hi.
i have an 86 volvo 740 turbo.

for the past three months, it has been giving me issues when coming out of idle.
the problem occurs after warmed up, and after sitting at 5 or so stop lights.
when i give it gas after sitting in idle for a while, it is as if there is no response for a second or two, the car kind of cuts out (and it gradually gets worse as i drive more).
once it begins doing this, it starts to stall out when sitting in idle for half a minute or so. (it will sputter, and when i give it gas it either A) kicks back in or B) there is absolutely no response and it sputters and dies) the longer i drive it for, the worse it gets, and eventually it dies and doesnt start.

i had the external fuel pump changed about a year ago, and it has always whined (sometimes louder than the engine itself).
it doesnt whine when the car first starts, but starts to whine about 3 minutes into idling.
when the car begins to sputter the fuel pump will whine louder.
also, when sitting in idle the gas gauge will read less, up to half a tank.
after i give it gas (and if it doesnt stall), it will cut out and then start going and the gauge will go back to normal.


its been doing this for about three months, gradually getting worse and worse.
now it doesnt last more than five minutes



ive replaced the fuel filter, temp sensor, and main fuel pump (and it still whines).
today i checked the both fuel pumps and they are good too -_-
unfortunately im a poor college student so this stuff hurts and i cant afford much >.<

my grandpa thinks it may be the fuel pressure regulator? i dont even know what this does...


and suggestions?

thanks !

 

Hey man,

I have an 87... but let me give you a little information about the car....

Basically there are 2 fuel pumps... the in tank pressurises the system to about 58psi... the second to the 74psi that are required... (I am at work... so these numbers might not be 100% correct... but you get the idea). The FPR is there to allow any extra fuel over that pressure to be returned to the tank. The reason for this is that the injectors need a certain PSI to allow for the proper amount of fuel to be placed into the cylinders...

Now onto your problem.... when the car is sputtering there are a few things.... what is the condition of the spark plugs... the wires and the cap? When the car dies... can you smell gas? The fuel pump in these cars are CRAZY loud... so I wouldn't worry to much about it!

For the gas guage and the it starting to stall there.... I am wondering if one of your relays might be gone.... this might be causing a drop in fuel pressure.... I could check that out....

 

i have noticed that the fuel pump relay does get fairly hot (as in i wouldnt mind touching it, but i wouldnt sit by it hot).

is there a way to test the relay? i know i read something earlier but im having trouble finding it again >.<


as for the pressure regulator... i have to wait two days for my grandpa to come over with gauges. (im pretty broke atm.)

 

and thanks for the quick reply! i think i love this forum. ha =P

 

Hey no problem at all man! When you turn on the car you should either feel or hear it click. It really shouldn't be getting that hot though! That would mean to me like something could really be wrong with it. If it is getting to hot.... it could then be causing it to actually arc back....

The FPR's really aren't that great on these things... but to be honest, I wouldn't be that worried about it!

 

The relay can easily be opened and inspected.

 

Gremlins are hard to pinpoint, but you can get used fuel pressure regulator and fuel injection relays at junk yards. Also, try replacing the air filter.

If your car ever dies and stays dead, go to www.stepbystepvolvo.com for free guide to 740 no-starts.