Idle and low speed surge

[C5 Scully]

I have not got this right from 2011 due to working away and never joining the HPTuners forum. So here I am in need

My combo is a forged 402 from Golen Engines and the topend induction from LME.

2001 Corvette.
I have 11.1 CR.
TFS CNC 235 heads.
FAST 102.
Nick Wilson 102.
LS7 100 MAF.
Meiziere water pump.
KOOKS 1 7/8 x 3" x 3"dual with free flow mufflers.

Cam specs:

Install centre line: 110*

Duration @ 0.50 241/256

Gross Lift: 0.623

Lobe Separation: 114*

I use to run a CL113* D230/236 L0.591/0.601 LS 113* and did a mail order from PCM for less and just used the HPT Pro to load the tune and send back the log for them to calibrate.

It worked and good chop idle nothing to worry about and not knowing better at that point the Vetter ran strong in open loop only and CNC ported stock heads from Golen and no AFR readings happy till I burnt a valve at a topend run 1/2 mile event after wining it a couple of time and use Nitrous it was over...

So went big or go home I thought and at this point I am almost there with my limited knowladge of HPTuners program do have the technical know how and back ground and do all the work at home on the Vette and others as a hobby.

This is one for the pro's as I have been reading for days while work offshore as we speak on hear and the Corvette forum and see there's many guys with the same problem, best thing I could do is to join here thanks to a couple of HPT members that convinced me to do so via the CF.... while looking for answers thank you

I have attached the origenal file from PCM for less and it ran really lean and would not idle at all once at temp.... I also see that the file had the same idle settings and some other than the previous cam with some work done to the VE and Spark tables.

I have done some MAF error and not got to the VE as I don't have a steady state dyno and do my own best with locking the TCC solenoid and in gear on the RPM level 7 4L60. Then from idle to mid range as easy as I can and therefore know the MAF g/sec calc is off but much better than before if you look at the recorded Lamba vs commanded and error display on that I set up as good as I could with demos and calibration success dvds being all the way down in Cape Town South africa

My file to date and a log plus the CFG file.

My email is [email protected] if you need to contact me direct for info and or Q&A.

[C5 Scully]

Anyone welcome

[C5 Scully]

I have just purchased a Halltech 103 MAF C6 system that I will fit on my C5 as above mentioned and it should help with the tuning of the idle and low spead surge.... Still looking for help and need to compare MAF tables for the new induction combo... anyboy have this ? I will check Halltech site aswell but believe its the same as the LS7 form the seller on the CF.

[jimmyblue]

I'm not really following the narrative, which seems to have a long list of changes
but not much description of the problem(s) at hand. That's a big cam and will
want some massaging.

Vour MAF table looks way unlike what I'm used to, but I've never looked at a
LS7 unit's factory table. It's hitting max air way, way early. And yet your VE
table is unreasonably low air mass, which situation ought to really mess up
transitional throttle. Not only that, but there is almost no slope in the Y (MAP)
dimension, which is physically unrealistic. I have seen MAP slope be a factor in
surging but haven't gotten to where I think I understand it; just messed with,
trying to figure out.

And your main spark table seems pretty high for that kind of compression.
Especially if you're getting good cylinder filling, which would be the point
of all that big intake plumbing & cam.

To me it looks like there's no method here, just an increasingly wrong
collection of stuff tried. What I think is, you should go through the
tune repository looking for Corvettes and F-bodies with roughly similar
cam and decent heads, and try out the VE and spark tables from some
that claim decent quality; the LS7 MAF I don't know about but pulling
something from a factory tune and using it would be a good way to
start.

[C5 Scully]

Well first of all thank you for the indepth reply and feedback. I have used PCM for less mail order tunes in the past with no problem and think this current combo is more than their mail order tune even with logs sent to and from.

At this point it came to an all stop.

I basically purchased my HPT Pro to load the new files only. I have over the last two years work with the tuning tool a lot more studing some videos and doning work as a hobby on mild modded to bolt-on Vettes only.

I no real plan where to go from here and would realy like some input and guidance to the point of using PayPal to get this tune in-line and learn from that to not waste anymore time.

I will work trough the tune file repository in the mean time and see how I get on with compare files. Also will redo my MAF table and MAF Lambda error best I can base on the new LS7 calc and based on the input from here and Halltech...

Did you use my CFG. file set-up to run my log file?

Thank you for your time and reply!!!

[edcmat-l1]

Yeah, the tune is pretty much a mess.

And Jimmy, the LS7/100mm MAFs in a GEN3 come out with some pretty crazy looking numbers.

[C5 Scully]

Yeah, the tune is pretty much a mess.

And Jimmy, the LS7/100mm MAFs in a GEN3 come out with some pretty crazy looking numbers.

Thank you for the reply and confirmation... So would you like to take up the challenge and help me here?

I need help and not being an @ss.... Think I'll need more than the Advanced Calibrated Success DVD to sort this one!

[blownbluez06]

Scully, you have so many things going on with that tune. Your ECT vs spark corrections changing your spark advance almost full time. I'm assuming you don't have cats if I understand your stated setup correctly, however you still have your cat lightoff engaged, yanking tons of timing on startup if you're idling with that low of an airflow. No way your VE table is right, your spark table needs love and attention. There are a handful of opportunities to stop your surge here, but based on your experience, you need a primer. That primer would come in the form of a platform to start from with all the basic housekeeping work already done for you. I would highly recommend that you get with the consummate professional, Ed at HiTech tuning and let him set you up a base tune with a MAF only scheme, a VE only scheme, your configs for logging the proper items to help you achieve success. It will still be a learning experience, but an accelerated one and with more immediate gains than the DVD that you referenced. Your other alternative is to read through all the stickies, tune some, read them again, log and tune some more, rinse, lather, repeat. It's a process that will take a ton of patience and time both in and out of the driver seat.

[C5 Scully]

BBZ06 thank you for a good reply. I agree and need help. Did you see what I had to work from as a base tune from PCM FOR LESS, it is also attached.

I have PayPal and have no problem to use it as in the past but need to say I have not used it wise enough here!

I am currently still offshore at work and will be back at home from about the 23rd and real would hope to have a good "real" platform to work from also set some MAF vs Lambda error on my HPT scanner to help as suggested on the beginners DVD and it help me to at least start and drive the Vette right down to a 14.3 AFR and good lambda error vs commanded in open loop which indicated the tune is of in closed loop.

So yes anyone welcome to take the challenge get the tune in line in good time. I have not given up in about two years on and off in two year.

I am working with subsea robotic equipment as mentioned and do understand and relate to most of what we dealing with here but! I am no PRO tuner at all and that clear so no worries to work step by step and do remote logs and tune no problem...

[C5 Scully]

Yeah, the tune is pretty much a mess.

And Jimmy, the LS7/100mm MAFs in a GEN3 come out with some pretty crazy looking numbers.

Sent you an email request for help.

[edcmat-l1]

Sent you an email request for help.

Mmmm, don't think I got it. You can contact me through my site too. My filters don't eat those emails as much as others.

[C5 Scully]

Mmmm, don't think I got it. You can contact me through my site too. My filters don't eat those emails as much as others.

Done!

[C5 Scully]

Money sent

let me know if you can use the attached files.