theMOSTWANTED

iTrader: (1)

Newbie from Monroe,La

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Hi guys I'm a new owner of a 99 z28. I been a part of the turbo buick community a while. I use to own 2 Grand Nationals. I decided to sell one and keep one. I being seeing guys on the turbo buick forum swappin over to ls1 I decided to give them a try. I couldn't do the swap into the GN it just wouldn't be right. I just found out the 99 z28 have the 5.7 instead of the 5.3. Is there any advantage in having this year model. The car has SS hood and wing, Hooker long tube headers and slp loud mouth exhaust. Car runs ok but idles up and down and seems to bog down when go over 50 mph. I accellerate and nothing change seems as if rpm never increase. I have a check engine light on and I went to auto zone it threw about 7-9 codes: P0154,P0412,P0418,P0480,P0481,P0507,P1635,P0135,P0 101. I only paid 3700 for the car so i don't know too much about these cars but I am a little mechanically incline so I do try to do all my repairs myself. i just want to know where to start off. i looking for a mid 11 sec car maybe high 10s. Please help me out. The car has 188,555 miles on it. I purchased it for 3700. It also has c6 wheels on it also 18s all the way around.

garygnu

you can use the search on here to find most codes.probably need to clean the MAF and the IAC.what trans do you have ?these cars like 3500+rpm stall converters with a stock cam.consider a ported TB and a cam swap.go to thunder racing or Texas Speed for cam pkgs and parts.these cars with full bolt on and cam only can run 10s.mite consider some ported heads ,or some 243/799 heads.

murphinator

iTrader: (2)

sounds like someone added some mods and left the tune stock. I would start with basics like fresh tune up parts ,clean maf sensor , check to see if maf has been descreened which will cause some issues especially if it hasnt been tuned.

seek out a good local ls1 tuner in your local forum section on here to get it tuned ,turn off some codes etc... to start with long tubes will raise some havoc with codes until tuned.

dont let the miles scare you one of mine has 234,000 and the others are close to yours in miles- of course if your looking to go 10's starting with a spare engine with lower miles may be wise and do aftermarket heads/ cam/intake before installing it.

mid 11's is very acheivable cam only in decent racing weather , just ask around here for suggestions for a good cam kit from one of the many sponsors on here which will also replace your high miles springs - dont skip that step if your modding a 180k ls1!! , my 234k car has been 11.9's stock internals when it had approx 215k on it

theMOSTWANTED

iTrader: (1)

My car is an automatic. So I will start by cleaning the MAF and the IAC and see what happens from there. I'm just use to the throttle response of a turbo car I guess. I'm just concerned on how the car pulls. the engine seems to run decent no ticking or anything. It idles ok sometimes and then there is times where it idles up and down. I haven't got up under the car I don't know if it has cats or not. I will get out there today and these things out so I will have more info and maybe I get more help with as much info I can post about the car. Thanks guys for your help and I will no all the support I can get. Thanks again. Stay tuned:

Is there any advantage of having the 5.7 vs. the 5.3? I have a 5.3 long block from a 2000 silverado. Are these heads off the truck 5.3 worth porting or buying some aftermarket heads better to put on my car. After I get some these problems taken care of I will take it to mad tunes to get a tune. Madtunes.com is local here around my area.

nomasterase

iTrader: (4)

all the f bodies came with the 5.7 in z28 or formula/trans am forms the only way youll get a 5.3 is if someone changed it out. advantage is cubic inches ftw and also teh 5.7 is an aluminum block vs the 5.3 being cast iron so its roughly 100 lbs lighter

theMOSTWANTED

iTrader: (1)

Ok I didnt know that. I cleaned the MAF,IAC and TB and my up and down idle issues are over. It idles around 780-800 RPMs. I still have a check engine light and car doesn't accellerate like I think it should. Its seems like around 55-60 mph it chokes out or boggs down so to speak. The trans shifts out fine no issues there. Its just its reaches that mph its slow at accellerating. I noticed behind the throttle body there is tie strap around the EGR tube that goes into the intake. Its has the bolt in also but I'm wondering is there a leak there or what . I don't hear any air or vacuum leaks thats noticable to the ear. If there is a leak there will it cause these issues that I'm having? What should I do from here. I want to get all the bugs out before I go have it tuned. Thanks guys you all are becoming very helpful. Keep the info coming.

theMOSTWANTED

iTrader: (1)

Come on guys any input on this.

theMOSTWANTED

iTrader: (1)

Any input here guys. can I eliminate the egr all together and remove the pipe from the intake and install a block off plate.

theMOSTWANTED

iTrader: (1)

I want to start with a few bolt ons first. Maybe just a 12 sec car to start with. Remember I already have LT headers so what will be next on the list and so on. I'm ready to get started on this project. I need it to be able to run with my Grand National.

murphinator

iTrader: (2)

add some good dr's with your long tubes and get the tune straightened out and it ought to run 12's , then add a 3600-4000 convertor and it should be solid mid 12's or lower.

as for running with your GN depends how that runs - they can be damn fast

theMOSTWANTED

iTrader: (1)

I will try that but first I have to get this thing tuned and clear all these damn codes. I know the car should more power than I getting. Its runs like a slug once you get up to 50 or so. All the power is gone once I get up to 50 mph.

theMOSTWANTED

iTrader: (1)

I deleted my egr and air pump today and found a major leak coming from the egr pipe that connects in the intake the bolt was stripped out and I just pulled it straight up. Could this have been the cause of the problems I have been having. The air pump also had some dry rotted air lines connected also. I haven't had a chance to block the headers off yet. I won't be able to do this until tomorrow but I was just wondering would this have been the reason for the lack of performance.

theMOSTWANTED

iTrader: (1)

I also pulled the number 1 spark plug and they had AC delco plugs but they were gapped at 40. Is this ok or should they be gapped at 60. Should I go ahead and change all the plugs just to be on the safe side. I was thinking of the NGK tr55s. Any advice on this issue also.

RPM WS6

iTrader: (3)

The Delco iridium plugs are supposed to be gapped at .040". The original platinum plugs were gapped at .060".

theMOSTWANTED

iTrader: (1)

Good deal I'll leave them alone then since the plugs look pretty good.