i just installed an LS/vtec into a 99 dc4

the engine runs great, still in the break in process but its time to wire vtec in.

the car has an obd2-obd1 conversion harness and using a stock obd1 p72 ecu

i have the vtec sol. wired into pin a4 on the ecu and the oil pres. switch wired into pin d6. the ls block doesn't have a knock sensor, and i dont have a knock sensor wired into the ecu.

the solenoid tests good and works (i wired it to a fused switch just to make sure it engaged.)

there is a memory fault code 14, IAC fault. it wont set off the CEL, but it sits in memory.

i can't get vtec to activate using the ecu, i need advise on how to get vtec to activate using the ecu.

thank you

 

there is a place on the back of the block to drill and tap a hole to add a knock sensor......... while this does not explain your problem with not having vtec..... a lack of a knock sensor signal will cause the ecu to retard timing (loss of hp)

check your connections again, also try a different vtec ecu if a friend has one that you can borrow.

as long as you connected those 2 wires correctly like u said then there should be no problem

 

i found the problem, it was the p72 looking for a knock sensor.

i plugged in a chipped p28 and it clicked vtec w/ my wiring all in the same positions.

the p72 was a borrowed ecu to just get the car running (because i was having problems with getting it running correctly and its untuned).

now i guess i'll run the p28, w/ no knock sensor (cause i dont want to buy one)

thanks for the help