92C4M6

So i put headers on the vet last night, now it runs like $hi7, wont rev past 4k nad stumbles to get there, now i have a pcmforless chip(tuned for removal of air and egr) that should be here tomorrow along with all the egr block off plates needed ot remove the egr crap. My question is with all the egr and air stuff being removed and no block off plates could this cause the stumbling? also throwing only code 26. Mind you this it racn perfectly for the first few weeks of ownership(just bought) and would destroy the tires in first gear, it did however one night just randomly start having a low rpm stumble and a slight loss in power, i was thinking it was probably a bad plug because it did have a bad 02.

Well last night while i was there I installed brand new NGK tr55s gapped @.35, and two new O2s along with some OBX LT's. Also yanked out all the EGR/AIR crap, i do however have two large holes in the rear of the intake where the EGR valve was since my block off plates didnt get here yesterday like i thought. So my question is did i make an existing problem that just randomly arose a week or so ago worse during the install, or is it possible i fixed one issue(the potentially fouled pkugs) and replace it with a worse issue in removing the EGR/AIR stuff?

cohocarl

I'm not familiar with the LT1's egr, but on my L98, I left the egr valve on it (just no vac to it) so it would seal it off. If not, it would have a major vac leak.... I could be 100% wrong with an LT1's though....

Would it be easy to bolt on just the egr valve to see how it runs?

92C4M6

Nope its gone, like i said though block off plates should be here tomorrow, im hoping desperately that between that and the tune removing them from the ECM fixes this issue. Just looking for opinions in the mean time.

vetteoz

Just a big hole to the atmosphere


]

hooked073

: *****:

kimmer

couldn't get much more of a leak than that

92C4M6

Actually madea typo egr valve is still their just all the plumbing that went to passenger manifold and into back of intake is gone, its left a nickle sized hole yet it doesn't appear to pull vacuum when cars running. So guess its a mystery problem and not that

cohocarl

I apologize to the O.P. for this being off topic, but like I said, I know nothing about LT1's so I'd like a little education.
Since you have the opti, I assumed the intake just omitted the old distributor hole, but I see it doesn't. What goes in there? Just a plug?

Thanks,

Carl

92C4M6

So trying to figure out how adding headers made a very mild slip turn into a full blown lack of rev capability and a lot of backfire(kinda) issues. Ive checked atleast 5 times to see if i crossed up plug wires because thats what it seems like and i dont thiknk ive done that.
----Here is all ive taken off: Smog pump under drivers headlight, there was two harness plugged into it that are now just chilling in its old space, also removed the ?valve? under the ASR housing and all its hoses and the one wire harness, also rremoved the t fitting that went over the nipplle in the middle of the drivers side of the intake that had hoses going both to the egr solenoid and that valve under the asr. Also removed the Large portion of piping and the small egr looking valve that is on the back of the intake to the right of the EGR valve itself(this is where the only hole in the intake that is open currently is but doesnt appear to be pulling vacuum from this hole.) Other than that all i removed as one of the braces that wasnt needed from the ALT/AC bracketry. So idk what is wrong.

EVERYTHING WITH AN ORANGE LINE IS GONE NOW, THE STUFF IN RED CIRCLES IS STILL THERE

65Z01

A vac gauge will reveal if you have an air leak in the manifold.
A diagnostic tool on the ALDL will likely be very informative.
Also, is fuel pressure holding when you rev the engine (vac line to FPR disconnected & plugged)?

tunedport85inject

I found this different pics of F-body LT1 intake lay out,is this different?

there isn't that big hole



http://shbox.com/1/EGR_pipe.jpg

Anyway i would let EGR bolted on and vacuum disconnected,block the unplugged vacuum fitting from EGR and try again.

tunedport85inject

I think the pic Vetteoz posted is misleading (may be a converted Lt1 manifold for hey dizzy) all pics i searched have just egr housing and egr pipe port

92C4M6

PCM4LESS chip got here today, installed <5 min. Then took her out and let it get in closed loop and hammered it. Instant pull all the way to 6k!!!!

cohocarl

92C4M6

Blows my mind air/egr caused this.

BacknBlack

When installing LT's, you need to get the car tuned. Otherwise, the car will run lean mid-upper rpm.

92C4M6

yes I know it will run lean but it just straight up would not rev past 3000and I have installed at least 5 headers on lt cars and never had a problem. Just guess this one missed it's egr stuff lol

lt4obsesses

Probably had alot to do with sealing everything up, and of course the new tune. The ECM probably kept the engine in "limp home" mode due to all of the removal of the emission hardware.

92C4M6

http://youtu.be/ThVMp6PMySc Got exhaust welded up and x pipe placed. Quick teaser vid

GKK

Here ya go...

http://www.youtube.com/watch?v=ThVMp...ature=youtu.be