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hello i am having a weird issue with my 95 z28 camaro. i recently replaced my optispark cause no spark was getting to the plugs. i replaced it with a cheap amazon opti (i kno bad decision) and it fixed my issue. i drove the thing for 4 days and it gave out on me again. i didn’t bother checking if it was the opti i just safely assumed it was the culprit since i had just replaced it and i was experiencing the same dam crank no start issue again . i called amazon and got a brand new replacement. now the car is sitting with another new opti and still only cranking.....im getting spark to cylinders (did spark test), im also getting fuel (put fuel guage on rail) heck i even unpressurized the lines to make sure my pump was actually pushing fuel through them and it did. fuel pump is new, ignition coil is new, opti is new , fuel filter is new, icm tested , tb and iac cleaned, inspected wires and no issues,

next to check is injectors but i doubt thats the issue, i hit a wall at this point . i had this issue before and replacing opti fixed it . now im having same issue and replacing opti did nothing. also cranked with starting fluid and nothing.... can an opti still send spark but still not function properly? how about a bad iac ? ive had issues before with cars not turning on due to a dead iac . i also was experiencing bad iac symptoms the day before the car gave out , like surging idle when warm and stalling at a light , i had to put it in neutral so it wouldn’t die on my way home. i have a vid of this.
 

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Have you hooked an obd 1 scanner to aldl and checked for codes? I as because ignition related codes don't light the cel. And even thoiugh your 95 has a 16 pin obd 2 type aldl, it's still an obd 1 computer system. Dtc 16 = opti low resolution signal missing. Dtc 41 & 42 are for icm.

You need to invest in a $70 PC based oscilloscope. With it you can check the low & high resolution signals that opti sends out. To see if they are the proper square wave signal that PCM needs to actually run engine.

Also, does your security light come on when you turn key on? Then go out after several seconds? This is normal. If security light stays on fuel injectors will not open. Engine won't run.

You can use the PC based scope to test for the fuel enable signal. It's also a square wave. You might want to download the 95 factory service manual at the following link. It has a driveability & emissions section with troubleshooting, codes explanations, & other useful stuff. www.mediafire.com/?40mfgeoe4ctti
 

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Have you hooked an obd 1 scanner to aldl and checked for codes? I as because ignition related codes don't light the cel. And even thoiugh your 95 has a 16 pin obd 2 type aldl, it's still an obd 1 computer system. Dtc 16 = opti low resolution signal missing. Dtc 41 & 42 are for icm.

You need to invest in a $70 PC based oscilloscope. With it you can check the low & high resolution signals that opti sends out. To see if they are the proper square wave signal that PCM needs to actually run engine.

Also, does your security light come on when you turn key on? Then go out after several seconds? This is normal. If security light stays on fuel injectors will not open. Engine won't run.

You can use the PC based scope to test for the fuel enable signal. It's also a square wave. You might want to download the 95 factory service manual at the following link. It has a driveability & emissions section with troubleshooting, codes explanations, & other useful stuff. www.mediafire.com/?40mfgeoe4ctti
I've installed a '95 lt1 in my '50 Chevy rat rod/street rod pickup. For all of the issues above and others, I'm going to convert it to a naturally aspirated engine. I'm 67 years old. I have no knowledge or the equipment to get a EFI engine, with the dreaded opti-spark, running. Hindsight, I should have bought an earlier sbc with all the accessories. (I knew the history of the lt1). Good grief, just reread the above potential solution(s). With a carburetor and a "normal" distributor you can get it running a keep it running using a 67 cent flat screwdriver from Walmart!
 

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Discussion Starter #4
Have you hooked an obd 1 scanner to aldl and checked for codes? I as because ignition related codes don't light the cel. And even thoiugh your 95 has a 16 pin obd 2 type aldl, it's still an obd 1 computer system. Dtc 16 = opti low resolution signal missing. Dtc 41 & 42 are for icm.

You need to invest in a $70 PC based oscilloscope. With it you can check the low & high resolution signals that opti sends out. To see if they are the proper square wave signal that PCM needs to actually run engine.

Also, does your security light come on when you turn key on? Then go out after several seconds? This is normal. If security light stays on fuel injectors will not open. Engine won't run.

You can use the PC based scope to test for the fuel enable signal. It's also a square wave. You might want to download the 95 factory service manual at the following link. It has a driveability & emissions section with troubleshooting, codes explanations, & other useful stuff. www.mediafire.com/?40mfgeoe4ctti
ok i guess ill have to do that before anything.buy the cable

i called amazon again lol let em know the new opti suks . they refunded my money so with tht im going to buy the cardone remanufactured unit.

i just got a job too , and im willing to start throwing parts at it , what would you suggest i start replacing ?

here is a clip of the latest soark test i did , seems kinda odd to but idk ...
 
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