revs fine cold.when warm hesitation from 3.5k and up

[WILDACEX187]

this is not for me but actually for a friend. this problem has been going on for a while and i've been looking at thread after thread on wat the hell is going on. ok well here goes. his car has a s13 blacktop. its running on a sohc maf. stock everything except for exhaust and arc sidemount. ecu was throwing a maf code but changed maf and now no codes. we've checked plugs, changed o2 sensor. maf was changed 3 times. we're stumped because the engine revs fine without hesitation or anything all the way but when it warms up to operating temp it starts to run super rich and hesitates as soon as it gets past 3500 rpm. wat can be wrong?

[pwhitersxs]

coolant temp sensor would be a guess. It could be a bunch of different things. Get a fsm and look at the troubleshooting, thats the best option.

[stockboostiscoolnyc]

this is not for me but actually for a friend. this problem has been going on for a while and i've been looking at thread after thread on wat the hell is going on. ok well here goes. his car has a s13 blacktop. its running on a sohc maf. stock everything except for exhaust and arc sidemount. ecu was throwing a maf code but changed maf and now no codes. we've checked plugs, changed o2 sensor. maf was changed 3 times. we're stumped because the engine revs fine without hesitation or anything all the way but when it warms up to operating temp it starts to run super rich and hesitates as soon as it gets past 3500 rpm. wat can be wrong?


Its my car he is talking about... also wanted to add the car is running EXTREMELY rich.

[WILDACEX187]

i said that :)

[WILDACEX187]

is this that hard?

[fliprayzin240sx]

ECU water temp...ECU thinks the engines still cold so its dumping extra fuel making it hesitate. Look at the water neck above the water pump and there should be 2 sensors, swap the bigger one out and that should be it. The smaller one is ur gauge water temp.

[WILDACEX187]

thanx alot flip, i'll let him know rite now.

[stockboostiscoolnyc]

ok guys changed the ECU water temp and the plugs (the old ones were fouled cause it was running so rich) problem is its still running rich. its better than it was before but it seems like its still running rich. also it seems more sluggish than it did when i first drove the car. any other reasons why it would be running rich?

[fliprayzin240sx]

double checked timing? gapped plugs .028? pressure checked pipings? its usually the water temp or o2 when it does this kinda stuff.