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top plenum/tpi

Jim D

Well-known member
Joined
Feb 11, 2002
Messages
140
Location
Mickleton, NJ
Corvette
1987 yellow vert
Whats involved in removing the top plenum on my 87. I"m going to replace the injectors, thanks Jim.
 

bossvette

Gone but not forgotten
Joined
May 19, 2003
Messages
3,233
Location
West Unity Ohio
Corvette
1968 1997
pretty straitforward, there are a couple of bolts hidden in the lower runners though relieve the pressure in the fuel lines before you start.
 

bosshogg

Well-known member
Joined
Jul 15, 2006
Messages
56
Location
Indiana
Corvette
1988 Coupe
When I did mine I found out you can remove all of the upper bolts on the plenum then take the lower bolts out of the runner on the passenger side first. Bossvette is right...there is a bolt hidden at the front of the runner that comes in from the driver's side underneath the runner very near the front. On the driver's side runner the bolt coming in from the inside is towards the back of the runner...that is why you need to remove the passenger side first and the plenum then driver's side runner if you need to. Re-install in the reverse order and you should be fine.
GOOD LUCK...AND THINK SPRING
Boss Hogg
 
M

mdsbch

Guest
One other suggestion, lossen the gas cap. I took my fuel injectors out last week on my 85 coupe and I did all the steps releasing the fuel pressure at the rail and all. The next day I had a puddle of gas under the car because the temperature increased causing the gas in the tank to expand and force gas through the lines and out the fuel line that was disconnected in the front. :confused

Mike
 

Ghost~3~

Well-known member
Joined
Oct 18, 2003
Messages
81
Location
So.San Francisco Ca.
Corvette
1985 Blue Coupe
Whats involved in removing the top plenum on my 87. I"m going to replace the injectors, thanks Jim.


Just finishing up mine....As stated above pretty straight forward deal, You'll need
a Torx40 socket and extension to reach the above mentioned 2 "Hidden" bolt's
and it would be a GOOD idea to change that Thermostat while ya got that Plenum off! :D

I had a Bad EGR Valve, so that got changed along with all the other sensor's under or near that plenum as a preventative measure, I'd HATE to go back in there a month from NOW because the T-Stat went BAD when ya "COULD" have changed it NOW!! :D

I also changed the water Pump as my car hit the 70K mark and at 20 Year's old
I figured it had done it's duty!! ;LOL
 
S

speedmaster4

Guest
on each side of the plenum/runner juncture, there is one ''end'' bolt that is ''angled'' and not perpendicular as all the others are...do not follow normal practice of starting all bolts before tightening any, leave those ''angled'' bolts on the bench until the ''straight guys'' are all tight, then install the ''angled'' ones.

if you are acquainted with the guy who will be next to remove the runners, visit the local sears hardware store and get socket (allen wrench) head bolts to replace the torx heads that hide under the runners at lower connection to the intake manifold.
 

nelson84

Well-known member
Joined
Aug 28, 2006
Messages
829
Location
Canada
Corvette
84 Z51 two tone bronze coupe 85 black on black
Just finishing up mine....As stated above pretty straight forward deal, You'll need
a Torx40 socket and extension to reach the above mentioned 2 "Hidden" bolt's
and it would be a GOOD idea to change that Thermostat while ya got that Plenum off! :D

I had a Bad EGR Valve, so that got changed along with all the other sensor's under or near that plenum as a preventative measure, I'd HATE to go back in there a month from NOW because the T-Stat went BAD when ya "COULD" have changed it NOW!! :D

I also changed the water Pump as my car hit the 70K mark and at 20 Year's old
I figured it had done it's duty!! ;LOL

How do you know you have a bad EGR Valve???
 

Ghost~3~

Well-known member
Joined
Oct 18, 2003
Messages
81
Location
So.San Francisco Ca.
Corvette
1985 Blue Coupe
In my case the EGR was "STICKY" and it didn't matter if the engine was cold or up to running temp's, upon start up it would intermittantly stick closed, and the engine would start misfiring and I'd have to restart it about 6-8 times to get it
to "Free-up" and then the motor ran fine.

That would happen about every 8-10 times I started up the car, when it was
cold, not as often if it was up to running temp's. Rather "Irritating". :W
 

KANE

Moderator
Joined
Mar 2, 2002
Messages
3,244
Location
KY
Corvette
Dark Blue 1982 Trans Am(s): Polo Green 1995 MN6
Whats involved in removing the top plenum on my 87. I"m going to replace the injectors, thanks Jim.

You'll need to pull the runners too.
:)
 

Ghost~3~

Well-known member
Joined
Oct 18, 2003
Messages
81
Location
So.San Francisco Ca.
Corvette
1985 Blue Coupe
Copy_of_vette_044.jpg


All back together....

"WHY" did I run the Plug Wires over the Valve cover's your Wondering??

Because I wasn't gonna have another set of $100 wire's "Baked to a Crisp" by the Exhaust by running them in the FACTORY location, so I went Old School. :)
 

Blue89

Well-known member
Joined
Mar 14, 2005
Messages
60
Location
Greater Cincinnati
Corvette
1989 Red Drop Top
I am going to attemp to replace the injectors myself and am reading as many threads as possible to build confidence, since I haven't done this before but just one question........I read about relieving the fuel pressure and how to do that but then I read about disconnecting coolant hoses and lines and wonder if the radiator should be drained prior to starting the project. Any help here??
 

KANE

Moderator
Joined
Mar 2, 2002
Messages
3,244
Location
KY
Corvette
Dark Blue 1982 Trans Am(s): Polo Green 1995 MN6

bossvette

Gone but not forgotten
Joined
May 19, 2003
Messages
3,233
Location
West Unity Ohio
Corvette
1968 1997
I am going to attemp to replace the injectors myself and am reading as many threads as possible to build confidence, since I haven't done this before but just one question........I read about relieving the fuel pressure and how to do that but then I read about disconnecting coolant hoses and lines and wonder if the radiator should be drained prior to starting the project. Any help here??

Drain the radiator and it will be a good time for a coolant change; but not necessary for an injector change there is a small loss of coolant but nothing that can't be managed by a few rags. I had mine all apart (three times) this last week chasing a vacuum leak and finally determined it was the heads that must have been cut not allowing the intake to seat.
 

Ghost~3~

Well-known member
Joined
Oct 18, 2003
Messages
81
Location
So.San Francisco Ca.
Corvette
1985 Blue Coupe
I am going to attemp to replace the injectors myself and am reading as many threads as possible to build confidence, since I haven't done this before but just one question........I read about relieving the fuel pressure and how to do that but then I read about disconnecting coolant hoses and lines and wonder if the radiator should be drained prior to starting the project. Any help here??


Blue89....Well if ya read what I said as to the "Reason" for pulling mine apart it
was due to a bad EGR Valve. My '87 has only 70,400 or so miles on it and wasn't
having ANY Injector issues, so I did not change them at this time.

As far as the coolant hose's...Yes! they run coolant up to the TPI Intake Butterfly
Housing, so you WILL have to drain the coolant. The radiator drain on mine is
Damned HARD to access so it was just "Easier" to disconnect the Lower Radiator
Hose. Just have a "Good Sized" Drain Pan handy when ya do that! :D

You DIDN'T mention your MILEAGE?? and if your having any "ISSUE'S" with the
Injector's, such as "Leaking"?? or getting Check Engine Codes?? Or if this just
is something ya felt like doing for some more "Performance"???

If it's just a "Performance" thing??? I'd SAVE the "HEFTY" price of the injector's,
and the related part's, and NOT change them if your not having any problem's,
and use the $$$ on getting the car in the the BEST state of Tune ya can "FIRST"
before ya go replacing Injector's, as the chance's of say a "Misfire" occuring due
to worn Spark Plug's, BAD Plug Wire's, or other ignition part's is more likely, and
if ya change injector's looking to cure a "Simple" Ignition problem, and it still
has a PROBLEM there AFTER ya put the injector's in, Your NOT gonna be too
"HAPPY" and WONDERING...."WTF" is going on??? :W:D

So get the BEST Quality Ignition Part's ya can "FIRST" and Tune that motor up!

My motor may "LOOK" like it's got a LOT of HP....It's basically "STOCK" the only
"Mod's" if ya can call it that?? are an Accel Ignition Module, Accel 8.8mm wires,
an Airfoil on the Intake Butterfly, and the "Smooth" Intake Coupler between the
Mass Air Flow Sensor and the Butterfly, and a 180 Degree Thermostat, and a
coolant sensor to trip the radiator fan's on at 205 Degrees, MSD Distributor Cap
& Rotor, Bosch Platinum Plug's, and don't "FORGET" to change the Fuel Filter!!

The rest is just paint, and some "Flash" with the Valve Cover's & Steel Braid,
and just a lotta "Elbow Grease". :upthumbs
 

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