740 lumpy idle

  • Thread starter Thread starter bodacious
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bodacious

Evening all ! This is my baptism of fire, so to speak. I have just taken
delivery of my first Volvo, an immaculate 740 GLE with 130,000 on the clock.
It starts and runs really well (asnd the body-work is also remarkable). But
the petrol pump occasionally makes a low unobtrusive whiring sound at idle.
Also the idle is not smooth. When warm the engine is quite erratic, not
smooth at all.
May I ask if anyone thinks these two symptoms are related. Or, is this a
common fault with the 740, please?
any ideas, guys?
Best wishes
Arty
 
Arty, you probably need to do an inlet tract (filter to inlet manifold)
including Idle Air Control Valve cleanup. This is needed every two years for
the engine to have the best inlet conditions for satisfactory running. When
thoroughly cleaned reset the slow running speed and throttle switch if
necessary. The pump may be responding to possible in-tank pump irregularity.
Unless your car has Regina/Rex fuel ignition system there are two pumps
fitted, one in-tank and one main (underneath car under passenger seat)
presuming you to be in UK. If Regina/Rex then there is only one pump which
is of in-tank variety but much stronger than two pump in-tank pump.

You may also need to check the condition of the ignition set-up.

Good idea to join the Volvo Owners Club, check out details and joining
instructions on the website URL is http://www.volvoclub.org.uk when you
receive your goodies package you will find a form for registration of your
car to the register below.

All the best, Peter.

700/900/90 Register Keeper,
Volvo Owners Club (UK).
 
I can't speak about the possible fuel pump problem, but...

I recently tuned up my 740 GLE (125k miles). It was only getting
16mpg, had a rough idle, plugs were terribley fouled with black carbon
soot, and I could feel the engine miss all the time.

I replaced distributor cap, rotor, and plugs. Adjusted the Air Mass
Meter flap, and the idle. It runs much smoother now, and gets 23.5mpg
in mixed city/hwy driving.

I also recommend cleaning the throttle body (carb cleaner, clean lint
free rag, toothbrush, and new gasket). The Throttle Position Switch is
plugged into the throttle body, and probably needs replaced, if it
never has been.

Regards ~
 
Many thanks to you both for taking the time to offer good advice. This
morning I had the injectors replaced by the local main-agent Speeds of
Nottingham, (£60 per hour BTW). I think the prob is cured but I'll bare/bear
(?) in mind the other suggestions.
Many thanks again
Best wishes
Arty Scott
 
replace main fuel pump or and fuel filter and most likely if the whiring
happens when the tank is half full the small in the tank pump may need
replacing as well .Its wise to do the two pumps at once .
 
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