non starting 940

[855 tdi]

Hi all,

I parked my 95 940 2.3 hpt up after getting a t5 V70, I should of sorted it properly for storage but didn't and am now trying to recommission it, must of been 1.5 years. Yesterday i checked the oil level and with a new battery tried starting it, it started with 0 problems, then a minute later it cut out and turns but won't fire up. My immediate response was check the fuel pump fuse, no problems, then checked the relay with a known working one and no problem, I couldn't hear any fuel pump priming, i chucked a new fuel filter on, perhaps in hindsight I should of before starting it, it had around 1/3 of a tank to which I added new fuel to. Today i grabbed a spare fuel pump which I plugged into the pump plug before fitting I got my dad to check it worked when I cranked the key, it did as expected.

I fitted another brand new much stronger battery (not just bought for this) after swapping the pump it still wouldn't fire up, thoughts? My fuel pressure regulator looks past it so I intend on replacing it anyway but could this be the cause for no start? I opened the shrader valve in the fuel line and a very little hiss and a small dribble of fuel was all that came out, is that normal? I'm wondering if its a fuel blockage? I pulled the fuel pipe into the rail and nothing comes out when I crank it, so i'm doubting wet plugs but will need to check to be 100% sure. Any other things to check out?

thanks,

Jason

[Laird Scooby]

Has yours got the underbody pump as well as the in-tank pump Jason? If so, try tapping that while cranking it if possible, if not give it a few taps then try cranking again. It sounds like the main pump has seized and/or blocked so tapping it usually frees it.

If that sorts it, add some Carlube ATF-U to the ful tank, about 50ml (double measure of spirits) should do it. This will lube and clean the pump and injectors.

Also check the RSR, probably left hand inner wing on yours as it might not be supplying the injectors with +12V (measured on the green wire if you pull back one of the boots on the injector plugs) and if yours is a lte enough 1995, maybe nothing to the coil either.

[TonyS9]

95 should have in-tank only pump. This is what I have (95 HPT).

If you unplugged the main feed fuel line and it does not shoot out fuel when you prime it, there is definately something wrong before that. So you have the filter under the car and then the pump, and the fuel pump relay that supplies it.

So are you still getting no priming noise or fuel at the manifol inlet with the new pump?

I'd check the voltage at the pump, there is a connector in the rear left cubby hole in the rear of the estate to access this. Use a meter or a bulb.

The white Fuel relay is usually the cause of no voltage, but maybe you have something more exotic.

Any of course check the rpms during cranking, you should see the needle flicker after about 1s of cranking. This will (mostly) confirm you are getting sparks.

[855 tdi]

Originally Posted by Laird Scooby

Has yours got the underbody pump as well as the in-tank pump Jason? If so, try tapping that while cranking it if possible, if not give it a few taps then try cranking again. It sounds like the main pump has seized and/or blocked so tapping it usually frees it.

If that sorts it, add some Carlube ATF-U to the ful tank, about 50ml (double measure of spirits) should do it. This will lube and clean the pump and injectors.

Also check the RSR, probably left hand inner wing on yours as it might not be supplying the injectors with +12V (measured on the green wire if you pull back one of the boots on the injector plugs) and if yours is a lte enough 1995, maybe nothing to the coil either.

thanks, annoyingly my car was the year they switched to just the in tank pump, I can't actually remember the noise priming made but i had a listen to my dads 850 and couldn't hear much on his either. The pump i fitted plugged into the connector and upon cranking sounded like it was pumping so to my knowledge that confirms a working pump and relay. I purely swapped the motor not complete sender unit etc so i'm wondering if the black pipe to the pump is blocked hence a new pump doing nothing? With a plastic tank obviously it isn't rust, the rsr is something i'm considering although not having luck finding one in this country.

Originally Posted by TonyS9

95 should have in-tank only pump. This is what I have (95 HPT).

If you unplugged the main feed fuel line and it does not shoot out fuel when you prime it, there is definately something wrong before that. So you have the filter under the car and then the pump, and the fuel pump relay that supplies it.

So are you still getting no priming noise or fuel at the manifol inlet with the new pump?

I'd check the voltage at the pump, there is a connector in the rear left cubby hole in the rear of the estate to access this. Use a meter or a bulb.

The white Fuel relay is usually the cause of no voltage, but maybe you have something more exotic.

Any of course check the rpms during cranking, you should see the needle flicker after about 1s of cranking. This will (mostly) confirm you are getting sparks.

Thanks, i'm no mechanic but following the line from the fuel filter to the rail I had nothing coming out when cranking, hopefully i'm looking at the correct hose. I don't know if the schrader valve before the the filter can be pressure tested? I should check again after the pump being fitted to see if anymore fuel comes out when I open the valve. My fuel pump relay clicks loudly when cranking and I have tried with a known working replacement so i'm not sure if i'm missing something obvious. I'm fairly sure it's not spark related as my tachometer moves when cranking, which makes another culprit, the crank sensor unlikely.

[Rversteeg]

A seized in-tank fuel pump is not uncommon on the 940s. It seems they all give up sooner or later. In the last 97/98 series Volvo changed from a gear pump to a longer lasting turbine type, but even that one can seize as I experienced last week. Replacing is not too complicated and got me up and running again.
If your pump is seized as well, a few thumps on the fuel tank with a rubber hammer might get it going again for a short time. Worth a try...

https://www.skandix.de/en/download-file/3000438/

[TonyS9]

Originally Posted by 855 tdi

thanks, annoyingly my car was the year they switched to just the in tank pump, I can't actually remember the noise priming made but i had a listen to my dads 850 and couldn't hear much on his either. The pump i fitted plugged into the connector and upon cranking sounded like it was pumping so to my knowledge that confirms a working pump and relay. I purely swapped the motor not complete sender unit etc so i'm wondering if the black pipe to the pump is blocked hence a new pump doing nothing? With a plastic tank obviously it isn't rust, the rsr is something i'm considering although not having luck finding one in this country.



Thanks, i'm no mechanic but following the line from the fuel filter to the rail I had nothing coming out when cranking, hopefully i'm looking at the correct hose. I don't know if the schrader valve before the the filter can be pressure tested? I should check again after the pump being fitted to see if anymore fuel comes out when I open the valve. My fuel pump relay clicks loudly when cranking and I have tried with a known working replacement so i'm not sure if i'm missing something obvious. I'm fairly sure it's not spark related as my tachometer moves when cranking, which makes another culprit, the crank sensor unlikely.

The RSR would not cause the pump to not work, I would leave it alone at this stage. Don't be buying parts on a guess, wait untill you have evidence a part is faulty.

So you are getting priming voltage, and potentially a priming pump, but no fuel. You need to concentrate there. Confirm there is voltage, then look for reasons the pump isn't working. Take out the pump assembly again if necessary and strip it down.

The priming is very quiet, you need a quiet area, not near a noisey road for example. Lifting up the seats and inspection cover in the back usually helps.

[Rversteeg]

I understood you just tested the fuel pump by connecting another pump to the connector. This only tells you that the intank pump is getting 12V, but not if it is actually pumping or not!

[855 tdi]

Originally Posted by TonyS9

The RSR would not cause the pump to not work, I would leave it alone at this stage. Don't be buying parts on a guess, wait untill you have evidence a part is faulty.

So you are getting priming voltage, and potentially a priming pump, but no fuel. You need to concentrate there. Confirm there is voltage, then look for reasons the pump isn't working. Take out the pump assembly again if necessary and strip it down.

The priming is very quiet, you need a quiet area, not near a noisey road for example. Lifting up the seats and inspection cover in the back usually helps.

I haven't replaced my rsr yet as you say I need to make sure it's actually an issue first but if I checked the wrong fuel pipe by mistake it could be a potential consideration.

I think there's some misunderstanding, I replaced the pump with a used known working one from a 97 940, hopefully the improved one Rversteeg mentioned.

Before replacing the pump in the fuel tank I plugged in the used pump I had into the connector in the boot and unlike the original it primed when cranked and pumped so I know it works. After plugging it in and confirming it worked I replaced it inside the fuel tank. This is why i'm struggling to figure out the issue, so basically it's not the fuel relay, fuel pump fuse or the in tank fuel pump, the fuel filter has also been replaced. As the car is at my dads I can't do anything till the weekend but i'll measure the voltage to the pump, is there an earth cable etc connected to the body that could be loose? Thanks for the help.

[Rversteeg]

So when I understand right, the original fuel pump did not work anymore, but he replacing one did. That seems too much of a coincidence.
Just a thought: the man that supplied me the new pump warned me to be careful when installing the new pump back into the tank. In some cases the suction strainer of the pump assembly gets stuck on top op the approx. 2" high transversal yellow ridge of the "rolling pot", so the pump strainer will remain 2 or 3" above the tank bottom. As the mounting pipe of the pump can slide in and out, you will not notice this during installation. As long as the fuel level is higher than 2 or 3" there will be no problem, but at lower levels the pump will run dry.
Is your fuel level low?
Rob

[TonyS9]

Did you use string to compress the pump assembly before putting it back in? Its quite difficult, I'm assuming you know how to do this.

There are 2 wires in the cubby hole 0 and 12V, the 0 might be earthed to body behind the trim panel maybe I can't remember. Just measure across the 2 wires, if you are getting no voltage then you can start to find out why. At the moment we just need to know if the pump is still getting power. You could also connect an open fuel line to a container and check if fuel is coming out from the tank during priming.