This is an extremely important point. If you didnt replace the knock sensor from the OBD2 setup with an OBD1 setup then you are porbably gettign loads of FALSE knock pulling your timing wAY out robbign you of EXTREME amounts of power! I would definatly look into this. The problem with the 2 different knock sensors is they eash have different OHMs resistance. This can really hurt performance if overlooked. one more thing, did you add an LT4 knock module into the PCM itself aswell??? Aftermarket headers sometimes cause false knock as well. I think you have jsut overlooked something simple and should be able to pull low 13's atleast if yo uget it fixed correctly.

 

Don't put money into parts until you have diagnosed the problem. Hook up the computer and run your program to check out the situation. If you're getting knock retard you will pick that up right away. I would run the fuel test that Gripenfelter suggested, and I would also take a look under the hood to make sure you have no burnt spark plug wires as well.

 

I put the LT4 Knock module into the PCM, on the OBD I computer.

 

yes, but did you change the knock SENSOR on the Engine block itself to the OBD1 type? If not your still using the OBD2 type knock sensor and its giving your PCM the WRONG knock information pulling your timing out bigtime!

 

errrr

If you used some standard Gen I parts, you may be in trouble.

I have a few questions-

What compression?
does it run smooth?
Can you post your FULL timeslip?
did the shop KNOW it was an LT1 and KNOW how to build one correctly?

My machine shop didn't know WTF it was or what do to. I told him to just hone and hot tank like anyother small block and give it back

I think its a fuel problem personally

 

Ok -- I will be absolutely honest here.. with everything I've did to the car, I didn't know there was a knock SENSOR on the block.

Where is it, and where do i get a new one?


Can someone show me a picture of this, where to get one, etc?

 

http://www.projecttransam.com/projects1.asp

go to computer/sensors on the left and go down until the LT4 KM install guide. You can get one off Jason Cromer for under $30.

 

I think i need the Knock SENSOR, not the Knock Module ( i already hae the lt4 KM, that goes into the pcm)

 

He already has an LT4 knock Module, he needs the KNOCK SENSOR that screws into the BLock of the Engine itself.

 

Just call your local GM/Pontiac parts dealer and tell them you need a knock sensor for a 1995 F-Body LT1. This will be the OBD1 type sensor you need.

 

i am pretty sure its not the knock sensor..if it was it would only take out 10% of timming, wich is not 100+ rwhp he is missing.
Is the car hard to start? How is the acceleration when the car is cold? what about after warming up? Any difference?

 

please answer my questions above

 

i will say one thing if the guys that worked on your car put all the mods in, and you said it never ran good after the install, ide bring the car back there dude and tell them the problems your having, and let them fix it

 

96BlackZ28, i encountered the same problem after i begun upgrading my car to heads/cam before maybe 5 years and i realy learned a lot from that until the car got moving right, so i have these suggestions for you :

1- check the rocker arm adjustment

adjust exhaust valve when intake valve just starts to close

adjust intake valve when exhaust valve just starts to open

how to adjust a valve : you have to reach zero lash then tighten the rocker nut 1/4 turn. you know that you reached zero lash by rotating the pushrod with very soft grip from your fingers once the pushrod stops rotating then you are at zero lash then tighten the rocker nut another 1/4 turn and lock it if it has lock.

2- check for burnt spark plug wires that lies on the headers, specially on the passenger side. buy a set of long spark plug wire and "Made For You" brand wire looms for centerbolt valve covers run them over the valve cover this way you will make sure the wires will not get burnt.

3- check your opti if it is dead or not.

4- check your spark plugs.

5- check your ignition coil.

6- if you have SES light then check for trouble codes using a scanner, these trouble codes could hinder performance sometimes.

7- when you ported your heads, did the porter do a valve job to the heads if not check if the vavles are closing right becuase if they don't you will loose pressure and power.

it is most likely you have number 1, 2 and maybe 3 then 7 assuming your heads are ported the right way. if your heads are not ported the right way you will loose power. hope that help.

 

What compression?

I haven't tested -- because I didn't feel this was a compression problem. I was told 11:1 when it came out of the shop when they tested it.

does it run smooth?

Runs smoothe, sounds great.

Can you post your FULL timeslip?

Hmm, i don't have that anymore -- I'll look around though just to be sure.

did the shop KNOW it was an LT1 and KNOW how to build one correctly?

They knew it was an LT1, but like I've said in teh past, they have never built one before.

------------------------

Is the car hard to start?

Engine barely has time to turn over, and it fires up.

How is the acceleration when the car is cold?

Car runs very very well when its cold -- and between 0-60mph. Over 60, it still runs good, but not the way it SHOULD be running. If that makes any sense.

what about after warming up?

After warming up, its a little more sluggish, but nothing terrible.