Hondata

so, i made some changes to the car and now (big surprise) it's not running right.

this is on a built 9:1 b18c1, the ignition timing is right on, i am starting with base maps.

the changes were:

new turbo gt3000 - not a factor (still tuning idel)
s300 upgrade from s200
id750 upgrade from dsm 450's
rewired fuel pump with dedicated 10awg line and relay.

i can get the car to run and idel around 800rpm with a a/f around 15, but to do this i have to set the injector size to 300cc. if i set it at 750 like the injectors are the car goes way lean and dies.

also, when i have it running at 300cc, if i give it any throttle the engine stumbels, like it cant keep up with the extra air. if i lightly give it throttle however, it will raise the rpm smothly.

any ideas? i am fairly sure that the dead time is set correctly. i used tonys sheet, and input the values for 43.5 psi.

well i got it running better now. idel is at 850rpm, vac is at -20, a/f is right at 15:1, EGT is at 600, and oil is at 20psi. also the throttle response is back to normal.

what i did was increase the low cam fuel table values and corrispondingly raised my injector size value back to 750.

i can get it to run good in closed loop, or open loop, but not both. if i am in closed loop and then i select open loop, the car goes way rich. any ideas?

oops, sorry.

i dont have a datalog of the problem, but like i said it runs good in closed loop (just idel, havent driven her yet), but if i switch to open loop for tuning, it goes way rich 10:1.

this is on a '98 gsr with a built 9:1 b18c1 gt3076. walbro 255 lp pump, bosch 750cc saturated injectors.

the ecu is a po6 set up to run vtec and boost.

is my map just too rich (at idel) and the stock o2 is taking the extra fuel out in closed loop?

It is impossible to really say without a datalog showing the problem.

ok. thanks for the look. i will run the car again this weekend and record a data log, then post it. thanks again for your time.

got that datlog. at 20 seconds i switched to closed loop, at 40 seconds i switched back.

any ideas?

Datalog does not show any movement of the TPS

dsm 450's are low impedance arent they?

If so,did u remove the resistor block when u went to the high impedance 750's?

Whats your O2 setup(narrow & wide)?
In that datalog the O2 is still not active when u switched to closed loop,it starts coming in just befor eu switched back to open loop.
Put up a longer datalog of a switch to closed loop with motor fully warmed & leave it for longer....

Also when u put 43.5psi fuel pressure in,do u know that is the case(like do u have a gauge or adjustable FPR or similar) or was that number a guess?

B18's usually run up around the 50-55psi mark with stock regs,43psi is like B16 territory.

Spunkster, that is correct. this was done at idle with no throttle input.

Fly_n, yes, i removed the resistor box. my o2 set up is a stock for narrow input, and a AEM unit for wideband input. i will put up a longer datalog this weekend. no, i do not know for sure the fuel press, i just put 43.5 as a guess. i may try the 50 to 55 psi and see how that works.

thanks for the look, working long hours (navy) so tuning is on the weekends only, but i do appreciate the help.

did some more driving/tuning. this datalog is about 2min long. just easy acceleration. whats weird is at 1:30 and 1:45 i lightly let off the gas and the car just hits a wall. it's like a on off switch, i messed with the tip in fuel, but it seams to have more to do with the closing of the throttle.

on this one i hit about 8 psi and ran it to about 7k, but the map log looks weird.

i'm going to take the car to a tuner so i dont waste anymore of your time, but i just thought you might be intrested in this and meaby be able to shed some light.

thanks!

fixed the lightswitch throttle at low vac. minumum tps was @4%.

also, i had the injectors set at 750cc, they are actually 725's.