This stupid lt1 knock is driving me crazy. I get it some runs and not other runs. I get sometimes that little part throttle knock and sometimes when just punch the throttle .Some quartermile times it reads zero and sometimes its pretty high seen like 8.9. I am trying to tune it and richen things but seems to not be helping much and strarting to wonder if have rich knock from overrichening.

I have checked fuel pressure and it seems good both at idle and wot taped to windshield. I haven't installed my new racetronix pump,harness or fast afpr yet though. I haven't changed plugs not sure if previous owner did and ditto on wires or opti but do have a new opti ordered in case its not working great.
Car seems to run fine but when make a bunch of gtech runs sometimes the car is about 4 tenths slower and 4 mph lower and other times its consistent and fine for mph. It doesn't throw any misfire codes ,don't have any codes at all showing except for some back 02 sensor heater but that is after cat o2.

I seem some runs to get knock when it shows low o2 like .851 and other times it shows like .890 and still gets knock. I am running 91 octane but am at 1900 feet above sea level.

I have taken off the brace under the ypipe and have been under the car numerous times checking for things that are hitting. Found nothing.
I plan on replacing the knock sensor with new one,installing the racetronix pump and afpr and harness and new opti plugs and wires possibly delteq system in spring. I hope the heck this knock is gone by then. I realize a wideband would help too but buddy is saying have to drill a bung ahead of cats to check so waiting for spring for headers and no cats and then use his wideband on the car. Its likely false knock and haven't tried race gas or toluene or xylene yet. I realise that can help to figure out if its fales or real.

So what have some of you guys found for solution if you had this sort of phantom knock. My ls1 don't have this problem. I tune it with maf translator and ls1 scanmaster ,same stuff that is in the 96z. I tuneed my 92 talon turbo with scanmaster and maf translater no wideband and it worked fine also.

I did get similar weird knock in my 92 talon turbo and cure in that car was programming to eliminate part throttle knock. Think lifters were causing it in that car. Replaced many things trying to get rid of it. Now my lt1 is doing the same thing. Sometimes its nice to not have a scanner and not see what your car is doing..

 

You have a stock bottom end. Stock exhaust manifolds AND cats. Your using a 58mm throttle body. Add to that equation god knows how old the ignition components are. Here's your sign.

It's always a good idea when you buy a used car, to change the oil and look at the plugs. AT THE LEAST.

 

Umm..no sorry if misunderstood.The car was stock when got it about a year or so ago and have given it its regular synthetic oil changes. I have installed and put in all that new stuff..new tps sensor,iat sensor,new iac,new gm fuel filter,new air filter. I got a 58 for later ,haven't ported the intake yet but plan on LE2 heads and kooks longtubes next spring,already have CC305 and 1.6 NSA pro mags and related hardware to install at same time. Just haven't changed the plugs or wires...mostly due to doing headers next spring so why go thru changing them with stock exhaust manifolds as we all know how much fun lt1s are for that. I have owned a 96 ta and 97 ta ws6 previously. I tuned them with my maf translator and lt1 scanmaster and never had the knock problems in those cars as having now in the current 96z.

The car is going into storage in a week until spring and will do a bunch of stuff to it so hoping it gets rid of this stupid erratic knock. I am mostly ranting here guys just annoyed at this car. Buddy has been supposedly getting tunercat ob2 and getting impatient as figure he can maybe tune out this knock for me. Its frustrating at the track or when racing buddies to have the car run great one run and then be a dog the next. And its more frustrating when sometimes the mph is down but the knock retard is zero.

Likely its something else doing this.just wish it would at least throw some codes or something.

 

I also installed an lt4 km. Its been in there for quite awhile. Maybe its a dud or something.

 

Have you considered the possbility that the MAF Translator + has **** the bed? That would explain erratic perfromance, even in the absence of knock retard.

 

Run race unleaded at the track and turn off the KS.

Rich

 

Before I replaced my lifters/seals/pushrods/springs etc... blah blah.. My card had developed a knock retard at wot. Randonly, sometimes bad sometimes not..

I discovered the Lifter on #8 cyl was not pumping up enough oil and the OEM lifter to pushrod contact point was showing signs of wear and tear also it had already gained a little bit of play.

I also discovered to my horror.... that the intake manifold bolts had loosened up to the point where I removed them all by hand..(and a shocket but did not need anything else).


Point being here is.... I after I fixed everything my Knock retard is gone. I can only assumed that I had the lifter not pumping up enough creating a slack in the valve train and making a knocking noise but it was random at best...... or I had such a vacum leak around the intake manifold gasket and it was leaning out at wot.... or both.

I would check with Racing Fuel and if you still have the knock it would probably be a good idea to check your lifters... maybe one is collapsing at certain RPMs... (sticky).

Just a thought.... check the intake manifold bolts .... I dont know how mine worked their way loose but it was almost as if someone had forgotten to torque mine ... the Manilfold was almost like just sitting on the block.


Marvin