Fuel issues @ WOT, TCC high slip RPM

[LS4FTL]

Car: 08' Grand Prix GXP, LS4, 5.3L, 72k miles

Background: back in June I noticed on some of my dyno runs the car started to lean out at higher RPM, didn't really follow-up on it...fast forward to now, I did some high speed WOT pulls and noticed that the car likes to fall on it's face at about 110-115 MPH and my low end of my WOT pulls 0-35 ish have been very boggy.

I did some data logging and noticed my injector flow rate is actually dropping @ WOT along with my injector delta pressure, from what I've read it sounds like this points to my fuel pump since the delta pressure drops as well, if it didn't change it would likely be the fuel filter, true? Doesn't benefit me either way the pump and the filter are in the tank so either way I'm in for quite the work. Is there anything else I should look out for?

Check out the data in the log file, the 1:34 - 1:41 section is the WOT pull I am referring to.

The second issue I noticed in that same stretch of data is my TCC SLIP RPM, it's slipping like no other...it's a single clutch converter which is on the weak side and it's been tuned not to lock-up under WOT. Slip is to be expected but more than 1,000 RPM until 25MPH something doesn't sound quite right...this is in TapShift mode which seems to be the only mode that VCM Scanner lets me log my slip RPM. You can visibly see where the slip drops considerably and RPM and MPH jump (1:38.655).

The converter locks up fine, when it should, the car doesn't shudder under load etc. The trans has less than 15k miles on it this converter should be solid still.

Also don't know why I can't log slip RPM in Drive, it's saying parameter not supported.

Any thoughts on any of this?

[IDRIVEAG8GT]

Um, are there any mods to the car? Is it stock engine stock converter with just a basic tune? Typically if it's boggy down low there's not much timing and/or too much fuel. Yet if the injector delta pressure is falling under high flow that would pretty much rule out the fuel filter. Is it returnless fueling? I'm thinking more towards the mechanical regulator in the tank is stuck or broke.

[LS4FTL]

My fault I should have posted them, still new to the forum...Doug Thorley headers, 1.85 Comp Pro Magnum Roller Rockers, K&N Cold Air Intake, Cat delete. Everything else is stock, 4T65E-HD transmission, LS4 engine.

I attached my tune and the stock tune if you want to take a look, it's definitely not optimized for best performance. I have had it mail tuned by a guy who only does W body cars, very knowledgeable however his tune seems to be a bit conservative. I had a local performance shop dyno tune it after mods, they added some timing and scaled my MAF, which still isn't scaled...AFR is targeted to 12.6, produced like 275/276 on the dyno, torque NOT where it should be to be honest. Dyno graphs show the power falling off at higher RPM pretty rapidly, which may point even more to the fuel issue.

I do believe it's non-returnless fueling, because the LS1 fuel rail mod that we can do needs to be non-returnless.

EDIT: also have LS6 Yellow springs.

[IDRIVEAG8GT]

Wow holy shit.

[LS4FTL]

Wow holy shit.

?? Information overload or something? Not trying to get you to analyze the tune just thought maybe you would want to look at it.

[IDRIVEAG8GT]

Dude we gotta start all over again. This is pathetic.

[IDRIVEAG8GT]

I'm going to start from your stock tune and go from there. The timing is screwed up, your not tuning in Pure MAF mode, and overall your MAF chart looks terrible.

The only thing that is set right is the PE table.

[IDRIVEAG8GT]

Also, it's hard to make a judgement off what your car is doing when it's only about 130-150 degrees ECT. Let it warm up first!

[LS4FTL]

Ok I appreciate any help you can give me. There are probably explanations as to why things are tuned the way they are, 90% of the tune is a popular mail order tune from one dude who kind of goes about things a little differently. The IAT, ECT and many of the other tables impacting timing have been completely removed without issue. He compensated for that in the main spark table allegedly. The only changes made to the octane tables on the dyno were the WOT cells, nothing on ramp-in I don't believe.

Not sure how familiar you are with this ECU but the E67 does not have the typical PE tables. It should only be allowed to be tuned via pure MAF or a custom SD OS from what I've read. There should be zero SD tuning, there are a lot of dead tables in there that aren't used and have default values in them.

The car had driveability done on a dyno, open loop with a wideband. To say his efforts were half-assed would be a compliment.

Otherwise if you have any questions about anything I can probably give you an answer.

[LS4FTL]

I have a ton of log files here is a longer one with higher ECT. I can log to specific .cfgs if it would help.

[LS4FTL]

Dude we gotta start all over again. This is pathetic.

You point, I will do. I have the pro setup so I can data log whatever and flash the ECM to make changes to correct. I just worry about WOT with the fueling issue, which I'm guessing will adversely impact a lot of the other data especially timing.

[IDRIVEAG8GT]

Here's the thing I see. If your Cats have been deleted, why is COT still enabled? That's probably your whole problem for WOT fueling right there.

Also, no matter what, to tune in Pure MAF, the enable RPM should be set to 2, and disable to 1 for pure MAF mode. The entire timing table looks ragged. I'll post up some screenshots here in a few of the changes that I personally would make.

[LS4FTL]

COT has to stay enabled or DOD will not enable, even with codes tuned out tried it six ways to sunday. The cot values are set to impossibly high temps and the enrichment rate to 1.0...even in the highly unlikely event the temps get that high the fueling shouldn't change. Would be great to see the spark changes you recommend

[IDRIVEAG8GT]

COT has to stay enabled or DOD will not enable, even with codes tuned out tried it six ways to sunday. The cot values are set to impossibly high temps and the enrichment rate to 1.0...even in the highly unlikely event the temps get that high the fueling shouldn't change. Would be great to see the spark changes you recommend

I didn't see that it had DoD. That actually kinda sucks.

Still, I think that the PE enable for the TPS threshold is set wayyyy too high.

[LS4FTL]

Need the hwy fuel economy, I can tune it out whenever I want so that's not a big deal. TPS settings have been played with quite a bit, if I lower it too much I'm into PE and wasting gas when I don't want to be. What's wrong with the spark tables though?

[IDRIVEAG8GT]

Try this MAF and spark table on for size. Use the Spark as your High and Low table.

[IDRIVEAG8GT]

Need the hwy fuel economy, I can tune it out whenever I want so that's not a big deal. TPS settings have been played with quite a bit, if I lower it too much I'm into PE and wasting gas when I don't want to be. What's wrong with the spark tables though?

What. You're using over 50% throttle input just cruising around town?

[LS4FTL]

No but it doesn't take much to cross that threshold, the car idles at 22-23% TPS, getting to 50% from that point isn't much past quarter of the pedal position. I need to get my MAF dialed and spark before I get too much into the personal preference stuff.

[LS4FTL]

I'll give it a shot

[LS4FTL]

Try this MAF and spark table on for size. Use the Spark as your High and Low table.

You have the lower half of the table?

I can't see below 9450 Hz. I also never see frequency values above 11khz so that part of the table has been neglected because those cells don't get hit (turbo would be nice though). I see you reduced the table a bit, it needed that I just haven't got around to it yet because I had been messing with my intake too much. Trims had been on the positive side for a while now but not too terrible.