Alright here goes,
Over the past few months I have been reading and trying to figure out how to get my car running good on the lex afm/550 combo, but have had not alot of luck. I have searched for many different settings on the afm screw and fuel pressure and can't seem to find the one that work's right for me. One good thing is the car starts up every time with out any trouble.
Also before I get flammed here are two good links for anyone looking for basic info on the lex afm/550 mod:
http://rob.carlile.home.mchsi.com/lexus/lexus1.htm
http://suprasonic.org/lexusriemer/lexusnotes.html
First let me list the mods I currently have on the car:
57 trim ct-26
precision 550cc injectors
lexus afm housing
aeromotive afpr
bypassed j-tube
k&n fipk
3" divorced downpipe from 935
blitz nur spec exhaust
2.5in hard pipes
spearco replica intercooler from drift motion
apexi safc 2
aem UEGO wideband
hks evc boost controller
walbro fuel pump
waiting to go on the car:
fuel dampener bypass hose - I have been reading about the fuel dampener and I think I am going to keep it on, it helps more than I thought with protecting the fuel pump.
UPDATE 5/3: Aright did a compression test today and all the numbers looked good and steady. Checked the torque on the headgasket bolts and all were right at 75ft lbs. I called the about dyno time and getting the car tuned the other day and hopefully after I get the few issues fixed that I am having with the car I will be getting the car tuned at around 14psi or so and finally getting to enjoy it.
Now my problems:
1. Every time I start the car when it is cold the afr's are steady around 14.8-15.0 when the car gets warmed up they will start jumping around all across the board and if the computer is trying to correct. I know that until the car is warm the computer will correct with the TCCS.
UPDATE 4/18: Alright just as every one has been telling me I had to check my vf voltage so I did. This was very simple in the diagnostic port just put the positive end of a volt meter in the vf1 pin and ground the other where you like. I noticed that sometimes the car would show 2.35v, which means no correction. Other times it would start running rough and go straight to 5v, which means the TCCS is seeing a lean condition and trying to correct by making things richer. I raised the fuel pressure and went in on the afm screw a little, but nothing seems to help. I have heard that and the lex/550 mod idle is always going to be lean.
UPDATE 5/3: I went to checking the signals on the o2 sensor and afm. Turns out that when the car starts to stumble the afm signal drops out entirely. Going to replace the afm and go from there.
UPDATE 5/7: You know it pays to be a supra owner because like most of us you always have a good supply of back up parts just lying around that you can't make yourself get rid of. Well I went through my pile and had a used by good afm. Got it on the car, cleared the codes and adaptations, fired it up and it ran like a champ. This weekend I am going to check my vf voltage and hopefully get the idle tuned out some.
2. FIXED: Problem with going lean under boost.
UPDATE 4/18:Alright after I got the walbro installed and replaced my fuel filter this cleared up this issue, I set my base fuel pressure w/o vac to 41 psi, which was around 40 with vac on, and I backed the afm screw all the way out and went one turn in. I drove the car so that the TCCS could make the corrections and now when I boost the afr's look good. They are in the 11's.
3. Over boosting issue:
UPDATED 4/18: Now that I have installed the divorced down pipe the boost creeping issue has gotten worse. Now the turbo will easily creep up to 14-15 psi and I will let off there. The boost controller is set at 10psi and the boost will hold there for some time, but around 4000 rpm it will start creeping. I have thought about just setting the boost controller and seeing what that does. Since the creep issue is coming from the waste gate on the ct26 being not efficient as needed maybe I can get the boost set to where the waste gate will do what it needs to.
UPDATED 5/3: Well I hit 17psi the other day while test driving, afr's were still safe, but I needed to get this figured out. Tested the actuator and everything seemed to function properly. The waste gate flapper moved freely. Here in the next week or so I am going to take the turbo off and try to enlarge the waste gate port on the turbo slightly and maybe even try and port the down pipe as well. I have my fingers crossed that this will fix the issue with over boosting.
A few things I need to note:
1. I have not yet started messing with the safc because I have read that the stock ecu should control the basics of the mod and only to use the safc to fine tune.
2. I have the stock lexus afm screw, I have read that there is a sonic afm screw, but I do not know if I need this or not or where to get it
3. Could the stock fuel pump be a big cause to this issue as well as the fuel dampener bypass. Possible even the 12volt mod, but I would really like to avoid having to do this one.
I am open to suggestions that anyone may have and would like to know what base fuel pressure people are running with the lexafm/550's set-up and what the afm screw is set at.
Thanks
James
