4.3 vortec intake question
 

I've got a question on the 4.3 vortec in a 93 s-series truck. I'm not to familiar with this engine but it sure looks like a sbc minus 2 cyl. The intake looks similar to a tpi with the word vortec on the center. A search on the web states its a CFI system? What does that mean? The intake looks like a TPI? Also are these engines any good. What are the weak points to look for? Thanks in advance.

Mike

RE: 4.3 vortec intake question
 

i had a 94 s-10 with the 4.3 liter vortec it was tbi(throttle body injected) it is assentially a 350 with two less cyl. as you suggested. same bore and stroke with the exception the head and intake have different wedge angle, so dont just put in any ol' intake as you will be mixing water and oil as a buddy of mine found out in his boat motor. he couldnt figure out where the water was coming from after he built the engine with a few mods and new intake. i had two inform him of the angular different in the wedge. as for your original question TPI is tuned port injected, TBI throttle body injected and i believe that CFI is central fuel injection. i had 156,000 miles on my s-10 when i sold it and all i did to it was plugs ,wires, oil changes and one freeze plugs seeped so i replaced it. oh yeah, once i went arround the corner and when i hit the throttle it died no response. it ended up being a pinhole burnt into the rotor button. didnt take long to find the problem though, it was the second thing i checked.

RE: 4.3 vortec intake question
 

thanks for the info. The reason why I posted this question is that on this engine, the intake looks like an upper plenum like a tpi. But after I removed the upper name plate I could not find any individual injectors located on each intake port like a tpi. I've seen tbi's which look just like a carb with two large injectors inside but this one does look like that. Maybe it's like a tbi but with longer runners? I'll have to buy a manual later. thanks again.

RE: 4.3 vortec intake question
 

Does it look like this?

[IMG]local://upfiles/4028/C5BFB430070F4BE5997AD8707DC02935.jpg[/IMG]

RE: 4.3 vortec intake question
 

The early Vortecs used a "spider" which distributed fuel to each cylinder. The spider was known to rot after some time, which was and is still not a cheap fix.

My dad's 97 C1500 with the 350 suffered from this. The shop he went to got all sorts of codes before I googled up what I had read about the spider issues. Probably saved him a literal ton of money, too, since the shop wanted to replace O2's, cats, MAF...a bunch of sensors. The noticeable symptom was rough running and a rich smell out the tailpipe.

RE: 4.3 vortec intake question
 

Hey Madmike that is it right there. I did some research since and a site explained that the fuel goes to a single injector and then to six poppet valves. It says that if the main fuel distribution system fails, I'd have to replace it as a unit (ouch). I'm alittle relieved that most people have been telling me that the 4.3 engine is pretty reliable and stout even though it's not a v8.

RE: 4.3 vortec intake question
 

Basicly the same thing used until recently. Now instead of the valves they are more traditional style injectors.