Lulled into confidence

[Pyro6]

First time this weekend we were at the track since June. The car til than was running flawlessly, if we could've dialed an 11.40 all would be right with the world. We've been mostly doing car/truck shows this summer cause Maple Grove has a busy schedule other than points races, end of June early July I have a busy fireworks schedule. So, this weekend after all the employee BS is ironed out, I saw a track opportunity Fri.-Sun. Friday = Test and tune, Sat. Sun = points race. I figured I'd unload the car Fri night and be ready to go. 1st pass is a 12.23 and the car didn't feel right at all. Hooked up the computer and the PL settings all read default. That's happened before, so I figured glad I'm here doing what I'm, doing, shoulda been better prepared . Reset and run. Next 3 passes were back to 11.5 and 6X, car felt good for a Friday night, usually damp with minimal track prep. Went back up to the lanes after the final run to pick up my buddy, as I was idling and waiting for a few minutes, the car starts searching at idle and stalls. We head back to the trailer and it shuts off prob 15 times, didn't think I was gonna make it. It acted like TPS or MAP, so I quickly thru my spares at it and nothing changed: stall after start, baby the throttle to run, try to accelerate and it would die. It was late, and thank goodness racing didn't start til 10 Sat AM. After I IV'd my coffee for the morning, got the computer out and discovered #2 setting went to 30, usually 125. So I readjust it, car does the same thing. Go thru the rest of the list, #9 is reading 30 also. Reset it and all was good. Drove around the pits and felt normal. We're gonna race today!!. Thomas puts in 2 good time shots. We're in the lanes for eliminations, one of the track crew walks by, see's our 11.50 dial and no rollbar and says to me: cutting it close aren't you? I say yea, but really don't want to put a bar in it. He says I understand and moves on. We make the run, lose on an 11.496 @11.50 dial. Call it a night. Next day Thomas techs, gets the word: slow it down or get a bar. We've been running low 11.4's for awhile and not gotten any grief. Our time shots in the AM are 11.4's but til the car heats up and the sun gets warm, we're usually high 11.4's. That lets the door open for Thomas to adjust. I figure for Sunday I'll just back the boost controller and we'll run 11.8 or 11.9 from my notes. Salt in the wound though: we only get one time shot. The car didn't like that pass at all: detonation and 14.XXX (boost controller wasn't happy)??. Put the controller back to where it's been, minus a turn,  figured we're gonna lose or get thrown out. We dial 11.55, come in at 11.56, lose at the tree. Thomas beats himself up and we review from the Jr. days how when changes to the car are necessary, chances of winning the race are minimized. Bottom line: how can only 2 settings change on a PL setup. If just cleaning the board connections are the answer, PL is gonna be history. If I have a bad PL, I may consider getting a replacement.

[Steve Wood]

Voltage glitch??

Not the Pl, pretty sure

[Pyro6]

Than how can it only lose two settings? Plus 3 good runs prior and another good run after. I trust my alt. guy, I'll test all + -. Two settings???

[Steve Wood]

seen it happen without a PL...but I won't argue

[daveismissing]

How old is your battery?

[Pyro6]

One year

[PacecarTA]

x
f
i
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.
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[Pyro6]

Paul, didn't you have one for sale???

[PacecarTA]

had a classic B2B ..its gone already

[daveismissing]

I 'm starting to think these ecm/logger/translator combos need an independent tank circuit to power them.

[Steve Wood]

I 'm starting to think these ecm/logger/translator combos need an independent tank circuit to power them.

Why do you think it is the battery or the alternator?

[daveismissing]

A tank circuit would isolate the ECM (et al) supply from any dropouts,
eliminate the power as a source of "glitches".
If "glitches are getting backfed from the injector drivers etc then it likely won't help.

 

[Pyro6]

What I don't understand is if it was a ground or feed issue, how it only affected two settings. Even if it was a spike from alt. inject. or other solenoid you would think it would affect everything. But as electronics go, anythings possible. I wonder how many other people have had this problem. Some kind of isolation diode might be more the solution???

[Steve Wood]

the prom has a bunch of programmable addresses and all it takes is a weak spot in chip, one too many touches with a finger that has not been grounded to remove static electricity, a slightly dirty contact, ad infinitum. 

If you have a chip that can be programmed from PL then maybe a connection or glitch in that circuit might do it.

Go talk to Eric.  Tell him you don't trust the chip, and see what he can do for you.

[Pyro6]

Good plan. I do want to double check all the power and grounds and charging system before I get with Eric. I run the speed density chip. Thanks again for your help Steve.