Help me figure this one out???

[turbov6joe]

Ok, here is the best explination of a problem I have and can put into type. I recently dropped a new cam (Reed 208-208) in my motor and it fired up immediately with barely any cranking involved....quickest start of any LC2 motor I've ever had.
Anyhow, the other day I was out driving and shut the motor off to run into a gas station. I came back out a few minutes later and when I tried to start the car, it initially started cranking fast like it always does, then after a few more cranks is started cranking REAL slow like the high comression motors do or a car with a low battery, then it back fired 1 time through the exhaust, then started cranking fast again and fired up. I've now figured out that it does this only when the motor is hot...fires immediately on a cold start.

Does this sound like the cam or crank sensor is out of adjustment?
Timing issue?
Is the direct scan cable screwing with the ecm?

The cam was installed straight up with a new timing chain. I made certain #1 piston was at TDC on the compression stroke, and the ballancer was at 25º ATDC when setting the cam sensor with the Kirban cam tool. I turned the cap 1/4 turn counter clockwise, then slowly rotated it clockwise until the LED light lit up. The motor runs like a top, pulls hard through all the gears, and I'm not seeing anything crazy on direct scan.

Any ideas or places I should start looking?


TIA

 

[GARY HARVEY]

I'd check the voltage at the starter while cranking... might as well get the easy part of this out of the way first. Good Luck.
Gary

 

[turbov6joe]

I'd check the voltage at the starter while cranking... might as well get the easy part of this out of the way first. Good Luck.
Gary

Ok, but what might be a reason as to why the voltage is correct at first, then drops, then goes back up, backfire, then the start? It just started doing this since I put the new cam in. I didn't pull the motor out so I never mucked with the battery wires

 

[Jerryl]

.......... I made certain #1 piston was at TDC on the compression stroke, and the ballancer was at 25º ATDC when setting the cam sensor with the Kirban cam tool. I turned the cap 1/4 turn counter clockwise, then slowly rotated it clockwise until the LED light lit up. .......

I think you have to turn CC to set the window.
So, set compression stroke, set timing mark 25 ATDC (you got all that correct). Now, turn the cam sensor CC to set it.
Cam Sensor Information
Try that and post back.

 

[m233roller]

You are saying you turned the cam sensor clockwise. Nope counter clockwise. Sounds like you have it 180 out.Retime the sensor and I think you'll be good.

 

[kerfman]

timing issue??

i just recently had weber racing install & degree a 206/206 roller cam & chain & they also installed the lifters & rockers, the valves & springs were already on the heads when i bought them. we used the cam sensor tool to set timing when we first tried to start the motor it turned real slow like high comp. then backfired a little we then turned the cam sensor a little each way untill we got it to start but motor sounds like it has an exhaust leak on upper right side almost like it is near the head, my buddy feels it could be an exhaust valve not closing all the way. my question is if we had to turn the cam sensor from the proposed setting we had with the sensor tool could we be getting this sound if the motor is out of time ???????

 

[MSDGN]

Sounds like the cam sensor was set wrong...turn the sensor clockwise until the LED goes out...then turn it counter-clockwise until it lights...lock it in..if you set it on the exhaust stroke instead of the compression then it is 180 degrees out...

 

[BlackBandit]

Another thing you might do is verify that you have a good ground between the battery and the block. I just had a similar problem to yours on a Monte Carlo and it turns out that that connection was dirty. Also, if my memory serves the cam sensor (in theory) shouldn't effect the timing on startup. I think it either is or isn't. That could be wrong though. HTH james

 

[SloGN]

set the cam sensor like everyone above has mentioned.

Also one thing you might what to do is swap out a known good coil pack and module if resetting the cam sensor does not help cure the problem.


it sounds like the ignition timing is set a little low so it's actually tring to fire a cylinder as the piston is coming up.



the way i set my cam sensor is i would take the # 1 plug out and make sure it no the compression stroke and turn the crank until the timing mark on the balancer is at zero then turn the crank 1.45 inches atdc then set the cam sensor. using the cam sensor tool. i have set several engines this way and it works great.


fo me using the 1.45 inches method is a tad easier than the 25 degrees if you don't have a degreeing tool