Totally lost

[snoman]

*This is kind of long, sorry*

I need the advice of someone more experienced than me at troubleshooting the SHO. I probably look like a bumbling newbie lately with my latest threads where I sound like a *******, but when it comes to really tearing into this engine I am a newbie.

OK, so I went in and changed the CPS/CKP and thought all would be right with the world. I did this because I had the symptoms(turning over but no starting...little while later it starts...shut her down, 5 mins later no start) and had a new one lying around so I figured what the ****. Get it in there, everything put back together, turn it over and no pop. It turned over but sounded like it didn't want to start. So we then began to play to try and figure out why it wasn't firing. Pulled out a plug and grounded it on the engine to see if we had spark and we did. Smelled fuel so there was some (didn't know how to check pressure). So we figured to let it sit for a while and think about it while we put new springs and shocks in. Come back to it and then everything starts to take a nose dive off a cliff. Turn it over, turns over but sounds awful. Hooked up friends truck to the battery through jumpers. Turn over but no fire. Then the negative terminal sparked, which I thought was weird, and then nothing. Just clicked and nothing. We pulled the battery totally out of the equation and tried again. No turning over of any kind, there was a click but no turn. So we pulled the starter, tested it and it worked fine..........ok fine. Put it back in and tested it when I turned the key, no power getting to the top terminal that turns the brushes. The wire going to that terminal is coming from the car not the battery cable. So we then decide to try and turn it by hand, no movement. So we dig down to the crank without the harmonic dampner on it, it moves about 60 degrees either way and then is impossible to move. I'm at a total loss of what it could be. I hope it may just be something to do with the clutch area and not inside the engine. ANY help or suggestions would be most welcome. This has to be one of the most frustrating things I've ever had to deal with in my life.......and I hate having to drive my parents mini van all over, you wouldn't believe how much **** I get at work and from friends. Anywho, thanks again, hopefully you guys can help before I take the long jump tied to a short rope.

 

[NotSoSlowSHO]

You say that you tried cranking it by hand, and it wouldnt turn beyond a certain point? Im thinking timing belt...

You also said you replaced the CPS, as in CAM sensor, or CRANK sensor?

If you replaced the crank sensor (located behind the Big bottom pulley (dampener) you must has removed the timing belt.

We need more info.

 

[snoman]

You don't need to remove the timing belt to get at the crank sensor, so no, I didn't remove the timing belt. CPS/CKP = crank position sensor

We were going to remove the timing belt tonight and check to see if the cam sprockets were causing the jam up or if it was coming from the crank itself. I was a little hesitant because I didn't know if doing that would cause the pistons to impact the valves or not. any idea? again, hopefully this doesn't turn out to be an internal engine problem because as much as I'd like to tear her down and rebuild, my transportation and fundage say new car........and that makes me sad.

 

[shoteen95]

pretty sure the v6 is a non interference engine and the pistons cant touch the valves

talk about confusing..if the timing were messed up would this allow the air/fuel charge to ignite outside of the combustion chamber damaging anything? ofcourse if it were internal wouldnt the starter still crank if the engine can be rotated manually, even just a little..

 

[Slo-Sho]

Did you set the gap to .030? Does the check engine light go OUT when you crank the motor? It also sounds like you have a bad/corroded battery cable(s) and/or connection.

 

[snoman]

I didn't set the gap when I put the sensor in cause I didn't know I had to, so I centered it up on the timing vanes so it wouldn't hit. Oh, and that negative battery terminal, we just cut that off and are going to get a new one.

When I try to start it up now, the whole dash seems to loose power/goes dark and the starter only clicks. Could there be a short somewhere in the electrical system that could be causing the power drain? My BCM has been acting up for sometime now, maybe a short somewhere along there causing a spike through the whole system?

Could it maybe be something in the clutch/flywheel area that's jammed up the engine somehow? I'm totally confused on why the engine won't turn manually. I'm pulling as hard as I can on that thing, and I'm not exactly a small guy, but it won't budge.

 

[snoman]

...ttt...

 

[k_mesaros]

pretty sure the v6 is a non interference engine and the pistons cant touch the valves

Mine did. Right after the rod exited the rear of the block through a hole about the size of a CD.

Kevin

 

[Denny]

Check the gap on the CPS with the vane. Make sure none of them are bent either. Are you sure you didn't move the timing belt? I can see how you can remove the CPS without removing the belt....but I've never thought of doing it that way, just removed it, removed the sprocket on the crank, removed CPS, installed new, installed sprocket, check gap and correct as necessary, then belt.

 

[Denny]

Oh yeah, if the spark plugs are in, you will have a hard time turning over the engine by hand. If you have the driver's side wheel on the ground and the pass side up on a jackstand, with vehicle in gear you can move the engine by turning the passenger side wheel forward. That's so long as the plugs have been loosened to let air out.

 

[SonicRiot]

So we then decide to try and turn it by hand, no movement. So we dig down to the crank without the harmonic dampner on it, it moves about 60 degrees either way and then is impossible to move.

WHOWHOWHOA!!!


STOP! Hold on! Before you do anything and snap a wrench or strip or break the crank pulley bolt!!!


Unless you weigh 300 LBS and can bech another 600 on top of your weight, you are NOT going to be able to turn that engine over! It's called compression and it must exit the combustion chamber before you can turn! Pull the spark plugs and THEN see if it turns over by hand! The air will rush out the plug holes. Even then, the engine will be somewhat difficult to turn over. Also, make sure the car is not in gear.

OK, so I went in and changed the CPS/CKP and thought all would be right with the world. I did this because I had the symptoms(turning over but no starting...little while later it starts...shut her down, 5 mins later no start) and had a new one lying around so I figured what the ****. Get it in there, everything put back together, turn it over and no pop. It turned over but sounded like it didn't want to start. So we then began to play to try and figure out why it wasn't firing. Pulled out a plug and grounded it on the engine to see if we had spark and we did.

Never throw parts at a car, especially when you have an electrical issue. You become a monkey fornicating a football. Diagnose the DIS and ignition system. There is a good writeup by (IIRC) PheonixSHO. Break out the multimeter.

And check the battery voltage while you are at it. I should be between 12.2 (low) and 12.6 (fully charged) Volts.

Turn it over, turns over but sounds awful. Hooked up friends truck to the battery through jumpers. Turn over but no fire. Then the negative terminal sparked, which I thought was weird, and then nothing. Just clicked and nothing. We pulled the battery totally out of the equation and tried again. No turning over of any kind, there was a click but no turn.

Did you hook the terminals up correctly while jumping the car? If not, you destroyed your battery and your control unit and possibly many fuses. Sparking is a normal occurance if the cable clamp is moved so that the electricity arcs to the battery terminal or if there is a bad connection or a lot of corrosion on the terminals, but still, LOTS of sparking is bad.

Smelled fuel so there was some (didn't know how to check pressure).

Stick an awl (or pencil that you can throw away) in the schrader valve on the fuel rail for a split second. Stand back, do not use fire stuffs, and keep your face clear. Put a rag over it if you want. It should squirt out. This will tell you that at least you have SOME pressure at the rail.


Hope this helps. Good luck.

 

[GEORGE 1992]

When things go wrong after you work or replace something on the engine when it did run before, I,ve been told, it must be something I did during that project. So, The guys above are on the right track. Would not lean towards the tranny end hanging up the engine. Most likely a step in what you did.
I wish I could tell you I do not know how you feel.

 

[Slo-Sho]

WHOWHOWHOA!!!


STOP! Hold on! Before you do anything and snap a wrench or strip or break the crank pulley bolt!!!


Unless you weigh 300 LBS and can bech another 600 on top of your weight, you are NOT going to be able to turn that engine over! It's called compression and it must exit the combustion chamber before you can turn! Pull the spark plugs and THEN see if it turns over by hand! The air will rush out the plug holes. Even then, the engine will be somewhat difficult to turn over.

This place is great entertainment! I love it!

I can turn the motor over with my own two hands using only the dampener (using gloves of course). I know because I've had to do it to time the motor. Granted the timing belt was off but thats neither here nor there. Also a trick to get the cam gears TDC is to use the old belt acting as a strap wrench...works wonders and your hands won't have indentations from the gears.

On a side note, said motor has pulled a steady 22" of vacuum at hot idle...just in case you were wondering about the compression.

 

[Slo-Sho]

Oh, and another thing...by your calculations what starter can produce 900 ft/lbs of torque?!? That's ungodly!

 

[SonicRiot]

I can turn the motor over with my own two hands using only the dampener (using gloves of course). I know because I've had to do it to time the motor. Granted the timing belt was off but thats neither here nor there.

Uhhhhhh.... it IS here AND there! Don't you realize that the valves seal off the combistion chambers... and by having the cams freewheeling the combustion chambers are not sealed off... like a poorly timed engine... or a broken timing belt...

Oh, and another thing...by your calculations what starter can produce 900 ft/lbs of torque?!? That's ungodly!

This was obviously a gross exaggeration... a joke. Ha. Laughter.

 

[Slo-Sho]

Well I suppose if you want to get technical, it's unlikely all 6 cylinders had atleast two of the four valves open at any given point while I manually rotated by hand the motor over atleast one full revolution of the crank. You induce many belly laughs. :laugh_ti:

 

[SonicRiot]

The cams may "spring." This would mean at least one valve is cracked in every cylinder. That's all it needs to release compression. Thus, the engine will turn over without much effort.

If it turns over too easily, I'd be worried. If it spins loose for more than one rotation, you have issues.

 

[Slo-Sho]

The cams were at TDC when I turned the motor over by hand. I didn't know one valve could be open on a DOHC motor. You must have custom dual pattern cams.

 

[SonicRiot]

A small displacement engine such as a four banger or lawnmower CAN be turned over without allowing the air to come out of the chambers during compression stroke by taking the spark plugs out. But they are SMALL and have less friction to deal with, generally lower compression, and a LOT less valvetrain tension to overcome. My buddy can use a long, long breaker bar to turn over his 1991 Celica GT engine without removing the plugs. But the egine is sporting 160K and is small.

In general, they still cannot be turned over by "hand by the average human." Use a breaker bar... work smart, not hard.

As for an engine such as the SHO, the compression is high and is hard to overcome. Removing the spark plugs will help ease the cranking. Try taking out the spark plugs and firing up the starter. Listen to how easily it spins over with no compression. Sometimes it will even keep spinning after the cranking from the starter.

Also, there is drivetrain tension to overcome. There's 4 valves per cylinder in this particular engine. Those valvesprings are tight and are tough to compress by hand OUT of the engine.

So, for you to say that the engine can be turned over by hand (with dampner) while the timing belt is OFF is a much story than trying to turn it by hand with the timing belt ON and the cams properly timed.

Two things occur with the timing belt off: The cams may "spring" and relax to a position that at least one side of the combustion chamber is open to the air (intake OR exhaust). The air will escape out the cracked valves. Also, there is no extra tension on the crankshaft during the rotation. Thus, it is MUCH easier to turn the engine over.

Don't believe me? Try it.



P.S: when I said "at least ONE valve is cracked or open," I was speaking in general, not neccessarily about a specific DOHC 24 vlave sixer... this theory is basic and applies to all engines. So lets say I had a 350 V8 with 16 valves in mind.

 

[SonicRiot]

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