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What is the dif between Z and W vin on 4.3 V6??

05-29-2006, 10:49 PM
I own a 1991 blazer and a 1993 Safari AWD. I got the blazer as a fixer to replace my van as my engine went from a oil starvation. After checking out the blazer it requires more work and money than I am willing to spend on it. The oil pump quit in my van on the highway and destroyed the engine before I could pull it over. The Blazer has a Z vin and the van had a W vin. What is the difference between the two motors and can I swap the Z vin into the Safari?? The motor in the blazer runs great but the body has too much rust to pass safety where I live.

06-07-2006, 06:43 PM
The 1991 "Z" engine is TBI (Throttle Body Injection). This system uses two injectors in a housing that looks similar to a carburetor and is mounted on top of the intake manifold.

The 1993 "W" has CMFI (Central Multiport Fuel Injection). This system uses one injector that is located in the plenum and feeds all 6 cylinders through a series of six tubes, one to each intake port. This system was an improvement over the TBI system.

The "W" engine was redesigned later to CSFI (Central Sequential Fuel Injection). This system uses 6 mini injectors in one housing, (also located in the plenum). Each mini injector feeds its own cylinder sequentially with the firing order of the engine. On the TBI and CMFI systems, the injector(s) is (are) energized every time any cylinder fires. CSFI was an improvement over the TBI and the CMFI systems.

The basic engines are interchangeable and will bolt right up however; the computer and fuel pump/injection systems are not interchangeable. In order to use the Blazer engine in the Safari you will need to utilize the existing electronic and fuel components that are in the Safari. Basically anything that bolts to the heads and block needs to be changed over. Big job, but it can be done. Hope this helps.

06-07-2006, 11:57 PM
Thanks Old_Master. That was what I figured but was not sure. Good thing I am a pack rat and never throw anything out. I still have all of the original parts with exception to the block that was thrown out at a buddies garage. I do have all of the fuel injection system and even the heads that are in good shape. Thanks again for your help.

06-08-2006, 05:50 PM
BTW, welcome to the forum.
Glad I was able to help. Post back on how things go with the swap. Pictures would be nice for anyone else thinking about doing a swap too. Better you than me, have fun :)

Blue Bowtie
06-09-2006, 08:21 AM
Not to challenge the Old Master, but simply to clarify, the early version CPI systems fired the injectors once every engine revolution, or twice per cycle, instead of three times every engine revolution (once per cylinder firing). The effect is the same in that it is a batch fire system instead of sequential, as the later systems are.

06-09-2006, 10:13 PM
Thanks all for the info. I will certainly document everything in pics with exception of removal of the engine from the van.

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