[/b]Most of this info was taken from an S10 forum, but everything will be the same besides maybe location and mounts of a few brackets......
How-to replace the CPI unit on a 92-95 (the one with aluminum upper intake (plenum)
It's mostly just unbolting stuff, you're only going to remove the upper part of the intake, so you won't need to remove any coolant. PICS can be seen in the FPR write up at bottom.
1. Remove the air intake duct from the throttle body
2. Unplug the IAT sensor mounted in the duct, get the whole thing out of the way.
3. Remove the VORTEC top cover (2 Torx bolts)
4. Disconnect the vacuum hose directly under the throttle body.
5. Disconnect the MAP sensor on top
6. Disconnect the internal air door actuator (top center of the intake)
7. Disconnect the IAC (idle air control)
8. Disconnect the vacuum hose at the rear passengers side, next to the distributor.
9. Remove the bolts/nuts holding the coil bracket on. swing the coil out of the way.
10. Remove the nuts/bolts holding the wire harness bracket (driver's side)
11. Remove the throttle cable guide loop from the right rear stud if it has one. Leave the cables and bracket on the intake.
12. Blow everything off with compressed air.
13. Disconnect the vacuum hose at the brake booster, you should be able to fish it through the plug wires and leave it attached to the intake.
14. Remove the nuts/bolts/studs around the perimeter of the upper intake. Try to note where studs go, and where bolts go, there are different lengths too.
15. Lift the upper intake straight up, flip it over, and lay it down somewhere over on the passenger's side, near the blower motor. I opted to just take mine all the way off and out.
This is when you will see excess fuel that leaked from the regulator into the intake on the passenger's side (see below pic). Next be careful to check for big carbon chunks stuck to the gasket near the EGR valve. Suck them out with a shop vac.
16. Disconnect the injector electrical connector.
17. Remove the plenum gasket. this can be difficult since it’ll crack. carefully use a small screwdriver or the like and scrape towards the OUTSIDE of the plenum. don’t want any of those little pieces falling in there.
18. Disconnect the fuel lines inside the intake, by removing the retainer clip (pull it straight up) cover with a rag, there may be pressure in there.
19. Carefully remove each individual poppet nozzle by squeezing the clip on it and pull straight out of the intake port. Be careful the plastic clips are very brittle and break easy.
20. Lift the injector (with poppet nozzles) out.
21. Replace the injector in reverse order, make sure to use new "O" rings and retainer clip on the fuel lines. Put a small amount of oil on the "O" rings to help assembly.
Change the oil and filter because the gas may have washed down the cylinders into the oil (bad).
Fuel pressure regulator replacement
So I was having problems starting...(Mainly I'd have to prime the system before starting). My fuel economy dropped from 20 mpg local to 12 mpg local, this was significant and that much of a drop I could not attribute to winter gasoline formulas. I knew it was the CPI
This how-to will focus on changing out of the regulator only though it can be applied to swapping the entire CPI... Typically it's the regulator that goes bad, but because of how detrimental this part is to running, I wouldn't advocate buying this part online. Since the regulator is now available at most autoparts stores from Help! Part #55162, it's much easier to swap out a defective unit.
Tools needed.
10mm deepwell socket (Must be a deep well)
8mm socket
T30 Torx Bit
Paper towels
Either a complete CPI
or
Help! Part # 55162 (the reugulator) Includes the needed Torx security bit for retainer removal. (About $40.00 at Autozone, Pepboys, or Advance autoparts) Also can be bought from 1A-auto parts from either ebay or their online store.
New plenum gasket.
First remove your intake air feed and disconnect the air temp sensor. Then remove the 2 bolts holding the VORTECH cover on. (The bolts holding this on are T30)
Here you can see where I disconnected the air intake temp sensor and started loosening the cover bolts.
Next Disconnect the linkage from the throttle butterfly and remove the 2 8mm bolts holding the top of the cable bracket to the upper intake.
Disconnect all sensor connectors and move them out of the way.
Using your 10mm deepwell socket, Starting with the bolt holding the bracket, work your way around the plenum. There are 9 bolts to be removed. As you get to the bracket holding 1st the coil bracket and then on the opposite side the fuel recovery module, you 1st need to remove the 2 top nuts then set the bracket out of the way then remove the bolt(s) holding the plenum down.
As you remove these bolts (and nuts) Lay them out in order. Several of the bolts are different sizes, so if you lay them out in order, you can simply put them in reverse.
Disconnect the small vac hose from the back of the plenum, then the larger hose at the brake booster.
Lift the plenum straight up.
Here we see that the passenger side of the upper plenum is very washed (note the gold covering)
Here we have the lower intake. Note that the passenger side is almost clean while the driver's side with the nutkit is nice and dirty.
Next I stuffed all the intake ports with paper towels. Why? Because you DO NOT want to take the chance of dropping something down there.
Here is a shot of the regulator SImply remove the 2 screws holding the retaining ring on. (Help! was thoughtful enough to provide the security Torx bit needed to do this)
A shot of the retainer ring removed
A shot of the new regulator (left) and the old one (right)
Here is the new regulator on the CPI (pre retainer installation)
Now make sure that the mating area is completely clear of any old gasket material. If needed, use a razor blade to scrape the mating surface. For some areas if too difficult, use sand paper.
A final shot prior to putting it back together w/ the new plenum gasket
Simply reinstall everything in reverse
Starting at the bolt at the bracket, torque in circular patter to 8 ft pounds
Wala your're done!
