Please Help! Sick Volvo '99 V70R - fuel issues?

Hi, I'm looking for a bit of help here. I've got a sick '99 Volvo V70R
on my hands. I've got a somewhat intermittent problem, and limited
funds, so I don't really want to take it to a Volvo dealer, throw up my
arms & say "some thing's wrong, fix it". Looking for advice & things
to look at to deal with my problem(s).

I inherited the car from my father, who bought it about 6 months ago.
Not too long ago, the car started giving me trouble every once in a
while. It'd stall out at low rpm or at idle, and also sputter quite a
bit when starting. There is also sometimes some black smoke when
starting, but usually goes away shortly after. The problem comes and
goes, running perfectly in between, and making the car almost
undrivable when it's bad. At it's worst, you can hardly get the car
moving. Usually you can start it, rev it up a bit, then when you put
it in gear it'd stall out. After a few attempts you can get it
moving, and as long as you keep the rpms up, all will be well for a
while.

Now.. I called the problem intermittent, but now that I've been paying
attention, it seems to be mostly (exclusively?) on a full tank of gas
that the problem happens. Below 3/4 tank, it doesn't happen I don't
think.

Since the car was purchased, there has been a vacuum in the gas tank
(ie: sound of air rushing in when gas cap is removed). I'm not sure
if that is a normal Volvo issue, or if it is related to my problem.
It's always been like that however, and the problem has only started
recently (and gotten worse).

I've put a code reader on the car many times, and since the last reset,
the following 3 codes have come up:

P0447
EVAP Emission Control System Vent Circuit Open

P0650
MIL Control Circuit Malfunction

P1139
Manufacturer Contrl Fuel Air Metering

Although I haven't recoded them, I believe checking it before I have
seen another EVAP code, and also a cylinder misfiring. If/when more
come up I'll update this post.

Anyway, obviously it looks like a fuel issue, but I'm not sure where to
turn to next. I can't really afford to just start replacing parts if
they're not causing my problem. Can anyone suggest where I might
start? Especially things that would be fairly cheap/free to try?

Thanks!

 

High negative pressure in the fuel tank is bad. Try removing the gas
cap when it's running poorly, as see what happens. If it improves, then
you know you need to look at the tank venting system. If it doesn't,
the problem may just be with your ETM (electronic throttle module) which
is covered by an extended warranty.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)

 

If it's the ETM it should code and set the warning light. (Mine gave
out cruising down the freeway a couple of months ago - luckily within a
couple of miles of my local dealer so I was able to limp to it rolling
on idle.) From what I understand they tend to give some warning before
failing; mine had coded a couple of times prior. The dealer cleaned it,
replaced the PCV valve and sent me on my way until it failed a week or
two later. Both services were free.

A bad AMM, (Fuel Air Meter) could cause your problems. I'd try cleaning
it's electrical connections to see if that helps - they'd be suspect
if you find them oxidized.

I never notice too much negative pressure when I open my gas cap on my
'99 V70R, As Mike suggests, that might be worth investigating.

-K

 

In my experience, the throttle module starts "gliching" (see you can
make a verb out of any word) before any codes are set. Slowly it gets
worse and worse, then finally codes are set. Often the light goes away
after a restart at this stage, but the problem inevitably gets worse and
worse, soon the light is on all the time, the engine runs poorer and
poorer, and finally won't go at all.

--
Mike F.
Thornhill (near Toronto), Ont.

Replace tt with t (twice!) and remove parentheses to email me directly.
(But I check the newsgroup more often than this email address.)