95 CPI Vortec Spider Tear Down

[Tynan918]

I've asked other forums and nobody seems to have never opened up a CPI Spider. Can anyone here tell me as much as possible about this piece here? What is it? What does it do? Why is it dirty? Is this what is clogged when you have a "clogged spider" ?

[Jsdirt]

I would have to say, the little poppet valves on the ends of the "spider's" legs (basically, GM's half-assed attempt at a fuel-injector) are the only things on that system that could clog up. Most of the time, the regulator fails, and dumps gas all over the intake, or, the spider-leg fuel lines bust with the same results. One of the WORST FI systems ever designed.

 

Never heard of them clogging, BUT ... if your fuel pressure isn't just about right on spec, the poppets WILL NOT open.

[grampadirt]

If your truck is indeed a '95 it doesn't have CPI,it is TBI or throttle body injection and has two injectors.It will look much like a carburetor.CPI started in '96.

[grampadirt]

Also,there is an upgrade to the CSI system...check this thread:http://CSFI to MPFI

[Jsdirt]

There was a CPI from '92 - '95 on the S-series Blazers. It was hands down THE WORST FI system GM had ever engineered.

[grampadirt]

Hm,didn't know that.

[Jsdirt]

In '94, you had the option of getting TBI or CPI on the S10 trucks (not sure on the Blazer, but I would imagine so).

 

Thankfully the guy that bought my '94 S10 plow truck new went with TBI.

[grampadirt]

Hard to imagine an S10 as a plow truck,how did it do?

[Jsdirt]

Works good for what I need it for. Full size pushes ALOT more snow, but this thing ain't too bad.

 

I can't complain since I got it for free.

 

[grampadirt]

Pretty cool,love the price I drove one at work for five years before I retired and never had a problem with it.I think they're very underrated.Think a 4x4 long bed 5sp. with a 4.3 would do me just fine

[Jsdirt]

I've owned quite a few of them myself. Love the 4.3, but not too crazy about the build quality of the S-series. Every one I've owned squeaked and rattled inside, and ate ball joints, brake lines, fuel tanks, and front brakes (and body rusted out FAST) on the outside. The full-sized Blazers were MUCH better in that regard, IMO ... except for the rust part. Many a full-size succumbed to that rear rot.

 

Even with all that, I still like the smaller trucks - easier to get in tight places with them, and they're great off road when you've got decent rubber on them. The 4x4 actuation system sucks ... but that's a whole other story!

 

If you do grab one, make sure it's TBI, and not CPI.

[grampadirt]

BTW the S10 I drove for work was an '02,if it makes a difference,that little thing hauled ass even with a load of glass on it.Noted on your TBI comment,a ZR2 would be cool as well.

[Jsdirt]

The '96 and up ones had some good power. A little bit different injection system, but still uses the spider. Best ones were '00 and up - roller lifters and rockers. Made some great power.

 

I took the 4.3 that was in my '00 Jimmy (which was a complete lemon) and put it in my '89 S10 Blazer. Slapped an Edelbrock intake and carb, and threw an HEI distributor in. That was a GREAT combo! Throttle response was amazing. That engine would've run circles around alot of the late 70's and 80's V8's.

 

Ran that thing for 6 winters, before the body gave up the ghost.

 

 

[grampadirt]

Pretty cool little Blazer,I'm sure it was a blast to drive in snow.Nice touch on the 4x4 graphic on the hood insulation

[Jsdirt]

Thanks. Yeah, I actually enjoyed driving that one over my '07 Silverado! Had about the same power (less on the top end, of course), but the Blazer had 20x better throttle response and low-end grunt. A V6 ... go figure! It just got out of the hole better.