ticking on injector rail

hi all
940 2.3 lpt 1996 auto.
the same noise as when we got car a year ago. when at normal temp there is a distinct dull tapping noise come from the fuel supply rail after its been to the injectors. its not there when cold and does not affect car in any way but is annoying me ! any one had similer noise. we got 125000 on clock. thanks.

[dgordo]

Hi Martin,
We've got a '96 945 l.p.t. & I became aware of a "knocking" sound from under the front passenger side of the car when we got it about a year ago.After some investigating it turned out to be nothing more than the sound of fuel "pulsating" through the system;from the tank to the motor & back again.I agree that it can be annoying but after reading through the post's on this subject at this site I decided the best advice was from George who simply said .. "live with it."
I suppose it may be possible top cushoin the fuel line at some point(s) to reduce or even remove the noise.Our car didn't make this noise at all when we got it,only a month or so after so thy weren't like it from knew,just one of those quirks.
Just out of interest; do you have 2 fuel pumps or 1?We've got 1.Our's is of the in tank type [those with 2 have another next to the fuel filter under the front passenger side].
By the way, our car's done about 87000 mls [& hope to match your milage,& alot more, before having to contemplate renewing the in tank fuel pump].
All the best,
Dave.

[migrator]

I've not come across a Volvo that only has an in-tank fuel pump. Are you sure that there is not one (roughly) under the nearside rear passanger footwell?

The extra pulsing and pumping noise is often associated with an overworked main fuel pump when the in-tank pump has failed for some reason.

[Peter Milnes]

Or the bracket rubber mountings may have been distorted by some previous owner allowing the bracket to touch the chassis.

The only reason that you could possibly only have an in-tank fuel pump is that you have the Rex/Regina system for fuel/ignition. I would be inclined to check this as I do not think that 940s had this fitted.

All the best, Peter

[dgordo]

Yes your're both right.Most 940's do have the 2 fuel pumps and noisy fuel supply can be a sign of overworked main pump [especially if it's getting hot]or, indeed, that the support brackets are in some way not properly mounted.
However, when I looked for an in line pump I simply could't find it!I phoned a 'volvo man' for advice & he insisted that I do have one - but it isn't there.
Finally, I was relieved to read on a post that later model 940's only have 1 pump & it's a Bosch system.If that's true then I suppose that's what I got-unless I'm missing something.
Therefore, I guess Martin, perhaps you should check the fuel pumps:
for the in-tank pump run the engine with the fuel cap off,put your ear over it & you should be able to hear it whirring nicely. If not;maybeit could be faulty.The main pump may be under the car close to the fuel filter & I suppose check it's electrical connections,moutings & feel if it gets hot.
Please keep in mind that the information I have gleaned was from a haynes book & this forum about a year ago & I am still very much on the learning curve myself.
If you ever discover the cause & solution please do letus know!
Regards,
Dave.

[Peter Milnes]

Just to confirm the position regarding pumps. The 1994 model year cars had two pumps for LH 2.4 system and one pump if Rex/Regina sytem used. 1995 model year onwards had one pump only fitted in fuel tank and was LH 2.4 system. The in-tank pump on the one pump systems was a more powerful version of the one used in two pump systems.

All the best, Peter