lex/550 VF tuning help

[lagged]

alright first things first, the set up is:

lexus AFM with adjustment screw
550cc injectors
aeromotive AFPR
walbro fuel pump @ 12v constant

heres the problem; i just got the car running again and have about 700 miles on it since then. ive noticed that while cruising my EGTs get kind of high for my tastes. at ~70MPH and ~3k rpms im seeing EGTs close to 1400F (the probe is pre turbo at the collector. at WOT the EGTs stay a little below 1400 and dont seem to go any higher (cant really keep a close watch on the EGT gauge at 100+ MPH). if i were to increase my speed while cruising, the EGTs continue to climb past 1400, i dont know how far past they will go because at that point i get a little nervous about melting the motor down.

also, i had my base fuel pressure set to ~ 37psi. once fully warmed up the car would miss pretty constantly. i lowered the base fuel pressure to ~32-33 psi and the idle improved. my EGTs didnt change with that change.

so i hooked up the volt meter to see the fuel trim (VF signal) and it is pegged at 5v.

i reset the computer and the vf signal changed to 2.5v (no adjustment) then after a few moments it jumps right back up to 5v. base fuel pressure adjustments seem to have no effect on this. and tried upping the fuel pressure to 40psi and there is no change in the VF signal, the car just idles terribly (which is expected..)

am i wrong in thinking i should be able to get the VF signal at idle close to 2.5?

as far as i can tell (without a second set of eyes) im not loosing fuel pressure at higher RPMs or under boost.

i also havent pulled the plugs yet to get a reading from those.

could i have an obstructed or kinked fuel line possibly? would i still have proper fuel pressure if a hardline was kinked?

 

[theDon]

I didn't see what wideband sensor and fuel management system you are running here?

 

[lagged]

I didn't see what wideband sensor and fuel management system you are running here?

none as of yet. im only on the stock turbo @ 10 pounds of boost. id like to get the car running right before i do any more mods such as adding a fuel computer.

im also not trying to really TUNE the car, just want to get the idle sorted out. from what ive read, i should be able to get the car to a point where the computer is making MINIMAL adjustments to the fuel mix.

 

[isnms]

I'm watching this. I have these mods waiting to go on and want to know what issues can pop up.
I found this is the sogi archives:
http://www.supras.com/pipermail/supras_supras.com/2004-January/thread.html#1285

I have been reading and re-reading the write ups by reg and john and
others but I am still confused. (yes Geoff I searched the archives). I
have my baseline fp set to 32psi, this is at idle, the voltage reads 3.5
to 5 (at the diagnostic port) most of the time. I was able to see 2.25
at one point but then I revved it a little and then it sat at 5 volts
again. Do I need to NOT rev it, just let it idle? The cars seems to
idle ok (I need to put in the new plugs and wires, maybe those are part
of the problem?) The #6 plug looked surprisingly good for how rich I
have been running since putting in the 550's. Since putting those
(550's) in the car has always been super rich, as evidenced by my a/f
meter pegging off the gauge and the black smoke coming out the back. To
compensate a bit, I screwed the reg reimer screw WAY out, and now I have
screwed it all the way in and back out 1 turn as Reg suggests in his
write-up. I still can at best get 3.5 volts. As I understand it this
means the TCCS is adding fuel to the basic calculation. If I lower my
fuel press to say 30psi (Others recommend even lower say 28psi) the car
begins to run poorly at idle. Again this may be attributed to plugs and
wires. Am I on the right track? Does the computer take longer to
compensate? Have I huffed too much gasoline?
mods:
hardpipes, alamo intercooler, aeromotive fp regulator, walbro, rc 550's,
upgraded ct 26 (57 trim), hks 3000 pipe, greddy bov, k&n fipk, lexus afm
with reimer custom screw
boost, egt, a/f gauges, and yes fuel pressure!
Ok thanks all,
Tony 92t

Set your fuel pressure to 43psi @ idle with vac line to AFPR disconnected.
If your ECU is trying to add fuel, it's trying to compensate for the actual
FP being too low, or the O2 registering too lean. You should be raising FP,
not lowering it.
-Rich

 

[Clifton]

It will eventually smooth out on closed loop. Mine always started out lean and richend up after a day or 2. You can measure narrow band voltage, .45v is stoich. I wouldn't bother with the egt. Get a wideband.

 

[lagged]

It will eventually smooth out on closed loop. Mine always started out lean and richend up after a day or 2. You can measure narrow band voltage, .45v is stoich. I wouldn't bother with the egt. Get a wideband.

thats what all signs are pointing to. ill be checking the output of the o2 sensor to be sure its working and wired correctly, then i have to stop messing around and get a wideband so there are no more guessing games.

 

[steve_mk3]

Do you still have the J tube installed? is it bypassed?