So, I just bought a '93 with the 4.3 Vortec, and it's running rough. It's also spitting raw fuel out the exhaust. A bit of googling leads me to beleive it is the CPFI "Spider" that has gone bad. Apparently when that happens, they can no longer regulate the fuel pressure, and in turn they dump fuel. A new spider is ~$300. That ain't happening. I am wondering if I could regulate fuel pressure up stream of the CPFI and be good to go though. Anyone ever played this game?
Yep, they're total E36 M3. Get one from a junkyard that gives a guarantee. It's pretty easy to change, so even if you get a crap one and have to take it back and swap it again, it's still going to be worth the savings.
Short version: Not really easily, but possible, kind of like anything is possible if you really really want to.
Long version: The fuel pressure regulator is in the intake's plenum, and it gets its pressure reference directly. If/when the regulator's diaphragm ruptures, instead of shooting gasoline out of a convenient vacuum hose, it dumps it all into the passenger side bank of cylinders (usually #4, sometimes also #2, rarely #6).
So, if that is the problem, you'd have to first bypass the existing regulator. I don't recall if it's something easily bypassable, but if you do have to replace the whole spider on that model then it probably isn't. (Newer Chevies, at least on the Gen III engines, take about five minutes to replace the regulator, and all you need is a screwdriver to pry out a retainer clip)
yeah...the "spider" is famous for dying.
convert to TBI and never have another problem
Buy a new "Spagetti and Meatball" from gmpartsdirect.com if its something you love or will keep. Buy a used one from a boneyard (hear it run or get a warranty) if its a flip vehicle.
if it is the regulator you can buy the regulator separately.
you now know the reason that I will not buy a pre - 96 Vortec. Sellers think I'm crazy when I ask for the 8th of the VIN
It' getting a V8 at some point, s I'm not going to dump money into this engine. If there was a "crimp the supply line with some vice grip's" fix that improved things until the swap, then great. If not, oh well. It runs, just won't idle worth a damn.
Trust me, spend the 60 bucks on the kit. If you are spewing unburnt fuel its not the injector. It will either be the regulator, or the fuel line inside the manifold....the line rubs against the rough casting and eventually fails.
If you keep driving it eventually you'll lock the motor up with fuel....ask me how I know... I tore teeth of my flexplate from this.
alchemist wrote: If you keep driving it eventually you'll lock the motor up with fuel....ask me how I know... I tore teeth of my flexplate from this.
I drained 2 gallons (!) of fuel out of the oil pan of a Blazer I bought. Along with pieces of main bearing. 
Yet another example of an ongoing well known problem which can substantially affect the operation/safety of a vehicle which GM chose to sweep under the rug.
alchemist wrote: Trust me, spend the 60 bucks on the kit. If you are spewing unburnt fuel its not the injector. It will either be the regulator, or the fuel line inside the manifold....the line rubs against the rough casting and eventually fails. If you keep driving it eventually you'll lock the motor up with fuel....ask me how I know... I tore teeth of my flexplate from this.
Where is the $60 kit? I keep seeing $300 kits. For $60, it's worth it just to make a few more bucks when I sell the motor. For $300 it's not.
In reply to Jensenman:
You mean like honduh transmissions? "Nothing to see here. Move along. . .move along."
How many miles is on that 4.3? and I agree, sounds like the spider is the root of the problem.
Bobzilla wrote: How many miles is on that 4.3? and I agree, sounds like the spider is the root of the problem.
200K
Bobzilla wrote: In reply to Jensenman: You mean like honduh transmissions? "Nothing to see here. Move along. . .move along." How many miles is on that 4.3? and I agree, sounds like the spider is the root of the problem.
'Move along, nothing to see here...'
Yeah, you do NOT want to debate me on who takes better care of their customers.
DILYSI Dave wrote:Bobzilla wrote: How many miles is on that 4.3? and I agree, sounds like the spider is the root of the problem.200K
only 200k? berkeley, jensenman's right, GM sucks.
Jensenman wrote:Bobzilla wrote: In reply to Jensenman: You mean like honduh transmissions? "Nothing to see here. Move along. . .move along." How many miles is on that 4.3? and I agree, sounds like the spider is the root of the problem.'Move along, nothing to see here...' Yeah, you do NOT want to debate me on who takes better care of their customers.
flounder. Way to derail the thread.
We had a TBI 4.3 run to 350K. They have good iron.
I'm still curious about this $60 fix...
DILYSI Dave wrote: I'm still curious about this man on man action...
fixed.
AngryCorvair wrote:DILYSI Dave wrote: I'm still curious about this man on man action...fixed.
Now THAT'S a proper thread derail! Well played, sir! 
In reply to DILYSI Dave:
Two parts...35 for each.
Regulator http://cgi.ebay.com/ebaymotors/92-95-S10-BLAZER-JIMMY-FUEL-PRESSURE-REGULATOR-4-3-S-10_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1205Q7c66Q3a2Q7c65Q3a12Q7c39Q3a1Q7c240Q3a1318Q7c301Q3a1Q7c293Q3a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem310111899744QQitemZ310111899744QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories
Fuel Line http://cgi.ebay.com/ebaymotors/92-95-S10-Blazer-Jimmy-CMFI-Fuel-Return-Lines-4-3-S-10_W0QQcmdZViewItemQQ_trkparmsZ72Q3a1205Q7c66Q3a2Q7c65Q3a12Q7c39Q3a1Q7c240Q3a1318Q7c301Q3a1Q7c293Q3a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem370093296647QQitemZ370093296647QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories
I was off in price by a bit.
Find out wich of yours is bad (I'd replace both) and go from there.
Jensenman wrote: Yet another example of an ongoing well known problem which can substantially affect the operation/safety of a vehicle which GM chose to sweep under the rug.
I am not sure about "safety" (you'd have to be profoundly sadistic to let one go for long enough for it to be a SAFETY issue, and I'm still not quite sure how that would work) but they typically fail outside the warranty period, as well as the emissions warranty period. They stopped using the design 10-odd years ago. What's the problem?
I have an early "Vortec" intake/spider injector, sensors, etc. I'll sell for cheap. $50+shipping (obviously shipping will be less if you don't want the metal bits and just the injection stuff). I removed it from a '95 4.3 S10 Blazer (IIRC) that worked fine, the engine went into my Bug and I used a different intake and injection system to use my megasquirt. Email/PM me if you're interested.
Bryce
Bump. Finally working on this thing rather than letting it remain a driveway ornament. The challenge is coming up and if I'm going to keep my "odd years" trend going, then I better get this thing built. I may end up using the 4.3, so I need to get it running decent.
I pulled the intake apart enough to see the spider. Any way to diagnose what part of it is bad? The plenum had puddles in it, of I assume gas. It also smelled heavily of gas when I took the top half off.
Also - Nashco - If you've still got yours I'm interested.
I don't know about the Vortecs, but on a 302 Ford the regulator will fail and pump raw fuel through the vacuum line into the intake. They act the same as your Vortec. Raw fuel out the exhaust and runs like crap.
In reply to Bobzilla:
mmm...Honda really extended the warranty on those 5 speed autocrap boxes. My folks got a brand new one installed no questions asked at 70k miles in their Acura TL-S.
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