LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Dyno'd Lean as Hell

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Old 03-22-2010, 08:19 PM
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mine was lean as hell one time could not figure it out put pump,filter,rubber lines in the tank with no luck ...got pissed started changing out stuff (have alot of $hit laying around)...ended up being the maf.....fixed it went rich as soon as i went out on the a/f gauge ..got lucky..
Old 03-22-2010, 08:22 PM
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Thinking about it now I think you guys are right. Something had to of happend. I have an AFR gauge hooked up to my car and it use to be active. At WOT it use to read 12.9. Something happend that the gauge no reads like at 14.xx while driving and WOT and leans out up top.

I wonder if it could be a burnt wire causing this problem??? If the car was runing this rich and lacking fuel wouldn't it at least pick up knock at 6400rpms??? I need to look over this and get to the bottom of it. Tomorrow before work I'll report back w/ my findings.
Old 03-22-2010, 08:24 PM
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Originally Posted by sepno77
Thinking about it now I think you guys are right. Something had to of happend. I have an AFR gauge hooked up to my car and it use to be active. At WOT it use to read 12.9. Something happend that the gauge no reads like at 14.xx while driving and WOT and leans out up top.

I wonder if it could be a burnt wire causing this problem??? If the car was runing this rich and lacking fuel wouldn't it at least pick up knock at 6400rpms??? I need to look over this and get to the bottom of it. Tomorrow before work I'll report back w/ my findings.

Pull a plug.
Old 03-22-2010, 08:28 PM
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Will do.
Old 03-22-2010, 10:15 PM
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go take it for a ride and go WOT then immediately shut it down and coast to the side of the road and pull a plug. the dyno a/f is being registered after the muffler and or cats. its not accurate. pull a plug on both sides to check bank 1 and bank 2. if they are running lean this is the only true reading unless you pull exhaust gas temps with a pyro meter and wide band 02's on both banks.

Its the way you check plugs at the track when your spraying to see if your pill size is correct.
Old 03-23-2010, 03:18 AM
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You guys preaching over and over that the 02s have nothing to do with wot fueling couldn't be more wrong...

Read up on how the ecm functions before giving bad advice. The internet is not the end all knowledge base and just because 1000 people repeat something doesn't make it true.

Last edited by gregrob; 03-23-2010 at 03:26 AM.
Old 03-23-2010, 03:30 AM
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Originally Posted by illusions
go take it for a ride and go WOT then immediately shut it down and coast to the side of the road and pull a plug. the dyno a/f is being registered after the muffler and or cats. its not accurate. pull a plug on both sides to check bank 1 and bank 2. if they are running lean this is the only true reading unless you pull exhaust gas temps with a pyro meter and wide band 02's on both banks.

Its the way you check plugs at the track when your spraying to see if your pill size is correct.
That will accomplish absolutely nothing but/more confusion if he doesn't put new plugs in immediately prior to the run...
Old 03-23-2010, 05:59 AM
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Originally Posted by gregrob
That will accomplish absolutely nothing but/more confusion if he doesn't put new plugs in immediately prior to the run...
I forgot this is ls1tech and your not suppose to assume anything. I guess I also forgot to tell him to use a 5/8 spark plug socket with ratchet, remove plug (lefty loosey), install new plug (righty tighty) turn key to start engine...etc I was giving him the benefit of the doubt. I guess I was mistaken.

I forgot brain cells are only handed out to the chosen few.
Old 03-23-2010, 07:25 AM
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Originally Posted by gregrob
That will accomplish absolutely nothing but/more confusion if he doesn't put new plugs in immediately prior to the run...
Not exactly true. If he were to pull a plug at the end of a run and he is bad lean, it will be very evident. The same goes for bad rich. Using the plugs as a tuning aid is another subject.
Old 03-23-2010, 07:27 AM
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Originally Posted by gregrob
You guys preaching over and over that the 02s have nothing to do with wot fueling couldn't be more wrong...

Read up on how the ecm functions before giving bad advice. The internet is not the end all knowledge base and just because 1000 people repeat something doesn't make it true.
Maybe you should expand on this for those that don't know?
Old 03-23-2010, 09:53 AM
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Originally Posted by gregrob
You guys preaching over and over that the 02s have nothing to do with wot fueling couldn't be more wrong...

Read up on how the ecm functions before giving bad advice. The internet is not the end all knowledge base and just because 1000 people repeat something doesn't make it true.
Let me clear up what I meant... o2's primarily have no function for wot fueling, however if your o2's are not switching properly, overtime it will alter fuel trims... Point is, normally if your o2's are shot the car will run crappy part throttle, wich the op has not mentioned anything of the sorts. Sorry for not being clear on this in my earlier post, I figured this was obvious, but I realize everything should be spelled out on the internet. Oh and its not an ecm its a PCM,unless you have a 93
Old 03-23-2010, 10:31 AM
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Originally Posted by 96capricemgr
I don't know about Alvin on the chipped cars BUT I do know Herter has broke more than a few pistons with 14:1 and leaner at WOT and extreme spark advance so don't put blind faith in a vendor just because they are popular. Again this is a comment specifically about Bryan Herter not Alvin.

May well turn out to be a fuel filter issue but could just as easily be tuning, don't dismiss anything till you test it and double check.

Between several of my friends' cars and my own we have all had problems with his mail order stuff. He was fine with the bolt on cars, not so much with heads/cam setups, strokers, and a blower car. I don't really have faith in anyone anymore. I ended up getting HP Tuners for myself.
Old 03-23-2010, 11:02 AM
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Originally Posted by fergymoto
Between several of my friends' cars and my own we have all had problems with his mail order stuff. He was fine with the bolt on cars, not so much with heads/cam setups, strokers, and a blower car. I don't really have faith in anyone anymore. I ended up getting HP Tuners for myself.
I decided long ago I was better off doing my own. My short experience was they were always RICH...like burn your eyes rich.

But in other posts I think he brag on his afr with wide ban so tune I think he will say afr was 'right' and no has gone bad. Think he even said it in this thread.
Old 03-23-2010, 11:04 AM
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Originally Posted by fergymoto
Between several of my friends' cars and my own we have all had problems with his mail order stuff. He was fine with the bolt on cars, not so much with heads/cam setups, strokers, and a blower car. I don't really have faith in anyone anymore. I ended up getting HP Tuners for myself.
I agree, the mailorder **** is no good for anything but a bolton car. Hell pcm for less cost me a motor years ago. Pretty bad when they send you some one elses tune and it blows your car up...This was on my bolton lt1 procharged setup back in 03' and was not even goin wot. Nothing like 38 degrees timing mixed with boost lol.
Old 03-23-2010, 11:16 AM
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The tail pipe readers always seem to be lean.

example: We tune our cars with an o2 right after the o2 in the headers (on each side). Dynoed the car with our o2s reading dead on 12.8 and the dynos was in the 14.3-15.0 range. Made 3 pulls and all were the same. Tried this on 3 different cars on 2 different dynos

If you have leaks and bad o2s get that fixed and check the plugs out while you are at it.
Old 03-23-2010, 11:29 AM
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Dyno is up^. For some reason they didn't send me the AFR. I sent them an email to send it to me so I have to wait on that. Going out to pull a plug and see if I could find a bolt for the headers that fell out.
Old 03-23-2010, 02:12 PM
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Pulled spark plug and from reading it the car is rich on idle and lean at WOT. Heat rang and timing seem fine.

Went to store and bout a box of grade 9 bolts w/ the allen head for headers for 13.00. Also went to fright tools and got a fuel pressure tester for 13.00. This will be done tomorrow.
Old 03-23-2010, 02:29 PM
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Dyno has been edited to show AFR.^
Old 03-23-2010, 03:07 PM
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Originally Posted by ks my ss
The tail pipe readers always seem to be lean.

example: We tune our cars with an o2 right after the o2 in the headers (on each side). Dynoed the car with our o2s reading dead on 12.8 and the dynos was in the 14.3-15.0 range. Made 3 pulls and all were the same. Tried this on 3 different cars on 2 different dynos

If you have leaks and bad o2s get that fixed and check the plugs out while you are at it.
My tuner does this too. He has more faith in the WBO2 after the collectors than the Dynojet sniffer up the pipes.
Old 03-23-2010, 03:40 PM
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WOW been trying to think back to what started the problem and it just hit me like a smack on the face. My fuel injectors are the svo 30's and it was leaking about 1-2 months ago cause the fuel pressure pushed the injector to far into the intake. I just remembered I don't have the injector clips hooked up to them. I guess that will be the 1st thing I do tomorrow.


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