can a coolant temp sensor not allow vtec to work?my car is a bitch to start in the mornings but runs fine when it gets up to operational temperature minus no vtec.my coolant guage only rises to the cold mark no matter how long i drive and last night my fan kicked on after 30 seconds of starting the car with it sitting for 6 or 7 hours in 30 degree temps.i can't get anything off my crome chipped p28 ecu cause the previous must have did something to it.i have no cel light so i went to that pin on the ecu to hopefully count how many times it lit up to get what number code it was but nothing.i need some help on this guys please let me know anything that could help me thanks.

 

one of the parameters that has to be met for vtec to engage is the engine has to be at operating temp. so yes, that may be your problem.

 

the gauge reads from the sender. the ecm reads from the sensor. the sender has no effect on vtec operation. if it reads cold all the time, i'd be inclined to say it's either an issue with the sender or wiring. as apposed to a stuck open thermostat.

check resistance of the sender. see if it falls within spec.
have you tried powering the solenoid directly?

 

no i haven't tried that,but i thought i put the wrong pigtails in place so i switched them between the fan switch on the thermostat housing and the cts and vtec worked but as soon as i pushed in the clutch to come to a stop the car would go lean and die but i could start it back up and it would run fine as long as i drove without engaging vtec.

 

oooookay. so that explains why the fan came on in 30 secs. was wondering about that piece of the puzzle.
so you had the fan switch and cts wiring mismatched. but that doesn't explain the sender issue. try shorting the sender connector to ground. it should read full hot, i believe