BuckarooZ28

Has anyone had problems with this cam throwing codes?? Keeps throwing codes for the maf and throttle position sensor out of range performance, and o2 slow response and switching....Any feedback would be appreciated...I have changed the maf and o2's....still recieving codes

Josh

iTrader: (9)

I've gotten the throttle position sensor code, but don't recognize the others.

Josh

slyws6

just curious what year is your car and where are you located?

-Sly

mikey

iTrader: (6)

With that sized cam, you need to disconnect the O2 sensors and tune it open loop. There's no other way.

SSactionLs1

can you explain the "open loop"?
thanks mikey

BuckarooZ28

2002 El Paso TX

mikey

iTrader: (6)

Sure. When you first start your car (cold), the PCM ignores the O2 sensors and rely's on the MAF, MAP and VE tables for fueling. This is called open loop. WHen the O2 sensors warm up, the PCM will begin to take data from the O2 sensors and trim the fuel based on this data. This is closed loop. This is where the fuel trims come in to play. The problem with larger cams is that the PCM will add too much fuel when going closed loop. So the solution is to pull the O2 sensors and tune the car using the injector flow rate and VE table for part throttle and PE / VE for WOT. Some of the more experienced tuners here have been doing this for some time now. It makes tuning larger cams quite a bit easier.

LIL SS

iTrader: (9)

Mikey.. It is not impossible to tune the TREX using the standard MAF style tune. It just takes a lot of time. To someone that is not familar with Mafless tuning, I would not suggest that to them. A budy of mine just did his own here in San Jose. He was not throwing codes when it started.

Look for some Danz28 posts as he did have a couple issues with things like down shifting problems and converter lock up once he went from the TR230 to the T-REX.

mikey

iTrader: (6)

I never said MAFless, just no O2 sensors. Read.

Slowhawk

iTrader: (12)

I actually disagree with this.I have a car running perfect with the T-rex and closed loop.Perfect hot/cold starts,excellent drivability and doesn't load up at idle.It does take time to tune in,expecially if your not use to large Cams and the extreme changes you need in the low rpm area's.The car has been daily driven in city traffic for around 2 months so far.

As for the TP code,we were getting it and actually fixed it with an idle rpm change.The 02's also came in for switching,that was cleared up with more leaning on the idle.

SMOKIN01TA

iTrader: (10)

yep, i throw them all. its just not tuned very well. im using a-tap to log a few hours of normal driving then we will take that info to get it to run much better down low. it will probably run like slowhawk when we get the data and adjsut the ve tables.
it runs great with my foot to the floor though.
or you can do what mikey said, tune it open loop.

SMOKIN01TA

iTrader: (10)

hey mikey, when i watch a-tap on startup the a/f will run like 11.8-12.3 for a min or so then all of a sudden it goes to 14.6 which is optimal a/f the cpu tries to maintain. is this when it switches from open loop to close loop. if so it seems that is starts registering to the cpu that it is running 14.6 but is really still running 11.8. is this sound rite to you. if so that explains the extreme richness down low.

jerflash

yo a friend of mine has this cam with a 6 speed
idle is set at 975, no codes what so ever, goes into closed loop, does not load up, no hot or cold start problems

if you have it tuned by people who know what they are doing it will me nice