GSRCRXsi

well i just built me an all motor engine. some of you may know some may not.

first the specs of the motor:

b18c1 block-
block decked/head shaved total approx .020" (estimate based on my own measurements)
itr pistons and rods 81.25mm
about 11.7ish compression
gsr head ported by portflow
skunk2 stage2 cams w/ gears
cometic .040 gasket
smsp b18 header
ib spec velocity stack

tuning:
laptop
crome pro
plx m300

pic for veiws



now for the problem. after the car warms up, it doesnt want to idle comming off the throttle. it will idle fine if its just sitting there idling, but if you rev it, when you let off the throttle it dies. the problem gets progressively worse as it gets warmer. it will idle REAL low, and often times die all together.

afr's seem ok, although a bit rich at idle, 12.5ish.

anyone?

96Spec Ek

12.5 at idle is to low u want it at 14.7

double11

Check the timing with a timing light. Make sure that 16 degrees in the program equals 16 degrees with the timing light.

Check for bad IAC valve or loose IAC plug.

How low are you trying to get it to idle. Will it idle at 1500?

Lightened flywheel?

it should still idle at 12.5.

mar778c

iTrader: (1)

What was your basemap?

I would try a GSR or Type R basemap for initial set-up then tune.

GSRCRXsi

basemap is p30 code, all the support in crome is for p30 code things like rev tools and such dont work on p72 code. timing is fine, ive checked. running stock p30 timing maps.

i know 12.5 is too rich, but its not rich enough to make it die. it idles fine if its just sitting there. ONLY when you come off the throttle will it die.

yes i have a lightened flywheel. again so do plenty of other people and they dont have this problem.

im not tryiung to get it to idle at any particular point, just dont want it dying everytime i have to stop for a stop sign or light.

bump

GSRCRXsi

also looking at my advanced idle in crome, my options are as follows:

cold idle cut ---------1628
cold idle resume---- 810
warm idle cut -------2930
warm idle resume --800
moving idle cut -----7324
moving idle resume 800

should i change any of these? maybe raise the moving idle? please i need responses from experienced tuners here, tbone, vtekkid, need some help.

wish i could post my basemap

GSRCRXsi

bump

GSRCRXsi

tuners. i know theres some that frequent here, please give me your insight

blundar

Pay someone else to do it. You can't run a serious all motor cam at 12.5:1 at idle and expect it to do anything other than hunt. Lean, lean lean. If you're intent on doing it yourself, step away from the car and do a whole hell of a lot more reading before you come back to it. I'll tell you this - target AFR is a pretty basic thing.

Aside from bringing the target idle up to 825, no other idle related changes were made in either the PR3-lsvtec or 12.5:1 ITR I tuned with S2S2s. It was all fuel and ignition adjustments paired with mechanical adjustments on the car.

GSRCRXsi

the majority of tuning WILL be done by someone else. but i have to get the car drivable to get there( tuner is some 2 hours away). stalling at every stop is hardly drivable.

im very familiar with crome, been playing around with it for months now while building my engine. i know how to set AFR's. ive done my homework, but everyone ive seen with this problem, no one has an answer. they all say "get it tuned" well duh, but like i said it has to be able to get there, and i dont have a truck/trailer. im not made of money.

you are convinced its too rich at idle and thats why it dies comming off thottle? help me make sense of this. to me it doesnt seem to be causing it since it will idle fine once alrady idling, ONLY WHEN COMMING BACK TO IDLE FROM GIVING IT THROTTLE does it die. it idles fine by itself. in my mind if it was too rich then it would be dying all the time. just say the word and i'll be ok with it.

blundar

lean out your idle. a lot. Like 15.0
richen up your stall cells (top row)
bump timing in your stall cells
bump timing at idle a degree or two.
open your idle screw 1/2-3/4 turn. make sure you unplug ECU or battery ground too.

GSRCRXsi

thank you, ill try all that out. only thing im confused about, why unplug the ecu or battery? to reset it i assume?

GSRCRXsi

ok so i tried it out, but didnt lean enough. i went from about 12.5ish to 13.5ish. and i made the stall area too rich i guess. but i had to stop for the night, the car is over heating somehow. my autometer guage was reading 250, but the crome was only reading 220, the stock guage was still in the normal range. so i dont know which one to trust

while driving the temps werent bad, but stopped it just skyrockets. i dont know if its the thermo stat, or fan (i didnt notice it on while idleing at those temps) or how i have my heater hoses routed (no heater core, just a line straight from the port on the head to the thermostat). im gonna replace the thermostat and make sure the fan works.

98vtec

i've read around that the bigger cams like a little more timing at idle to keep it from stalling. 13.5 is still too rich. What is your base timing at?

from 500 RPMS at 26.48" of cacuum to 797 RPMS at 14.55" of vacuum should all be the same number.

thats another thought, when it does idle, what does it idle at? You may need to raise your idle.

I dunno, just some thoughts that might help brainstorm.

blundar

the 500 row I call the "stall" row. If you're having issues with stalling, bump timing in that row ONLY, but leave top-right corner alone. Otherwise, keep timing flat for about a 5x3 area.

GSRCRXsi

wen it does idle, it idles at about 800. just when i blip the throttle or comming to a stop while driving, the car will drop real low in RPMs and sometimes die. but this only happens when the car gets hot. not when its still cold.

pic of my timing:



thats after making the changes it was 16.50 from 500-1000, 26.48"-11.16"

GSRCRXsi

ok so i tried this map out and it seems to work. the car didnt once stall on me but i only drove it around for about 10 mins (it was fully at operating temp). it seemed like it wanted to die a couple times but never dropped below 500, would dip down to 500 then pop back up and level off at 750-800. i think part of my problem may be the IACV valve too while warming up the idle was surging like no other from about 1000-1400. i unplugged the IACV (while it was running) and it stopped and went right to about 750ish. ten i plugged it back in and it had stopped doing it. maybe the timing changes can cause it to surge like that?

but i thank everyone for their help, it looks like this timing was the issue as it doesnt seem to be dying anymore, but only time will tell, ill have to get more and longer drives in the car to be sure. i have to fix this problem of overheating too. i bought a new fan switch and a new thermostat, and im gonna route the coolant hoses sligtly different and see if i cant get it running nice.

ill keep everyone posted. would like some feedback on the timing map though

GSRCRXsi

ok i think i might be over reacting a little on it over heating.

im pretty sure the autometer guage reads so high because of the placement. i have the sender right in the water neck on the head. and the coolant flows from top to bottom in te radiator correct? if so then it would be reading the temp before the radiator and when it was at its hottest, but crome was still reading 220. thats too hot isnt it? that was at idle. what temp is the fan supposed to come on?