Being OBD2 is one thing, but there is still a VERY stark difference between the CPI system in every 95 blazer and the SCFI system in your 96. The largest difference is that the CPI system uses a single batch fired maxi injector (only two wires to control it) while the later SCFI system uses 6 individual sequentially fired injectors that have two wires each. Beyond that, the SCFI system uses a MAF sensor, MAP sensor, and two upstream O2 sensors to monitor airflow into the engine and oxygen content on each bank and alter fuel injector pulse width accordingly in a mass air flow scheme while the CPI system uses a MAP sensor and one upstream O2 sensor to control fuel in what is called a speed density control scheme. Each system requires vastly different PCM communication & control.

So Captain's comment is spot on. But good call on the rear wiper!

 

Actually, not every 1995 blazer has the earlier CPI system.

The biggest difference is that it was impossible to meet the OBD-II standards with the earlier injector, sensors and electronics. OBD-II required an upstream and downstream O2 sensor on each primary cat because it requires DTC's for catalyst failures on each bank. You also can't have a single injector feeding both banks on an OBD-II compliant system because any injector related DTC's and fuel trim data streams must identify the cylinder bank (but can optionally identify a specific cylinder). That's why separate injectors were required for OBD-II. All of the differences you mentioned are the very definition of "OBD-II compliant."

A friend of mine has a 1995 S-10 pickup. It's a 1995 model with "S" in the VIN for the year, but it was manufactured in July of 1995, and it is fully OBD-II compliant. It has the same spider as my 1996 Bravada, with the same big wiring connector. It has the same PCM over by the coolant recovery tank. It has 4 O2 sensors and all the other things you mentioned, all of which are required for OBD-II compliance. The only thing it doesn't have that a 1996 S-10 pickup would have is the "T" in the VIN. It was made before the calendar rolled over to "T" VINs.

In 1995, it was a very unusual year. Every GM assembly plant had major retooling because every GM engine changed electronics and fuel system components for the 1996 model year. OBD-II was mandate by the government, with huge fines per unit for any 1996 model year vehicle (VIN with a "T") made with non-compliant parts. If GM missed the deadlines, the fines/penalties for producing non-compliant vehicles would have been over $1 million per plant per day for most of their assembly plants. So, the retooling teams went out about 3 months earlier than most years in order to convert all of the plants over to the 1996 engines, electronics and fuel systems before the deadline. Once an assembly plant was converted, it turned out vehicles with 1996, OBD-II compliant engines and electronics. Every plant was operational and producing vehicles with 1996, fully OBD-II compliant engines while the timer/calendar on the VINs was still in the 1995 model year (VINs with an "S"). When the calendar switched to VIN "T", 1996 models, the letter in the VIN was all that changed.

When you have a fully OBD-II compliant, late production "1995" GM vehicle, your engine is identical to a 1996 vehicle of the same model and engine. The only difference is the model year letter in the VIN.
Thanks. I just had the exact same experience a week or so ago. Mainly dumb luck there.

 

Now you are just arguing for argument's sake... My exact words were "every 95 blazer" which is 100% accurate. I am well aware of the change over in the 95 s-series pickups, but this is BlazerForum...

 

Actually, you're the one arguing. I was taking the OP at his word that he had a fully OBD-II compliant Blazer, with the PCM by the coolant recovery tank, and with all the parts you mentioned which you now say weren't ever installed in a 1995 Blazer.

BTW, you're also arguing with yourself. Quoting this post of yours from 2009:

PS: a number of other posters on that thread reported "fully obd2" 1995 Blazers, with build dates as early as February 1995.

 

Nothing in that post is contradictory to my statements. Not once here have I stated that 95s were not OBD2, only that your statements of the "nearly identical" setups between the op's 95 s-series suv and your 96 was incorrect for the stated reasons as you will find if you actually read what was posted. You are mistaking OBD2 compliance (PCM on the coolant tank) with the actual controls of the fuel system and the wiring/programming involved which are considerably different between the two years. The SCFI fuel system with MAF controls was not implemented until the 96 model year for the s-series suvs and did not exist in a 95 model year s-series suvs, period. The production numbers were not there to warrant a change over in the suvs like the trucks went through.

I'm not arguing, just stating the facts of the matter.