83 245T - Rough running and craps when cold?

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Larry

83 245 Turbo

When I first start my car it runs a little rough and the vacuum is low;
10ish. When cold, if I accelerate the engine will cut-out/crap and black
smoke comes out the tailpipe. After about 20 minutes everything is fine;
good vacuum and no hesitation or roughness when accelerating. The plugs are
new and white. Rotor, cap and ignition timing are new and correct.

I suspect my injector seals are leaking a bit but I don't think that's all
the problem. The air filter and fuel filter are new.

The crapping out on acceleration lasts awhile past when the engine is warmed
up.

Is it just the injectors and/or seals?
 
Larry said:
83 245 Turbo

When I first start my car it runs a little rough and the vacuum is low;
10ish. When cold, if I accelerate the engine will cut-out/crap and black
smoke comes out the tailpipe. After about 20 minutes everything is fine;
good vacuum and no hesitation or roughness when accelerating. The plugs are
new and white. Rotor, cap and ignition timing are new and correct.

I suspect my injector seals are leaking a bit but I don't think that's all
the problem. The air filter and fuel filter are new.

The crapping out on acceleration lasts awhile past when the engine is warmed
up.

Is it just the injectors and/or seals?
Click to expand...


Get a Bentley manual, It will really help you get your head
around the K jet fuel injection system. My '82 used to run like
crap when cold (but no black smoke) and would magically run
great after 20 minutes as well. Turned out that theres a little
vacuum daly valve inline with the control pressure regulator
that had shit the bed. I'd guess that there's something wrong
in the control pressure regulator system...bad sensor, bad
vacuum delay valve, cracked vacuum line etc. The key here is
that there appears to be a coolant temp sensor that opens or
closes after about 20 minutes and changes the routing of the
vacuum through the CPR. Check that vacuum valve, your symptom
sounds remarakbly like mine!

BobW
15 Volvos (58-91)
 
Bob Wennerstrom said:
Get a Bentley manual, It will really help you get your head
around the K jet fuel injection system. My '82 used to run like
crap when cold (but no black smoke) and would magically run
great after 20 minutes as well. Turned out that theres a little
vacuum daly valve inline with the control pressure regulator
that had shit the bed. I'd guess that there's something wrong
in the control pressure regulator system...bad sensor, bad
vacuum delay valve, cracked vacuum line etc. The key here is
that there appears to be a coolant temp sensor that opens or
closes after about 20 minutes and changes the routing of the
vacuum through the CPR. Check that vacuum valve, your symptom
sounds remarakbly like mine!
Click to expand...

It sounds like that delay valve is the problem. About the size of a half
dollar located just behind the distributor? Did you remove the dist. to
replace it?
 
volvowrench said:
On the side of the fuel pressure regulator there is a delay valve that
controls/assists fuel enrichment throughout the acceleration range. The
replacement interval was hidden deep in a footnote for the maintenance
services. As a consequence it is rarely changed and less frequently
checked. When it fails in cold weather just as the engine goes to boost
it belches black smoke for a few seconds, falls on its' face and dies. By
the time you look under the hood to investigate the wax valve opens and
the motor works normally.
Click to expand...

I think that's it. I found a white valve in the vacuum/pressure line just
behind the distributor. Do you know if it would be available somewhere other
than the dealer? Is it expensive?
 
Larry said:
I think that's it. I found a white valve in the vacuum/pressure line just
behind the distributor. Do you know if it would be available somewhere other
than the dealer? Is it expensive?
Click to expand...

Make sure the vacuum lines that the valve is in are going to the control
pressure regulator, not the distributor. As I remember the delay valve
you're after is blue and black.

Also, if you suspect the injector seals are bad, why not just replace
them first?
 
Larry said:
It sounds like that delay valve is the problem. About the size of a half
dollar located just behind the distributor? Did you remove the dist. to
replace it?
Click to expand...
It's disc shaped and the size you describe. I believe it is
black on one side, red on the other but it's been a while since
I've seen mine. It's not hooked to the distributor, Like Mike
said, it's in a loop of vacuum lines going to the control
pressure regulator. It's on the drivers side, towards the front
of the block and under the intake manifold. I got mine in and
out without removing anything but it was very difficult to get
the clamps off and back on, space is very tight in there.

Probably easiest to source one at the dealer. I found a good
one at a wrecking yard. See Bentley manual for proper procedure
for testing. Mine would not pass vacuum in either direction,
causing my symptoms.

Good luck

Bob W
15 Volvos (58-91)
 
Bob Wennerstrom said:
It's disc shaped and the size you describe. I believe it is
black on one side, red on the other but it's been a while since
I've seen mine. It's not hooked to the distributor, Like Mike
said, it's in a loop of vacuum lines going to the control
pressure regulator. It's on the drivers side, towards the front
of the block and under the intake manifold. I got mine in and
out without removing anything but it was very difficult to get
the clamps off and back on, space is very tight in there.
Click to expand...

I have the green/white Volvo service manuals for my car. It shows the
position of that delay valve. I might remove the distributor to make the
repair a little easier. It's very tight in there.
 
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