serious tune prob

[gr8fj40]

hey guys ,how are ya?
need some help here i have installed an ls1 engine on a landcruiser fj40 the engine came out of a 2001 caprice ss ,australian "comodore" i had someone due the tune using the hptuners ,the program that is running on it is a gmc yukon and there are no o2 sensors ,engine was working great .
after that i did some mods to the engine installed a camshaft "lg5x3" liftters ,push rods ,dual springs,double chain,slp high press oil pump,and ls6 air intake,more power to the engine but it seems that now i am having some knocking and detonation issues if any one can help or tell me where to find some ready tunes for this cam,or hat to do to manege spark advance and retard cuz i dont think this guy can do it,befor i burn this sweet engine plz help

[tblu92]

Hello--If you are not running any 02 sensors then I suppose you are running in "speed density" mode--you must not be using a MAF either ???--True speed density is MAf less---Without 02's you cannot run in closed loop and must run in open loop.Any stock computer program would utilize the 02's for tuning together with the MAF sensor to set the fueling. The only way to get the fueling correct is with a tuner.
You are getting detonation because with your new mods you are VERY lean--lean enough to melt it down--be careful---You need to do 2 things--re-do the VE table and all the open loop fueling then adjust the timing curve by logging all different load situations and add or subtract timing
Did you ever consider instaling the 02's and a MAF ? that would be the best I would think as it would gaurantee 14.7 at part throttle closed loop and you could easily calibrate the MAF to set the WOT open loop fueling.

[gr8fj40]

thanx for the reply tblu92 ,ido have a maf installed strange thing is befor the mods when i connected it the engine dies on me now it works fine and if i disconect it the engine will not idle and die,i am thinking of installing the o2 sensors but i guess that they dont include them to try to get the most power out of the engine in the open loop ,to tell you the truth irealy dont know much about tunning but i have read about the stuff you have mentioned "VE and timing curve " in the efilie users manual ,
my question is if i installed the o2 sensors would the pcm tune the fuel by itself or i would have to tune to get the 14,7 ratio and would i loose power if i run it in the closed loop ?thanx

[tblu92]

Hi--I have EFILIVE Workshop ( unlimited tunes ) There is table entry( b3601 ) that is set at 14.63 for closed loop operation----14.63 is known as stoichiometry--which is the most efficent use of fuel for mileage and power.The 02 sensors are centered around this number and are only really accurate close to it. There is another table ( b4206) which when enabled allows you to use the 02's in open loop fueling instead of closed loop.Closed loop only works with the 02's operating and is centered around 14.63 which is great for part throttle operation.When going to wide open (WOT) the ECM falls out of closed loop and into open loop--the 02's now are not used and typically the MAF now sets most of the fueling .There is a table called PE@RPM which also sets the commanded AFR fueling---When an engine is stock everything works fine--but what happens with mods--the commanded AFR never matches the actual AFR--thats where all the problems begin--and tuning is required and logging with a wideband is required to see what your actual AFR is--For example on my modded C5 (heads & cam) I have to command an AFR of 12.2 in order to achieve an actual AFR of 12.8.
I probably really confused you now--but If you can't grasp it don't worry--it is complicated
One question you asked was will the ECM tune itself ?? I think what you mean is if you installed the o2's will it command a 14.63 during closed loop---The answer is yes--as long as you haven't changed the tables i mentioned earlier--b3601 & b4206--all you would need to do is hook up he O2's and the ECM will read the info they acquire---There is more to it than this and I purposely left some stuff out as it will really confuse you--but this is the basic explanation and a starting point---If you want to call me and talk on the phone that would be OK I am in Calif--my cell # is 209-603-2983.

My personal opinion is that any engine less than 475 RWHP and is still used on the street is best suited for 02's and a MAF-A stock screened MAF can handle 500 RWHP according to many experts.

[gr8fj40]

thanx again tblu92
wow thats lots of info ,i am so confused right now as you can tell i am trying to get the most out of this engine without melting it ,if it is ok with you i would like to talk to you soon,hope you can help me with this one ,till then have agood one,thnx

[jimmyblue]

With no O2 sensors you are full time open loop, fueling is based on
MAP reading (EQ Ratio vs ECT vs MAP table) for target. Whether
you get that target or not depends on how well the MAF (probably
OK) and speed density (VE table, probably not OK) are modeling
the airflow. First order of business is figuring whether what you say
is what you get. You want either a wideband O2 meter or a lot of
time spent logging with narrowbands and a 1.000 EQ as far into
the higher-MAP range as you can take it (with a gimp spark table
for some safety). Get the fueling true and then move on to the
task of learning what the new combo, its cam and compression,
can tolerate and respond well to for advance. It won't be the
same as before, with better airflow. More charge means a
faster burn and less spark needed. You should not expect to
tolerate or need the same advance as you did before the cam.

[gr8fj40]

hey jimmyblue thanx for the reply man ,it looks like i am not going to figure out any thing without an o2 sensor a wideband and a good tunning program ,i am looking into efilive i think it would be agood one ,plus the fact that tblu92 overed to help me start didnt hurt either, i just dont know whats the diference between prsonal and comerecial once and for the vin cuz i got the engine and the ECM for the engine out of the same car from a junkyard am not sure if the body of the car is still there any more ,would the vin be saved in the ECM and can be retrived ,thats bout it
thnx