92 s10 blazer:glowing exhaust manifolds

Ok guys my 92 had (before motor rebuild) and still has the same power lose as member Drive24's did even after a fresh rebuild, now I can't get the timing to stay in one spot and I noticed this morning that while trying to set the timing the exhaust manifolds were turning fire red. When I first turned it over without the exhaust pipes on, I noticed fire shuting out of the exhaust manifolds, I thought it was from no back pressure, but now I dont know. still dont have power going up hills. any thoughts???? Thanks

Ok guys my 92 had (before motor rebuild) and still has the same power lose as member Drive24's did even after a fresh rebuild, now I can't get the timing to stay in one spot and I noticed this morning that while trying to set the timing the exhaust manifolds were turning fire red. When I first turned it over without the exhaust pipes on, I noticed fire shuting out of the exhaust manifolds, I thought it was from no back pressure, but now I dont know. still dont have power going up hills. any thoughts???? Thanks

This happened to my 2001 only the exhaust pipes were red but I didn't check the manifolds.

What is happening is unburned fuel is being blown into the exhaust system and igniting when it hits the hot metal. MY PROBLEM was the distributor itself. The distributor shaft bearing/bushing was worn so bad that you could wiggle the shaft from side to side over a half inch. The Rotor inside the distributor finally broke off inside of the distributor and the engine quit all together.

$1600, two catalitic converters, a new distributor, O2 sensors, and few other parts later, we're good.

DO NOT DRIVE OR START THE VEHICLE UNTIL YOU FIGURE THIS OUT OR YOU WILL IN ALL LIKELIHOOD DO MORE DAMAGE.

The spark should be controlled by the ECM, and should not be jumping around. Remove your distributor cap and try to wiggle the shaft from side to side, it should not move more that a few thousandths of an inch. If you can wiggle it by hand, you will need to rebuild or replace your distributor.

Good Luck

would that also make it sound like it has a slight exhaust leak?

plugged cats could cause that!

would that also make it sound like it has a slight exhaust leak?

I am sure it probably would. With the exhaust system taking on all of the added temperature and pressure that it isn't design to take not to mention the metal expansion due to the high heat, I would be surprised if it didn't leak. Mine melted the Cats and the O2 sensors.

I would take this one step at a time. Find the timing issue first then see about any possible leak.

plugged cats could cause that!

He said it was happening even without the manifolds on. This is unburned fuel blowing out of the combustion chamber. But you will Melt, plug, and destroy the cats if you keep running the engine like this.

ok checked distributor, cant move by hand. when moving the timing i notice when i get to 0 degrees it jumps up to about 4, when it get it back to 0 from there it drops to about -6. I have not changed the EGR valve out just cleaned, new o2 senser. the fire red on the manifolds where on the #3,5, and 6 cylinders after driveing 15 miles( if that makes sense) . Do I need to change out the EGR valve or would another senser make this happen??

also I was told by a mechanic (when I had it inspected) that the high idle was from running lean, and I needed to change the EGR valve. But all I did was clean the sticking plunger????

Are you getting any SES lights or Check engine lights or codes? According to the mechanics that fixed mine, the ORIGINAL problem was a bad MAF sensor. I am not 100% convinced of this, but they claim that is what started the problem. It was throwing codes, but I think most of my problem was the distributor. In any event, they zonked me for $300 for a new MAF sensor claiming I would repeat the entire episode if I left the old one in there. Whadda going to do?

havent checked codes, but the only time i get the check engine light is when im checking timing.

I dont have a reader for this blazer. only thing i know to do is jump out the 2 terminals and count the flashes.

I dont have a reader for this blazer. only thing i know to do is jump out the 2 terminals and count the flashes.

What are the codes?

would that also make it sound like it has a slight exhaust leak?

plugged cats could cause that!

That should make it a little clearer on what I was replying to.

only getting 3 codes, 22, 23, and 42

only getting 3 codes, 22, 23, and 42

See this thread in the How-To section. Thanks Blazee:

http://www.automotiveforums.com/vbulletin/showthread.php?t=553044

ok thanks, 22 is tps, 23 IAT, 42 unpluged EST, but would this cause unburned fuel in the exhaust? also when adjusting timing which mark should be on 0 degrees at #1 piston at TDC on compression stroke?

ok, with #1 at TDC on the compression stroke, the distributor is at 12 o'clock facing the front of the engine so im not 180 out there right?, on the timing marks the trailing mark is on 12 degrees BTDC. Is this the correct timing?

could it be possible that i am one one wire of on the cap?

bad cats can cause that!

ok, with #1 at TDC on the compression stroke, the distributor is at 12 o'clock facing the front of the engine so im not 180 out there right?, on the timing marks the trailing mark is on 12 degrees BTDC. Is this the correct timing?

If #1 is at TDC on the compression stroke, does the rotor point to the #1 spark plug wire on the cap? Trace the wire up from the plug and make sure you have the correct wire if you have to. You may have to hold the cap above the distributor and get a good eye ball on it but you should be able to tell if the rotor is lined up with the correct wire. If you are 180° off, the truck will not start.

When you install the cap in its proper location everything should be static timed close enough to start the truck.

Is the a TBI engine or CPI engine? Is it a balance shaft engine? When your adjusting timing, base timing, and your on number one, is it jumping around at that point? Does it (the timing) change when you rev it up to about 2000RPM? If its jumping around when you setting base timing, you have a problem to solve right there before going any further. Were the timing chain and sprockets replaced when it was rebuilt? If its a balanced engine with the balance shaft, how were the sprocket gears on the balance shaft and the cam? These have to be tight, if they are loose as a result of wear, this can cause timing issues. Also, like Rick mentioned, was the distributor/distributor shaft checked closely? A worn shaft and/or gears can cause problems too.

You have to get base timing to be accurate and constant first, anything less and the engine will be all over the place.

Is the a TBI engine or CPI engine? Is it a balance shaft engine? When your adjusting timing, base timing, and your on number one, is it jumping around at that point? Does it (the timing) change when you rev it up to about 2000RPM? If its jumping around when you setting base timing, you have a problem to solve right there before going any further. Were the timing chain and sprockets replaced when it was rebuilt? If its a balanced engine with the balance shaft, how were the sprocket gears on the balance shaft and the cam? These have to be tight, if they are loose as a result of wear, this can cause timing issues. Also, like Rick mentioned, was the distributor/distributor shaft checked closely? A worn shaft and/or gears can cause problems too.

You have to get base timing to be accurate and constant first, anything less and the engine will be all over the place.

The timing chain and sprockets was my next item up for discussion, but you beat me to it. Here is a good way to check for a loose or sloppy timing chain that is free and easy.

Get a (½ inch drive) socket that fits the bolt head on the front of the crankshaft (Harmonic Balancer), maybe a short extension and a breaker bar or a ratchet, remove the distributor cap, and slowly turn the crankshaft in the normal direction using the socket wrench to take the slack out of the chain. Once you see the rotor in the distributor move in its normal rotation, stop, mark the balancer with a piece of chalk or black marker, then reverse direction and rotate the crankshaft in the opposite direction until you see the rotor start to move in its opposite direction, then stop and see how much the mark moved before the rotor moved.

If the Timing Chain and sprockets are loose and sloppy, the mark on the balancer will move quite a bit before the rotor begins to move in the opposite direction. You can expect to see a little movement of the mark before the rotor moves but not a lot of movement (sorry if this is a little vague). The last time I did this on an engine, I seem to remember the mark moved over an inch, and I could not keep that engine timed either and ended up replacing the chain. At any rate, the more slop in the chain, the more movement you will see, and eventually if left unrepaired, the chain will jump a tooth on the sprocket. If necessary, try this on a good engine for comparison to get an idea of what a lot or a little movement should be. You may need to rotate the crank back and forth a couple of times to get the hang of it.

If you determine that you have too much slop in your Timing chain, your only option is to replace the chain and sprockets. And BTW, if you do end up replacing them, I stay away from the plastic coated sprockets and try to get the all metal sprockets. The idea behind the plastic sprockets is noise reduction, but I will tolerate the slight amount of additional noise for a sprocket that will last longer.

The timing chain and sprockets was my next item up for discussion, but you beat me to it. Here is a good way to check for a loose or sloppy timing chain that is free and easy.

Get a (½ inch drive) socket that fits the bolt head on the front of the crankshaft (Harmonic Balancer), maybe a short extension and a breaker bar or a ratchet, remove the distributor cap, and slowly turn the crankshaft in the normal direction using the socket wrench to take the slack out of the chain. Once you see the rotor in the distributor move in its normal rotation, stop, mark the balancer with a piece of chalk or black marker, then reverse direction and rotate the crankshaft in the opposite direction until you see the rotor start to move in its opposite direction, then stop and see how much the mark moved before the rotor moved.

If the Timing Chain and sprockets are loose and sloppy, the mark on the balancer will move quite a bit before the rotor begins to move in the opposite direction. You can expect to see a little movement of the mark before the rotor moves (sorry if this is a little vague). The last time I did this on an engine, I seem to remember the mark moved over an inch, and I could not keep that engine timed either and ended up replacing the chain. At any rate, the more slop in the chain, the more movement you will see, and eventually if left unrepaired, the chain will jump a tooth on the sprocket. If necessary, try this on a good engine for comparison to get an idea of what a lot or a little movement should be. You may need to rotate the crank back and forth a couple of times to get the hang of it.

If you determine that you have too much slop in your Timing chain, your only option is to replace the chain and sprockets. And BTW, if you do end up replacing them, I stay away from the plastic coated sprockets and try to get the all metal sprockets. The idea behind the plastic sprockets is noise reduction, but I will tolerate the slight amount of additional noise for a sprocket that will last longer.
ahmen brother,the metal sprokets are the rght way to go if u need them!:biggrin: