gf's mr2 running bad

[supra_750]

ok ive had this prob. for a while what it has is a small port with big port stock computer and harness. when u drive it it has no power until 4.5k like tvis kicks in or somethin. it feels like it wants to go just somethin holds it back if u get it above 4.5k and keep the shifts above it runs good just missin that bottom end. thinkin maybe a coolant sensor or something crackin out. bout to just rip the whole thing out and go mega squirt and hell turbo it to hahaha jk.

[dr.occa]

what injectors are you running?

the smallports run a 53cc bigger injector set. your largeport ecu is set to run an engine with 183cc injectors, .46 higher lift cam profile, less aggressive timing curve due to the lower compression, etc...

if you're not running the smallport injectors then do so and jumper the injector resistor connector.

some things to consider.

[supra_750]

i am running the bigport injectors so ur sayin i should run the small port ones. k makes since motor starvin for fuel then in higher rpm factory ecu runs richer

[dr.occa]

i am running the bigport injectors so ur sayin i should run the small port ones. k makes since motor starvin for fuel then in higher rpm factory ecu runs richer

that's my initial impression.

[GTSRolla34]

You won't get the full effects of either injector if you're not running the smallport ecu. Regardless of the injectors you use, the fuel system is still being controlled by the bigport ecu, which assumes TVIS is installed. The fuel curve is going to be set up for a TVIS equipped car. It will provide less fuel under 4.5K. I had the same issue when I just put a smallport head on my big port block. I could audibly hear the change when the TVIS should have opened...even though it had been eliminated. The engine is running on less fuel, but it's more attributed to the ECU. It makes the situation worse when you use the bigport ECU and bigport injectors b/c you're not only flowing less, but below 4.5k your fuel curve is much less aggressive than a smallport would be.

[dr.occa]

i'm going to agree with GTSRolla34 that the smallport engine is going to run best with a smallport ecu AND the larger high impedance injectors.

[CBR_TOY]

what if i put the smallport injectors on my bluetop with thin headgasket?

my car has no balls til 4ish as well

[dr.occa]

what if i put the smallport injectors on my bluetop with thin headgasket?

my car has no balls til 4ish as well

the smallport is rated for 140 fwhp with bumped compression and high impedance injectors.

your largeport 3rib is 120 whp with lower compression. bigger injectors won't really due anything for ya rob.