jacked1

I mentioned the TPS because I’m out of ideas basically. I know from what you have pointed out it looks like a vacuum leak. I’ve gone over everything in the vacuum line diagram and the evap canister located behind the driver side rear tire and have not been able to find another vacuum leak. Header gaskets look brand new and I couldn’t detect a leak in either of those areas.

is there anything in the logs that would point to the opti as being the issue? The idle issue happens in open and closed loop @ idle and feels like it could be a plug wire is not sending spark to a plug but i have checked all of those also.
Rick

Injuneer

Are you checking for vacuum leaks by visual methods only? You need to use typical techniques like propane torch, carb cleaner, or have a leak test done by a trained mechanic with a smoke machine. When looking for a vacuum leak, using test methods, not just visual, remember there are places where vacuum can leak that don't involve vacuum lines. Don't forget the fuel injector lower O-rings, the brake booster, the intake gaskets, valve seals, etc.

There are limits to the scan data. In OBD-1 there is no misfire detection. In OBD-2 that helps localize problems. And there is no monitoring of the high voltage side of the ignition. You have both the Opti high and low resolution pulse signals. Your engine is running and you have spark and fuel. Without the low res signal, you would have neither. But there is no check on that spark. You could have all the wires crossed, the Opti cap could be carbon tracked, burned contacts, wires could be arcing, plugs could be damaged. Can't see that in a data log. Similar situation with the fuel delivery. The PCM checks the electrical circuit for each injector. If the voltage on the injector is not correct, you would get a code. But if the injector is plugged and not delivering fuel, or stuck open and pouring fuel into the engine, the only symptom you will see is screwed up LTFT's.

Your problem seems to be affecting only Bank 1. That tends to rule out anything that affects both banks equally. If the vacuum leak tends to affect one cylinder on Bank 1 more than the other three, you end up with 3 cylinders running excessively rich, and on running somewhat OK. If one injector is not flowing enough fuel, the lean condition at the O2 sensor causes the PCM to add more fuel, and now you have 4 cylinders messed up - the one with the plugged injector that still sin't flowing enough fuel, and the other three that are now delivering excess fuel those cylinders don't need.

Then there is the possible issue of the O2 sensor condition. There's lots of feedback to the PCM on the sensor problems if they are major, but a sensor that it a fraction of a volt off in it's responses will cause problems on the bank but not be reported. I don't remember if you have new O2 sensors. You could try swapping the sensors side-to-side to see if the high LTFT's stay on Bank 1 or move to Bank 2.

The individual banks of the engine can be affected by an exhaust leak before the O2 sensors. That requires a detailed look at the entire exhaust system between the head and the O2 sensor, looking for carbon tracking from the leak. That would not cause high idle like a vacuum leak, but maybe you have more than one problem.

Brian Kinney

DELETED - this guy needs to grow up.

Injuneer

Tell that to Jonathan Atkins so he can ditch his destroked 327ci LT!: LOL

https://www.tickperformance.com/happ...est-gm-6speed/

PS: Old news, his record is down to 7.309 @ 199.10 MPH

jacked1

LOL.. The thought doesn’t even cross my mind although it is a little frustrating @ times. This machine has more value to me than any other car would. It belonged to my best friend who passed away in 2017 after the most well fought battle with cancer - i got to witness that 1st hand and I could not have done it any better myself. His name was Danny - great dude. Anyway about a year and 1/2 after he passed his wife sold me the car and I consider it a real privilege to own it.
I don’t mean to bust your ***** or sound like I’m looking for sympathy or anything - your advise could be a sound solution for some - just not for me. I do have to say it was pretty entertaining to read. It does get frustrating and time consuming debugging these things.

Good luck with things. Rick

Injuneer

Ignore him. He’s just a troll.

jacked1

Yea - I hear that Injuneer! I laughed when I read that post.

I have gone over everything you suggested (both O2 sensors are new) tested injector O rings with the smoke and carb injection leak tests. I put the car up on stands and got under it while it was running to check for exhaust leaks before the O2 sensors and all and did not find a thing using the smoke test method.

I did find one faulty plug wire - cylinder 1 on the drivers side. I replaced it with a wire from the old set and while the rough idle is a bit better this didn’t take care of the issue. I’m thinking this bad plug wire may have caused the Bank 1 running lean/rich after correction condition you pointed out.

Now this rough idle is happening in both open and closed loop - although i did check extensively for pre O2 sensor exhaust leaks, I’m m thinking this is something other than O2 sensors since it is happening in both open and closed loop.

I do appreciate all the time you have put into diagnosing this bug for me. Now what I have done, which sounds illogical, is ordered a new optispark which is under warrantee since the current opti is only 4 months old.

Thx Rick

David94TA

Any luck on diagnosing the problem?

jacked1

Hi - Sorry I let this go without a response for so long. So first off I just wanted to thank Injuneer for all the time spend analyzing the logs and giving me ideas as to where to look next and thx to the couple other members who dm’ed me with ideas. Really appreciate all the help.

After tracking down and fixing 2 major vacuum leaks the issue still remained. I went over this motor and couldn’t find anything else so i broke down and threw in another rebuilt Opti from Summit. That worked good for 3 days (the uneven idle and missing/vacuum leak sounding issues all were gone) until I’m guessing the Opti optical sensor started to stop working when the car got warmed up - heat soaking issue. No error codes were being thrown. It would die out on me while driving and would not deliver spark until it cooled off. I then ordered and installed an Accel Opti from Summit which after 2 weeks seems to be working correctly. This is my 5th Opti in 18 months.

Thx again for all the assistance once again.

Rick

David94TA

Glad to hear that you are up and running! 5 optis in 18 months is crazy. Hope the Accel will give you good service. It is just baffling to me that a new opti of any brand would only last a few days like you have experienced.

WhiteWS6

Hopefully the current one you ordered will continue to run for a bit. In the future however (or once this one dies) you may want to consider a Petris Enterprises optispark unit, I know they are currently out of stock due to COVID-19 hindering some of their parts availability. That may be your best option to end the cycle of killing optisparks without the much higher cost of a coil on plug setup. Another cheaper but odd option that I've seen on youtube is from a guy named HorsepowerTube, he shows himself using the 411 PCM from a vortec 350 van and only the cap and rotor (not optical sensor) to run his engine. However, this is process is a bit more complicated for a non 96-97 LT1 Camaro/Firebird. Probably just a simpler option to invest in a well built optispark.

Link to HorsepowerTube in case you're interested:
Best of luck, Grant

Injuneer

The Bailey Engineering LTCC runs 8 LSx coils with the stock PCM and just the cam position signals from the Opti. Not expensive and no complications like swapping the PCM or harness, no reprogramming, very simple.

Bailey LTCC setup

He still sells this system, but apparently waits to get a minimum number of orders before he builds them.

22+ years ago (before the LTCC existed) my engine builders put together a similar system using only the cam position signals from the Opti, coupled with a MoTeC engine management system and MoTeC's IEX 8-channel Ignition driver. I have their second install, and it's performed faultlessly for 20 years. I converted to the vented Opti, primarily to use the LT4 extreme duty timing set, using a “new in box” OEM Opti I paid $200 for. The MoTeC is expensive, but offers open architecture, DIY programming, optional built-in data logging, diagnostics, and the ability to run multiple programs for NA and nitrous, with the flip of a switch. And I know for a fact the system including the Opti sensor, can handle 8,000 RPM....... ooooops, missed shifts.

jacked1

Thx David. So far so good. Not driving much these days with the whole COVID thing happening but I too hope this Accell Opti will last. If not I guess it’s a good thing I can replace it in just over three hours door to door with all the practice I’ve had Lol.. well least in my car where I don’t need to contend with any unknowns coming up like frozen bolts, etc..

Be safe out there. Rick

jacked1

Thx Man. I appreciate it. Thx for the other options also. I just came across Petrie Ent. Opti recently but I will keep that in mind. I did see this vid you posted .. pretty interickresting stuff.
be safe out there,

jacked1

Hey Injuneer,

Thx for the additional options. I’ll definitely keep these in mind for the future.

What. Missed shifts? Man I wish I had the manual setup. It would make driving even more fun. The automatic is still fun to drive but nothing beats the feedback you feel from a manual.
Thx again for all the help along the way. It has been greatly appreciated.

Be safe man. Not like us Jersey guys have much of a choice with all the mask requirements and closed business we have to deal with in Dirty Jersey.
Thx, Rick