by hooking it up to a motorcycle battery, but as soon as I let it stop it needed a tap get it going again. So now I wait for my new bosh pump motor to arrive Monday. I've already cut a length of fuel hose to ensure that it goes all the way to the top of the steel tubing. This time even if it shrinks there should be plenty of overlap for the next 1/4 million miles.