LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Optispark? PCM? Need Some Help!

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Old 04-26-2018, 06:08 PM
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Default Optispark? PCM? Need Some Help!

Hi folks. Looking for some expert advice on a new project. I recently purchased a 97 LT1 car, it has H/C/I setup and was tuned by someone pretty reputable. The car after a few days started giving me a P0372 code and it would usually show up after not starting or taking a few tries to start. After reading a couple of hundred articles on Optis I figured the 2 year old dynaspark probably was the issue. I had a shop here locally replace it with a summit opti 2 and while it fixed the original problem it now shows a P0336 code and it appears that the timing is out of range (around -15 at idle.) I then ordered a new opti from Petris, shop installed it today-same issue-timing is retarded P0336. I also replaced crank sensor for good measure but that didn't help. The shop doing the work is good, they know their stuff. Any ideas?
Old 04-27-2018, 08:21 AM
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Default Opti Alignment

Hi Jo, I manufacture MY version of the Opti Spark with internal Hall sensor. The crankshaft four tooth TW is for fuel injector timing reference.

I believe you have the late "spline tooth" Opti ?

You could post a picture of the rear spline ?

That tooth count is low with incorrect position almost impossible AND allow the engine to operate.

One guess is that the Timing Chain Sprocket could be loose/chain stretched/cam timing changed by "offset" sprocket ?

I would have your shop check for Split Overlap valve timing, an EASY read by removing the valve covers.

Lance
Old 04-27-2018, 03:56 PM
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Hey thank you for the advice. Mine is a late model with the PIN drive, it is fairly straightforward as far as proper alignment. Obviously it can be installed incorrectly but I feel pretty confident that is not the case. The cars has less than 20k on rebuilt bottom end with a new LT4 chain and gears, and the car ran (mostly) fine up until changing the opti.
Old 04-27-2018, 04:21 PM
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Op...the use of non AC Delco Optis seems to be the common denominator in Opti failure/codes

I have read the Petris is better than other aftermarket Optis but have no direct experience with it. Seems the wheel disc alignment when they build the opti is "slightly" off

IDK of peripheral issues to the Opti can cause your code (intermittent wire in the 4 pin opti harness or ICM)...but given the # of Optis you have installed may be worth a look

Is the damper hub the correct hub for your F-body and is it installed flush against the reluctor wheel for the CPS?

You have confirmed wiring & connector to CPS is good?
Old 04-27-2018, 10:20 PM
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We looked at damper hub, reluctor, wiring. Scoped opti and CPK today no issues. Verified the old Dynaspark was full of oil and the bearing failing but the car mostly ran good especially under WOT. Either of the new optis do not run good, pull SES hard code almost immediately and show run -15 degrees of timing. I also am aware of scanners showing this number as positive however it is truly -15 retard. and the car runs like it. Tomorrow going into to definitely look at harness and wiring.
Old 04-28-2018, 02:02 PM
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the dyna spark opti...you might want to clean the oil from it as it was not throwing this code but likely throwing the code it was because the oil got in optical sensor. Your worn bearing though will cause oil to enter that way again and eventually cause the same initial code due to oil contamination on optical sensor.

The other off brand ones unfortunately have a 50/50 shot of being bad right out of the box...you have 2 that appear to be that way

I have held on to my AC delco even though the bearing is slightly lose allowing oil to get inside it but I have cleaned it twice over the years and it still works fine. Ironically never had a code or problem because the oil was inside it...I just check each time I had the Opti off thinking it was my problem (turned out to be ICM once and bad plug boot on another occasion)

Problem now is reman AC Delco Optis are not available anymore or very hard to find leaving only the off brand ones which seem to have chronic issues like you are having

Maybe you will discover a wire or plug issue causing your code...or opti # 3 of whatever brand will work
Old 04-28-2018, 09:11 PM
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Well unfortunately I had to drill the rivets out of the dynaspark to get the cap off and inspect it. I really didn't even know if they are still around or not so I planned on going another brand but now I am feeling I might regret it. The Petris seems like a very high quality unit and I have a 5 year warranty, I emailed them and they are going to call me next week. I spent some time today at the shop with mechanic, checking grounds, voltage, etc. We scoped everything again. No codes except the P0336, I did learn that the CPK is what is reading the -14, actual Spark advance is at 38-40 at idle. However the car runs terrible, this is the first day I actually got to be there and have it idle, test, throttle, etc. but it is messed up. No doubt ran better when I brought it in. The only thing that has changed is the opti, so I am just skeptical of PCM, timing chain, etc, etc. I do HVAC for a living and generally if you change something on a system and it is not running right afterwards, start looking at what you changed first.... We eliminated a lot of stuff today, I still feel like it is the opti- I am getting a lot people saying it is on wrong... My mechanic knows his stuff, we looked at it several times after the second install and basically you would have to force it on if it is not in the correct position, I mean if you index that thing wrong the cam pin could be in the clover area but the cam bolts are not going to clear-they would be hitting the face of that plate. Anyway I know a lot of them have been installed wrong however they seem to be "no start" condition and even if it ran I don't see how because the timing would be way off-not 5 degrees. Anyway I could be way off, I'm just looking for advice and appreciate the help.
Old 04-29-2018, 11:39 AM
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Default Opti Hall Sensor

Hi Jo, I am able to send you one of MY Opti Hall Sensors.
That cost is $45.00 + USPS of $10.00.
The footprint is as OEM.

Lance Panteraefi.com
Attached Thumbnails Optispark? PCM? Need Some Help!-opti.jpg  
Old 07-14-2018, 10:39 AM
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Any resolution on this issue? I just installed a reman ACdelco Opti from RockAuto on my car. It seemed to fix a couple of the issues I had been seeing, but now the car doesn't want to idle when warm, and I'm also getting the P0336.
Old 10-11-2018, 03:14 AM
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FYI the optispark CAN be installed with the pin in the wrong slot, I know because I've done it before, the engine can run without the CKP sensor, it's used to detect missfires.

They either installed the pin on the wrong slot or I would double check the sparkplug wires.
Old 10-11-2018, 03:17 AM
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Originally Posted by alone_and_insane
Any resolution on this issue? I just installed a reman ACdelco Opti from RockAuto on my car. It seemed to fix a couple of the issues I had been seeing, but now the car doesn't want to idle when warm, and I'm also getting the P0336.
If you crack the TB does it correct the iddle? If so I would clean the AIC and check for vacuum leaks.
Old 10-12-2018, 04:53 AM
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Originally Posted by LHB_131
FYI the optispark CAN be installed with the pin in the wrong slot, I know because I've done it before, the engine can run without the CKP sensor, it's used to detect missfires.

They either installed the pin on the wrong slot or I would double check the sparkplug wires.
I had a "professional" mechanic improperly install a brand new and warrantied optispark! The warranty was then void after he couldn't get the car started and the rotor tore into the cap because he forced the optispark on the pin in the wrong slot. After my fiasco when I got the car back and installed my own Petris optispark MYSELF, I nearly installed it in the wrong slot! It clicked, but I could feel resistance and I could bolt it down but it had ever so slight resistance. I pulled it out and readjusted the shaft to align correctly and it clicked again and was totally flush against the timing cover.

YES, YOU CAN INSTALL PIN DRIVE OPTISPARKS WRONG! My Petris is operating flawlessly with no codes and it runs better than any other optispark I have had on my car since I had the Jasper LT1 put in her.

Last edited by Phoenix'97; 10-12-2018 at 07:47 PM.




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