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vtec does not work

Posted: Thu Apr 02, 2009 9:37 pm
by b16_sol
I have tried everything I can think of to figure out why it's not working.

set it up to not look for the pressure switch, didn't work.

Checked to make sure the solenoid works.
Checked resistance for the wire coming from the ecu to the soleniod.

Both checked good.

Installed a light on the vtec wire, it did not come on when vtec should have engaged... Could there be something wrong with the hondata chip?

What else should I check? if it is the chip, what do I need to do to get it replaced? It's only 6-8 months old and was installed by a shop.

Posted: Thu Apr 02, 2009 10:23 pm
by k_boi
is this a LS/vtec or b20vtec setup? I've heard of cases where you have to pin the vtec wires into the ecu wiring.. I dont really know.. But I'll keep you posted. Good Luck bro..

Posted: Thu Apr 02, 2009 10:25 pm
by k_boi
Ooh.. I think you have to have the press. switch hooked up to make it work.. Because if the ecu isn't getting a feed back of PRESSURE then the vtec will not pop.

Posted: Fri Apr 03, 2009 12:27 am
by b16_sol
it's a b16b. and the s300 has a setting to turn off the pressure switch. The pressure switch is there and works. And no wiring was changed. it's all stock wiring.

The problem appears to be no signal from the ecu to the solenoid.

Posted: Fri Apr 03, 2009 9:05 am
by h22acivichatch
Most likely the transistor inside the honda computer is fried. It has shorted to ground so that everytime the hondata says to turn it on it grounds out so no vtec. Removing the cover off your ECU it will be burn or checking it with a multimeter on connuity with black on a ECU ground and touch the metal tab of the transister that is associated with the vtec if it is shorted it will be shorted to ground. if not check the transister by settinga multimeter to diode setting. if the transistor reads in both direction from left leg to right leg. (switching red on left leg and black on right leg, and swapping them) The transistor is most likely shorted.

Posted: Fri Apr 03, 2009 9:29 am
by Spunkster
http://www.hondata.com/forum/viewtopic.php?t=3772

Have you tried this ecu and s300 in a known good working vehicle?

Posted: Fri Apr 03, 2009 12:54 pm
by b16_sol
I have not tried the ecu in another vehicle.

I have a 94 del sol si, with a b16b swap, jackson racing supercharger, rc 550cc injectors, msd digital 6 ignition, blaster ss coil, hondata s300 in a p28 ecu.

Posted: Fri Apr 03, 2009 1:09 pm
by Spunkster
you must post a datalog showing the problem

Posted: Fri Apr 03, 2009 1:19 pm
by b16_sol
Spunkster wrote:you must post a datalog showing the problem
I don't have one yet, but will soon.

Posted: Sat Jul 25, 2009 4:57 am
by Ivan
Check your datalogs to see if the computer is even giving a signal to turn on vtec, and go from there.