Hi guys, I was wondering how do you tell if the opti is in timing? I have been having lots of trouble with my opti on my car and have tried several opti's. My first problem is the car would start but would run like it is out of timing. It was really hard to start so I pulled the valve covers and found one of the rockers off. I put the rocker on and adjusted on them and know it want even start but its a different opti. Both opti's where new and know its back firing through the intake.

We checked several plugs and getting fire. Also getting good fuel pressure. We sprayed gas in the intake and still no start. Keep in mind that the car was driven from my house to my brothers to be worked on and only problem was it was throwing a DTC 36 code. The rocker had to come off after we installed the opti because the car ran good except for the code.

I have read on here that if you get #1 at TDC the rotor should be pointing at 6 o'clock if this is true the rotor points more toward 7 o'clock. I have checked all the ground wires and opti harness and everything looks good. I know I have put the opti on several times and it seem to go in good with no force. I really need some help on this I am about to give up.

thanks
Josh

 

The opti has nothing to do with timing. The PCM controls the timing in the LT1. The opti rotor position is controled by the camshaft. If you have doubts as to the cams position for TDC, take off the opti and use this for reference:

http://shbox.com/1/4th_gen_tech2.html#cam_timing

By the way, DTC 36 is your MAF sensor. Tap the sensor with a screwdriver with the engine running. If the engine stumbles, the MAF is bad. If it is bad, don't use an Autozone one. Buy from GM.

 

With the 94s I've heard of several people not getting the new Opti keyed (indexed) correctly with the cam.

WD

 

Your opti is installed correctly according to what you said about the rotor placement with 1 at TDC.

I think you have some plug wires crossed.



Even if you think they are correct, check em again

 

ok we have checked the plug wires serveral times and I will check them again. We have put the opti on about 6 or 7 times and its going on good with no force. Only thing I can tell is that when #1 is at TDC the rotor is pointing more toward 7 oclock instead of 6.

thanks
Josh

 

When you say it was driven from you house to your brothers to be worked on? What all was done. Just brought it there due to the DTC 36 code or did you guy do some other work as well.. I see you have LE1. Was that installed then?

Sounds like you getting the opti installed right.. If the rotor is still pointing to 7 oclock, then sounds like the cam was installed a tooth off or the chain jumped an tooth.

 

yeah the LE1 package has been on since april and ran good untill now.
Is it possible for it to jump a tooth? If it did jump a tooth should it still start?

thanks
Josh

 

Here's a helpful pic from Shoes web page.



It's marking the contact points for each cylinder on the outside. With 1 at TDC the rotor should be pointing to the 1 contact (obviously). You have to more accurately view the cap when you remove it to see exactly where the number one contact is. The cap I have in front of me looks close to 7 O'Clock.

If the problem is the cam timing, you have 2 direct problems as a result. The ignition timing is off and the valve timing is off. Another indirect problem is the injector timing since it is timed by the feedback from the optical portion of the distributor.

Incidentally, I'm the one that said 6 O'Clock in the past by mistake having looked at the inside of cap instead of from the front view reference.

Now. I still think you are ok with install and cam timing. So before you go tearing it apart, it's time to eliminate everything else. Scan for DTCs again since some like a 16 will cut out the engine but will not show an SES. You should check compression in at least a front and back cylinder on both sides if you can't do them all. Spark should be confirmed on ALL cylinders since it only takes 3 dead cylinders to keep the engine from starting. Then try the fuel squirt in the intake after that is done.

If All that is confirmed and it still won't start, the ignition timing is the only thing left. But I caution you, don't jump to conclusions.

One last comment about checking spark. Remember, if you don't pull the plug from the cylinder but simply plug another plug into the wire, this could give the false impression you actually have spark in the cylinder. However the plug in the cylinder may NOT be sparking. the better and simpler test is put an inline spark tester between the plug and the wire. If ALL is good, it will show it. If any one of the items in the chain so-to-speak is bad, it will show that too. But it keeps you from having to pull all the plugs.

 

Incidentally, back firing through the intake as you mentioned in your first post is a sign of either spark timing is incorrect. Or a sign of valves not opening and closing properly as in misadjusted. In the case of the latter, it would have been detected by a compression test.

Since you been messin with the valves. I would recommend you start there and watch the order in which you do the procedure. Fool proof is EO-IC

 

thanks alot, I really appreciate the help. As soon as its gets warm I am going to get a compression tester and spark tester. Thats what I was doing putting a different plug to test for spark.

thanks again
Josh