RPM WS6

iTrader: (3)

P0106 = Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance Problem. Hmmm. Anyone else getting this code or anything like it from VE table adjustments?

gillbot... about how long did it take (in miles) before this code popped up for you?

I agree that it would be nice to run some a-tap data and moniter a parameter to give us feedback as to where our VE changes lie. But, at this point I am just glad that I have found somewhat of a happy medium between my car warm starting decent and the "idle hunt" while coasting down the road that developed from to much taken off the VE table.

Prior to now, I was running big holes in the TB plate to get the car to warm start at all, but this lead to the cruise control effect over time getting worse as IACs settled more and more.

The more data we can get into this thread about people's experiances with VE changes the better an info base we can help to create.

Cal

iTrader: (1)

My car has never thrown a code due to VE changes, and I've tried some extreme values. I would think that MAP code is being caused by something else.

As Nic00Z28M6 pointed out, you will always get some raw gas smell at idle with any cam that has overlap, because both exhaust and intake are open at the same time, so some fuel/air mixture gets blown all the way through. This condition also confuses the O2s.

I'm still not positive your idle hunt was caused by too low of a VE change; that can happen anytime you reflash the engine parameters because that seems to cause the PCM to do an idle relearn. You need to give it time to do that before you make a judgement on what caused it.

Monitoring the gas smell at idle, stumbling with low speed acceleration, and idle pulse width are the only ways I know to tune idle VE.

Bink

^ ^ ^ Yes to what he said. Most of you young guys are used to cars with cats.
joel(Bink) I like the smell of Raw Exhaust- it's like Grandma's cooking = great memories!!!

Bink

If you monitor INJ. PW you'll see it decrease (msec decrease) as you reduce the VE table in a given RPM range.
I believe the MAP code is for PCM predicted value, based on throttle position and Baro, being out of line with actual MAP value.Have you changed your TPS?
joel(Bink)

Cal

iTrader: (1)

Joel, I know what you mean: raw fuel exhaust, and cam lope bring back some fond memories for me! I was 21 and had a '67 Firebird with way too much cam (320 degree advertised.)

gillbot

iTrader: (27)

About 100 miles or so, never kept track. I made the VE tweaks and all was well until recently and the Cruise effect keeps getting worse, and the warm starts are being picky again.


I have done nothing to the TPS. It threw the code while idling in traffic. The car started to shudder (Like the converter lockup was engaged and wouldn't let go) then the ASR/TCO off light came on. I had to throttle slightly to keep the car running. I got out of traffic and into a parking lot and checked under the hood for anything loose/missing/etc and found nothing. At this point I thought it was the infamous ASR/TCS issue as something similar happened before. When I got home and pulled the code I was suprised to see it wasn't the usual misfire code but the MAP code.

The only changes up until this point have been the VE tweak, and I used the "blind" 60% for all values 400-1200.

XFiveLiter

I set mine to 75% last week, it is MUCH improved. I was having some bad surging issues on cold starts. At the same time I increased cold idle slightly, so I don't know what helped more.

PS: After changing the VE tables I was able to lower the hot idle from 850 to 750.

RPM WS6

iTrader: (3)

Cal, I can see your point. I only drove it maybe 5 miles between changes. But, I did complete the proper idle relearn procedure for my year car. Is that not enough? I'd really like to try 70 or 75% again as it really warm started so much better in that range.

How long (in miles) would you say I should give it till making a conclusion on the idle stability? Just some ballpasrk number so I have an idea. Thanks

Bink

Way back in 1971 -
'67 Nova SS.
Car wasn't mine -Best freind was 17 and had the cash. I was 16 and had some of the knowledge. What I didn't know I could find out...family etc.
Bought the car -stock 327/300. Blew it!
331ci, TRW pistons and rods-11.5:1-notched,Isky solid cam 320/320, 0.575",106 or 108? ( advertised of course- 1971). Balanced. Ported fuelie heads(2.02/1.60). Headers. Flex-lite fan. Torker manifold(Wrong choice! Should have bought a Tarantula) with 850 cfm Holley double pumper.
3 trannies (saginaws) and 2 (10 bolts) rearends later-3000# ZOOM clutch/ M22 Muncie with 2.52 1st and set 5.13s ZOOM 12 bolt. I forget the weight of the car but it was LIGHT.
Stoplight to stoplight...too much fun! And the sound at 7000 RPM -
joel

Man I loved that car. After I put the new cam in my car I looked at my buddy and said " it reminds me of the Nova". He said he was thinking the same thing.

RPM WS6

iTrader: (3)

I decided that I was still unhappy enough with the warm starts to once again change the VE table. This time I went 75-75-80% for 400-800-1200rpm. That is a 5% drop in the 400 & 800 colums from the last setup. At first it started the low rpm rolling surging again, but I did the idle relearn and drove it about 25 miles in mixed style driving and now the surging is better, still there a bit but getting better with more miles. I'm gonna head back out and put some more miles on it after this post.

Here is what I have observed, Cal and others correct me if I'm misguided here. It seems to me that the changes I've made to the VE table in the past couple of days have had waaaaaaay more of an effect on idle and startup quality than any IAC changes ever have. Is it safe to say that perhaps the VE table really is more important in the adjustment of one's idle than worring about IAC numbers? I know that in the past it has been widely assumed that IAC numbers were everything, but perhaps this VE adjustment is proving that false?

Currently I have an IAC value of high 60s to low 70s, yet the idle has never been better.

Also, is it safe to say that making changes to the VE table may also change the "ideal" IAC range? I say this because now that the PCM is being told to expect a less efficent air/fuel charge in the low rpm ranges, perhaps the IAC number should be higher than the previously-thougt-to-be-ideal 30-50 range? I may be way off here with this theroy but I thought I'd toss it out there. What are all your thoughts on this?

Bink

IAC = AIR
VE = Fuel
We need both. It does seem like VE is CRITICAL in fine tuning Idle Quality.
I don't think the numerical IAC value is that important. Your idle quality/stability is tho.Keep us posted.
joel(Bink)

Cal

iTrader: (1)

Yep, exactly the same thing I've observed. No matter what you try and set your IACs to, the PCM will just change them to whatever it thinks it needs. So as long as the hole in the TB plate is the right size, the PCM will take care of the rest. I used to play around with the IAC values, but I didn't get solid results, so I did a bunch of data logging with EFILive and discovered the table values are only a starting value and PCM changes them to what it wants anyway. Once I got done with the VE tuning, I tried putting the IAC tables back to stock values, and it didn't make one bit of difference, so I just run the stock tables now.

IMO, the only missing element now to getting a perfect startup idle is being able to tune the timing temperature table. If you log with EFILive, you will see that the PCM only allows about 15 to 20 degees of timing on startup. When the engine hits about 100*F, suddenly the timing jumps up 10 degrees and the idle instantly improves! But we need that next version of LS1edit to gain access to this table . . . come on, Ken Kelly!

Cal

iTrader: (1)

Wow that's a familiar sounding laundary list! Everybody must have been running the same parts back then; but I guess it's the same way now. Even the list of parts killed in action is the same! My 4 speed was just a M21 though; but I always wanted a rock-crusher! The first four gears of my T56 have almost the same ratios as a M21. Those Muncies were sure stiff when cold; no oil pump so they counldn't run ATF.

gillbot

iTrader: (27)

Well, after more miles on the 60% VE tune for 400-1200, the car has reverted back to it's stalling and surging with hot starts and seems to be getting worse.

Any Ideas now?

Bink

What mods do you have? Specs on the cam? Wha t have you changed with Edit?
joel(Bink)

gillbot

iTrader: (27)

Probably would have been wise to include that first off!

TR230/224 cam (230/224 @ .575/.563 111 LSA)
Mac Mid Headers with ORY (No Cats)

VE was set at stock, then I tried the 60% from 400-1200
Tune based on O2 readings by a local guy to get me in the ballpark, still needs a Dynotune.
Idle set at 850 in park, 900 in gear AC Off.
6700 rev limit, shifts at 6300

Anything else needed? I didn't put in the intital tune so I'm not 100% sure what was changed. Before it has horrid warm start issues and surging until I did the VE tweak, which worked at first but seems to be fading as time goes on. Surging and hard warm starts are returning, as is my problems with coming to a quick stop. It feels like the torque converter doesn't want to let go. At first I thought it was the converter till I did the VE tweak, then everything was GREAT, now as I said, it seems to be returning.

ADDED> I love this cam but the idle issues about have me fed up to the point of yanking it out and going back to stock.

MyLS1Hauls

iTrader: (2)

Just got the new 1.29 version and it indeed has the temp vs. spark. I'll try that out and see how it works. There are quite a few updates in ver. 1.29. Theres also a Secondary VE table that has been added.

RPM WS6

iTrader: (3)

I am still having issues after a lot of VE table tuning. My issues are centered around coming to a stop though. The car goes into "surge mode" when it downshifts during normal stopping. As soon as I come to a complete stop, it idles perfect. The catch is, sometimes it stops perfect I have it to a point where both cold and warm starts seem to be good at the moment (knock on wood).

My Ltrims are elevated and split at idle, (about +13.3 and +7.8) not sure why they are split but they pretty much even out as I drive. Strims are good (and even).

Do you think Ltrims are my issue? I have messed with all kinds of IAC changes and many different VE table chnages in the 400-1200 range and I'm getting frustrated again. I was gonna try raising the idle some, but I don't think that will help any (idle is at 800rpm in P & D).

Should I try adjusting my IFR table to bring down the Ltrims a little? Would that have an effect on my intermittent surge while stopping issue?

purevilss

RPM WS6, have your LTrims always been pos at idle. Mine are neg and the more I try to get my cruise LTFT's neg the LTFT's at idle get more neg. I have the 227/227 and have the same idle surge issues. I can get it to idle good for like a week, then it just goes bad. Seems to be about ever time I try any change.

Ed Blown Vert

iTrader: (2)

Wow I must be lucky because all I did was turn my idle screw a bit and it idles like a champ.

224/224 114