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Old 01-17-2008   #1
32valvZ
 
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Default Pulled plenum...lots a ??'s

Ok, I got the cojones & did it. What should I look for or test while its off? How do I tell which injectors I have? I tore the gasket on the throttle body to plenum, can I get a new one? Can I re-use the plenum to intake port gaskets? I see some oil on the plenum floor & on the throttle body & blades...is this very bad? I got some coolant in one or 2 of the intake ports.....now what?

Theres mere to come I'm sure......Hey you guys gave me the confidence to do this, now dont be mad if I'm a pain in the ***!!
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[B]1990 #2815[/B]
[COLOR="Red"][B]Red/Red[/B][/COLOR]
Ported Plenum & IH (by Pete)
Haibeck Chip
Rebuilt FPR (by Phil)
FIC Injectors
Watson LT Headers
3" Stainless Works exhaust
Lingenfelter Open Air Lid
Bill B Built Transmission
Shifter & C Beam Plates


[FONT=Impact][COLOR=red]1992 [COLOR=black]#[/COLOR] 091[/COLOR][/FONT]
[FONT=Impact][COLOR=#ff0000]Red/[COLOR=silver]Gray[/COLOR][/COLOR][/FONT]
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Old 01-17-2008   #2
guinnessdood
 
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Default Re: Pulled plenum...lots a ??'s

Quote:
Originally Posted by 32valvZ
Ok, I got the cojones & did it. What should I look for or test while its off? How do I tell which injectors I have? I tore the gasket on the throttle body to plenum, can I get a new one? Can I re-use the plenum to intake port gaskets? I see some oil on the plenum floor & on the throttle body & blades...is this very bad? I got some coolant in one or 2 of the intake ports.....now what?

Theres mere to come I'm sure......Hey you guys gave me the confidence to do this, now dont be mad if I'm a pain in the ***!!
Well...you could test the secondary actuators if you have a vacuum pump.

you could do the drain mod...redrill the hole to allow proper drainage of the valley. you could inspect the starter.

you should replace the breather box gasket and loctite the bolts on that.(that is likely where the oil is coming from)

you should have purchased some gaskets prior to starting.

what color are the injectors? do they have any writing on them?

you can reuse the gaskets if they are OK.

you could buy some new Samco breather Box hoses from Kurt White (expensive)

the oil in the throttle body and blades is common...esp if its a 90. no valve seals.

the coolant in the intake ports is nothing to worry about if it's not a lot.

why did you pull the plenum in the first place?
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Old 01-17-2008   #3
32valvZ
 
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Default Re: Pulled plenum...lots a ??'s

I pulled the plenum in hopes of finding something that pointed to my off idle miss or vibration problem. I dont see anything obvious.....I wish I did. Where is the hole I need to drill? Is the breather box the thing with 2 big hoses on it? Injectors are black with pt #'s on the tops.
__________________
[B]1990 #2815[/B]
[COLOR="Red"][B]Red/Red[/B][/COLOR]
Ported Plenum & IH (by Pete)
Haibeck Chip
Rebuilt FPR (by Phil)
FIC Injectors
Watson LT Headers
3" Stainless Works exhaust
Lingenfelter Open Air Lid
Bill B Built Transmission
Shifter & C Beam Plates


[FONT=Impact][COLOR=red]1992 [COLOR=black]#[/COLOR] 091[/COLOR][/FONT]
[FONT=Impact][COLOR=#ff0000]Red/[COLOR=silver]Gray[/COLOR][/COLOR][/FONT]
[B]SOLD[/B]
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Old 01-17-2008   #4
guinnessdood
 
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Default Re: Pulled plenum...lots a ??'s

Quote:
Originally Posted by 32valvZ
I pulled the plenum in hopes of finding something that pointed to my off idle miss or vibration problem. I dont see anything obvious.....I wish I did. Where is the hole I need to drill? Is the breather box the thing with 2 big hoses on it? Injectors are black with pt #'s on the tops.
Well...injectors could still be an issue. There are ways to test them with a meter...but they won't always catch a bad injector(s) but it could. It's basically a resistance test of the coil in the injector itself. Using an OHM meter you should be able to verify the resistance of each injector itself by connecting directly to each one. You should get a resistance of ~12-13 OHMS (not K OHMS) on each injector. if you get a lot higher (open condition) or lower (8 OHMS or so less) then that injector should be replaced. Keep in mind that even though an injector tests fine electrically...it can still fail mechanically, i.e. injector leaks or binds causing leaking.

The Drain Hole. - Look over here. http://www.bcvettes.org/ look at the How To Section. It is the one for the starter motor...has great pics so you don't have to be nervous about where to drill the hole. BTW...the coil packs will have to be removed as well..and that's also in their HOW TO section.

Breather Box - yup the one with the two big hoses. typically the bolts are loose and oil is leaking from the box where the upper half bolts to the lower half.

Injectors - Black with steel bottoms - most likely they are Multec (original equipment). replacing injectors is ALWAYS a good idea if you have the early style Multec injectors. The new fuels (with lots of ethanol) are hell on these injectors...and it significantly shortens their life. I would recommend replacing them if you can afford it. Accels (P.N. 150121) are about the cheapest way to go for ~$550 a set of 16 and the RCs are about twice that price.

One more thing...do you have a Factory Service Manual? If not...get one here. http://tinyurl.com/ysrbpn
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Old 01-17-2008   #5
Pete
 
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Default Re: Pulled plenum...lots a ??'s

Get mad phooey
Some of us love this sh!t

You didn't have to pull the TB we forgive you this time,since it's your first time,damn virgins J/K

If Plenum gaskets look ok reuse.
Oil in the plenum is common just sit it up right for it to drain or spray some brake cleaner into it but make sure the hoses and MAP sensor are off.

Water in the intakes/cylinder for safety pull all the plugs and crank the motor.

Check injectors (Ohm check) with a voltmeter inexpansive one from Radio Shack

Check your wires just in case they are chewed up from mice (common) i would replace them for $50 since plenum is already off.

If you don't feel confident on drilling a hole take an air hose and blow out the drain hole (under coil packs and starter have to be removed make sure battery is disconnected before taking starter out)

You can also check coils.(do a search or check manual)

Also check/do what Guinnessdood suggested
If you see oil residue around the breather box (yes with the 2 big hoses) do what guinnessdood said.

Vacuum pump can be bought at Sears for around $60

If you need a TB gasket i might have on laying around $15

Pete
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Last edited by Pete; 01-17-2008 at 04:23 PM.
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Old 01-17-2008   #6
Jeffvette
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Default Re: Pulled plenum...lots a ??'s

Pull the plug wires off of the coil packs. Inspect for orrosion or arcing. Clean like a mad man. Check the vacuum pull on the secondary actuators. Should be fully open ad 8 inches of vacuum. Should be a smooth transition.

Also check here for some images. http://www.pnwzr1.net/PNWZR1.htm
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Old 01-17-2008   #7
Pete
 
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Default Re: Pulled plenum...lots a ??'s

Just in case.
How to check secondary actuators with the vacuum pump.
pull the vacuum hoses off the actuators install the vacuum pump hose and pump the pump they should be wide open where Jeffvette mentions.

Pete
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'91 #1635 PoloGreen 350 LT5
11.09 @ 129.27
11.04 @ 128.86
474RWHP 400RWTQ
http://www.youtube.com/watch?v=SFNFOhGGlR4
http://www.youtube.com/watch?v=ZlRIOMwaDYY
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Old 01-17-2008   #8
guinnessdood
 
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Default Re: Pulled plenum...lots a ??'s

...continuation of the above...the opening of the plates should be smooth (I guess Jeff already said that)...no binding and they should be fully open at 8 inches of vacuum. Each side can be checked independently.
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