grabbem88

.622/.637 .231/.241 at 112 +5 cam
le2 dart heads 2.08/1.60 54cc 180cc
30lb
exhaust
48mm t-body
stock m6 3.23’s

1-2 fine 3rd 22-2500 got a weird jerk/surge
4th at 18-2k
5th fine till I hit 22-2500 same as 6th. Below that 18-2k it does good in 5/6

wideband at those ranges it’s 13-16 and back and forth

I’m at a loss

Gtpguy

I've been paying attention to your progress as my 93 also recently crapped the bed. Did you ever get your AFR zeroed in? Some guys added a tiny bit more fuel, 2%. Have you considered stepping up to 3.73s? I understand the m29 makes it more like a 3.42 but shorter gears are proven surge killers.

grabbem88

don’t get me wrong the car runs great but I’m being a picky bitch lol.
my afr is decent and my wot pulls are 12.2-12.9
depending on where I pull from band how much room I got to stretch it out.

yes I’ve considered gears.most recommend 4.10’s

Gtpguy

Stock TB? Are you doing the tuning yourself? Have you tried to level out the spark advance tables around your idle rpm / load range? Also try to set the IAC counts ( minimum idle ) to around 35-40 in neutral. Double check the TPS settings as well. How much have you played with the VE tables? If not look at the VE tables in the area where you are having cam surge. Probably need to lower VE a tad more.

I remember a dude who tuned his 99 GTP for speed density. It was faster than everyone else's by far, mod for mod. One day he showed me his VE tables. The MF'er was literally frame by frame, cell by cell smoothing it all out. It had to take quite awhile. But again, his GTP would MOVE!

grabbem88

iac are 125 cold 30-40 warm tps .61

added timing subtracted
added fuel subtracted 1% to 10% both directions and in between
I can make it worse but never better

Injuneer

What is the programmed cold idle speed RPM vs coolant temp? IAC seems high, but would depend on RPM you are trying to maintain.

As I understand it, the more cam overlap, the harder it is to control surge at low RPM. I'm no tuner - which is probably evident from my comments - but I believe I've seen tuners control surge with the timing tables. Are you running totally closed loop?

I'm just rambling.

grabbem88

I’ll have to check on the idle speed and coolant deal. Did not like 35* timing in that area. So I’m at 39 which is tolerable at given range where this flares up. 125 is when I turn key but not start. My cold running is 88 actually my fault on that part

grabbem88

Btw I’m learning to tune so I’m definitely not well apt to this.

closed loop starts at 140*. Thought about shutting it off and stay on open loop...like I said not smart enough to know

ULTM8Z

You should probably get TunerproRT and start datalogging. Take a look at the fuel trims in that area. It'll probably give you an idea what's going on.

TunerPro and TunerPro RT - Professional Automobile Tuning Software

TunerPro and TunerPro RT - Professional Automobile Tuning Software


Coupe things on your injectors...

Which injectors are you running? Bosch-III? Also, did you adjust the injector constant in the calibration?

grabbem88

I have tunerproRT but as usual I neglected to add this is a 93 but I do my logging through scan9495
injectors are the Bosch 30’s

the car made 365whp on a 11.0 tune with little timing. And runs great unless I’m in 4th at 2k 40mph. And 3rd gets out of shape only at 2400 at 40mph. 1/2 is fine and 5/6 cruises at 65-70 no problem

ULTM8Z

Tunerpro has the ECM definition files for $DA3 mask, which is what your 93 is.

The reason I ask about the injectors is if you're running the Bosch III style, they're notorious for needing to have the voltage offsets adjusted for in the calibration.

I have the $DA3 ECM definition files because I used a lot of the values fueling tables as a baseline starting point for my Gen1 SBC with a Miniram intake. Amazing how well they transferred over to the 3rd gen ECM.

There is a table in the calibration called Injector PW correction vs battery voltage. For Bosch-III's, you need to update that table with the values for the injectors you have. I'm also running Bosch-III 30 lb injectors and the car ran like crap until I got that table updated.

grabbem88

These Bosch 3’s?

ULTM8Z

No, those don't look like Bosch III's. What is the p/n?

grabbem88

I had it but I cleaned my phone out.
pcmforless tuned this and so did Solomon

so I’m trying to figure it out myself but the consensus is that I need gears to clear this up..

ULTM8Z

The p/n should be molded onto the orange part of the connector body.

That 13 to 16 swing in the AFR you described in the original post doesn't sound like something that'll be cured by a gear change.

Have you played with the accelerator enrichment tables? These short runner manifolds are pretty sensitive to that. You cam change may need some more delta MAP AE.