I am getting hard to find idle on starts and cam surge also.

I get my HP tuners today, so I hope someone will be able to help me out......

Mods in sig.

228/228 588.588 112 +2 cam and 5.3 heads unmilled

 

My trex surges qquuiiitteee a bit at 40 mph @ 1200 rpm, I also want to figure this out.

 

Most of the time surge is caused by rich conditions

 

you may find large cam reversion at low rpm's fooling the o2 sensors. Have you thought of disabling the closed loop system at that rpm range and dialing in a nice a/f to see what happens?

honestly hptuners needs vcm control to add/subtract fuel and timing while driving, would take alot of guesswork out. however the closed loop system will probably counter alot of the fuel overrides

 

Now theres an idea that would save alot of people ALOT of time. But can it be done? The PCM probably locks the file (file becomes read only) so it cannot be edited at runtime, because two sources cannot change the value at the same time. They might be able to force release focus to the tables to gain access to it but your looking at unsafe and unstable programming. Maybe someone can suggest it to the hptuners programmers and see what they think or maybe one of the programmers can chime in here.

 

I think large cams fool the Maf more than they fool the o2 sensors. The o2s see 14.7 as 14.7 and that is it... the maf on the otehr hand reads air twice because of reversion

 

I am still a little baffled by my cam surge. I still get some bucking while creeping at low RPMs if I get stuck in bumper-to-bumper traffic. And I still have mild surging below 2000 rpms. I have pulled timing, changed idle air, lots of stuff. I am wondering if it is just something I will have to live with on a 112 LSA cam...

 

My 110 doesnt seem to surge now that i have gotten rid of the maf. Usually with a cam people add timing in the idle cells all the way to 1600 to help wiht teh surging. Timing is also added to the spark in drive table.

 

Yeah, that doesn't make a lot of sense to me though. My understanding is that too much timing will just contribute to surging. I think I have an airflow issue. I think it may be partially caused by tuning my airflow with the lid. Since the MAF is not reading the correct airflow, it can't accurately determine how much air to add now can it? So now that I am not using it I need to tune my tables for the cam. Of course once again, as soon as you plug your MAF in you are screwed because it will try to calculate all your idle air, and air in gear, etc off of incorrect airflow reading from the MAF. Lids are the root of all evil. Waaah....I want an SS Blackwing lid. I think that will solve the problem instead of trying to figure out a new freakin table.

 

I'll post my solution to surging problems I was experiencing with my setup. I have a '00 model Holden Commodore A4 LS1

mods (i.e. cam only or H&C): Grand Am Cam, headwork, forged 346 short, A4 SY3500 stall, 3.46 gears
cam duration and LSA: 239/251 @ 0.050, 0.570 lift, 106 lsa
tweaks to timing between 1200 - 2000 rpm: more timing
tweaks to VE table: A lot lower VE values
changes to Idle Air in gear: Increased until idle was stable @ 1050 A/C off, 1075 A/C on in Park and in gear
Anything else you did specifically to solve non-idle cam surge.

I agree with Humpin SS. Most of the time surge is caused by too rich condition. The other time is caused by insufficient timing imo.

I tuned my car in S/D mode, using an '03 PCM to overcome the 2 VE tables in the '00 and earlier PCM's.

Currently the car is running in open loop mode. I have unscrewed one of the O2 sensors from the header and install the Innovate LM-1 Wide Band O2 sensor in it's place. I also use EFI Live V6 to do the data logging. I'm able to hold RPM and MAP using EFI Live, and monitor AFR on the wide band.

I have an idle speed of 1050, and an AFR or 14.6 - 14.9 at idle (fluctuates a little). I had to remove a heap of numbers from the VE table below 2800 at get a target AFR of 14.7 @ cruise. E.g. MAP 80/1200 RPM stock value was 1770, new value is 890.

I'm also running 40 deg spark at 2000 rpm in the lower gms/cyl points e.g. from 0.2 to 0.32. Less than 30 degrees of spark would cause bucking at 2000rpm.

I was not able to accurately log AFR at idle with an O2 sensor placed at the tip of the exhaust. The only was to accurately gauge AFR was with the sensor in the header. This IMO is the key to tuning for fueling with big duration camshafts to eliminate surging.

There's no magical program to help issues with cammed setups. It just requires a lot of time and good logging tools to make the car nice and driveable.

 

NoGo did a write up about getting big cams to idle one of the recommedations was to add timing to the idle cells.

Here is the thread
http://www.ls1tuning.com/iboard/index.php?showtopic=9

 

I added timing to the idle cells. I didn't want to go too crazy with the spark table. 98s are already more aggressive in the areas most people have surging. I did the idle in gear and in neutral. Should I be raising the timing under 2000 rpms on the main tables too? Where in the kpa range?

 

the timing tables are referenced by g/cyl instead of map

 

i get surging when i'm goning down the road, and when i push in the clutch to stop, the car drops below idle and stays there

 

Ok, so should I be adding timing to the main tables too?

 

The suggestions added timing to the high octan and the base spark in drive table 3 to the highoctane and to the base drive table

 

Ragtop how you coming on yours?
I have a very simular setup with mine being on a 112+2
I would like to maybe compare notes.

 

Ok....HPTuners has added most of this. Anybody got some new stuff to add to this thread?

 

was there ever a solution found for this issue? i have a f10 on a 114 and want to try to eliminate my surging issues also.

 

Most of my surging has gone but I am getting some bucking from 1350 to 1900 RPM when at 0% TP. Should I increase the spark below 2K? Has anyone else fixed a bucking problem? I have a WB and have my VE table close. I was thinking of going to Open Loop SD all the time. I already removed my MAF. It sure is running better except for the bucking...

Bill