I have a 1987 740 (non-turbo) with 200,000 miles. Mine was in bad shape
when I bought it 6 months ago for $500.  I did a restore job on it and
now it is as good as new.

First, where is it smoking from?  If it ran then smoked and won't
start, the spark plugs may be fouled and might need to be replaced.

Second, for $400, what do you expect from the car, realistically?  If
someone is mechanically inclined, a lot can be done on this car with a
little talent and knowing where to buy parts.

My personal choices are FCPGroton.com, IPDUSA.com and the local parts
store for common items.

It will be hard to sell a car that won't start, unless you try to sell
it as a project car or a parts car.

Being a turbo, there may be other things that I am not familiar with,
but something is coming to mind that I cannot recall exactly. I think
there is something in the turbo system that can smoke if damaged. I am
sure someone else will chime in, but please offer up a few details:

1) Condition of the car:  Excellent, Good, Fair, Poor
2) Previous owner: How many? Did they seem to maintain the car well?
Records?
3) How many miles?
4) How does it look under the hood? Clean? Dirty? Dry? Oily?
5) Do you see any exposed or cracked wiring?

Jamie

OK, thinking more about this, $400 is not unreasonable for this car,
but your circumstances are curious.

Here is what I think:

A) This car was in good running order, then something broke.

B) The car broke, someone put a quick patch to sell the car and the
patch failed.

I am an optimist, but am leaning towards B. That being said,
investigate. My raw, gut feeling is either the turbo failed, or maybe
someone hot-rodded this car, cracked the heads and patched it with JB
Weld to hold it over until they could sell it.  Or, to a lesser degree,
the rings are shot and they filled it with some "treatment" to mask it
and not foul the plugs until the car was sold.

Have a mechanic check out the turbo and the head.

Suzanne Browning-Jones wrote:

If it's cutting off, the first thing to check is the engine wiring
harness, I'm sounding like a broken record on this newsgroup by now but
until '88 or '89, if the harness is original it WILL be bad and the car
WILL NOT be dependable. Thankfully this is a fairly simple if not super
cheap repair unless you do what I did and carefully replace each damaged
wire and rebuild the harness.

Next, suspect the fuel pump relay, it's in the center console behind the
ash tray.

What color is the smoke? Black smoke could be the wiring harness causing
the injectors to stick open, blue smoke is probably a clogged crankcase
breather or worn oil seals in the turbocharger.

Fantastic car if you get it fixed up, if it was only $400 it probably
needs quite a bit of work but they're a real joy to drive and super easy
for a shadetree mechanic. I have the same car and I love it.

If the smoke is blue, is not seen when the engine is first started, and
especially if it is worse at idle, start by cleaning the crankcase
ventilation system. If it gets restricted the crankcase pressure will build
up and oil will dribble out of the turbo into the exhaust.

The entire ventilation path has to be cleaned, but at least it isn't
terribly hard to access. Most of it is the large hose that extends from the
side fitting on the turbo intake duct, across the top of the engine (that's
where it is most obvious), and dropping through the intake manifold branches
on the other side. The hose can be pulled out completely for cleaning. I
know it looks big, but mine was nearly plugged solid. Under the intake
manifold the hose connects to a plastic box, held down by the two bolts (10
cm heads). The box can be removed and cleaned with carb cleaner or lacquer
thinner, but it is hard to clean effectively. Reaming with a knife helped
mine a lot. Others like to replace it, and I understand why! Anyway, when
blown through it should have about as much resistance as puckering up to
blow out a candle. The O rings on the underside should also be replaced to
prevent oil leakage.

That may be why you got a good deal. The seller didn't know what to do about
the smoke and assumed it was a bad turbo seal.

Mike