I know there are some write-ups on this doing this on an LT1 but I've got some more specific questions that pertain to my situation. I'm absolutely done with the opti-spark distributor on these cars. I am on my third one in the past year and a half alone. I'm toying with the idea of just putting a standard style distributor on the car so that I don't ever have to deal with opti-issues again. With that being said, I have a couple questions. I am planning so keep the fuel injection, so what must I do to my manifold in-order to accommodate for the standard distributor? I can send it off to someone if necessary. Is there enough room to install a low profile distributor while the motor is in the car? And is there any problem in leaving the opti installed once I convert over to the standard distributor?

Thanks, Grant

 

The LT1 PCM requires the cam position signals from the optical module in the Opti to time and sequentially fire the fuel injectors. You would have to incorporate the shutter wheel and optical module in the distributor. Someone may have done it, but I'm not aware of it. Or, look into an aftermarket fuel injection controller, but you'll lose almost everything else controlled by the factory PCM.

If you delete the Opti, you either need to convert to an LS1 PCM using new crank and cam position sensors and timing cover (EFI Connection 24X, or Torqhead). You end up with an ignition system using 8 LSx style coils in direct fire, from the PCM. Relatively expensive:

https://www.eficonnection.com/home/c...efi-24x-lt1lt4

TORQHEAD LTD - HOME

Another solution is the Bailey Engineering LTCC. This system uses an Opti case with only the optical module, and direct fires 8 LSx style coils. Removing the high voltage from the Opti generally extends it's life. But the currently available optical modules are almost all Chinese crap. I run a system similar to htis, using a 20+ OEM vented Opti.

Bailey LTCC setup

A more basic question.... what brand Opti's have you been using, and what is the failure mechanism? There is at least one seemingly reliable Opti. Anything from ebay or cheap auto parts stores are usually Chinese ripoffs that fail right out of the box sometimes.

Or you run the GMPP LT1 carb intake, with distributor hole, and give up everything related to the PCM.

 

Ok gotcha, my hope was that I could leave the opti in to retain some of the electronics such as the cam position sensor. I want to retain most of the PCM features however so it may not be a great option. I did look into the Bob Bailey LTCC coil conversion kit but my worry was that it still requires the opti to function somewhat properly which seems to be a pain for me. I'll have to check exactly which opti I put in last, I'm not buying some cheap Amazon opti lol. Each one has cost me around $250 a pop, I had a knowledgable mechanic friend of mine install one over the winter when I was busy. He's owned multiple LT1 cars and had good luck with the units unlike me. The torqhead system is a pipe dream with my budget although I would love it. First opti that died was because of the cap and rotor just coming apart however that one was there when I bought the car. The other two just developed misfire issues and once a new one was in they went away and car ran great. I'll get you more info on those in just a bit.

Thanks, Grant

 

In your previous thread, you indicated you found a new AC Delco unit.

https://www.camaroz28.com/forums/gen...tumped-887906/


High $$$ does not indicate high quality, unfortunately. The MSD is approaching $600, and has major problems. Dynspark is $600, although they do make a unit with only the cam position sensor for $525, but they have been plagued by failures since they were bought out many years ago. The current unit that appears to be much more reliable, having seen no reports of failures to date:

https://petrisenterprises.com/collections/frontpage


If you feel the optical module is not reliable enough to run the :LTCC system, what makes you think that it is reliable enough to provide the PCM with the info it requires to run the engine? It either works, or it doesn't. The PCM needs the Opti signals to turn the fuel pump on as the engine starts. With your OBD-2 97, it uses the Opti signals for the misfire detection. If the PCM doesn't see the low resolution pulse from the optical module, it shuts the engine down. The PCM runs the tach based on the Opti signals.

There is someone who rebuilds the optical modules, gets a lot of recommendations, and haven't seen anyone provide negative feedback. But there are so few people left on this site that unless its a newbie with an Opti problem, there's little feedback.

 

Yep the AC Delco unit was the second unit that was installed in the car, between that thread and now the car is on optispark number three. Yes I understand that lots of money does not indict high quality. Unfortunately you are totally correct about the MSD and Dynaspark units having major problems. Really when it comes down to it, there aren't any great options that don't cost an arm and a leg. I don't believe that it's not capable of being an accurate unit, but with the way the car acts up I'm just in a spot where I want to actually have the thing run right for once. What are the chances that the optical unit in my current optispark is toast? Considering it's a newer unit, I'm going to assume probable because as you stated earlier that really there are only cheap Chinese ones available. Thank you for all your time writing up detailed responses to me.

Here is the link to the one in the car, had to look at the part number on the sheet. I think I found why this one isn't doing so well. *Facepalm*, https://shop.advanceautoparts.com/p/...archTerm=t1833

Thanks, Grant

 

Let's go back to square one. You've replaced the Opti 3 times, in an attempt to correct a problem with the engine “acting up”.

What diagnostic work led you to replacing the Opti?

When you replaced the Opti, did the engine stop acting up, at least for a short while?

After removing the old Opti(s):

- did you open it up to see if the was any damage to the cap or rotor, carbon tracking, burned contacts/rotor tip?

- Did you check for the presence of rust or oil inside the housing?

- Was there any evidence of coolant inside or outside the housing?

- Was there any evidence of excessive bearing wear?

- Was there any evidence of the cam dowel pin being too long, and forcing the rotor into the cap?

- Was there any evidince of corrosion in the harness connector socket?

 

Ok, back to square one. What led to me replacing the opti-spark was the engine severely stuttering and in an effect making the car undriveable in high gears as it would get progressively more "jerky". I talked about this a bit more in my previous post as you pointed out. I got a flashing check engine light, but no readable code. I looked it up and that meant there was a multiple cylinder misfire, not like I couldn't tell already. So I knew I had three areas to check, fuel, air and ignition. I have a fuel pressure tester and I had good consistent pressure at the hookup between all rpms. I cleaned my MAF sensor, filter and put the K&N assembly in hopes that maybe a vaccum leak was occuring. In terms of the ignition system, I had a spare coil and ICM laying around so I tested both of those separately to see if it had any effect. It made no difference to the car, I also checked my plug wires and they were all in good shape. Which lead to my belief it was the opti-spark. I was not there to see the inside of the opti-spark when it was opened up unfortunately because I had my friend do it. However, I know that the unit had never come in contact with any water or oil, it was completely dry and untouched, I was able to check this while it was still in the car, atleast on the outside of the unit. Once the opti-spark was replaced the car ran great for about a day, soon afterward it really seemed to not be running so hot. The engine just wasn't very happy if you know what I mean. Car was a little bit more untame and was prone to stalling a bit more. One thing worth noting is that this setup is not fully tuned, it may be possible I'm fouling spark plugs each time but I'm unsure of this. I'm going to pull them out in a couple of days to see. I put new spark plugs in while my friend replaced the opti. Since this was my third opti being replaced, I thought it may be possible there was a harness issue so I got a new opti harness as well. The car always ran better after the new opti, for a bit. But each time it got a new optispark I put in new plugs as well, so my car may be fouling them each time due to the tune-up in the car. I really wish I was there to have opened up the unit, but it got tossed in the trash unfortunately. I'm not a huge mechanial genius to say the least, so I know this may be frustrating for you to read since there are a lot of open holes for assumption here.

Thanks, Grant

 

Fuel pressure needs to be tested under load, not just at RPM. Did you measure fuel pressure with the engine under max load, WOT, above 5,000 RPM. Did it stay above 40 PSI?

Without looking in the Opti, how did you determine there was no oil? The oil can enter from the drive mechanism being exposed to the oil in the timing cover. A vented Opti can assist penetration due to the slight vacuum applied by the vent system. If the vent system is incorrectly installed, vacuum can be higher than it's supposed to be. At any point did the person who replaced the Opti check the length of the dowel pin? Too long, and it can quickly destroy the cap/rotor.

http://shbox.com/ci/ci289.jpg

Based on the earlier thread, the overall condition and quality of the stroker build seems questionable. The lack of a tune makes troubleshooting extremely difficult. And the repeated problems with O2 sensors seems to indicate a fueling problem.

Could it be the Opti - yes. With absolute certainty - no. To start replacing the Opti wit another system, without absolutely determining the cause could be a waste of money. If I recall correctly, you indicated the engine ran fine, fully warmed up, during a full WOT pull. It was primarily a problem with throttle tip-in, and accelerating at low RPM in the upper (overdrive) gears. That to me is indicating a problem with the tune, the ignition,

 

Yes I should have worded myself a little better, I tested it at all rpm's under load, had the thing taped to the windshield while I drove around. Consistently stayed above 40 psi. I would have been doubtful of any oil or fluid entering the system due to how dry the surrounding area above, below and on the opti-spark was. I don't know if they ever checked the length of the dowel pin to be honest. Yea, unfortunately the quality of this build from the previous guy was beyond questionable, all kinds of crap was backwards or just done in a half-assed manner. Not having the tune is really a big roadblock here, I am no longer having any problems with the O2 sensors. The driver side one that was acted up tested out to be good, however once I replaced it and cleared the code it has stayed off. It's been a couple months since I replaced that O2 sensor. Yes you are re-calling correctly, the power is there arguably but it seems as though the car has to overcome a rut before it really comes in. If I stomp on the gas from a lower gear and power shift the whole way, I never feel the engine stuttering or acting up. However, if I were cruising along and just lay into it in third gear per say, then the car will hesitate. This may be related to the tune, but I'm in the dark on terms of that subject which is why I am here, seeking advice from a person that is a little more knowledgeable than I.

Thanks, Grant

 

I went through a similar problem with my car. Mine was running rough when I bought it from the PO so the cost of getting it running right was factored into the price. There is a lot of information on the web (good and bad) regarding Opti's. I was glad I did some research and reading before jumping on a parts store Opti as they are a real gamble. I didn't want to be diving into the job again any time soon, so I tried hard to find a 'reliable' Opti to use as a replacement.

I ended up going with one of the rebuilt eBay ones from seller optisparksolutions1 that use a new sensor combined with a MSD cap and rotor (with the benefit of being vented). I've also heard / read good things about the rebuilt units from Petris Enterprises.

While I was replacing the Opti I also did plugs, wires, water pump and front timing cover seals. It's been two years since the work was done and it's still running great.

 

Alright gotcha, I'll definitely keep that seller in mind. At this point, I really just need to determine what the actual issue is. Replacing every piece of the ignition system is not only pricey, but practically what I have already done. In the last 200 miles the car has got new MSD Wires, spark plugs, opti-spark and harness. Yet something seems to be causing an issue here. It may not be related to any ignition system component at all, I'm just not sure. I'm glad you were able to get your car running right. If I can determine that the optispark is my failing component that seems like a great option.

Thanks, Grant

 

What are your plans for getting it tuned? Do you have a reliable list of modifications that a mail-order tuner could use to do the tune? Are you certain it's the LT4 HOT cam? Do you have any idea who ported the heads or what the flow numbers are? Do you know the injector brand and flow rating? Have the things like AIR, EGR and EVAP been removed? Were the after-cat O2 sensors removed and tuned out?

 

I've been talking with the guy that tunes on LT1pcmtuning.com, Solomon. I'm not going to do a mail order tune for my situation. I'm going to use his cable and software loan method, that way I can accurately data-log the car and have it tuned correctly regardless of the the mods. I'm almost positive it's a Lt4 Hot Cam, It's definitely not a stock cam I can tell you that. The car has the stock injectors, yes I know that makes literally no sense considering the engine modifications but I'm running out of time and money here. At this point, I just want to have the car run reliably, I don't need all the power in the world at the mercy of my foot. The car still retains the emissions controls like the EGR Pump and EVAP system. The car still has all four O2 sensors, both the before and after cat. There are no catalytic converters however.

 

Also Injuneer, these are the spark plugs I've been using in the car, are these suitable for the motor in your opinion? https://shop.advanceautoparts.com/p/...-940/5392098-P , Another thing that's on my mind is going through the sticky thread for diagnosing a bad opti-spark. Will the method described work if my opti is partially functioning? Or will it not be accurate enough to detect the issue and prove a certain point of failure?

Thanks, Grant

 

Here are some pictures of the plugs on specifically the driver side, the easiest side to get to. They are not all the same age, and have very little run time on each.