dyno results and A/F ratio

[Craig 94 TA GT]

Wow, just in time...thanks for the tips Joe. I would have installed them the wrong way if it wasn't for you

So I guess this is the wrong way to install it...convex side towards the header.
It's hanging on there right now...but luckily just hanging and not tightened/flattened.

[Craig 94 TA GT]

Joe, what did you tighten your bolts to? I'm at 30 ft-lbs and notice a ticking from the driver's side header. Thanks in advance

[fastTa]

Joe, what did you tighten your bolts to? I'm at 30 ft-lbs and notice a ticking from the driver's side header. Thanks in advance

How did you get a torque wrench on all the header bolts? I guess maybe you can get a crow's foot on their or something similar. I would not try to go over 35 lb/ft if you can get to measure it.

Those Breslin Split-Locks seem to be the hot ticket right now.

[Craig 94 TA GT]

I can only get a 3/8" drive torque wrench on the left bolts of the #1 and #3 primaries. But I use a 5/16" wrench, put a 3/4" socket over it, with a 6" extension on the socket to tighten. I tighten to what I think is xx ft-lbs. Then, with the torque wrench, I see how much more turning the real measured xx ft-lbs requires. Then, just add that amount to all the bolts with the wrench.

I'm still hearing a nasty leak...very loud ticking and extremely noticable above 2k. I think the leak is right where the other gasket leaked. But I haven't had much time to examine it.

Can I pour some ATF in the manifold vacuum line and see smoke of where the leak is coming from?

[Joe 1320]

I have to admit, I don't use a torque wrench. My method is to get in there with the 11 mm short wrench and torque them by hand. I like to be able to feel the fastener threading into the block. I also don't just torque them down, I torque it and loosen it, then torque them in steps. Then I start it up and let it idle for a bit to heat it up and let it cool. I then go back and snug them one last time, put on the locks and clips and I'm done.

I can't imagine how there could be a leak with as thick as they are and the crush to conform design. Perhaps the old tighten by hand method might be best?

[Craig 94 TA GT]

Well, the weird thing is...I can't find where the leak is I tried using a mecahnics stethoscope, inspecting the flange to gasket mating, listening closely, etc. But all I can confirm is that the ticking is definitely coming from the driver's side. I checked all the rockers and they're fine. I guess it could be from the header to y-pipe flange, but I listened underneath and I couldn't hear it. Maybe I'll try the ATF-to-see-smoke method.

[Craig 94 TA GT]

Well, I tried the ATF in the brake booster line (and this time I unplugged the MAF so it would idle right), and I saw some smoke out the tail pipes but no smoke whatsoever around the headers. The most smoke came out of the booster line after I shut it down. I'll try to retighten them the way you mentioned, Joe, but I'm not quite sure it's a header leak anymore

I decided to scan the thing to see the BLMs. Cell 16 was at 133 / 112. A measure of 133 doesn't seem like much of a problem...that's what, a 3.9% increase in fuel.

BTW, thanks for bearing with me guys. I know this thread is too long, too old, and getting boring really fast.

[fastTa]

Craig, the ATF trick is usually used to find vacuum and intake leaks as soon as you kill the motor. You will normally see smoke emitted from wherever the leak is once you shut the motor off.

The exhaust gas pressure and velocity are pretty strong right where the exhaust port and header meet. You won't see any smoke visibly emitted because usually eduction is takling place if there is a leak their. It is likely pulling outside air into the primary and not pushing it out like you would think.

The only real way to perform a visible exhaust leak test is to plug the tailpipes and pressurize the exhaust with a type of smoke or visible gas. Some shops have what they call a smoke machine that is used for this purpose.

That picture you have of a level laying across your header flange.....do you have it in a higher resolution?

[Craig 94 TA GT]

Kev, I accidentally deleted the original pic with the straight edge on it but I did manage to find the leak. I just removed the gasket.
Percy Leak

Sorry for the bad quality...was taken with my phone. But you can see where the leak was. For some reason, though, I was unable to hear it with a stethoscope. And what's weird is that I didn't have any kind of leak there with the Felpros. I guess I just tightened them wrong. I hope they're not "crushed" wrong, such that I need new ones now.

[Joe 1320]

Those gaskets don't look crushed at all.

[Craig 94 TA GT]

You're right Joe. They don't look like they've been crushed too hard, yet the bolts were over 30-35 ft-lbs. I re-installed them, torquing them in steps, from the inside out. Previously, I think I may have snugged one down, while others weren't even on. That's probably the mistake. Also, after closer inspection, it was actually leaking from every port except #5. Maybe that's why I couldn't distinguish where the leak was coming from...since all of them were leaking.

I started it up again and couldn't hear any more ticking. I'll try to drive it some and observe to make sure. If I still have a leak, it's time to take them in to Napa and get the flanges even. I'm very scared, though, that it'll ruin the ceramic coating.

Testing it, I got a MAF failure code twice. It was due to a loose connection, but maybe it's a sign to get a new one. Since my BLMs are high on the drivers, low on the passengers, it would be nice to verify that this is correct, or if one is really higher/lower.

[fastTa]

Kev, I accidentally deleted the original pic with the straight edge on it but I did manage to find the leak. I just removed the gasket.
Percy Leak

Sorry for the bad quality...was taken with my phone. But you can see where the leak was. For some reason, though, I was unable to hear it with a stethoscope. And what's weird is that I didn't have any kind of leak there with the Felpros. I guess I just tightened them wrong. I hope they're not "crushed" wrong, such that I need new ones now.

It looked to me also as if they weren't crushed. You probably need to put a little more torque into the bolts. Using a torque wrench in the manner you were describing can produce deceptively low readings. Drive it, let it cool down, then snug them just a bit more one more time.

[Craig 94 TA GT]

Well, I tightened them nearly as hard as I could with the given space, tools and attempting evenness. I measured an estimated 40+ ft-lbs. I'm not sure if it's a slight tick still, or the rockers, but I hear something. And my BLMs show it something. So it's time I take in the headers to Napa and get them right. I'd say SLP should pay for it since they were brand new.

But I do have another question. How is it, in open loop, cell 16 is showing BLMs of 137/128, Cell 18 is 138/128 and cell 17 is 128/128. All short terms are 128/128. I thought in open loop, the BLMs should be 128/128?
So by these numbers, I'd assume the PCM took the last values during closed loop and is using them during open loop. But that statement doesn't hold... since the passenger's side BLM is usually under 128 in closed loop, why won't it stay under 128 in open loop? During closed loop cell 16, BLMs are 135/117. Doesn't make sense to me

EDIT: Nevermind, I did a search on cz28 and found that the PCM does used stored values when in open loop. Just doesn't make sense though...it seems that the passenger's side is under 128 a lot, but open loop is showing a perfect 128.

[Joe 1320]

At least the gasket isn't toast.

[fastTa]

Well, I tightened them nearly as hard as I could with the given space, tools and attempting evenness. I measured an estimated 40+ ft-lbs. I'm not sure if it's a slight tick still, or the rockers, but I hear something. And my BLMs show it something. So it's time I take in the headers to Napa and get them right. I'd say SLP should pay for it since they were brand new.

But I do have another question. How is it, in open loop, cell 16 is showing BLMs of 137/128, Cell 18 is 138/128 and cell 17 is 128/128. All short terms are 128/128. I thought in open loop, the BLMs should be 128/128?
So by these numbers, I'd assume the PCM took the last values during closed loop and is using them during open loop. But that statement doesn't hold... since the passenger's side BLM is usually under 128 in closed loop, why won't it stay under 128 in open loop? During closed loop cell 16, BLMs are 135/117. Doesn't make sense to me

EDIT: Nevermind, I did a search on cz28 and found that the PCM does used stored values when in open loop. Just doesn't make sense though...it seems that the passenger's side is under 128 a lot, but open loop is showing a perfect 128.

Cell 16 is normally used only while the TPS is reporting 0 and the motor is at idle, Cell 17 is normally used during deceleration when the TPS is reporting 0 (DFCO), and 18 is essentially a "made up" cell that still uses LTFT’s, but they are queried from the other normal operating cells at the instant you transition into Cell 18. Additionally Cell 18 can be used at any MAP and RPM value, but as long as the TPS is not 0%. <----This got me brainstorming.

I remember you saying before that in some of your scans, you saw the PCM using Cell 18 while at idle correct? This shouldn’t be the case and this makes me wonder if your TPS is not reporting 0 even though your foot is off the throttle. Your split BLM's may partially be caused by an IAC setting that is too high or too low. 40-50 is about the norm with stock heads and cam. So this leads me to believe that you may need to adjust your throttle stop screw in order to get the PCM to adjust the IAC to within a normal range (if it's not already.) Insufficient or too much air flowing through the IAC passageway can split up the BLM's like yours.

Another thing that can be exacerbating these split BLM's is reversion into the intake manifold. With the LT1's "open" one piece plenum, intake runner reversions can allow extra fuel to reverse back into the plenum during valve overlap and are then allowed to re-enter other cylinders. Since the PCM is under the assumption that all the fuel it is responsible for metering comes from the injector, extra fuel being inducted into a cylinder from another cylinder can show one bank being rich and the other bank being lean (split BLM's). This can be caused by both a rocker arm being too tight as well as too loose. Being too tight is the more likely candidate. This reversion into the the plenum can also create an anomaly related to the AFR table because of erratic MAP values. The AFR table uses values from the MAP sensor and ECT data to help suggest a/f ratio.

The PCM does set the BLMs to 128 during PE mode, but if the PCM was trying to compensate for a lean condition and the last BLM being reported was 132 or higher at the instant the PCM entered PE, the PCM will use that BLM during WOT instead of 128, even if it's pegged at 160.

Just brain-storming and trying to offer some suggestions!