You've got the coil pack harnesses swapped, or the cam is in 180° off

Since you verified the cam is in right and you haven't smashed valves by now <img src="gr_eek2.gif" border="0"> it's gotta be the coil packs.

cyl 1 is the first to fire, and 6 is the 5th to fire.

The passenger side bank should have the white stripes on the wires of the coil pack connector. The driver side has no stripes. Both connectors have the same base color wires.

 

IF the signs of the timing chain gears are
correct (crank gear sign is upside and camgear sign is downside, like stated in the service manual that is firing position cyl #1) then the cam should be right in, is that correct?

Can the coil packs be on the correct side and only the connectors be connected swapped (I mean can the connector from the drivers side coil packs be connected to the passenger sides), or won`t that fit.
If not, then my mechanic must have installed the complete coil packs on the wrong sides?? Is that possible??
I think he left it on the valve lids??


Just talked to my mechanic and he sais he doesnīt think he meixed it up as the wiring has given lengths(passenger side goes to the throttle body...) and that makes it nearly impossible to swap the coil packs.
Is that correct??

Thanks,
Michael

[ March 09, 2002: Message edited by: Austrian Vette ]</p>

 

The coil packs themselves are identical, side to side.

So it won't make a difference if you swap the packs from one bank to the other.

It's the connections from the engine harness to the coil pack harness that is in question. The plugs on each coil pack are identical, and you can plug one into the other and not notice a thing. That's why i said check for the white strips on the wires for the passenger side.

The cam is in right. Unless you have a really flakey cam sensor, it should be right.

check the plug that plugs into the gray connector in the center of the coil packs. See if the wires have white strips on them, and make sure the striped ones are on the passenger side.

 

Iīll check it tomorrow!

Any other ideas what could cause my problems??

Is it possible that the cam has a wrong grind
for the cam pos. sensor (180° off)??
Could such a thing cause the problem then or is still the crank pos. sensor telling what cyl. has to fire??

Michael

[ March 09, 2002: Message edited by: Austrian Vette ]</p>

 

Yeah

A cam grind w/ the tooth 180° off will do exactly the same thing. assuming the coil packs are plugged in right.

The crank sensor only knows 4 cylinders, it takes the cam sensor to figure out which 4, the first or last.

That's way you're on number 6 instead of number 1. It's firing the wrong half of the engine cycle. so, if it's not the wires, it could be a bogus cam grind or a bad sensor.

 

Thanks for the help, I appreciate it!!

About the cam:

If it is 180° off, would I have compression then when the timing gears are lined up (#1 firing position??). Think no (not sure), but I do have!
Only that damn #6 spark plug is firing instead #1.

Can that be that the cam is correct and only the rear part (where the cam pos. sensor reads) is 180° off??

Michael

 

[quote]Originally posted by Austrian Vette:
<strong>Can that be that the cam is correct and only the rear part (where the cam pos. sensor reads) is 180° off??

</strong><hr></blockquote>

I guess anything is possible <img src="images/icons/rolleyes.gif" border="0">

But if you have compression at the right time, the pickup for the cam sensor is off or the harness is swapped.

I vote for the wires <img src="gr_stretch.gif" border="0">

 

How can I find out if the cam pos. sensor doesnīt work?? It looks not damaged.

Also the service manual sais that even with a non functioning cam pos sensor, the engine would start and run???? But how would it run?? If the cam pos. sensor doesnīt read, then the PCM doesnīt know what bank to fire??

So I hope the wires are wrong!

But my mechanic sais he desnīt think he mixed them up as they have other connectors on them that cannot make them mix up, like the throttle body and maf sensor.....

Iīll look at it myself.
Hope heīs in the office, tomorrow.

Michael

 

DOt to dot is not TDC #1 on compression stroke, i know this from Gen 1 small blocks, it probably is #6, now im not sure where yopu went wrong from this point but i thought you should know this.

 

[quote]Originally posted by LS1derfull:
<strong>DOt to dot is not TDC #1 on compression stroke, i know this from Gen 1 small blocks, it probably is #6, now im not sure where yopu went wrong from this point but i thought you should know this.</strong><hr></blockquote>


You sure???

Iīm pretty sure the service manual says dot to dot is Nr.1 firing position.

Michael

 

I am a Gm tech, and i will go on SI2000 and look this up for you, give me a little time.

 

[quote]Originally posted by Austrian Vette:
<strong>


You sure???

Iīm pretty sure the service manual says dot to dot is Nr.1 firing position.

Michael</strong><hr></blockquote>

Just looked it up and dot to dot IS compression stroke ... firing pos Cylinder #1 (not #6)

 

Ok your right and motor should start even without cam signal, maybe pcm is causing your trouble, try substituting your old computer or suspect crank sensor as problem.

 

PCM will try one bank, then the other if the CAM sensor is not there.

But, if the CAM and Crank are valid signals it'll crank and fire away.

Check the wires <img src="gr_stretch.gif" border="0"> it's too much of a coincidence for 6 to fire instead of 1. 180° off is a swap of something.

BTW, Gen 1 SBC's are not much like a Gen 3 <img src="gr_stretch.gif" border="0">

 

My mechanic just finished the head/cam,LS6 intake,#30Injectors,underdrive pully install.
He also installed an other PCM and did the PCM swap procedure.
When he cranked up the engine it didnīt run.
He checked and found out:

when #1 Cylinder is on compresson then the spark plug from cylinder #6 fires
and when Cylinder #6 is on compression then sparkplug form #1 fires

So the engine will never run, I think

I first thought the Camshaft position sensor may be it, but I donīt think it can be hurt during the cam install and also the service manual says the engine would run without that sensor?!?

Now Iīm frustrated big time!!!

We pulled the timing chain housing to rechek the position of the gears, but they are correct. The lower gear has the sign on top and the upper gear
has it on the downside. So thatīs #1 firing position, but that damn engine still fires at Cyl. #6 when Cyl. #1 is on compression?????


NEED HELP!!!!!!!!!!!!!!!!!

Thanks,
Michael

 

I will check the wiring first.
If that isnīt it Iīll try the cam pos sensor.


When I now unplugg the cam sensor and crank the engine then it will try to fire
1st bank first, right?
Then if I start again it will turn igniton 180°.
That is how 'I understand the cam pos sensor thing.
Am I right on that?
It turns ignition 180°vereytime I crank the engine, as long as the cam pos. sensor is unplugged, right?

What I need to know is, can I leave all uninstalled when trying that??
I have the throttle body, maf, intake, timing gear cover.....off right now.

It would be a real pain to install all and the find out itīs not the sensor and deinstall all again to start the search again.

As I havenīt tried to unplug it yet, it sure may be the best option I have.
(Still hope the cam is not grinded 180° off where the sensor reads!
Anyone heard of such a thing happening, yet??)

Michael

BTW, tried to swap back to stock PCM....does the same, so that isnīt it.

 

Hello all!

Engine is running!!!!!!

But Iīm not sure, if all is right.
It still seemes that Cylinder nr.6 is firing position nr.1. as I think we have compression on Cyl. nr. 6 when the timing signs are lined up.
But I cannot change that.
The signs (timing gears)are lined up and then the crank and cam position is given, right??
I think Iīm right when I say it doesnīt do anything if I turn the cam or crank 1 turn and then reinstall the chain. It always is in the same position.
Am I right on that??
Or would that change anything??

I disconnected the cam position sensor and after
little starting the PCM turned the ignition 180° and the engine run.

But as soon as I reconnect the sensor it turns 180°again and the engine will not start again.

What I need to know now is:
Can we have mixed something up with the timing gears?? Will something change if I deintsall the chain, rotate the crank one time and reinstall tje chain?? Or turning the cam 1 turn and then reinstall the chain??
Would that change the firing positon from 6 to 1?

However the car runs now, but only with the cam pos sensor unplugged.

I pulled the sensor and it looks ok, no signs of damage?? Can it be damaged anyway??
As soon as I plug it in I cannot start again.
If the sensor is damaged wouldnīt it do nothing??
But for me it always turns the ignition into the wrong 180°

So what is left:
1) I still have something wrong with the cam-
crank position.
Can I get it 180° false though I have the
timing gears alined???
Thatīs Nr. 1 Question, need to know that.

2) the sensor is damaged


3) I have a bogus grind cam, so the sensor gets
the correct info, but the cam is 180° off.
Can that be??

Another Question:
When I leave the sensor unplugged the car runs.
It only needs to start a little whenever I disconnest the battery.

Will I be able to drive the car without that sensor without problems.
Seems that I only need it to start the first time.
The next starts are OK, as the PCM seems to remember.

Michael

 

What still makes me thinking is that my mechanic says that Cyl. Nr.1 has NO
compression when the timing gears are lined up, but Cyl. Nr. 6 has compression?? (Isnīt that wrong)

Can I somehow bring the Nr.1 Cyl. to compress when the timing gear signs
are lined up?? (Thatīs how it should be , or not)??

How??

Michael

 

Hold on there sonny.

9 times out of 10 it's something that makes sense.

Your car can run with funky cam sensor.

Harl, how about a funky crank sensor?

I am wondering if your pcm is messed up.

The odds are unlikely you have a bad cam grind. Your motor would be trash by now. If you were off a tooth your timing events would be off by 23 degrees and you would have bent all the valves.

Check all the wiring.

Make sure all the connectors are secure to the pcm... Check all grounds.

I think it's electrical.

 

[quote]Originally posted by Pro Stock John:
<strong>Hold on there sonny.

9 times out of 10 it's something that makes sense.

Your car can run with funky cam sensor.

Harl, how about a funky crank sensor?

I am wondering if your pcm is messed up.

The odds are unlikely you have a bad cam grind. Your motor would be trash by now. If you were off a tooth your timing events would be off by 23 degrees and you would have bent all the valves.

Check all the wiring.

Make sure all the connectors are secure to the pcm... Check all grounds.

I think it's electrical.</strong><hr></blockquote>

Tried switching back to stock PCM......nothing changed.

Wiring is OK.

If cam is not the problem, why is the Nr. 6 Cyl. on compression when the timing gears are lined up. Shouldnīt Cyl. Nr. 1 be on compression then.
Couldnīt that declare why I am 180° off??

If I can drive without the sensor, then I let it as it is, especially as I will do a complete new engine next season.

Anyone can tell me 100% sure that the unplugged cam pos sensor dosnīt effect anything like timing or so.
Would hate it to blow my engien on my 225 shot NOS because of that.

Thanks,

Michael

[ March 10, 2002: Message edited by: Austrian Vette ]</p>