I've been searching the forums for a week now and still have some questions. First I believe I lost yet another opti due to multiple missfires and then one big one and then a tow ride home due to no start. Tested opti and got 2.5 volts showing instead 5.0 volts. This one was MSD. Regardless of brand I am sick and tired of replacing opti's, so I'm looking at one of these conversions.

What I don't understand is will I still have to replace the opti to do the LTCC and does the harness that comes with it replace the wires that go down to the starter that feed into the PCM.

In regards to the 24X, will I have to take out the dash in order to hook up the wiring harness and do I have to purchase the EFI Live scan and tune software in order to tune the PCM. I'm not a turner and know nothing about tuning. If this is purchased will I still have to pay for tuning?

The LTCC seems like it would be much easier to install and cost less than half, but I have had numerous problems with PCM's burning up in this car too. So the 24X is appealing for the computer upgrade with what seems to be a complete new wiring harness.

Thanks for your assistance.

I have a 383 forged stroker built to run in the 11's. Street/Strip

 

On what wires on the Opti did you get 2.5V? Under what conditions? Were you using an AC or DC volts scale? What part has failed in previous Optis? How many have you replaced? How many PCM's have failed?

Unless you are going to forced induction or nitrous, the stock PCM and Opti should be more than adequate.

 

This will be the second opti replacement within 30K on this motor. Golen, 383 Stroker. First one was GM, this one MSD. On on my sixth PCM this motor. Same part of the PCM burns up every time. The part that sends ground to sensors as I was told. I believe the PCM problem is being caused by a bad ground that goes from the starter to PCM. Those wires have gotten stuck on my headers before.
A friend of mine did the opti test that is listed on this site. Coil, checked out good. ICM checked out good. Two of the four opti wires test good. The two that are supposed to have 5 volts only had 2.5.

Engine turns over and over and almost starts, but never does. Fuel is NOT the problem. Like I said multiple small back fires after 0 to100 mph acceleration, left off throttle then one huge backfire, than it shut down and hasn't started since.

 

Have you scanned it for codes? A faulty optical cam position sensor will set codes. The two signals (high and low resolution) are 0 - 5 volt square waves. If you rotate the engine very slowly you should see them switch from 0 volts to 5 volts. If the engine is rotating rapidly you are going to get a 2.5 volt reading.

Are you refering to the black PCM ground that attaches to the block NEAR the starter? That wire does not connect to the starter. Or did I misunderstand?

 

there are two. One grounds to the block near the starter. The other is black and white and attaches to back of starter and goes to PCM.

 

CORRECTION: Your right. It goes to the block not the starter. Disregard post.

 

Been a lot of rain here and I don't have a garage. I will be charging the battery back up and checking for codes hopefully tomorrow. Beginning to think this maybe another PCM issue. Hope so, that would be an easy replacement if I can locate some flash software. I think Tunercat has it for $19.95. It used to be available for free for thirty days. I have ALDL cable, but might need drivers for it to work on my new laptop.

 

The LTCC needs the high/low res pulses to fire the coils correctly. If those are still working then the LTCC should work just fine. The harness that comes with the LTCC doesn't go anywhere near the starter.

You don't have to remove the dash though it is helpful to get under the passenger side of the dash to fully remove the engine harness from the car in order to repin it.

You don't have to purchase tuning/scanning software. Just let the tuner work their magic. It's not much different than tuning an LS car at that point with only minor differences. I prefer HP Tuners myself.

Both ways work. I had the LTCC and bought the 24x kit. The newer PCM has more options than the old LT1 pcm. If you don't mind repinning the harness yourself you can actually do the swap pretty cheaply.

 

Thank you for answering my questions.

 

Just scanned the PCM. No codes. That seems odd since the check engine soon light came on just before the multiple backfires. Not sure where to go from here.

 

You seem set on the LTCC or 24X.

 

Well with no codes coming up, it appears the optical cam sensor and PCM are working. So if the rest of the opti took a crap the LTCC conversion seems to be the right direction to fix the problem without paying much more than the cost of a new opti with less labor involved.

 

As indicated in the other thread, you appear to have lost the code by letting the battery go dead. It wasn't the fatal (DTC16) code for the cam position sensor because that doesn't turn on the SES light. That code will also set when the engine is cranking.

As Rob/Shoebox has indicated in the other thread (2 separate threads are confusing) could be rotor failure. That's why I asked what part failed in the first Opti and I don't believe you answered. Could be an issue with the dowel pin length or excessive cam movement. If that's the problen, damage to the cam sensor shutter wheel may be nextn

I know you wanted info on the other systems, but the questions I asked, which didn't seem to be appreciated, were intended to get to the underlying problems with the Opti and PCM failures. Without identifying the underlying problems, you may be putting a $500 - $1000 band-aid on the problem, which might not cure it.

 

Actually sounds like the symptoms I had when my MAF failed. Okay, I was trying to maintain some dignity. The MAF didn't fail, the hose clamp wasn't tight enough and it fell off.

 

Thanks Fred

The DTC16 code information is very useful. Now I know the optical cam sensor is still functional. Sorry about the two threads, They weren't supposed to bleed into one another. I appreciate your effort about the dowel pin. I checked that a couple years ago after you advised me to back then. I think I'm going to try the LTCC kit since I can't afford the 24X right now and hope the sensor holds up until I can afford the 24X.

If anyone has a LTCC Kit for sale, email me at macs95lt1@gmail.com

Thanks again