740 refuses to start for more than a second!
 

Ok, so it's my own fault..... I got the Mini on the road finally... and the Volvo's taken the hump now!


Tried to start it today and it fired straight up as usual.... and ran for about 5 seconds before dying.

Tried again and sounded like it was trying to fire a bit at first but then was just turning over and over. Left it a bit as I guessed I'd flooded it.

Tried it again a few minutes later and it fires up, spins a few times then stutters and dies. The longer you leave it inbetween tries, the longer it will run if/when it does start (even though I'm talking 5 secs max).

Tried starting on full throttle and nothing. Took a plug out and it looks normal - not sooty, not wet in petrol.. just normal. Tested sparking the plug against the body and it sparks fine (even started up with just the 3 plugs in for a second while I was testing it).

Now one thing I think is strange is when I switch the ignition on, rather than the fuel pump 'whirring' it's more like a 'fizzing' (the fuel pump under the passenger side floor).

Do you think it sounds like a fuel pump issue? Do they only have one fuel pump, or are there 2?


It's a 1988 Volvo 740 GLE B230E, 159,800 miles (obviously scared of reaching 160,000!!).

sounds like a fuel pump or pump relay . There are two , one in the tank to feed the main one under the floor . it will start and run if the tank one is faulty ..

Well, you can rule out both pumps if you check line pressure. In-tank pump will not cause such failure, it will only force the main pump to work harder. You might have problem with leaking injectors or cold start injector or control pressure regulator.

Could be aux. air valve aswell, as there isn't enough air getting into engine. Control pressure regulator and aux. air valve are all heat-based elements. If they're hot, they close, if cold, they are open. Might be related to that.

Maybe just try to measure resistance of the aux valve and resistance of the control pressure regulator. If you don't know correct values, i will dig them out somewhere.

Ok, thanks guys. So to some up things to check:

- In-tank pump.... car should still start even if this has failed?

- Under car pump.... possible culprit. I don't have a fuel pressure tester/gauge - any other way I can test this?

- Fuel Pump relay.... where can I find this? Any tests I can do on it, or any way I can see if it's faulty?

- Leaking injectors or cold start injector or control pressure regulator.... wouldn't imagine it's leaking injectors - surely that wouldn't happen in a day of not driving the car? Was working Thurs, and everyday before then for the last 7 months
Where can I find the cold start injector and control pressure regulator? Could you find me resistance figures please so I can check these?

Aux. air valve.... again, where can I find this? Is it in the air filter casing? And if you could find the resistance figures that would help.


Tried it again bit later, and if you've left it for a bit it will start straight up and run for about 5 seconds before spluttering and dying. If you touch the accelerator at all when it's running it instantly dies.

could the fuel gauge be faulty ?,has it run out of fuel ? as you mention the fuel pump sounds different,ie like no fuel to pump,could be split pipe on tank sender inside the tank,try taking off the fuel pipe to the inlet of the pump under the car and flick the ignition key fuel should flow to the main pump,if not fault in tank sender/pump,if fuel flow to main pump try changing the main pump.

Don't think it's the gauge - have ran it very low on petrol before now, and it just made a louder whirring noise, not the fizzing noise it's making now.

Will have a look, see if I can check the fuel supply to the main pump. Is it a good idea to take the fuel supply to the engine off and turn it over.... see if fuel comes through, or is this too high pressure to be doing this with?

easiest is to trace the fuel line to the engine fuel distributor and just crack of the union a full turn,this is the high pressure side and should spray out like you have put your finger over the end of a hose pipe,if not remove hose to inlet side of pump and crank ,this is low pressure and should have good supply but not under any extreme pressure,if you have the main pump is faulty,if not problem in tank/sender/pump.

I would try primeing it I:E Put a cap full of petrol in carb or injectors

I ran out of petrol once and had a little petol in a can and it drove to a nearby filling station by doing this

Mine has a Manual pump so not sure if you can get to the pump but the old trick to get you home was to give the pump a clout with a handle of a screwdriver

Ok, so undid the union to the fuel distributor and it p*ssed out, and covered me... so there's some fuel getting there at least.

However, after the pressure died down to a dribble, I switched the ignition on.... but I don't think it sprayed out again.... hard to tell as I was in the car turning the key though.

I took no.1 injector out and cranked it over and couldn't see anything coming out of it... but then I was in the car peering under the bonnet and it was chucking it down with rain.

Have disconnected the air pipe to the airfilter and that made no difference. Is the aux. air valve in the air filter box anyway?


Anyone got any things I can try? The car's got a quarter tank of fuel so I don't think it's low.

It did start up for a second, and I managed to start to rev it with a light throttle, but just got a loud pop/bang from the engine bay and a bit of smoke!! Like a backfire, but through inlet not exhaust.

Please, any ideas??

hi Ian,it should keep spraying out like mad as you keep cranking,need 2 people but while its cranking does the pump under the car keep buzzing/pumping? it should,also if it fires and you release the key for normal running it should keep buzzing/pumping to maintain pressure.