LT1 Tuning


#1

My dad has gifted me his 1994 Camaro Z/28 that has a few ignition issues. Ignition issues aside the car has some mystery mods like high flow heads, larger fuel injectors, cold air intake and long tube headers. Moral of the story is that it runs very rich and i think it needs to be tuned.

I know there is tuning software out there for the LT1 but i’m completely new to tuning in general. Anyone local with some knowledge they would be willing to share would be greatly appreciated.


#2

@LZ1 would probably know.


#3

I used a guy named Solomon to tune mine. He’s from lt1pcmtuning if you google it. Did a street tune with me for a week until it was just right.


#4

I take it you email him your datalogs and he changes the tune based off that? That is interesting.

Only problem I could see is that I don’t know what injectors are in it. Might have to pop one out and see if anything is marked on them.


#5

You can either mail your pcm out to that Solomon guy or pcmforless and wait a week or so to get it back. Or you can simply buy another computer from them with a tune already loaded onto it, they usually have extra computers. I had my car tuned locally by my friend Paul, but I’ve lost touch with him. You could also purchase the tuning software yourself and get the laptop-obd/port cable. Take it to any competent tuner and they should be able to figure it out. A lot of the tables are the same. The only issue with LT1 computers is that they take 10 minutes to load a tune, and if anything happens during the “load” of the tune, the cars pcm is toast.

Are there any markings on the heads?


#6

One note on this, In recent years, pcmforless’ reputation has declined quite a bit. I don’t believe Alvin tunes the LT1s anymore (he had a stellar reputation and I actually used him personally) and there have been horror stories about Bryan’s (Brian’s?) tuning. It’s a bad habit to blame a tuner but when these people have then performed no fixes aside from removal of the pcmforless tune and the car runs good again, it kind of points to the problem.

Also, if you want a mail order, you better know exactly what mods are on the car. Those tunes can only be as good as the information you give them. If you don’t know the exact mods, datalogs can help them but there is still only so much they can do accurately.

If I’m allowed to, LTxtech.com has a wealth of knowledge and probably the most active LTx community nowadays. MoeHorsePower on that forum is a sponsor of ours and also has a great reputation he gave me some tuning suggestions on my never finished build haha.


#7

Thanks a lot guys. Here I thought lt1s were a dying breed with all the ls1 love lately.

I think I’m gonna start by tearing into this engine a bit and find out which mods are actually installed. I took a look at the injectors and they certainly look like the factory ones to me. I can see it has pacesetter long tubes and k&n cold air but I want to know for sure what is actually installed.

Im going to get the Tuner C.A.T. kit so i can just do the email tune and try to learn a bit myself.


#8

Yes, he does datalog tuning. Basically drive around plugged into a laptop make a few pulls and cruise while recording, send him the file, he tweaks it, sends a file back to load and see how the car likes it.Moe on the other forum mentioned is very knowledgeable, and does tuning as well. I’m having a 396 lt4 built very soon and gonna have Moe tune it this time around. Solomon was very good to work with, but i’ve later learned he tunes a little more on the conservative (rich) side.


#9

I’m fine with a bit of a safe tune for now. My problem now is trying to diagnose this temperature based shutdown I have. As soon as it hits midway on the temp guage it dies and won’t restart for half an hour.

So far its got a new optispark, 3 icms and a new coil. I’m going to put another coil as I had some weird voltage readings coming out of it after it shutdown so wish me luck.


#10

I was initially going to say ICM until I read the rest of your comment as those are common to do that when they are bad and get hot. People will often put some type of spacer to keep it off the head or relocate altogether.

What kind of Opti did you get? Often best with a stock AC delco as MSD had many bad batches. I never had issues with an MSD coil though. I’ve been out of the scene for years so I’m not much help anymore.


#11

I think I’ve pinned it down to the optispark as its the only thing that i haven’t replaced in the ignition. I have relocated the ICM to the shock tower, spaced the coil off the block and added a second heat sink where the ICM was located, fixed every worn and cracked wire i could find and tried a known working PCM.

The opti that’s in it is a MSD unit that is 2 years old. I also found a intake manifold oil leak running right toward the opti so not a big jump to think its done for. I’ve got it torn down to the water pump already so hopefully it will be up and running this weekend.


#12

Stop throwing parts at it, and do some diagnostics. There are 2 coolant sending units. One is in the cylinder head and goes to the gauge in the dash. The other is in the front of the water pump and goes to the pcm. That one is the important one. If it’s faulty or not hooked up, the computer will always think the engine isn’t warmed up and it will be in cold start fuel-enrichment mode. You don’t want that. It will run like ass when warmed up, probably die, and then it won’t start again until it cools down.


#13

Already changed the coolant temp sensor in the water pump and rewired it as the wire was rubbed bare in two places. I ordered a tuner cat set up so i can get a better idea on how it running but i need it to run for more than 10 minutes to do that.

Ive gotten it torn down to the opti tonight so hopefully i should be able to have it buttoned back up this weekend.


#14

For those following along it’s up and running finally. the problem was the optispark, turns out the pcv valve was shot pressured the crankcase and was blowing oil out of the hose connected to the throttle body. That oil then leaked down to the connector on the optispark. No clue on why it only acted up when warm but it’s running well.

Thanks for the help guys