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Well, it looks like my opti is bad.... was supposed to be the one thing I didnt have to worry about... sent it off back in august to be refurbished, because was working and had the sought after Mitsubishi sensor.. just emailed the guy that did it, he wants me to send it back, he will check it all out and take care of me!!! So back outside I go to strip front of motor down... toodles..
Sorry to hear about the Opti, Darren. I've been following your swap since your first post and I am about 6 months behind you with mine. I, too, am going to use a genuine GM Opti-Spark that has been rebuilt and sold by GM. Mine is a 1995 LT1 with the vacuum "ventilation". How did you decide the Opti was bad? Was it just and "crank-no fire-no spark" situation or did you spot something else? I'm not familiar with the Mitsubishi sensor, is it in the Opti?
I hope your friend gets it working for you, looking forward to you hearing it run.
Being as you are doing same thing as me, I will assume you are familiar with shoebox, and injuneer over on ltxtech. There are tests for no spark and no injector pulse, I am not getting the pulses out of the opti to the ignition control module, I have pulled the opti back off, and will be doing one final test spinning it slowly by hand watching the white wire at the icm for 5 volts then 0 and 5 and 0 etc, with opti out I wont have to run starter so it wont be going as fast!!
The Mitsubishi sensor is the optical pickup inside the opti, it's what gm used, supposed to be the best one. Mines the 94, has the vent conversion done via the msd cap..
Last edited by Darrenmb; Feb 14, 2020 at 06:08 AM.
Because the LT1 uses the Optispark, I would never have another of those engines. I went through three types of Optis before buying a brand new original GM unit. It was working when I sold the car. That is the weak link in that engine design.
I have various articles still saved that tell how to diagnose those units...plus, with the Meziere water pump it was easy to do the R&R. Still have the defective Dynaspark unit ready to add to my Wall of Shame that already holds the Sanderson
headers that repeatedly cracked and were welded up twice by the manufacture. .
My current Jag Series 1 SBC 383/200R is a daily drive that is VERY reliable. I have about 25000 miles on the setup and it is now converted to EZ-EFI fueul injection.
seems 75% of Opti's went bad over time!
JagCAD converted to a LT1 and his opti went bad also, lucky his son changed some things and last i heard it was running good?
i do remember a friend who had a Corvette and it failed , like $1500. at a Chevy shop!
there must be some aftermarket change over kit or something by now?
Well, now it appears it isn't the opti, once I removed it, I plugged it back in, grounded it and spun it by hand, fuel pump runs and injectors are pulsing, but no spark, ohms look good on the Coil, so it's all pointing at the ignition control module now.
Spinning the opti by hand also let me see the pulses at the icm.. I m guessing that my multimeter doesnt refresh fast enough to catch them on the starter..
off to find a decent icm, locally if possible, wanna hear this thing come to life!!!
Just a note- the GM factory shop manual has great sections for problems like this -"cranks, but won't start"- for example. It gives a great step--by-step process to solving the issue quickly and without any guesswork. I advise all of our customers to have this book for their donor vehicles. There are always a few of them for sale on Ebay-used- and for the $40-$60 are well worth it. In this case it would be the 94 or 95 B-body (Caprice/ImpalaSS/Roadmaster). It will save you a ton of time and money. Here are a few:
We obviously won't need the sections on suspension, brakes, body, etc.,., but the engine, engine running, diagnostics, etc.,. are so good it's well worth the cost.
And if the donor is Camaro, there are versions out there as well.
Only use the factory versions- chiltons, haynes, etc.,. are really not detailed enough for us...
Here are two great ways that I found helpful diagnosing those type of problems...
The second document has both ways, but I cannot remove the first one???
Last edited by Roger Mabry; Feb 16, 2020 at 09:07 AM.
Here are two great ways that I found helpful diagnosing those type of problems...
The second document has both ways, but I cannot remove the first one???
Shbox.com has been my best friend through all this!!! Lol
I even have the fsm for the camaro ( sent to me by someone on z28.com. ) sometimes.car people are the best people!!
My OPTI turned out to be just fine. But, the HT wire from the coil to the OPTI was badly corroded at both ends. Cleaned and worked. It is an "odd" wire. Now has a new one and all is well.
Andrew:
For sure the GM factory manual is great. Mine was a hundred, new from GM. But, well worth it
Not only in the installation, but as a guide to get the referee to approve the installation.
After many headaches and chasing issues that made no sense she fired up!!!! Wasnt the opti, wasnt the icm or the coil.. it was the wire for 12 volts ignition source Inside car to feed pcm was dropping to zero when engaging starter... gotta figure that out now, but I'm so happy, , now I can put front of motor back together again and move forward .
Yeah, it's all about paying attention to the s57.... which circuits are hot in positions 2 and 3, not 1 and 2.. all sorted.. now I can continue with the rest!!!
Had some help... scan9495 software and injuneer over on ltxtech helped me to no end..
just so you are aware when you wire yours, fig 4.1 in the s57 tell you which wires are hot and in what key position....
Yeah, it's all about paying attention to the s57.... which circuits are hot in positions 2 and 3, not 1 and 2.. all sorted..
This is why I had the Wiring Diagram from the ROM for my Series 2 enlarged to 24x36 inches (big as they could make it), big enough to actually SEE stuff, and then labeled every component.
Then I tacked it on the wall Right by the shop door! As I work on a circuit I color the lines to match wire colors.
(';')
was supposed to be the one thing I didnt have to worry about... sent it off back in august to be refurbished, because was working and had the sought after Mitsubishi sensor.. just emailed the guy that did it, he wants me to send it back, he will check it all out and take care of me!!! So back outside I go to strip front of motor down... toodles..
