Broken Down again!

[James_N]

Broke down again this morning. Same symtoms as yesterday. Turning over, trying to start, but not firing. The
fuel pump relay does click when turning on the ignition and if i mess about for 10 mins, i can sometimes get
the car to fire by messing with the relay.

Is this likely to be the prime culprit? the car ran fine last night to the shop and back, so i doubt its the fuel
pump? I see eurocarparts sell the relay for £12, and given my car is now abandoned on a country lane a few mins
from home, is it worth trying this as the first port of call? car will start sometimes, stutter, then die.

I'll perhaps order a fuel pump relay today to arrive tomorrow. I need the car ASAP. So is this likely to be the cause?

Thank you for all the help again

James

[mocambique-amazone]

Hello James, the first pump at 163000miles? if yes she is gone. rip.

Inside the rear left smuggle box you will find the electric connector for pump and tank sensor. I don't remember the coulors, the thicker ones are the pump. At directly 12v and you will see (hear) ist the pump is running. They are prone to die suddenly.

Your 940 is only with one in-tank-pump.
Expensive the fuel unit, less the pump. Don't use a standart rubber hose inside the tank!!! skandix etc have a kit.
Never try a used one, they won't last long if stored dry.

Good luck, regards, Kay

[James_N]

186,000 miles now actually, my sig is a little outdated! The car does run sometimes, but then sometimes not, but then just stutters and dies now.

It worked fine last night as i had it running after fixing my coolant leak!

Surely if it was the pump, it wouldn't start at all?

[Phil Croxley]

What about the coolant temperature sensor? I would be looking to replace that. It's been referred to as the master sensor because it can affect many aspects of the engine's running. A different car of course, but my wife's Corsa kept breaking down, I replaced the CTS, took 60 seconds and it was fine ever after. Just a thought.

[James_N]

would this make the car not start?

[Laird Scooby]

I'd lay bets it's the fuseholder in the fusebox for the fuel pump. I know 940s have a different fusebox to the 740s but i had a fair bit of trouble over the years with that fuse in the 740. In fact i'd lay bets it starts when you get back to it.



Usually if a fuel pump goes, that's it, they're gone as you rightly say. Sometimes they give trouble but that's usually shown as idling ok but holding back under load.

As you can see from the pic above, the fuseholder has got a bit warm! It may not be so obvious in yours. In simple terms there's a bit of resistance there because the fuse hasn't been touched and the pump takes a fair bit of current. This resistance causes heat which in turn creates more resistance and it then becomes a vicious circle until it's so hot it no longer passes current and the pump stops. When it cools down again, normal service is resumed until it gets hot again.

If you locate the fuel pump fuse, remove it, clean the contacts and refit - that should solve the problem if it's what i think it is. Either way it won't do any harm.

This is the quickest, simplest and cheapest thing to eliminate from your fault finding procedure - it may be there is a fault with the pump and/or the relay but i've found it generally pays to work on the "KISS" principle - Keep It Simple, Stupid!

In other words, go for the basics first and by the time you've gone through those you should have all (if any) evidence to point the way to a more complicated fault if you haven't already cured it.

[James_N]

Thanks Scooby. I did take the fuse out to make sure it wasn't knackered or anything like that, but then i got it to start, so yes i'll maybe put another fuse in and have a look at the box. Ive got a fuel pump relay coming tomorrow also. I'll check the simple stuff first and pray!

[Rversteeg]

Resoldering of the internals of the fuel pump relay will probably do the trick. It is quite a current that runs through it, so the soldering joint will crack over time. I bought a new one and keep a resoldered one as a spare. With a cracked soldering joint the relay will still click, but is not able to transmit the required current to start up the pump. I would check this before doing anything with the fuel pump.
Same cracking soldering joint problem you will sometimes find in the relay
switching on the AC compressor, also quite a current.

[James_N]

This is what i thought. Its still clicking but something is happening where it cant supply the current needed to the fuel pump. Hopefully the new one being delivered tomorrow will solve this problem.

Its not a genuine volvo one, i'm not sure if this makes a difference or not!

[Phil Croxley]

Originally Posted by James_N

would this make the car not start?

Generally a duff CTS makes starting from hot difficult and needs to be left for about 20 mins, but it can also make cold starting difficult. It's amazing how they can affect an engine. My wife's one cost £6 or so from Eurocarparts.