Hi, I'm New Here

Hi everyone,
I've owned a 1995 Z28 that I've used as a summer weekend car for the last 6 years. When I first bought it the car was beautiful, but every light on the dash was lit and It was running only on 7 cylinders. Over the last few years I've been able to resolve these issues, especially with the help of diagnostic software narrowing down the locations of the issues. Every year I try to learn a little more about tuning the powertrain on the vehicle as it does have some light modifications, but plan on replacing the cam and possible the cylinder heads in the future.

Currently I have the car running great in closed loop, but struggle with engine knocking occurring in WOT. I installed a wide-band sensor behind the headers last fall, and now pulling the vehicle out of storage, plan on using it to diagnose if my engines receiving the correct amount of fuel in this condition.

Recently I've installed an Android double din head unit, replacing the old cd player. With this unit I'm hoping to datalog aldl information rather than lugging my laptop along with me, and demanding that passengers must share their seat with it lol.

Outside of tuning this car, I'm also an avid 3D printer. I love reconditioning or replacing the original parts on this car that experience low stress, and I find 3D printing to be a great answer for this.

welcome, lots of LT1s around these days....

aldldroid should work well for your datalogging, and when you want to analyze those logs, my trimalyzer tool is well tested with its log output. it does pretty good analysis of where the knock occurs and its magnitude as well.

are you going to run your wideband through the ECM so they're logged together?

another thing to check you might not have thought of... make sure your exhaust doesn't hit anything. if it hits the floor pan or whatever due to old engine mounts it'll set off the knock sensor under heavy load. its a pretty common reason to get false knock on these old cars.

Thanks for the advice,

It's really awesome to hear from you Steveo. I've actually been using your software for the past 3 years, $EEHack to tune my closed loop using the stock O2 sensors and have found it to be a wonderful tool along with trimalyzer to adjust my MAF and MAP tables in Tunercats.

Last October I wired up my wide band to the the AC pressure wire and was able to test it out for a day or so in $EEHACK before winterizing the vehicle. It recorded a range of ratios between 14-11:1 AFR in WOT, but it was really limited logging of 6 miles around a country block.

For the exhaust that's a really good idea that I hadn't considered. The previous owner installed long tube hooker headers, so I'll check if my they used enough braces for the exhaust. I'll inspect the engine mounts as well.

I have noticed the engine forming a ticking sound on the driver side when giving it throttle from a low rpm (well above the lugging stage in each gear.) I timed it with the rpms and it occurs once every rotation which make's me believe it's coming from a single cylinder region. I've check the rocker arms and carefully adjusted them to fit well with the push rod dampers and the valves... which made no change. So now I'm considering replacing the exhaust gaskets in case a leak has formed. If so I'm wondering if this might be the cause of my knock?

I'm hoping to get the car out more this week but our forecast isn't looking great and we're still dealing with flooded roads and damaged bridges in my area of Michigan.

LT1 headers are a blessing and a curse

they're really hard to install and remove

they never fit right and clear everything, and end up hitting stuff

they constantly blow exhaust gaskets or warp or bolts back off

they melt plug wires

if you don't have poly engine mounts with your headers in a 4th gen you're doing it wrong

As steveo said, I found If you get persistent knock at a particular RPM regardless of what you do with fuel and spark advance, it's probably something hitting exhaust or suspension under the car.

For exhaust leaks, I have found that even stock manifolds benefit from being planed flat by a local machine shop, and then for headers with thinner flanges, use high end gaskets like Earl's Pressure Master or Percy's Dead-soft gaskets. That's likely what you're hearing, my guess.

These are the best I have found to date and I've been around for a couple days :innocent2: Try to have longer bolts available as the gaskets are thicker. It's a good time for some 3/8 head ARP's.

http://catalog.remflex.com/

100% yes to remflex. they'll even seal a badly warped flange for a few years. just snug those bolts up after a few heat cycles.

Quote:

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Originally Posted by steveo

another thing to check you might not have thought of... make sure your exhaust doesn't hit anything. if it hits the floor pan or whatever due to old engine mounts it'll set off the knock sensor under heavy load. its a pretty common reason to get false knock on these old cars.

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just out of curiosity, does this apply to L98/3rd gens too...?

it would apply to any car where the exhaust hits the car, yes

you know how people tap the block with a hammer to test the knock sensor?

metal parts banging around definitely causes knock counts

Quote:

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Originally Posted by steveo

it would apply to any car where the exhaust hits the car, yes

you know how people tap the block with a hammer to test the knock sensor?

metal parts banging around definitely causes knock counts

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Well, I feel dumb like a rock.

exhaust hits everything on this car.

some may argue with me but i would have zero problem just yanking a couple degrees of timing where it would hurt the most, disabling all knock retard, and running mid grade fuel, at least until the exhaust problem is resolved.

the risk is really minimal.

i ran my trans am at the track with no knock retard, because when i powershifted at high rpm, the slamming into gears would cause tons of knock counts.

I just ordered the Remflex kit my LT1 through Summit.
That's an awesome product sherlock9c1, I had no idea that existed. Otherwise I would have probably ended ordering some Fel-Pro gaskets, which you're right, if there are any imperfections in the headers would probably do nothing.

I'm planning on inspecting under the can later this week, have to re calibrate the WB o2 anyway while I'm there.

I was able to get ALDLDroid to communicate with my car using EagleMark's ADX file ($EE-16188051-V3.8a-engine-1.adx) which is missing the guage for a Wide Band o2. I was able to get the WB o2 guage to work with his ($EE-16188051-V3.8.adx) file but suffer from frequent Checksum Mismatch. Is it possible to bring copy the coding for the WB o2 guage from one adx to another using TunerPro?
Attachment 15623
Note: my AFR is not actually that high when it's running lol

Thank you for your help guys, I'm excited to see the progress made over the next few weeks on this vehicle.