Bringing a 740 back to life

[Ian21401]

That fuse box is also difficult on my 940 but does eventually come out so far. It could have some of that Volvo extra sticky black gooey stuff under it. Mine had.

[Challo]

Originally Posted by Ian21401

That fuse box is also difficult on my 940 but does eventually come out so far. It could have some of that Volvo extra sticky black gooey stuff under it. Mine had.

I had pulled some of that black stuff out before. God knows what’s underneath it.

[Challo]

Quick update on progress this morning:

Checked the spark plugs, and all getting spark when cranked.
Checked the fuses and all correct with none broken.
Changed the fuel pump relay and you can tell the original one was faulty. As soon as it was plugged and ignition turned on you could hear the pump prime. This didn’t happen previously

Tried starting the car again and nothing. Keeps cranking, but doesn’t start.

With that in mind I took off the pipe to the fuel rail, cranked the car again and no fuel coming out of the pipe. So it looks like there is no fuel getting to the engine to fire. Before I did all this I had to take off the filter and pump again from the car as I hadn’t replaced all the brass washers, and there was a slight leak. Everything is replaced and all connected.

Any ideas?

I know I need to check the one in the boot as mentioned by Laird, but couldn’t do this on my own.

[Laird Scooby]

Originally Posted by Challo

I know I need to check the one in the boot as mentioned by Laird, but couldn’t do this on my own.

Yes you can!

Originally Posted by Laird Scooby

Open the tailgate and remove the left hand cubby hole cover between the wheelarch and D-pillar - should be a loop at the front end to make life easy for this.

Find the 3-way connector, this feeds the fuel pump and brings the sender output back. The two wires you're intersted in are pink and brown on the tank side of the connector. Back probe these with the +ve of your meter in the pink and the -ve of your meter in the brown. For 1-2 seconds when you first turn the key to position 2 you should see battery voltage and then also during cranking and for 1-2 seconds after.



You can see the pink and brown wires (with a grey one) more or less centrally)

Once you've got the meter probes in the pnk and brown wires, with the back seats down you can position your meter so you can see it from the drivers door - reach in and turn the ignition switch to position 2, job done!

In case it's not priming or you miss it, turn to position 3 (start) and watch the meter, you should get battery voltage while cranking and for 1-2 seconds after you release the key.

If you are getting voltage but still no pump action, cralw underneath and find the main pump and give it a couple of gentle taps with a hammer handle. Likewise at the back of the tank, in the centre at the bottom, a couple of sharp slaps with the ball of your hand.

Try starting again, you may need to repeat the "tap and slap" routine 2 or 3 times but unless those pumps are seriously siezed, if you have power reaching them they should run.

Once you've got them running, add about 2 egg-cups full of synthetic ATF (Carlube ATF-U is good for this) to clean the system including injectors and lube the pumps and revive any rubber seals that have dried out.

[Challo]

Originally Posted by Laird Scooby

Yes you can!



Once you've got the meter probes in the pnk and brown wires, with the back seats down you can position your meter so you can see it from the drivers door - reach in and turn the ignition switch to position 2, job done!

In case it's not priming or you miss it, turn to position 3 (start) and watch the meter, you should get battery voltage while cranking and for 1-2 seconds after you release the key.

If you are getting voltage but still no pump action, cralw underneath and find the main pump and give it a couple of gentle taps with a hammer handle. Likewise at the back of the tank, in the centre at the bottom, a couple of sharp slaps with the ball of your hand.

Try starting again, you may need to repeat the "tap and slap" routine 2 or 3 times but unless those pumps are seriously siezed, if you have power reaching them they should run.

Once you've got them running, add about 2 egg-cups full of synthetic ATF (Carlube ATF-U is good for this) to clean the system including injectors and lube the pumps and revive any rubber seals that have dried out.

Thanks. Just checked again and upon cranking I’m getting power at that connector. I’ll give the tanks a tap tomorrow when I have some more time. The fuel pump directly under the car is brand new.

On the ATF where do I add this?

[Laird Scooby]

Originally Posted by Challo

Thanks. Just checked again and upon cranking I’m getting power at that connector. I’ll give the tanks a tap tomorrow when I have some more time. The fuel pump directly under the car is brand new.

On the ATF where do I add this?

Same place as you add petrol.

In fact, if you're not going to tap the tank until tomorrow, add some ATF before you start trying to coax the in-tank pump back to life by tapping the bottom of the tank. It might just help to free something off.

[Challo]

Originally Posted by Laird Scooby

Same place as you add petrol.

In fact, if you're not going to tap the tank until tomorrow, add some ATF before you start trying to coax the in-tank pump back to life by tapping the bottom of the tank. It might just help to free something off.

Thanks. Just to check this is the stuff?

https://www.amazon.co.uk/Carlube-ATF.../dp/B00HOGNXK2

[Laird Scooby]

Originally Posted by Challo

Thanks. Just to check this is the stuff?

https://www.amazon.co.uk/Carlube-ATF.../dp/B00HOGNXK2

Yes, but not at that price!

Try this for 1L :

https://www.ebay.co.uk/itm/CARLUBE-A...L/284152043980

.........or for 1 gallon (4.54L) :

https://www.ebay.co.uk/itm/Carlube-A...L/233257297843

You can also use it in your PAS and if you have an auto, it's a vast improvement over Dexron II-D.
I have found many other uses for it as well, 50/50 mix with acetone (nail varnish remover) and shaken it makes an excellent penetrating fluid. Needs sealing after each use to prevent the acetone evaporating and shaking before each use but that's a small price to pay for how good it is.

[Challo]

Originally Posted by Laird Scooby

Yes, but not at that price!

Try this for 1L :

https://www.ebay.co.uk/itm/CARLUBE-A...L/284152043980

.........or for 1 gallon (4.54L) :

https://www.ebay.co.uk/itm/Carlube-A...L/233257297843

You can also use it in your PAS and if you have an auto, it's a vast improvement over Dexron II-D.
I have found many other uses for it as well, 50/50 mix with acetone (nail varnish remover) and shaken it makes an excellent penetrating fluid. Needs sealing after each use to prevent the acetone evaporating and shaking before each use but that's a small price to pay for how good it is.

Thanks. I’ll have a look online for a good price.

[Laird Scooby]

Originally Posted by Challo

Thanks. I’ll have a look online for a good price.

Those are about the best prices delivered on ebay UK.