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It is time to change the under car (under driver's seat) main fuel pump and filter.
There is a device connected to the fuel pump that I believe evens out any pulses in the fuel delivery. I changed one of these fuel pumps back in 2011 on another 1994 940 and can't remember the proper name of it so can't find the part no. The one I would like to replace is quite rusty and replacing it now when the fuel pump assembly is out of the car seems like a good time to do it.
Also, I would like to order a replacement line from the pump to filter, the short line maybe 6 inches long with the two sealing washers on one end but again, I don't know the proper name.
Can someone help an old Volvo driver/backyard mechanic? Thanks!
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Mine:3-940s running; 1-740, 2-940 parts; dtrs:4-940s running
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I'm curious why a new fuel pump
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89 240 wagon, 94 940, 300K, 94 940, 141K
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I want to replace the under-car fuel pump and filter in my daughter's car just because it has 173K miles on it and I don't want her to get stalled. She hasn't started driving it this year yet (it is her summer 940 here in MN).
I have to find out a replacement fuel line (replaces the pulse dampner) between the green steel line and the under-car fuel pump that would handle the fuel pressure. Pressure would be the output of the pre-pump in tank and the inlet of the under-car pump.
The green steel line and under-car fuel pump diameter is .475" (inches).
Any idea on what the pressure is between the green steel line and the under-car fuel pump this replacement fuel line would see or is it a negative pressure and do I need a line that will take a negative pressure?
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Mine:3-940s running; 1-740, 2-940 parts; dtrs:4-940s running
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I recently replaced the original main pump on a 940t.
https://www.brickboard.com/RWD/volvo/1684379/main_pump_failure_307k.html
Be aware that the supply line from the tank will probably need to be plugged so that once it’s detached it doesn’t try to siphon the fuel from the tank onto the floor. Have a 12mm bolt ready to screw into the hose and a small clamp to insure the leakage is stopped.
On another 940t we have the pulse dampener you reference developed a leak due to rust. I simply removed it and used a piece of fuel hose to span the gag. The only difference I experienced was that the cranking time increased. I never used a pressure gauge to verify but my guess was that it somehow helped maintain pressure in the system while at rest. I try to remember to cycle the pumps once before actually engaging the starter when the car has been sitting for a period of time.
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Any twenty minute job is just a broken bolt away from a three day ordeal
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Dear jd620,
Hope you're well and stay so. The first device - #1389725 - is an "absorber". See: https://www.skandix.de/en/spare-parts/engine/fuel-mixture-formation/fuel-supply-system/fuellines-and-accessories/pulsation-dampener-fuel-supply-system/1048988/ .
I do not believe this part is still available from a U.S.-based Volvo dealer: it was not standard on 940s with the Bosch, two-pump system. It was used on some Volvo 740s.
As to the fuel pipe that connects filter to pump, that is #1312297. The two copper seals ("gaskets" in Volvoese) are #947621. Finally, the hollow bolt, through which fuel flows from pump to filter, is #968179. All of these should be available from a U.S.-based Volvo dealer.
Hope this helps.
Yours faithfully,
Spook
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The fuel line coupler end that goes to the filter also needs an insert for the Banjo bolt. Any idea what that would be called or it's part no.?
I have another 1974 940 that does not have the "absorber". I may try omitting the "absorber" to see if there is any difference in how the old car runs.
Once again, thanks for the help Spook. You have helped me a lot over the years.
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Mine:3-940s running; 1-740, 2-940 parts; dtrs:4-940s running
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You shouldn't need the fuel pressure pulse dampener (absorber) and can likely safely omit it. The fuel pressure regulator at the fuel rail should be able to cope with it. My understanding is that these absorbers were more important with carb'd systems where there was no similar FPR. If yours is a North American 940, someone may have installed it to try coping with a failing FPR. Europe (and elsewhere) continued to get carb'd engine variants for many years after they stopped in the North America market, some time around 1984 as I recall.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now
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Leave it out, the vast majority of these Vovlos never had one to begin with.
I theorized here that the fuel pulsation damper (FPD) was such a short lived application that it never found its way into drawings and/or diagrams.
The FPD sits between the in-tank pump and the main pump, meaning that it is on the low pressure side of the fuel system. The pulses caused by the injectors opening and closing are on the high pressure side and are close to a device that already should dampen the pulses by its nature of operation: the FPR.
I don't see how a carburetted engine would benefit from an FPD. The fuel is fed into a float chamber, which acts as a buffer. The float controls the input flow and the feed is often a mechanical pump operated by the camshaft (as e.g. on the B18/B20), which because of the rocker operated membrane would be a pulsed flow by default).
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Yes, I can't say as I could figure out why a carb'd engine would benefit from it. Like Randy says, if it lives between the in-tank pump and main pump then you have to wonder how much of a difference it makes up at the fuel rail past the main pump and main pressure regulator, let alone at the injectors? It strikes me as precious little difference. The only pulse I can imagine in the line prior to the main pump is when the pumps initially spin up with a slight suction created by the main pump and pressure created by the in-tank pump taking a split second to balance out at the beginning of cranking. Ahaa, I wonder if the fact that LH 2.4 runs the fuel pumps for a second when the key is first switched on in order to pressurize the fuel rail prior to cranking obviates any need for this little rust-prone device. Regina of course wouldn't need it as most if not all of those had a single in-tank pump.
[Edit] I just found a better engine fitment list for it (Volvo p/n 1389725, Bosch p/n 0280161037) on a European parts site in case this helps shed any light on it. The only engines available in North American were the B23E, B230F and B234F. Interestingly there were no fitments listed for 900s (Skandix was the only one I could find that lists it for 900s). I note that no turbos had it. In Europe, many of these would have been K-Jetronic. I don't believe any were carb'd, oops the B200K and B230K had carbs, so go figure (could be an error in the fitment list). Is this list mostly all low pressure injectors? At US$200 or more, it's not a cheap device. In other Volvo forums it was also a mystery device and deleted with no ill effects:
Volvo 744/745 (engine, production dates)
B 23E 1983/08 - 1984/07
B 200E 1987/01 - 1988/08
B 200F 1990/09 - 1992/08
B 200G 1985/08 - 1992/07
B 200K 1988/09 - 1990/08
B 204E 1987/09 - 1990/08
B 230A 1984/08 - 1986/07
B 230E 1984/08 - 1988/07
B 230F 1984/08 - 1992/07
B 230FB 1988/08 - 1990/07
B 230K 1986/08 - 1988/07
B 234F 1988/08 - 1992/08
[EDIT2] In Bentley (page 230-10) a "fuel pressure damper" is mentioned as a Volvo remedy to resolve complaints of fuel pump noise. This may well have been a device that was only installed in the field based on a TSB.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now
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I just had a look on the Skandix site for that Volvo part# and my eye fell on this remark in the additional info section which might explain a thing or two:
" "Service alternative". At some cars, this part has been retrofitted at the Rail-Intake line to reduce noise."
Aha, noise suppression...
Looking at the original German text it's subtly different and Google translates it more correctly to:
" "Service Alternative". Was used in some vehicles to reduce noise in the rail feed line."
Hmm, "used", instead of "retrofitted"... That's a subtle but important difference. If retrofitted is correct, then the FPD may be a device that a dealer would fit before delivery of a new car [edit] and which spook's remark "which suggests it was not factory-installed" seems to confirm.
It also makes me wonder what kind of noise it would have made without the FPD...
My 245 doesn't have one, and despite being a LH 2.4 with the pumps that prime at iginition switch on (which I wait for to finish), it still feels like it takes a tiny bit long to get started. But it always does and so did my previous 245. It's just the nature of the beast.
BTW, mine is a B200F, so engine capacity doesn't seem to be a factor.
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Dear Det. Dave Stevens,
Hope you're well and stay so! Volvo VADIS - a superseded dealer parts/service database - does not show this part for 1994 940s. This part shows up, e.g., in the parts diagram/list for a 1990 740. But in that diagram, this "absorber" sits in a box - all by itself - which suggests it was not factory-installed. Other parts in the diagram are shown relative to where they actually fit.
A '94 940's main pump has a "check valve". That maintains system pressure once the pumps shut-down. Thus, the "check valve" shortens the fuel pumps' "spin-up" time. When the check valve fails, it allows a slight drain of fuel away from the fuel rail. So, the engine may crank for a few "extra" seconds to build pressure.
In short, this part may have been intended to help smooth fuel flow when, for some reason, the pumps did not work consistently.
I'd simply do as rstarkie suggests: remove this "absorber" and bridge the gap with injection-rated fuel hose, properly clamped.
Hope this helps.
Yours faithfully,
Spook
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I’d give Voluparts a call and tell them what you’re looking for.
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