940 Turbo wagon has encountered starting issues. When it began it was simple difficult-multi attempt start ups. Some time later it had to be bribed with ether (starting fluid) straight down the intake on the R side of the engine before it would start. A week or so of that and it is now refusing to start! The car owes me very little since it runs like a champ 99% of the time I have had it. A dealer overhauled the top end of the engine at +/- 180k. I suspect that one of the fuel pumps might be at the center of my current pickle. Any input will be appreciated. Thanks!

Thanks Mr.Spook,
I will seek out said relays. I've been dealing with these Swedish/Bosch relays off and on for years. Just not in the last eight or ten years. The "rollover" relay port you describe was a popular place to trick the fuel pump into running on the Saabs. I don't remember why it was necessary.
Does this car have two fuel pumps? I seem to remember an in-tank pump as well as another in line pump somewhere between the tank and the injector system. Another problem is not having "known working" components in hand. I may have some injector relays in a box left over from a 240 but who knows if they are compatible or even a matching component?

Barrelhouse

You can always temporarily jumper around or manually close the contacts on a relay for testing.

The 1993 940 with Bosch fuel injection (some NA, all turbo) will have a small lift pump in the tank and main pump about under the driver's seat. The main pump live a long happy life normally...most seem to go over 300K miles...though there is anecdotal evidence that this can be shortenned considerably when running for long period of time with a non-functional tank pump (easy to do and not realize it if you always keep the tank over 1/4 full).

Most of the green books with full, overly-comprehensive schematics are online at someplace (used to be kjet.org) if you end up needing them.

One thing not mentioned is the partial melting of the socket on the relay tray...if the relay is really hard to get out and shows signs of scorching around the large lugs, that is a potential cause but much less likely than a bad relay cold solder joint.

Thanks for the input. I discovered this to be the problem after beating on the fuel tank and the car promptly starting. I had an in tank fuel pump fail on a Saab many years back and ended up changing it out myself due to rural location and limited access to my usual service guy.
In that car, it was a matter of simply pulling back some carpet and exposing a cover plate that allowed access to the in tank fuel pump. The mechanic that verified that he found virtually no fuel pressure coming from the 940 pump is temporarily physically limited and has passed along the info but believes (though not sure) that changing the pump out will require removing the fuel tank. The car being a 940 wagon, I have no reference and, as you all have pointed out,these components are virtually trouble free. Before I start looking for access from above, I thought I would ask you all if the tank has to be dropped to get to the pump. Changing out the pump as I did on the Saab (900) is within my wheelhouse. Dropping fuel tanks not so much. No lift etc.
So, if the tank has to be removed, I will have to find someone with the proper equipment. If anyone has information about this matter, please advise ASAP! Thanks!
Barrelhouse

Dear barrelhouse,

Hope you're well. There's no need to remove the fuel tank to change-out an in-tank pump on a 940 wagon: I've done two such.

There's an access plate in the cargo space floor - under the carpeted load space floor panels - through which the top of the fuel tank send unit (to the bottom of which the pump is attached) may be accessed. See the site's FAQs for detailed description of how to remove and replace the fuel tank send unit.

At the risk of laboring the obvious, the in-tank fuel pump removal and replacement should be done in a well-ventilated area.

Be sure to remove completely the heavy-duty rubber hose, that connects the steel fuel tank filler pipe to the top of the send unit. If this heavy-duty rubber hose is not completely removed, it will be next-to-impossible to re-install the fuel tank send unit.

When seated into the fuel tank opening, the send unit's barrel points straight down towards the fuel tank floor (towards the ground), parallel with the fuel tank's rear-most wall.

There's an anti-slosh plastic baffle inside the tank, over the top of which the send unit's barrel must be "swung", before the barrel may be turned so that the end points towards the ground and is parallel with the fuel tank's rear wall.

Hope this helps.

Yours faithfully,

Spook

I have never heard of dropping the tank for a pump replacement on a Volvo either and I know the 940 pump is accessible from the car. I have never done one (on a 9/7-series) so hopefully the supplied link by the other guy is sufficient.

FYI, the in tank pump on a Bosch system does not provide hardly any pressure but it does supply a significant volume/flow. I believe I have seen the pressure rating a low as 2-3 psi but cannot recall from where. The primary pump provide pressure before the regulator of 50-85 psi.

I don't own a 940, but I've never heard of needing to drop the fuel tank to replace an in-tank pump on a Volvo. Look for an access door on the top. That was the design on my 90 240 when I replaced that car's in-tank pump. Maybe the following link will help even though pictures`are from a 240.

Once you have access to the pump, since you were able to start it by banging on the tank I would also check the condition of the wiring going through the fuel sender. Specifically look for looseness, corrosion etc. If you are in luck, maybe loose wiring is the only problem. OTOH - I ended up replacing both the in-tank pump and then the sender due to rust. The sender is expensive, the pump is not.

https://www.brickboard.com/FAQ/700-900/FuelTankSenderReplacement.htm

Dear barrelhouse,

Hope you're well. When you turn the key to start, do you hear a brief (1-2 second) hummmmm? If not, then the fuel pump is not getting power. That could be the result of: (a) a failed fuel system relay (rectangular, white, on the central relay panel, behind the front center console ashtray) or (b) a failed fuel pump.

As the fuel system relay is easily accessed (remove ashtray and the storage bin above it, see FAQs for particulars) I'd check that first by inserting a new or used (known-good) fuel system relay.

If the fuel system relay is in good shape, then the fuel injection relay (in the engine bay, on the inner fender wall (driver's side, I believe, on turbos) just behind the headlights. This relay is a very dark brown, almost black. I has a four-wire connector. Here too, a new or known-good used relay can quickly ascertain the state of the in-service relay.

If both relays are in good shape, then check to see if there's spark. If not, then the crank position sensor (CPS) - mounted atop the transmission bell housing, just behind the engine - may have failed. If the CPS signal is lost, the engine computer turns-off the fuel pump. This is a safety feature: if a collision rips open a fuel hose, stopping the engine, the fuel pump shut-down keeps fuel from getting loose. CPS sensors often fail as you describe: cracked insulation lets moisture get to the wires, causing signal loss.

Post your findings and we'll go from there.

Hope this helps.

Yours faithfully,

Spook