I've been a diehard bmw guy for a long time and finally decided that I had to own a 242 before at some point in my life so this summer I bought a 1976. Now up untill this point I have had had mixed experiances with volvos, I've always loved them and they have always hated me. I'm not kidding,EVERY time I rode in my friends' otherwise trusty car it would break down and we would end with a long walk. Well, the curse has followed me.

So, the current reason I'm taking the bus to work is that my fuel pumps are acting up. I've replaced both the main and in tank (the main twice) and the car still hesitates badly and fails to run smoothly. The symptoms corrispond to the sound the main pump continues to make, a dry running sound as if it is picking up air bubbles and though intermitant the same sound it made when the intank had totally failed.

Like I said both pumps are new and there doesn't seem to be any other obstruction or bad electrical, they're just not always putting out enough fuel. Could this accually be a symptom of a bad accumulator???

Anyway, I like the car and hope one day we could come to a mutual understanding but as it stands I may soon find myself driving a trusty old BMW soon with fond memories of that summer I had a slick volvo parked in my driveway.

I greatly appreciate any help that can be offered.

 

When you did the in-tank did you check the rubber hose from the pump motor to the metal tube for cracks?
They crack and air gets in the line.
Worse with low fuel in the tank?

 

Yes I did and there didn't seem to be anything wrong. I'm double checking everything and will go over it again. Any other ideas?

Thanks for the help.

 

Did you replace the fuel filter?

 

I doubt that the accumulator is the cause of your problem.
The accumulator is there simply to keep the fuel system pressurized on the K-Jet injection system, (which I'm assuming you have being it's a 76 model).

The K-Jet is a (CI) continuous injection system, and the (4) main fuel injectors are entirely mechanical (spring closed) and open on pressure alone.....unlike the later models engines with Jetronic injection that have solenoid operated injectors.

The accumulator consists of a spring opposed diaphram, and stores pressure so that the(1) solenoid operated cold start injectorcan inject fuel immediately upon cranking the engine.
This stored pressure is lower than the pressure required to open the (4)main fuel injectors.

If the accumulator is bad, the fuel injection system won'tstore any standing pressure, and it will take a lot longer when cranking for the system to inject fuel into the intake.
This causes a lot of grinding on the starter before the engine will crank.

If any of the injectors leak (cold start included) this will also cause hardstarting, as the fuel pressure will leak down over a period of minutes (or hours) depending on how bad the leak down is.

So....if the accumulator is bad, it will take longer to start...but...the engine will run OK after the system reaches operating pressure.

I would check the fuel pressure with the engine running.
If you don't have the required gage and attachments, you can buy it, or make your own (as I did).

Fuel pressure is critical on the K-Jet system.

Another poster mentioned the fuel filter.
That's a good thing to check, as it can cause your symptoms if it is clogged, or if there is water in the system.

Also check for any vacuum leaks on the intake mainfold (including the boot connection between the intake and the fuel body (damper).
This also will cause problems similiar to yours.

Hope this helps
steve

 

I had a similar problem with a 740, but that was because the In Tank pump was not grounded. Double check the ground and make sure your grounded.