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

Modified lt1 issues! Help!!

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Old 11-28-2015, 06:59 AM
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Injector size has little to do with how it runs, injector size MATCHING the tune has EVERYTHING to do with how it runs.

Just putting O2s on wont fix anything. For you to get a new tune to use them you NEED to identify the injectors on it.

If the previous owner actually had the O2s tuned out though I would worry he did a LOT wrong because that was a bad decision. About the only reason to consider deleting O2s is to run leaded fuel and to need leaded fuel in an LT1 compression needs to be quite high, like north of 12.5:1 depending on cam/quench etc.

How much compression does it have?
Old 11-28-2015, 08:46 AM
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Originally Posted by 96capricemgr
Injector size has little to do with how it runs, injector size MATCHING the tune has EVERYTHING to do with how it runs.

Just putting O2s on wont fix anything. For you to get a new tune to use them you NEED to identify the injectors on it.

If the previous owner actually had the O2s tuned out though I would worry he did a LOT wrong because that was a bad decision. About the only reason to consider deleting O2s is to run leaded fuel and to need leaded fuel in an LT1 compression needs to be quite high, like north of 12.5:1 depending on cam/quench etc.

How much compression does it have?
It's an 11:1, and I don't know the specs off the top of my head, but the cam is a CC 306
Old 11-28-2015, 09:17 AM
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I also checked the injectors again this morning. A buddy told me that when you un-hook the injectors and put an ohm meter on them, they should read 0? This correct or not? Because I'm still getting 14.5 on all 8 of them
Old 12-02-2015, 08:02 AM
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I think 14.5 is normal.

Start with the basics:

Did it ever run right? Did it ever NOT burn your eyes? Did this just start all of a sudden or its done this since you bought it?

What has been done to the car? We need a total build sheet. What has been added and what has been removed.

Get an ALDL cable and download the software online, there's a sticky on this here or on ls1lt1.com. Pull the tune and look at it, then pull a stock .bin from online and compare. If they look the same, it has not been tuned for the mods. I have never done this, moehorsepower or someone who knows how to look at and modify a tune might chime in to help here, I'm only giving an idea.

You need a tune for a cam or an injector change. If you don't have a tune adjustment for the injector change, your PCM is still opening them for the same amount of time as of it had the stock 24lb injectors, but your 30lb injectors are pumping more fuel in since they are bigger. The PCM needs to know how much fuel you are dumping in per each pulse. A cam change changes valve events, so the PCM needs to know that info too. Without O2 sensors, the PCM is blind to what it is doing as well. It can't make adjustments because it doesn't know it's too rich.

Gas is thinner than oil. When your oil is diluted with gas, it's too thin to lubricate the bearings, which can wipe the bearings and kill your motor. STOP DRIVING IT until you fix this or you are going to screw up the bearings. If the motor is healthy, when you sell it you'll get money towards your LS swap, if its fucked you will have a boat anchor worth nothing.
Old 12-02-2015, 12:57 PM
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Originally Posted by bufmatmuslepants
I think 14.5 is normal.

Start with the basics:

Did it ever run right? Did it ever NOT burn your eyes? Did this just start all of a sudden or its done this since you bought it?

What has been done to the car? We need a total build sheet. What has been added and what has been removed.

Get an ALDL cable and download the software online, there's a sticky on this here or on ls1lt1.com. Pull the tune and look at it, then pull a stock .bin from online and compare. If they look the same, it has not been tuned for the mods. I have never done this, moehorsepower or someone who knows how to look at and modify a tune might chime in to help here, I'm only giving an idea.

You need a tune for a cam or an injector change. If you don't have a tune adjustment for the injector change, your PCM is still opening them for the same amount of time as of it had the stock 24lb injectors, but your 30lb injectors are pumping more fuel in since they are bigger. The PCM needs to know how much fuel you are dumping in per each pulse. A cam change changes valve events, so the PCM needs to know that info too. Without O2 sensors, the PCM is blind to what it is doing as well. It can't make adjustments because it doesn't know it's too rich.

Gas is thinner than oil. When your oil is diluted with gas, it's too thin to lubricate the bearings, which can wipe the bearings and kill your motor. STOP DRIVING IT until you fix this or you are going to screw up the bearings. If the motor is healthy, when you sell it you'll get money towards your LS swap, if its fucked you will have a boat anchor worth nothing.
i don't drive it anymore , since it's started this. The car has always ran rich since I've had it. With that being said, it has gotten worse the more I have drove it and raced it till now. It does run good, very good, just to rich. I can get a cable this week sometime and pull the tune and post it. Thanks for that info! Didn't know I could do that. When I get off of work today, and get home I'll make a full build list and post it to. Thanks !!!
Old 12-03-2015, 09:33 AM
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look up LT1 PCM tuning Solomon is the ultimate LT1 god! hands down the best LT1 tuner and he is very helpful and quick, I will never use anyone else he has my 383 running super strong and sweet gas mileage
Old 12-03-2015, 09:54 AM
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Originally Posted by chaney1974
look up LT1 PCM tuning Solomon is the ultimate LT1 god! hands down the best LT1 tuner and he is very helpful and quick, I will never use anyone else he has my 383 running super strong and sweet gas mileage
chaney! Since you have used him, would he be able to tell if something is wrong or off? Or just re do the tune for what it needs to be ?
Old 12-03-2015, 10:00 AM
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Buy the two front O2 sensors and get a new tune..
Old 12-03-2015, 10:06 AM
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If its tuned well for OLSD, you don't need 02s. So that won't fix anything.
Old 12-03-2015, 11:50 AM
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Ok, so finally got my dads camaro off our lift and got to put mine on there for the first time! I guess I'm a jack *** for taking someone else's word. I was told the car has no 02 sensors.... Well that is wrong. It does have 2 at the end of the headers where it meets the y-pipe. so with that being said, how do I tell if they are good or working right ? I pulled them out and they are both solid black and smell of gas bad. Do I test them some how? Or just get new ones or what? Help?!
Old 12-03-2015, 01:05 PM
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both are the same, think this gives a good example of how rich its running lol
Attached Thumbnails Modified lt1 issues! Help!!-img_1927.jpg  
Old 12-03-2015, 02:01 PM
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your tune may be suspect assuming you don't have a pre-02 exhaust leak causing your 02's to see more air and commanding the PCM to dump more fuel

If you have addressed the mechanical side for no intake manifold or exhaust manifold leaks, your injectors are not leaking and working correctly than contact a tuner of choice and discuss with them.

They may ask for a data log if you have that ability for various functions they will advise.

If you are not confident your existing tune was done right, might want to contact a different tuner who can look into your file and make what he feels are the correct adjustments

02's do get "black" normally but to much is like fouling spark plugs. 02's are a service item. Given you have run rich for some time I suggest you buy new AC Delco 02's. Maybe wait to install them till after a new tune if that is what you do

I assume you confirmed your 02's are actually plugged in. Sometimes long tube headers you need "02 extensions"
Old 12-03-2015, 04:27 PM
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Just because the o2s are there and plugged in doesn't mean that they are even being used though. They may be tuned out and just there to plug the holes.
Old 12-03-2015, 05:20 PM
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Originally Posted by fbody_brian
Just because the o2s are there and plugged in doesn't mean that they are even being used though. They may be tuned out and just there to plug the holes.
Originally Posted by ******
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If you are not confident your existing tune was done right, might want to contact a different tuner who can look into your file and make what he feels are the correct adjustments
yep...which is why the "tune" needs to be looked at along with any potential mechanical issues which can cause a rich condition
Old 12-04-2015, 08:06 AM
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Originally Posted by ******
yep...which is why the "tune" needs to be looked at along with any potential mechanical issues which can cause a rich condition
How do you check the o2s to see if they are working or even getting power? I know they put off there own, but the wires that connect to them? I have the O2 extensions as well.
Old 12-04-2015, 08:24 AM
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Originally Posted by Nuzzy
How do you check the o2s to see if they are working or even getting power? I know they put off there own, but the wires that connect to them? I have the O2 extensions as well.
You can easily check for power and ground for heater circuit but that will not truly indicate if the sensor aspect is working.
http://shbox.com/1/HO2S_connector.jpg

Otherwise you need a scope or scan tool that can read sensor outputs
Old 12-09-2015, 12:10 PM
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yes he can he does live email tunes, he will send you a tune to start with all hardware and cables needed to install his tunes and data collector to send back to him, for just over $240 he will tune that monster in! and you keep driving it with no down time.



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