SUX2BU

iTrader: (14)

Ok my car has a tune in it and it drives great. My only problems are that it sucks *** on start up. I have to give it gas and slowly back off of it everytime i start it or else it won't idle. Even when at full operating temp.
Also if i stab the throttle even a little bit or just let off in first or second (RMVB th350 so 1st and 2nd have engine braking, its like being in neutral when i let off in 1st and 2nd) it dies.
I have the idle set at 950 with the IAC counts at about 30-40 in N/P and about 70-80 in gear. It also surges a little in N/P.
Its an M6 computer with a th350 tranny so it doesn't have in gear idle/ P,N idle differences.
I have Hp tuners available but have no clue where to start.

DrkPhx

iTrader: (15)

A couple basic tips should help. First lean out the VE table from 0-1200 rpms, then increase the airflow in the Friction Airflow Correction table (under idle), add a couple degrees (3-4 depending on what it's set at now) of base timing in gear and P/N, increase the airflow for Fan 1 and 2 (when they are on). I would also raise the P/N desired idle in the colder temps then transition them down slowly by rpm as the temp increases. This should help out. It just takes patience.

98A4LS1

iTrader: (1)

Exactly which Friction Airflow table are you talking about? I have 5 or 6 tables related to startup friction airflow and none of them say "Correction."
Thanks

SUX2BU

iTrader: (14)

Primary or seconday?
Primary is
MAP---400--------800--------1200
15--22.00394-----33.99962---36.00285
20--23.00160-----36.00285---40.99907
25--24.99692-----37.99817---47.99853
30--27.00016-----40.00141---50.00176
35--27.99782-----41.99673---51.99708
40--29.00340-----43.00231---53.00266
45--30.00106-----44.99763---54.00032
50--30.99872-----44.99763---54.99798
55--30.99872-----46.00321---54.00032
60--36.00285-----46.00321---51.99708
65--37.00051-----47.00087---53.00266
70--37.00051-----48.99619---54.99798
75--37.99817-----50.00176---56.00356
80--39.00375-----50.00176---57.00122
85--40.00141-----51.99708---57.99888
90--33.99962-----50.99942---60.99978
95--34.99728-----51.99708---61.99744
100-36.00285-----54.00032---64.00068
105-36.00285-----54.00032---64.00068
Secondary is
MAP---400--------800--------1200
20---38.13278---42.04424---43.38237
30---43.04190---46.78708---49.24164
40---44.56214---48.30733---46.31201
50---44.30085---48.96452---45.52813
60---45.71024---44.37211---42.50348
70---49.90675---46.57330---46.48620
80---52.08418---50.75397---51.47450
90---49.11496---51.07069---53.92114
100--51.95750---53.86572---56.19359

BTW i have no clue what these numbers mean or how much to change them.

There is no "correction" just "decay", "initial" and "delay". I also have no clue what this is or how to change it.

its at 23 for 400 qnd 800. and 25 for 1200 in drive and in park. all values are all the way down the Cylinder air mass.

I have a TH350 so the comp doesn't know when its in P,N or in gear. And i have these problems no matter if it hot or cold.

WeeWolf

iTrader: (16)

mine would surge on start up and after a hot soak would hesistate and try to die. i cleaned my MAF and all cleared up. we were trying modding the tables with no avail. so if this just started try cleaning the MAF first.

DrkPhx

iTrader: (15)

1. Lean out the Primary VE table by 10%. Those values look pretty high. you may have to go leaner. This may your culprit. What are the LTFT's at idle once warmed up?

2. Friction Airflow> "Initial". This adds airflow on initial cold start based on temp. Generally you want more airflow the colder the temp. Add 2.0 gms to all temp cells and see if this helps. You may need to go higher depending on the cam. I had to jack mine up pretty high because the cam I run does not like cold start up. You also need to slow the delay rate down.

3. Timing should be fine.

4. Skip that step.

5. I would also increase the IAC motor "Parked". This controls how much the motor pintel opens or closes with engine off and car in park. Which allows more airflow on startup.

6. Be patient. I struggled with mine for a while.

SMOKINV8

iTrader: (6)

Stock cam? Stock throttlebody? MAF still in place?

Sounds kind of like a RAF issue to me, but if all the above is stock I don't see why any of it would be out of line.

red90cobra

iTrader: (36)

juan call me when you get off I can come over and adjust all the suggestions here

SUX2BU

iTrader: (14)

Trex
TPIS 90mm
FAST 90mm intake
85 mm MAF
pretty much open 1 7/8" KOOKs
no A/C
no P/S
TH350 w/M6 computer
8" 5300 non lock up stall (i thing this super light weight converter is why my car doesn't like to idle)

DrkPhx

iTrader: (15)

That can definitely alter how it idles. How much does it weigh?

jimmyblue

iTrader: (11)

First thing I would do, is compare the observed airflow
when it is idling, with the running airflow values for the
approximate engine temp. If your real value is more than
you see in the table then up it to at least 90% of what
the real need is.

Then since this is a dive problem, make sure the throttle
cracker table is not all weird in the low-RPM, low-MPH
corner. It's supposed to make for a soft landing and not
have spikes on the runway.

The small converter will destabilize the idle loop some.
Even 10" do. You can help it by not making the loop
work so hard to find idle (airflow) and by making the
engine recover better (upping idle spark advance,
leaning out the idle mixture, working on the stall
saver stuff).

TRex cam wants substantial VE table modifications.
I've posted that VE table before from one of my older
tuning exercises. All VE tables want to be kept
consistent. Likewise all spark tables want to agree
in the areas where they overlap or abut. Any step
discontinuities are just things to trip over every time
the engine slides across them.

DrkPhx

iTrader: (15)

Any results yet?

00transamnh

iTrader: (1)

i have the same EXACT problem with my car... please post up what you find out

DrkPhx

iTrader: (15)

With a small cam like the F13 with a M6, your car should be near stock driveability. Do you have tuning software?

00transamnh

iTrader: (1)

heres the thread i started a lil while ago about the situation... i dont have tuning software... it was tuned by a guy near by

https://ls1tech.com/forums/showthrea...87#post5115287

if it helps the car also shutters a little bit between ~1300-2000 rpms

Keenov

iTrader: (5)

So, is it fixed??

ninobrn99

iTrader: (8)

Juan, if you like, you can email me your tune and a log so i can look it over and see if i can help. A cold start idle logging raf would help, then if you have a WB, log your afr error. you may wanna have your olfa tables richened up, then adjust the ve accordingly. since ur still running the maf, u will be running off the Primary VE. I think i still got your #, ill give ya a call.

TA TECH

iTrader: (8)

Mine idle'd like crap till a few minute's ago!I have the fast 90 set up. Also my trottle plate felt like it would stick just a little if ya let of the gas super quick and then tryed to mash it! So I just run my throttle stop set screw out till it didn't stick and it must have cracked the blade alittle and it fires up everytime right on (so far)!Does the tpis come with a hole in the blade?

red90cobra

iTrader: (36)

nope he's still haveing some issues.

LS1 Sounds

iTrader: (11)

I've only tuned one H/TRex/TH400 car so far, but was able to get it to start/idle/drive surprisingly great at 900rpms without drilling the TB. Base running airflow (RAF) was increased a LOT, also Startup airflow was added as well. VE was decreased <= 1600rpm, and timing was added. Idle overspeed spark values were cut in half.