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 ***!! :mrgreen:

Re: Pulled plenum...lots a ??'s
 

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?

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.

Re: Pulled plenum...lots a ??'s
 

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

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

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

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

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.

Re: Pulled plenum...lots a ??'s
 

Ok, heres what I know from the previous owner. The plug wires were replaced in May (ish) 07 They look really good. Also, a few weeks ago, I checked the injectors with an ohm meter while hot. They all specd out between 13.7 & 14.0 ohms.......should I replace them anyway? The 2 hoses on the breather box are really hard...does that mean replacement?

Re: Pulled plenum...lots a ??'s
 

If you can afford replacing the injectors you should.

My breather box hoses were hard too...but they still work. Kurt White has some of the original hoses and some Samco hoses for the breather box. The hoses cost at least $45 each....which to me is ridiculous. You may be able to take the hoses off and go match them up to some that will work at a parts store.

Re: Pulled plenum...lots a ??'s
 

Were the wires replaced with OE used ones(w/LT5 on them).

Again check the gap on the plugs i had an issue where they were gaped too much with one of those snake formula plugs you know the ones that cost more then there weight in gold and it felt like a misfire like it was putting out the flame acted like a turbo/SG car.
I also had a plug that was loosing compression.
Just a thought and easy checks

Pete

Re: Pulled plenum...lots a ??'s
 

From the peanut gallery.......sorry.

I thought that GM changed the later injectors to be okay with the ethanol additive, but didn't go back past the first model year that ethanol was added to the gas. The mfg's knew in advance when the ethanol was going into use.

Check over at the netreg site for the exact yr because the later injectors are resistant to ethanol....I think. Why buy injectors if you don't have to, right?

The OEM's are actually a great design for being self-cleaning. They're just not entirely made from s/s. I think it's just the nozzel & the disc are s/s and the body is steel. I think I have that correct?

Tom

Re: Pulled plenum...lots a ??'s
 

It's the 90-92 injectors that are the major problems. He has a 92.

Re: Pulled plenum...lots a ??'s
 

I will learn that eventually, I think.:o

I keep forgetting which year was the cut off for the crumy injectors... my RC's cost me 1088.00 and that was before the price increase....figured it was worth a shot :redface:

Re: Pulled plenum...lots a ??'s
 

Well, theres no tuning back now!! I am down to the breather box. I noticed though, that all the bolts holding it down were hand tight. I put the socket on with a 10" extension and can remove pretty much all of them with my fingers. If I were to tighten them up, would that suffice instead of waiting for a gasket? Fter removing the 2 breather hoses, theyre actually in good shape. Not hard to the point of being brittle & no cuts.

The valley is frikking filthy!! I found all kinds of neat stuff in there...bugs, little pieces of hose & lots a grime.

Re: Pulled plenum...lots a ??'s
 

Yea on my 90 they were all hand tight also....what a mess it made. I had enough oil for it to run out the drain tube and stain that corner of the pan!

Yes you proly can re-use the gasket. Just clean up the mess & the mating areas and I used a bit of that new stuff...comes in a thing that looks like a fat lipstick thingy....it's light blue....well I should say "new to me" from permatex.

I noticed that I could have re-used all of my gaskets....but I had all the stuff on hand before I dove in as I was tooooo nervous about doing the plenum pull...:mrgreen:

Re: Pulled plenum...lots a ??'s
 

I've got new oem breather box gaskets.

Pull out the coils and the starter. Vacuum it out. Spray with brake kleen. Get the area clean!!!!

Re: Pulled plenum...lots a ??'s
 

I cleaned everyhting up......

http://inlinethumb63.webshots.com/42...500x500Q85.jpg

http://inlinethumb50.webshots.com/38...500x500Q85.jpg

Did the drain hole mod.....
http://inlinethumb48.webshots.com/40...500x500Q85.jpg

Re: Pulled plenum...lots a ??'s
 

I've never been a fan of the drain mod. As the one from the factory actually has a drain tube to route it down. You are no dumping any kind of fluids onto the clutch assembly.

Just like every other car, your actuators are installed upside down. Don't worry about it unless they are binding really bad.

Re: Pulled plenum...lots a ??'s
 

Well, too late now for the drain hole mod......I dont really plan on wetting the engine an extreme amount. Is that why the arm is cocked to one side on the actuators?

So, should I replace the injectors, the TB gasket & the breather box gasket as well as the coils?

Re: Pulled plenum...lots a ??'s
 

gosh this is great i allways wondered what the actuators looked like when installed wrong , thanx , coil replacement would be optional, ask jeff as to the tests to find out if they are ok. buying a setwill setyou back 160.you will be very happy you did your first pull after this its cake . good job

Re: Pulled plenum...lots a ??'s
 

Why are the Accel injectors so much cheaper than RC? I have around a grand to spend on this little project. What is the best thing to do? I could probably do the Accel injectors, coils & the gaskets for less than that. Then I wouldnt have too much to wonder about under the plenum anymore.

Guidence please..........

Re: Pulled plenum...lots a ??'s
 

Coils
Plug wires
Injectors
Possibly the actuators
Gaskets

Re: Pulled plenum...lots a ??'s
 

The plug wires are less than a year old. Theyre AC Delco. Hey Jeff, can I get all this stuff through you? Prices?

Just an fyi car has 46k miles on it. I would like the Accel coils...are the Accel injectors ok?

Re: Pulled plenum...lots a ??'s
 

John, give me a shout.

Re: Pulled plenum...lots a ??'s
 

Cause RC has to pay for the hi priced advertising and over paid sales people to sell them to you.
Ask yourself this question,is McDonald's burger the best you've ever had,if you had better then why are they the worlds biggest burger joint.

I have Accels i run low 11's a friend has Accels in his 10 second ZR-1.
If RC could guarantee me 10 RWHP over the Accels i will give them double there price,a bunch of overpriced advertising BS.

Go with Accels you will be happy don't buy into the advertising BS.
There's some that will praise RC but ask them for test results.
Of course they will praise them they are still trying to convince themselfs they got a good deal.:wink:
Accels are withen 2%
If 1% is worth $1000 more then go with RC's

Some might think i'm a bit harsh, just my opinion.
Sometimes the truth hurts.

I will put my money where my mouth is if they can guarantee me more power.
Pete

Re: Pulled plenum...lots a ??'s
 

Dang Pete!! I see youre a little passionate about the subject.:) Seriuosly though, I follow what youre saying. I dont have a race car, so I dont need every part to spec to the "gnats arse". Reliability is the main factor for me. Thank you for the input.

Also, a thank you to all you guys who added your valuable information.:handshak:
I dont want to seem like a puscy, but this was a sort of a big deal to me. A year ago when I first started considering a ZR-1, I would never have pictured myself doing what I am. I'm having fun though. I love this stuff. When I was turning wrenches for a living, it sucked. Working on cars for pleasure is waaaay better.:mrgreen:

Re: Pulled plenum...lots a ??'s
 

From personal experience check the torque on the injector housing bolts. When I pulled mine for porting they were finger tight.

Re: Pulled plenum...lots a ??'s
 

Yes, youre right....mine were all loose too. I cant help but believe the car has to run better than ever after this....:thumbsup:

Re: Pulled plenum...lots a ??'s
 

WOW, this thread is great! I'm about to do a plenum pull and this is a great refresher! :thumbsup:

Re: Pulled plenum...lots a ??'s
 

Hey 32 V
You might want to cover over the IH holes while you wait
or are working. Sure wouldn't want to drop something down
the endless hole...... or spill.... or

PS Damn, you sure cleaned up that valley purdy.

Re: Pulled plenum...lots a ??'s
 

Got it done...duck tape over the holes..:thumbsup:

Re: Pulled plenum...lots a ??'s
 

I had an Accel coil failure after two years and about 6,000 miles of driving. Replaced with the MSD's for approximately the same $$. All is well now. I've heard of at least one other Accel coil failure in the last few years. The stock coils are also an excellent choice. FWIW.
I'm heading to the Accel injectors as well. Hope it turns out well for both of us!

Re: Pulled plenum...lots a ??'s
 

:mad: ...I already ordered the Accels coils & injectors....I'll have to hope for the best!

Re: Pulled plenum...lots a ??'s
 

when buying the accels do you need special o rings for them? if so where so you get them?

Re: Pulled plenum...lots a ??'s
 

John, your an animal buddy.........how did it look under there!?


Ry:-D

Re: Pulled plenum...lots a ??'s
 

Also........yank the coil packs and starter(if you already havn't) and pressure wash the hell out of it!!! How did your secodaries look and feel?

Re: Pulled plenum...lots a ??'s
 

Hey Ry.....I removed pretty much everything in the valley....breather box included. It was pretty grimey....like you said, thats probably where the burnt oil smell was coming from (brthr box gasket). The breather box bolts were loose as heck!! I am replacing coils, injectors and all needed gaskets. I'm getting a vacuum pump today to check the secondary actuators. (old one broke)....anyway, Jeffvette was saying how 1/2 the new ones available were bad.....I would like to buy a couple for insurance & just install them. I guess I need to buy 12 at a time!!! Looking to get the dealer to test them for me before I buy.....

Wow is right!!! Great thread
 

I'm also a noobee to the Z, and also poised over the plenum. I was going to wait till I could afford to do the whole nine yards, but from hearing 'bout the loose IH bolts, that alone would warrant investigation. Injectors might have to wait, but I think it's time to dive in and have a look-around!

Like you said, GREAT THREAD!

P.

Clarification??
 

Sorry to be so obtuse, but 1/2 of what are bad?

TIA:wink:,

P.