240 Turbo won't boost

Hi all,

Just a quick question: my 83 240 Turbo is running well BUT the Turbo
doesn't seem to be giving much boost (if any). The indicator shows the
boost maxes-out at about one third and won't go higher. Also the
characteristic screaming of the spooling-up Turbo has disappeared.

Is it possible that the fan isn't spinning? If the fan seized would it
necessarily start burning oil (oil-cooled turbo) or could the oil just
flow through without trouble?

My chief suspect is a leak in some pipe attached to the Turbo but I
have yet to find such a leak so I'm looking for other possibilities.

Tanks in advance for any ideas.

Cheers,
blurp

 

Search well (i.e. disassemble everything). Small openings become
larger under boost and are easy to miss, check all of the "vacuum" lines
too (I've noticed that the line to the distributor is often a problem) .
Also check your check valves (on the brake booster, charcoal canister
and interior vents [the tap off of #4 intake]) to make sure they are not
opening under pressure.

The other possibilities are:
Timing issues: If your timing belt has jumped a tooth the cam and/or
distributor may be retarded limiting your performance.
Clogged catalytic converter (if your car has one). Usually caused by
running too rich to due a leak under boost.
Collapsing or kinked hose in front of the turbo, clogged air filter or
other blockage ahead of the turbo. Check inside the valve inside the
elbow leading in to the air filter box (that draws cold air from the
front or warm from the exhaust manifold) since that has been know to
become blocked as well.

Bill

 

This is a classic sign of a clogged exhaust, usually the catalytic
convertor, as noted by Bill.

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

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

 

The "usually" is an excellent point. A muffler with some rusted out
baffles can cause the same symptoms and may not even be loud.

Bill

 

Thanks very much, gents! I will examine as much as I can this weekend
and leave the rest to my talented exhaust guy.

Cheers!
blurp

 

Ok, I've cleaned and checked the air filter and intake. I have
removed, inspected, and reinstalled all the hoses and none seem to
have cracks or hotes in them. There still seems to be a fair bit of
exhaust coming out of the tailpipe and the sound is still a throaty
rumble at idle. I will still ask an exhaust guy I know for additional
guidance here.

What it comes down to is how do I actually test the vacuum? The
"Vaccum-advanced timing" has been fingered as a possible culprit in
several issues so I'd really like to get a closer look at it but I
don't know what I'm looking at/for. I can see the distributor but only
see electrical wires attached to it... does the vacuum exert its
influence elsewhere in the system?

Thanks,
blurp