2010 Corvette famous spinmonster 230/234 cam surging

[zchrisz1986]

i've played with stoich to command the lower value and that worked. open loop runs pretty good and my wideband shows 13.5 -13.8 once in closed loop it shows lean and the maf is showing -15 % fuel. for the sake of time i called some local tuner places and they wont touch my car because they didn't do the work...

[Alvin]

Adjusting Stoich isn't really the right way to go about this.

There are a lot of remote tuners on this site that can help you with this if you can't find a local tuner.

[zchrisz1986]

thanks Alivn,

i agree. i find myself more worried about time. but i'm a diy'er so i battle myself daily

this cam isn't that big. i'm confused why i find it harder to tune than a gen 3. don't get me wrong i'm not a professional by any means but i know enough to be dangerous

[zchrisz1986]

Guys, bringing this back from the dead. the weather is getting nice again. it sucks driving my car at cruise WOT it's a beast. it surges/misses at light throttle cruise. i had plenty of tuners look at the logs and say they see nothing causing a surge. the car ran great before i did the cam install. my next step is to put the stock cam back in and call it a day.

2010 corvette LS3
TSP 230/234 .615/.600 114+2 cam (i went with this as recommended due to the stock driving manors which are non existing.)
katech c5-rt timing chain
TSP .660 dual valve springs
TSP 7.4 pushrods
ATI LS7 balancer
Kooks coated 1 3/4" long tube headers and catted x-pipe
Hurricane cold air intake.
everything else is stock.

as i said car runs great WOT. cruising light throttle it feels like light surging, not bucking.

Attachment 146717current.hpt

[Alvin]

Where. what timestamp is the car surging?

I'm surprised this feels good at WOT. It has very little timing in it.

Is the surging better if you forced open loop? Is it better if you force speed density?

The injection timing has been changed IMHO a bit too much. Go back to completely stock on the injection timing..that will at least work and see if it gets better.

[zchrisz1986]

Alvin,

today i played with the minimum air flow i lowered it and it made it worse. although when i raised it it was surging still and would self drive. i don't think it's that. it's in open loop off idle that we did with another tuner. it will surge even worse in CL targeting 14.7, MAF only or VE only it's still there.

i'll go back to stock injection timing and try it.

thanks

[Alvin]

Alvin,

today i played with the minimum air flow i lowered it and it made it worse.
thanks

Just to be clear.. i wasn't referring to anything min airflow related.. I would be sure that forcing it in speed density or open loop improves or doesn't change the situation. Maybe retest. It's easy enough

Also. Timestamp the surge.

[zchrisz1986]

Just to be clear.. i wasn't referring to anything min airflow related.. I would be sure that forcing it in speed density or open loop improves or doesn't change the situation. Maybe retest. It's easy enough

Also. Timestamp the surge.

hi Alvin, i was just explaining what i've tried.

i went back to stock injection from original file.

car seems different but surge is still there.

see attached log. this is the SD only with stock injection timing time chart 15:06:09 and continues to the end. this is steady throttle and surging will get worse at light throttle down hills.


also, just took it back out in SD only with maf failed. throttle is more responsive but the surging is still there.
sd only stock injection timing.hpl

[edcmat-l1]

It's dead ass lean. O2s are in the dirt.

@ 24 seconds it looks like a possible miss on bank 1.

The VE table does not look right. The shape in general can't be correct.

I'd dial in the VE with the trims as close as you can get it at full operating temp.

Check the plugs and wires.

[zchrisz1986]

working with a tuner on here. the VE table want's that shape for some reason.

i replaced every coil, plug and wire on the car as well.

i've been asking why the o2's don't oscillate. in closed loop the car will barely make it down the street targeting 14.7

[edcmat-l1]

The O2s aren't oscillating because the trims aren't working.

The VE doesn't "want" that shape that's why it's lean as Thanksgiving turkey at that cell.

The trims worked for the first 10 seconds or so.

You have your closed loop enable temp set to 255 so that's a problem.

[zchrisz1986]

thanks ED, again. working with a tuner he made it OL off idle and richened it up as that made it more manageable. where are you seeing it as dead ass lean? my WB doesn't show lean.


i just threw together the stock file with that vve table and ran it MAF only. it changed the surge i'm feeling in the 1800-2000rpm zone. i still feel some oscillation.

[edcmat-l1]

thanks ED, again. working with a tuner he made it OL off idle and richened it up as that made it more manageable. where are you seeing it as dead ass lean? my WB doesn't show lean.


i just threw together the stock file with that vve table and ran it MAF only. it changed the surge i'm feeling in the 1800-2000rpm zone. i still feel some oscillation.

You might wanna consider working with a different tuner because that guy don't know WTF he's doing.

Your data log you posted and even pointed out the time stamp, at the time stamp you pointed out the narrowbands are less than 100 mv. That's dead ass lean. I don't care what your wideband says, and neither does your PCM.

Fire your tuner. Move on to someone who knows what they're doing.

VERY lean.jpg

[Guy With A Chevy]

If the vehicle has injector issues such as partially stuck or clogged it can produce the bucking and surging feel. I struggled with this for a while one easy way to tell is how well it idles.

[sgod1100]

The O2s aren't oscillating because the trims aren't working.

The VE doesn't "want" that shape that's why it's lean as Thanksgiving turkey at that cell.

The trims worked for the first 10 seconds or so.

You have your closed loop enable temp set to 255 so that's a problem.

I think it's the table right below that 255 value, "ECT vs. Startup ECT" that enables CL. His is set to 102 deg so he "should" be entering CL while at operating temp..I think.

[edcmat-l1]

I think it's the table right below that 255 value, "ECT vs. Startup ECT" that enables CL. His is set to 102 deg so he "should" be entering CL while at operating temp..I think.

I think you're right, partly. I think the 255 value is more like your master switch and the "ECT vs. Startup ECT" is exactly as it reads. At 25* F startup coolant temp you'll need to reach 149. But it'll happen way before that based on "O2 readiness ECT" and delay. Normally you can't get them to stay in open loop without raising the O2 readiness ECT. But this one is weird. It starts out in CL then goes OL and it stayed there with the exception of a flicker of trims a little later. Would like to see a much longer data log. It is ridiculous lean though as long as it's in open loop.

[sgod1100]

I think you're right, partly. I think the 255 value is more like your master switch and the "ECT vs. Startup ECT" is exactly as it reads. At 25* F startup coolant temp you'll need to reach 149. But it'll happen way before that based on "O2 readiness ECT" and delay. Normally you can't get them to stay in open loop without raising the O2 readiness ECT. But this one is weird. It starts out in CL then goes OL and it stayed there with the exception of a flicker of trims a little later. Would like to see a much longer data log. It is ridiculous lean though as long as it's in open loop.

Ok, that's good to know. I just checked mine and that 255 value is 36 deg for mine. Yeah OP, change that 255 deg back down and take another drive

Yeah, I actually have my o2 readiness match when I go into closed loop because I found that the o2 sensors were still active even though my car was in OL (cold engine) and was trying to pull fuel out back to stoic. So once I matched when my car goes into CL it no longer does that and I'm pretty close to commanded fueling even in OL while the engine is cold

[GHuggins]

That setting is actually used to switch to advanced algo's or in laymens terms, a more rapid oscillation that will also add and remove more fuel for the oscillations. Basically a switch for colder O2 operations. Doesn't have anything at all to do with closed or open loop. Just another table mislabeled by hpt The description however, is mostly accurate.

[zchrisz1986]

just an update. i did work with another tuner. the car really moves now as far as power goes. the miss that i'm feeling is still there. i'm going to order a set of stock flow matched injectors for it and report back.

thanks

[zchrisz1986]

just an update. new stock ls3 flow matched fuel injectors, no change in car.