Another CPI How-to (focus on regulator)

[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 regulator) 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
http://www.pghconsulting.net/teal/cpi/cpi1.jpg

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)

http://www.pghconsulting.net/teal/cpi/cpi2.jpg

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.

http://www.pghconsulting.net/teal/cpi/cpi3.jpg

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, :D)

http://www.pghconsulting.net/teal/cpi/cpi4.jpg

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)

http://www.pghconsulting.net/teal/cpi/cpi5.jpg

A shot of the retainer ring removed
http://www.pghconsulting.net/teal/cpi/cpi6.jpg

A shot of the new regulator (left) and the old one (right)
http://www.pghconsulting.net/teal/cpi/cpi7.jpg

Here is the new regulator on the CPI (pre retainer installation)
http://www.pghconsulting.net/teal/cpi/cpi8.jpg

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
http://www.pghconsulting.net/teal/cpi/cpi9.jpg

Simply reinstall everything in reverse

Starting at the bolt at the bracket, torque in circular patter to 8 ft pounds

Wala your're done!
[B]
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

[ONE BAD BLAZER]

my 94CPI runs rich at idle and completely rich at W.O.T. does sound like a regulator to anyone and the fuel gage bounce inbetwen 8psi rapidly when cruising

[rlith]

8psi??? WTF, you wouldn't even be able to run at that pressure. CPI requires 56-60 to start and 61-65 to run properly. Or are you talking about your oil pressure gauge? If that's the case the gauge will bounce up an down as you accelerate and decel. I don't buy the 8psi reading on something like that though. Replace the oil sender unit if that's the case.

As to running rich, the only real surefire way to tell is to pull the upper plenum and check for washing.

[ONE BAD BLAZER]

no it idles at 42psi and W.O.T runs 58psi and when crusening it bounces inbetween thous 42psi and 58psi rapidly

[ONE BAD BLAZER]

it bounces inbetween 42psi and 58psi rapidley when crusen and W.O.T. has only 58psi

[rlith]

it bounces inbetween 42psi and 58psi rapidley when crusen and W.O.T. has only 58psi

The oil gauge or the fuel pressure?

[dbinnc]

Reposting first post to include pics

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 regulator) 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 VORTEC 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

http://www.s10planet.com/forum/attachment.php?attachmentid=6224&stc=1&d=1224550211

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)

http://www.s10planet.com/forum/attachment.php?attachmentid=6225&stc=1&d=1224550211

Here we have the lower intake. Note that the passenger side is almost clean while the driver's side with the nut kit is nice and dirty.

http://www.s10planet.com/forum/attachment.php?attachmentid=6226&stc=1&d=1224550211

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. (Last time I did I destroyed a motor, :D )

http://www.s10planet.com/forum/attachment.php?attachmentid=6227&stc=1&d=1224550211

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)

http://www.s10planet.com/forum/attachment.php?attachmentid=6228&stc=1&d=1224550211

A shot of the retainer ring removed

http://www.s10planet.com/forum/attachment.php?attachmentid=6229&stc=1&d=1224550211

A shot of the new regulator (left) and the old one (right)

http://www.s10planet.com/forum/attachment.php?attachmentid=6230&stc=1&d=1224550211

Here is the new regulator on the CPI (pre-retainer installation)

http://www.s10planet.com/forum/attachment.php?attachmentid=6231&stc=1&d=1224550211

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

http://www.s10planet.com/forum/attachment.php?attachmentid=6232&stc=1&d=1224550211

Simply reinstall everything in reverse

Starting at the bolt at the bracket, torque in circular patter to 8 ft pounds

Wala you'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