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Need help pulling plenum...!!!

Norsky4360

Well-known member
Joined
Apr 28, 2002
Messages
64
Location
Minne-snow-ta
Corvette
'70 convert ("The Toy"), '90 ZR-1 ("The Beast")
Need help pulling plenum...!!! -- UPDATED - Got 'er done!

I'm attempting to replace the injectors and I'm stuck at the moment. I've disconnected everything I can see on the topside and have pulled as many torx head bolts that I can see holding the plenum on. But the dang thing seems to be welded on...!!! What am I missing...???

Any help would be appreciated. I'll return call if a phone number is PM'd to me.

Thanks!
 

bossvette

Gone but not forgotten
Joined
May 19, 2003
Messages
3,233
Location
West Unity Ohio
Corvette
1968 1997
Not sure on a ZR1 but on the TPI the lowers must be at least loose to remove the plenum and there is a bolt that comes in from the back on each lower runner.
Personally, I would remove the runners also to replace all gaskets.
good luck
 

Aurora40

Well-known member
Joined
Jul 12, 2004
Messages
1,147
Location
The Old Dominion
Corvette
1990 red on red ZR-1
If it's never been off, it will be stuck pretty good. Pull up on the airhorn to get it going. Just be careful because things are connected to the bottom of it, so don't yank it way off. You could also probably put a block of wood on the side and hit it to try to break the seal with shear.

Did you remove one of the fuel lines at the back of the plenum? Good idea if you haven't. It'll be in the way a bit. I stripped one of the threads in the IH by trying to tighten the plenum up with the fuel line in the way, I had to get it repaired when I sent my upper end for porting.
 

Norsky4360

Well-known member
Joined
Apr 28, 2002
Messages
64
Location
Minne-snow-ta
Corvette
'70 convert ("The Toy"), '90 ZR-1 ("The Beast")
Thanks guys!

To the best of my knowledge it has never been taken apart. There's just under 8k on the odometer and the only repair tickets I've been able to dig up (we're the 2nd owners) have been for minor things (oil changes, etc).

I've taken out the 6 bolts on either side, disconnected all the electrical connections that I can see, and have all the vacuum hoses pulled (except the one on the front left - no wiggle room on that one until the plenum is loose). I've disconnected both fuel lines and a bracket by the firewall holding a little black box.
:bash So I guess it just needs a little love tab to come loose.
 

Norsky4360

Well-known member
Joined
Apr 28, 2002
Messages
64
Location
Minne-snow-ta
Corvette
'70 convert ("The Toy"), '90 ZR-1 ("The Beast")
Thanks again for the help, and most of all - for the moral support...!!!

It took a lot longer than I expected, probably because I was venturing into new territory, but "The Beast" is back together - AND RUNNING...!!!

The "love tap" with a chunk of 2X6 on each side of the plenum did the trick and it popped free. Then the "fun" began. That rear connector secured by the 1/4" bolt is a real P.I.T.A. to get at. Not only to loosen and unplug but to reconnect and tighten down.

The left side of the fuel rail was real easy to get free. Didn't take much pressure from a pry bar to get all 8 of the injectors loose. The right side though wasn't as nice. All 4 primaries didn't want to budge and as a result I had bent clips to straighten out and a little fuel dribble out. All 16 of the old ones were a real dirty mess. Spent about an hour cleaning out the injector holes with Q-tips. The new Accel injectors fit into the fuel rail very nicely and everything went back together quite easily (except for the afore-mentioned connector! :hb ).

Once all buttoned up it cranked for a few seconds more than usual on the first start but quickly idled out real nice and smooth. After cleaning up a bit I took it out for a test drive and am happy to say it pulls hard and smooth up to the century mark (that's where I had a reality check - a warm night after dark on a country road means critters are moving about) so reeled it back down to 5 over the posted limit.

Thanks again!

Jim


btw - #1 cylinder had the failed injector. Total failure. I should have written down the numbers on the others as there was quite a spread.
 

korvettekarl

Well-known member
Joined
Nov 24, 2003
Messages
472
Location
Las Vegas, NV
Corvette
2017 Grand Sport 90 ZR1 57 Bel Air
Congrats on the repair. As someone who just did the same repair, I feel your pain. Mine also ran better than it ever had before. Have fun with it and watch out for the critters. A guy at work hit a deer on his crotch rocket last Friday while on his way back from the Grand Canyon. He is alive but both wrists are broke and his neck is seriously messed up. The deer didn't make it.
 

90 Corvette ZR-1

Well-known member
Joined
Jan 11, 2001
Messages
561
Location
Pittsburgh
Corvette
90 Red ZR-1
Congrads on being a memember of the plenum pull club. The real fun is driving down to bowling green from pittsburgh with 4 bad injectors and pulling the plenum in the NCM lot to fix it.
 

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