1988 Chevy 350 - HELP!

I tried to post this last night from home, but I don't see it this
morning at work. If this is a duplicate post, I apologize.

> Okay, I'm about at my wits' end, and I'm about to start pulling out
> hair.
> If anyone has ANY suggestions, they would be GREATLY appreciated. This is
> my first "play" vehicle with TBI, so there's a bit of learning involved
> here. Bear with me.
>
> Vehicle - 1988 Chevy K1500 350 (5.0L) TBI 4x4
>
> Problem - will not start
>
> Here's the low-down. The truck had set for 2 years when I bought it.
> Basically, I charged the battery and it started right up. I noticed that
> the idle was a little high, but other than that, it seemed to run fine. I
> ran a couple of tanks of gas through it and all seemed to be okay, but I
> noticed the idle seemed to be getting higher. It was getting tough to
> hold it back at a stop light, so I figured I should do something about it.
> The first thing I did was I had the fuel system "cleaned" or "flushed", I
> can't remember what terminology they used. It seemed like it helped a
> little bit, but after a very short time (less than a day), they idle
> climbed back up to where it was, if not higher. The next thing I did was
> I replaced the IAC. Again, no help. Then I general tune-up. No help. I
> continued to drive it, and it seemed to get worse. Then one day I noticed
> it was very difficult to start. Once I got it running, I got about a half
> mile down the road and it quit. It smelled like it had flooded itself
> out. I got it started again by holding the throttle to the floor, got it
> back home and parked it. I replaced one part at a time, and started it
> after each replacement to see if it was right. Each time I tried, it
> seemed harder to start. To me, it seemed like it was flooding out. Now,
> it will not start at all, and rarely even "hits". I've checked the
> injectors, and they're both giving what appear to be good, symmetrical
> cones of fuel. I've checked the electrical system all the way to the plug
> and it seems to be getting fire. I read in this NG about these engines
> being susceptible to gasket deterioration between the TBI and manifold.
> After reading that, I just presumed this was the reason for my high idle
> (getting worse) and then to the point of it wouldn't even start. I picked
> up a gasket today, confident that it would solve my problems. I replaced
> it, and still nothing. I'm at the end of my rope here lol. Any advice is
> welcomed. Here's a list of everything I've replaced to date -
>
> IAC valve
> MAP sensor
> distributor rotor button
> distributor cap
> spark plugs
> plug wires
> air filter
> fuel filter
> ECM
> O2 sensor
> TBI gasket
> ignition coil
>
> I checked the TPS with an ohm meter and it tested fine
> I moved the crank shaft so the harmonic balance was at 0 degrees and
> checked the distributor to make sure it didn't jump time - seems fine.
> I've tested the spark using a screw driver in the end of the wire and let
> it go to a ground. Did this on cylinders 1 and 3, both were fine.
> I precisely marked the distributor location, and moved it ~10 degrees in
> each direction to see if it's a timing issue - no effect what so ever so I
> moved it back to its original setting.
> Another reason I thought maybe it was a vacuum issue is because the inside
> air controls will not switch to "defrost" - continues to blow through the
> dash vents
> I've checked ODB1 codes early on and it gave me codes in the 40's - lean
> and rich mixtures, and a reference to the MAP sensor. No real help there.
>
> At this minute, the engine will not start, but after every 10-20
> seconds
> of cranking, it'll give a quick little "hit", but never start. Sorry for
> the long post, but I wanted to be as detailed as possible. Thanks for
> your help!
>
> - Jeff
>
>

Sound To Me Like The Tbi Is Cracked Or There Is A Stuck Injector. If It
Was Flooded Then You Should Pull The Spark Plugs And Dry Them With A
Lighter Or Just Put In New Ones Agian.{ Once Plugs Get Wet With Gas So
Many Times They Become Junk.} I Would Replace All The Plugs. When You
Pull Them Crank The Engine Over To Clear The Cylinders. Then Put In The
Plugs. Before You Start The Motor Double Check That The Wires Are On
Correct. Rotation Is Counter Clock Wise- Order Is 18436572- Another
Thing Could Be The Fuel Regulator Is Stuck Closed And There Is To Much
Pressure. Try Changing The Plugs As I Said And See Where You At. Ps. A
350 Is 5.7 Liter And A 305 Is A 5.0 Liter. Good Luck.


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Thanks for the response. I'll replace the plugs this afternoon. Where
is the fuel regulator? Is it a pain to get to? I may check it, too.
The 5.0 was more of a type-o, kinda like 3"50". Good catch, though.
And for the record, the distributor spins in a clockwise motion, not
counter-clockwise Like me, I'm sure it was just a type-o. Any more
suggestions??

- Jeff

Well, you were 100% right. For some reason, the new plugs I put in
must have some how gotten fouled. I went home at lunch and put a new
set of plugs in and it took right off. I didn't have time to let it
run up to operating temperature, but it's running, and that's certainly
better than where it was as of this morning. Now I can tweak it if
need be. It's a little embarrasing to think that I pounded my head
against the wall for a week over this, and something as simple as spark
plugs was the answer. But a fresh perspective always helps. Once
again, thanks a million!!

- Jeff

now look into you dash problem and you might find a vacuum leak that is
causing a high idle

Once again, thanks for the responses - but I think I declared victory a
little early in this one. Let me follow up:

Like I said, after I replaced the plugs, I got it started, but didn't
really have time to let it run for long. When I got home, I took the
truck down the road for a test drive. About a mile later, the engine
stalled again and smelled like it had flooded - again. Which makes
sense.... Plugs usually have a reason for fouling. My hope was that
what ever cause it was one of the 50 parts I had already replaced. I
got it running again by disconnecting one of the injector terminals and
limped home with it. I replaced the fuel regulator diaphragm and
spring, still the same. I sat in the engine well, with the engine
running on one injector, absolutely distraught. Couldn't figure it out
for the life of me. And then, I looked down and saw a small sensor
next to the water "goose" neck. I figured I had replaced everything
else, I'll see what this did. I unplugged it, and the idle settled
right to where it should be! I connected the other injector and it ran
like a top. I looked out the side and it had stopped smoking like a
freight train. As it turns out, the Electronic Coolant Temperature
(ECT) sensor had bitten the dust and was causing it to run EXTREMELY
rich. Like I mentioned in an earlier post, this was the first TBI that
I had ever worked on. I didn't know what was the proper amount of fuel
from the injectors. After I unplugged the ECT, the fuel flow went from
an absolute deluge, to a small trickle. It's idles perfectly and runs
great. Talk about a burden that's been lifted. I suppose the moral of
this story is "if a TBI is flooding out, check the ECT sensor!". If
this thread helps to save some poor soul (like me) some time and money
years down the road, it'll be time well-spent!

-Jeff