Rich3fan

You're the first one here who's actually indicted the dealer, and I'm beginning to think rightfully so.

Hey dude!!! Good to hear from ya! What's this V6 Bird bit I'll PM ya about my GM conspiracy theory, some other reminiscings and the info you're requesting later. I haven't buzzed out each plug wire yet because I replaced them not long after buying this Formula with the sharper looking MSD's, and at the same time changed the plugs to TR6's. I had a much more noticeable misfire problem a couple years ago; Ewing blamed that on the heat shields not being on the wires, and I was able to verify that when I put the stock wires back on myself. The question I'd have to ask though: isn't it important to know the inductance of the wire more so than the resistance? The spark is actually a high amplitude AC signal right, therefore making the impeadence in the wire the determining factor in the strength of the spark? I could bring home an oscilloscope, but I don't have a probe that could handle the voltage.

I agree that it's probably not an injector issue because the engine is running very smooth when I've got some foot in the throttle, witnessed by 0 misfires on any cylinder recorded by ATap. My thinking though was to try to eliminate all possibilities.

I appreciate your kind offer, but it wouldn't be right for me to subject anybody to the 120 degree environment that is my garage.


Yes, I'll swap the coil packs, wires and see what happens. I also think I'll swap back in the original TB after that job, just to make sure it really was causing the surge.

I know that if it's set at too low a voltage, the PCM will throw a code. The fact that the actual idle is only about 8 rpm away from desired would tell me that it's okay. Maybe I'm wrong?

I agree. That's why I ask if y'all think ATap v2 is a worthwhile tool for me to troubleshoot with.

If it's the parameter that I think you're talking about, that value equals 20, at all instances of idle. It was 4 when I logged the misfires at 1654 rpms.

Unfortunately I didn't include that parameter (Throttle Position Angle) in the log file.I see in its description though that its computed by the PCM based on the TP sensor voltage.

There are two catastrophic conditions that keep popping into my mind: the PCM's at fault, or my eight year old torque converter, who's life started out as a 2800 stall then re-stalled to 3000, and is causing the idle surge is in need of some freshening up. Keep in mind the surge was most noticeable when shifted into gear.

I guess you're all suspecting now that I have no life outside of this forum, huh?

Let me edit this a little... When I mention my TC, I say that because I still notice some minor surging when I shift back into park (more than what I'd consider normal), but no where near the amount it had with the other TB in place...

P Mack

iTrader: (6)

Since you were in fuel trim cell 20 I guess the throttle position isn't the problem.

Rich3fan

I sure would like a Fuel Trims 101 course. I'm sure it's been discussed here thoroughly, but you tend to get opinions and disagreements mixed in which causes the subject to become convoluted, which in turn causes me to become disinterested.

How 'bout: What does Fuel Trim 20 indicate or provide to the engine? What about Fuel Trim 4?

V6 Bird

iTrader: (15)

20 is the coordinating table for a variety of parameters where the computer basically cross references things like TPS, RPM, and G/SEC of airflow across the MAF and it points to the cell 20 for fueling. It may read IAC as well as MAP pressures. Its been awhile since ive been in an Edit table on LS1 edit. My car hasnt run in 1 year now...

I simply wanted you to check resistance in the wires because i wanted to make sure they were all within the reasonable amount of resistance to rule out a plug wire. Ive never had issues with the heat shields not being there on the head side of the wire Rich, but thats not to say that you cant install them. They are a direct swap you know?

The V6 Bird part is all part of a secret society of street racing stuff i was in for a while....My car was just like yours except sleeper and stock like... It was dubbed by some of the regulars on the street a "V6" which it never was and ran hard. Enough of that, shoot me a PM.

BTW, your garage and mine, run about the same temps..I do side work sometimes on the weekend and work in it often... Im conditioned to the environment Id say.

P Mack

iTrader: (6)

0-15 are normal driving based on map and rpm. 16-19 are closed loop idle. 20-22 are open loop (idle, decel, and wot).

Rich3fan

Interesting. I gather this is an HPT window? Two questions: What is the formula to convert *in Hg* to *kPa*? Atap expresses MAP as the former. Also, what is that percentage number I see next to the Trim number?

What pisses me off is the fact that, for the money I just spent at the dealer (potentially needlessly) I could own the HP Tuners tool right now!

V6 Bird

iTrader: (15)

Its never too late for you to purchase the software

Rich3fan

Mr. Savings Account would disagree! But, since you need to upgrade from your old version of LS1 Edit, let's split the cost of a multi-VIN license, if that rule applies. Whattaya say ace?

V6 Bird

iTrader: (15)

I dont own edit...

Im not in the position to purchase anything right now except Big Stuff 3.

Rich3fan

Just wanted to note that the idle surge issue and my questions concerning the IAC have been resolved by replacing the TB. Looks like it was either the TB or, but not likely, the IAC valve. At this time I have no driveability issues, including no noticeable "misfires" as was reported by ATap previously (I would think that I would notice 22 on one cylinder during one count cycle at idle). I swapped coil pack and wire #7 & #5 last weekend; the misfires still showed as coming from #7, so I think I can rule those two elements out. Fresh AC plugs were installed during the new TB install as well. What I find interesting (or maybe I just don't understand what constitutes a misfire) is that, after a WOT run, powering off the motor and then restarting after a bit of cooling, one cylinder was definately not working for a short period. ATap reported NOTHING during this event.

BTW, the tech at the dealer reconnected the TB coolant lines but forgot to reconnect the vacuum line after he replaced the TB. (Yes, I did notice a slightly smoother idle and pickup during acceleration after I reconnected it.)

I think I need to start an HP Tuners or EFI Live savings fund.

-OR-

V6 Bird, what is Big Stuff 3, would it be beneficial for my car, and, we learned SHARING when I was growing up.

Thanks again to all for your input. -Rich