dyno results and A/F ratio

[Craig 94 TA GT]

Thanks Kev. Very interesting points you mentioned.

Regarding Cell 18 at idle, I haven't seen it being used when at 0 mph, however, I see it used a lot at 0% throttle (.55 TPS volts in my readings), and RPM is >= 575 where desired idle = 550. Interesting that it isn't supposed to be used at 0% throttle.

Regarding the IAC, I'm always questioning the condition of mine. Although the readings have always appeared to be correct (could have sworn Fred said 20-40 at idle), it's definitely not close to 40-50.
The reason why I question the IAC, though, is...I had a problem that started a few years ago. Every I started the car within 4 hours of previously driving it, the idle would shoot up to 1500+ RPM for several seconds. After several seconds, it would slowly decrease to normal idle. I hate this because just as the oil pressure is building, it's as if I'm revving the motor. I thought it had something to do with the IAT sensor resting right on the coolant line. So I relocated it to the CAI, and the problem went away. As of last month, however, it's back and as bad as before. So I'm thinking, maybe it's the IAC? Why else would the startup idle shoot up to 1500+ (up to 1800 at times) for several seconds when the motor was warm?

I did try adjusting the stopper screw on the TB to decrease the split in idle BLMs. However, I had no such luck. I ended up getting the TPS volts to .76, and the BLMs around 128/109 in cell 16, but the split didn't decrease. So I figured I'd stop playing around with it. And anyway, the BLMs are split across every cell (ranging from 5-19 difference) except in cell 9 - where they're 128/128.

Regarding the rocker arms, I re-adjusted all on the driver's side a few months ago. Originally, both sides were at 1/2 turn past 0 lash. I ended up re-doing the driver's side to 3/8 turn past 0 lash, and no difference.

Wow, thanks again Kev, you got me thinking on a few other potential problems.

[Joe 1320]

I did try adjusting the stopper screw on the TB to decrease the split in idle BLMs. However, I had no such luck. .

Remember, certain items will affect a single bank, certain items will affect the system as a whole. The IAC affects the entire system, highly doubtful that would have had any effect.

In addition to the things that Kevin mentioned, The EGR and it's fittings, the AIR fittings, exhaust gaskets, injectors, 02 sensors all affect a certain bank. Also the condition of rings, valves and cam can also affect a certain bank as well as the entire system. I cannot remember if you ever swapped injectors from side to side to see if the problem switches sides along with them.

[fastTa]

Thanks Kev. Very interesting points you mentioned.

Regarding Cell 18 at idle, I haven't seen it being used when at 0 mph, however, I see it used a lot at 0% throttle (.55 TPS volts in my readings), and RPM is >= 575 where desired idle = 550. Interesting that it isn't supposed to be used at 0% throttle.

Regarding the IAC, I'm always questioning the condition of mine. Although the readings have always appeared to be correct (could have sworn Fred said 20-40 at idle), it's definitely not close to 40-50.
The reason why I question the IAC, though, is...I had a problem that started a few years ago. Every I started the car within 4 hours of previously driving it, the idle would shoot up to 1500+ RPM for several seconds. After several seconds, it would slowly decrease to normal idle. I hate this because just as the oil pressure is building, it's as if I'm revving the motor. I thought it had something to do with the IAT sensor resting right on the coolant line. So I relocated it to the CAI, and the problem went away. As of last month, however, it's back and as bad as before. So I'm thinking, maybe it's the IAC? Why else would the startup idle shoot up to 1500+ (up to 1800 at times) for several seconds when the motor was warm?

I did try adjusting the stopper screw on the TB to decrease the split in idle BLMs. However, I had no such luck. I ended up getting the TPS volts to .76, and the BLMs around 128/109 in cell 16, but the split didn't decrease. So I figured I'd stop playing around with it. And anyway, the BLMs are split across every cell (ranging from 5-19 difference) except in cell 9 - where they're 128/128.

Regarding the rocker arms, I re-adjusted all on the driver's side a few months ago. Originally, both sides were at 1/2 turn past 0 lash. I ended up re-doing the driver's side to 3/8 turn past 0 lash, and no difference.

Wow, thanks again Kev, you got me thinking on a few other potential problems.

I've personally adjusted on a few cars that had split BLM's, and we solved it by adjusting the throttle stop screw and forcing the PCM to adjust the IAC. I suspect part of the reason is it will cause a fluxuation in MAP values and consequently exacerbate a pre-existing bank specific lean or rich condition. A bunch of things can affect the learned idle for the IAC. This may or may not be the case on yours. Sounds like it may not be.

Yes, 1/2 turn past a true zero lash is too much. You can almost be assured that you are hanging the valve off the seat slightly at 1/2 past zero lash. 90-100 degrees past zero lash is just right. Did you re-adjust the passenger side rockers?

Ok, here's another thought. What if somehow, when your fuel system was tampered with, you managed to end up with a clog somewhere along the lines of your CCP system. If you have some kind of blockage or if your CCP valve was blocked somehow or not working properly, this could cause problems with fuel trims due to erratic CCP duty cycles or the lack of, and/or erratic or overly high MAP values. I believe that on LT1's, the CCP purge solenoid is energized to prevent purging and de-energized to permit purging of the carbon canister. The CCP PS is supposed to be energized(closed) when the motor is cold, and is supposed to be de-energized(open) when the motor is warm(specific ECT value I believe) and has reached a specific RPM.

It would seem that the CCP DC should be zero in cells 16-18 and any other value other than zero in all other cells 0-15. At least all the scans I have seen would suggest this. There is somehow a connection between abnormal operation in Cell 18 and a faulty CCP system and split or abnormal BLM's. The increased MAP values caused by the increase in vacuum can also create a brief and high startup RPM even if the motor is warm.

No vacuum leaks still? Brake booster, PCV valve? Have you ever switched the 02 sensors from bank to bank to see if the BLM's follow the 02 sensors?

[Craig 94 TA GT]

Kev and Joe, I just removed the header...again...to check the flange evenness.

http://s94938520.onlinehome.us/pictu...ange_level.jpg
http://s94938520.onlinehome.us/pictu...nge_level2.jpg

In both pics, the level is flat against the #3 and #5 primaries. I used 2 different straight edges to make sure they're level.
You can obviously see a gap...going from #3 to #5, it slopes upward. And heading from #5 to #3 (towards #1), vice versa. In addition, #7's flange slopes upward when looking from the front of the header. Those obvious "lows" on each flange is where they were leaking on the Percy's. Although, #7 didn't leak at all on the Felpros But anyways, they're going in to Napa tomorrow to get sanded down. Will this start to chip the ceramic coaing?

Once I re-install the newly flattened header, I'll reset the PCM and see from there. Then, I'll look in detail about all the other stuff you've mentioned, Kevin and Joe.

BTW, Joe and Kev to answer your questions...
- I swapped injectors and the driver's side stayed exactly the same, while the passenger's side BLMs went even lower. Not sure what that means. #5 and #7 injectors were half filled with gunk. This was only after 1 year, < 3000 miles of driving. All others were spotless. I wonder if the fuel contamination had anything to do with it?
- EGR is brand new and tightened to spec. I'll check for leaks again.
- I haven't readjusted the passenger's side rockers...still at 1/2 past 0 lash. PCV has no leaks...I'm pretty sure, and when the O2s were installed, they were new. Since the problem existed previous to the new O2s, I'd assume that they're OK.

Thanks again guys

[fastTa]

As long as the tech who is machining the flange is careful and takes his time, the ceramic coating should survive without flaking off the sides of the flanges.

[Z Ya Later]

Need a hand getting them to Napa? Gimme a buzz and let me know man

[Craig 94 TA GT]

Thanks man, I'm just gonna take it to the Napa on Cedar before work in the morning. Then I'll pick it up before coming home. However, if they won't or can't do it, then I'll definitely need help in finding a close machine shop that can do the job. And I'll make sure the tech seems competent, as Kev says.

Hey, at least I got the driver's side header removal job down to 30 minutes. That includes the header, gasket and y-pipe, plugs & wires, steering shaft, steering column pulled out of the way, valve cover, and AIR fitting to remove the header from the top. Guess I've done this way too much now thanks to SLP

[Joe 1320]

- I swapped injectors and the driver's side stayed exactly the same, while the passenger's side BLMs went even lower. Not sure what that means.

And how many miles on those injectors?

[Craig 94 TA GT]

Joe, the injectors have less than 6000 miles on them. They were replaced by a shop after the sugar in the tank incident. I've been thinking about getting new ones because these seem to be an "old part." I mean, the p/n (17124187) is not the same in Shoebox's web site. They're old Rochester that are supposedly rated at 24.7 lb/hr, but I can't find too much info on them. They're fat just like stock...maybe they were the original p/n injectors? And just to add another "iffy" issue, they're past 90% duty cycle at WOT above 4800 or 5000k. I've read that Fred said Datamaster often shows bad PWs, but I'm using Freescan...I don't know if it has the same problem What's tempting is that SVO 30lb/hr injectors are only $200 through summit.

As far as the headers go, I took them in to 6 different places and 5 of them said they couldn't do it. Napa and many machine shops said they couldn't do it. Another automotive machine shop tried to put it on a big belt sander, but said it would take forever to do with his equipment, since they're stainless...but they're definitely warped. A touch on the belt sander showed how uneven everything was.

Finally, the last shop I took it to could do it. He put it on a true straight edge and said they're definitely warped...but not the worst he's seen. The flanges are thick enough to cut down so they're all even to within a few thousands. I'm definitely happy with that. And the price is exactly as you mentioned, Kev...$30-$35. Hopefully, they'll be ready by tomorrow.

[fastTa]

Any updates Craig? I'm hangin' on a limb here man!








j/k

[Craig 94 TA GT]

lol No updates. Haven't heard from the shop yet. If I don't hear by tomorrow afternoon, I'm definitely calling. I mean, how long can evening the flanges take!

Hey, what would happen if I tried to start the car without one header? j/k!!

[fastTa]

Hey, what would happen if I tried to start the car without one header? j/k!!

Your neighbors would not like you anymore.......well I don't know if they did in the first place. Steve said you smell weird and your Mama dresses you funny!

[Craig 94 TA GT]

LOL, dang it, Steve gave away my true personality. At least he didn't mention the pink tights. Oops LOL

No, no, no, what kind of manly man works on his black T/A and acts like that

[Z Ya Later]

Your neighbors would not like you anymore.......well I don't know if they did in the first place. Steve said you smell weird and your Mama dresses you funny!

Dangit Kev, I told you not to say anything!! Now he won't trust me with any secrets anymore...err, crap...ummm...go Seahawks lol

It was just the one header that was uneven? You didn't take them both in?

[Craig 94 TA GT]

Dangit Kev, I told you not to say anything!! Now he won't trust me with any secrets anymore...err, crap...ummm...go Seahawks lol

It was just the one header that was uneven? You didn't take them both in?

Dang it man! I told you to keep my peculiar (I call them quirky) characteristics to yourself! Now, I'll have to make sure no more are divulged.



Yea, it was the one side leaking. The passenger's side is dead quiet, and the BLMs are below 128. There is no 1 cell where it's above. Also, the Felpro showed no signs of leaking, besides the cylinder-cylinder leak. So I'm 99.9999% sure it's good.