Re: 97 Suburban major engine problem

My Name wrote:


I would start by pulling the air cleaner housing off and looking very hard for something shorted out from water, something that's come loose, jammed up, etc... I believe you probably managed to disconnect or short something that's causing the computer to totally spazz out.
Ray
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The water in the filter cannot reach the injectors, the are seperate from the aiflow. I wonder if you have checked engine vacuum, if it is very low the Cat may be bad, this would cause a loss of power, but the miss is hard to figure. Also check the O 2 readings on the scanner that will point you in some direction also.

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As you have said.. the water from the filter does not get into the fuel injectors. I have been thinking this all along but most everyone that I have talked to says that it sounds like fuel injector problems. As I said earlier this engine ran great until I got the filter wet. The wet filter got the MAF sensor wet and damaged it (it has been replaced) and in my thinking this in turn screwed up something else that is causing it to have to multiple cylinder misfire. The scanner test no longer comes up with a bad MAF. The only other error from the scanner is MCM. As I said to someone else that has tried to help me out..........I have thought of purchasing a new engine but am afraid that it won't run any better because the misfire problems are not in the engine itself but in the so called "brains".
Thanks for you help MJ

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You washed the air filter? On or off the truck ;) You cant do that, well er.. I guess you did.
Sounds like the water has worked its way in to the ignition system. Does this Vortec have a Cap and rotor? If so, dry it out. Also inspect the wires.
If you got water into the intake you might have caused hydro lock when you started it. That can cause a cracked head, block, and other problems.
Cheers
Martin

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I did not get anything wet other than the air cleaner and that was damp not soaked. Nothing near the distributor or spark plug wires is wet. I recently replaced the wires and plugs. I did remove the number one plug and looked at it to see that it still has the proper gap (platinum plugs)...the plug is dry and covered with black soot. I am planning on removing the plugs tomorrow (I would have done it sooner but my back went out on me six days ago......like the engine problem isn't enough) and check out the compression on each cylinder. One thing that is really puzzling me is the fact that it starts up so easy.
Thanks for your input MJ

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wrote:

Now we know it's running rich.

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This may seem obvious and you probably already considered it. You spent a lot of money already and surely went over everything that you touched. My question is just how wet did you get this air cleaner when you washed it? If that paper was wet when you started it up there just could have been enough water pulled into a cylinder to bend a rod or two. It really takes very little and water could have been hanging in the pleats ready to get sucked in. Experience shows that you can drive into a puddle and stall an engine due to water. Dry everything out completely and replace the filter and you are OK. Try to start the engine with that wet filter and the engine can be toast. That is essentially what you say you did. Do your own compression test and you will know the answer.
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I went through much hell with my S10 waste spark system until i realized the plug wires could make it run that bad. (I had MCM too on a code scan) Worse when it was damp or wet. I would put new set of FACTORY wires on it and change the plugs. Inspect the plugs while you at it for signs of deposits (shows which are misfiring). Look closely for any vacuum hose that might have come disconnected or accidentally cut. Maybe you will get lucky?
Bob
My Name wrote:

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Did you by chance wash the engine down at one of those quarter washes. If you did try changing your plug wires. Its a shot.

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As I have said to others, nothing is wet. The engine has never been washed. The friendly dealer says that I need a new engine. I could be wrong but it seems to me that after installing a new engine I am going to have the same problem. As far as I know new engines don't come with CSFI fuel injector systems or throttle bodys.
Thanks for your input MJ

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One of the few things that I am sure of it that the plug wires are dry. I will remove the plugs and inspect for any cylinders that are different than others.
Thanks MJ

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do a compression and leak down test. if something is wrong that is THE way to find out without pulling it apart.
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My Name wrote:

One thing i did on my s10 was to put my timing light on each plug wire to check for output. On the defective ones, it would not flash as bright or was intermittently flashing. A cheap a quick test for dead or intermittent firing. Not fool proof, but it found my bad ones. Could be a bad coil pack too. I take it you coolant sensors checked ok on the scans? A stuck coolant sensor could tell the computer the engine was ice cold and rich up the mixture. Or maybe a intermittent connection on the sensor? You might find out where it is and check the connection for corrosion. Would not be that expensive to change out. Note: this sensor may NOT be the one the controls the temp gauge on the dash.
BOB
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No I did not wash the air filter while it was in the truck. I shook it out to be as dry as possable. I have removed everything down to the throttle plate and everything is bone dry. The only thing that I can think of that could get wet is the MAF sensor that did go bad but I have replaced it. It is such a misfire that I too think something is causing it to fire at the wrong time like you have called it a "computer totally spazzed out". What can I do to get it to fire correctly again?
Thanks for your reply MJ

completely
Vortec
great.......until
a
cleaner
the
very
it
rough
two
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wrote:

Any time a vehicle develops a (new) symptom after a 'repair' the first thing to suspect is the repair itself. It rains on cars and MAF sensors get wet all the time and the vehicle still runs OK. I would look very hard at vacuum lines knocked loose, disconnected wiring, etc. Keep in mind that the person who did the repair is going to have the hardest time finding such a fault as it was overlooked the first time.
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I don't know if this engine uses a MAP sensor as any part of fuel control, but water may have gotten into it thru the vacuum hose, remember these sensors really are not used till the engine is in closed loop, I can't see a new engine required here, if so why would it run ok till warmed up, there is a piece of the puzzle missing with the engine diagnosis.

completely
great.......until
cleaner
the
very
rough
two
I
40mph).
I
that
test.
I
compression
with
tell
do
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Yes it does have a MAP sensor located in the intake manifold behind the throttle body. It does not show up as defective when using the scanner. The engine does not run OK until warmed up...instead it does start up easy, it will run with enough power to get up the driveway (or get it onto a flat bed trailor). But as it warms up it looses more and more speed and power until it will no longer run. When it is running it smells like a very very rich mixture (like its running with the choke closed). The check engine light is on steady for awhile and then it goes to a blinking state.
thanks again for your support MJ

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wrote:

That was indicated by the black plugs.

I'm surprised there are no other codes indicated as the MIL on steady would seem to suggest this. The blinking MIL is an indication that engine misfire has been detected.
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I'd have to check a diagnostic chart and don't have one here. So,it's running rich,like it's cold.Does it have a MAT sensor.If it indicates the manifold temp is freezing the comp will richen the mixture.You may not have had it running long enough to set code. Just a guess. Good luck.
wws

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On Sun, 20 Jul 2003 10:29:38 -0400, "David J and Lynne J Shepherd"

The MAP sensor is only used in running the EGR diagnostic on this engine. I doubt that it could be the cause of any drivability concern unless the vacuum hose itself were leaking.
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