Another CPI How-to

[rlith]

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)
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? Becuase you DO NOT want to take the chance of dropping something down there. (Last time I did I destroyed a motor, )



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!

Note: Prior to putting it back together, it's a good time to pull the distributor cap and check the condition of your cap and rotor. The reason I mention this is because of how difficult it is to get to that front screw.

[Nuts]

Great job!! I'd just like to add a couple of things.

Part Numbers...
17113673 - MULTIPORT FUEL INJECTOR
17112705 - NUT KIT
10105939 ? GASKET
Fel-Pro fel MS95818 (Rock-auto)

And if you end up removing the cpi and forget which injector goes to which cylinder. You're in luck because it doesn't matter where each injector goes. They actualy all fire at the same time.

[JasinC19]

I'm not positive, but I think some years don't all fire at the same time. You might wanna double check that.

[Black95Blazer]

Thats how i had to do mine a few months past just couldnt get good pictures and it took a bout a hour to do so it worth doing yourself.

EK

[rlith]

I'm not positive, but I think some years don't all fire at the same time. You might wanna double check that.

Correct, CPI was only available from 92-95, it's a batch fired system. 96-current is CSFI which is fired sequentially, this how-to only is for 92-95 motors

[JasinC19]

Wow, I have a '95, and two of the nozzles on the passenger side of the cpi were crossed (i forget which two), but I was pretty sure it mattered which plugs you put them in.

So if all the nozzles are fired at the same time, does that mean that all 6 fire every time a cylinder ignites? Isn't that a waste of gas?

Jason

[rlith]

Wow, I have a '95, and two of the nozzles on the passenger side of the cpi were crossed (i forget which two), but I was pretty sure it mattered which plugs you put them in.

So if all the nozzles are fired at the same time, does that mean that all 6 fire every time a cylinder ignites? Isn't that a waste of gas?

Jason

Not really because the gas does get burned...For the CPI unit it doesn't matter which one goes where, with CSFI you have to have them plugged in to a specific port. CSFI is more accurate in its burning though.