1988 Chevy Blazer S-10 4x4 4.3 TBI Z
Engine was redone 52,000 miles ago
Transmission was redone 3,000 miles ago.
Recently installed new water pump, viscious fan clutch.
About two months ago I started to lose coolant, but couldn't find a
drip. The oil wasn't milky, nor the coolant brown, so it wasn't too far
gone. I had vapor in the tail pipe and decided it was probally the head
gasket. It ran ok for the most part, but the last 2 days before I pulled it
apart, it barely could idle, would hesitate tremendiously, and stall. I
pulled both heads, and sure enough the drivers side, rear cyl (#5) was full
of coolant, I mean FULL. The gasket had a small defect in the side wall and
I guess the winter (when I installed the new water pump) some small defect
in the gasket was injected with water, then it froze, then it melted when I
ran it, and then filled up again.. and so forth until I got had the hold
that I did.
While doing the "clean parts as you go" thing, I noticed my PCV valve
was kinda' gunked up, so I clean that out with carb cleaner(maybe this was
bad?). I cleaned the valve covers (which were milky), pulled the rods out
(thew them in cleaner for a few days), set the rods back (after blowing them
out really well), new head gaskets, new intake gaskets, cleaned out the
intake manifold, cleaned the gasket surfaced, replaced an aging vaccume line
(from the top of the air intake block), cleaned the TBI, new air idle
control valve (the old one was getting black and for $20...), new cap,
plugs, rotor, wires.
I had a little trouble getting the distributor in place, but I did. We
were trying to set the timing and had problems with the timing light. It
would idle sometimes, but would stall. Black smoke would come out of the
tail pipe, it was struggleing, and hesitated greatly, even in PARK! Forget
under load, I could get it around the driveway. We knew the light to be
good, but it was working erraticatly, and the timing mark was jumping
I did at one point get a ECM code 33 and 43 (knock sensor?)
I knew there was something else I was missing. My father and uncle (who
are old-school mechainics working in a work of EMCs and whatnot) were of the
idea that I just needed to "get it on the road, run it hard for a few days
and it would staighten out". Then I remember about "the tan wire". So I
grabbed a new timing light, and without disconnecting the timing connector
(tan wire), tried the new (induction style -- fancy!) light. It jumped
around just as before. I disconnected the connector, and tried again, and
the mark was nice and steady -- but I would guess -- it was 15° ADVANCED.
They wern't kidding in the book about the ECM being able to retard/advance
So I set the mark right at where I think 0° BTDC is supposed to be. The
scale on the damper pully is rusted a bit and I can't make out the numbers.
I compared it to a '88 Silverado, and I think the markings are (from right
to left) 0, 8, 12. 0 being the resessed arrow, then 8 being the 2nd
protruding arrow, and the 12 being the third. So I set it to the 0° mark.
Reconnected the timing wire, reset the ECM, started it back up and it
struggled to idle, then it idled after about 15-30 seconds. My SES came on,
and idled a bit, then stalled. I checked the codes and got 33 (MAP sensor)
but no more 42 (the 42 had to be because we were messing with thedistributor
while it was trying to compensate.)
At this time I could mash the pedel and it would come back strong and no
smoke, so I thought all was well. After about 1-2 minutes of idleing, it
started to hesitate as I was going to take it for a test drive, then
So I said, ok, the MAP sensor was looking old -- So I bought a new one.
Reset the ECM, no change. Then I started reading my books and said well
maybe it's my EGR valve. I did warn about solvents, and I did have that can
of carb cleaner ;) -- so off to the local store to get that.
Installed that with the correct restrictor washer and gasket, still the
I've checked every vaccume line I can see/find. They all look ok, but I
THINK I can hear a vaccume leak. I know how the engine usually sounds, and
there is an extra "sorta vaccume leak" sound.
I think that covers everything I did.
Any help is appreciated,