chidoks

Ok,
Heres the deal people... My friend has a 92 Si Prelude with 4ws(4 wheel steering). It came with a five speed h23 motor... We swapped an h22 into the car about 2 months ago, we retained the factory h23 tranny with an act clutch. We also used the stock p14(h23 ecu) to run the motor and an msd switch to activate vtec. We also used a factory h23 harness. Now the switch has a 4600rpm pill in it so vtec kicks in at 4600. Since we were using an h23 ecu and the stock redline was 6500 on that ecu, for a while the powerband was just from 4600 to 6500. We then figured since it would be really hard to locate a jdm p13 with 4ws, we could just chip the p14 with an h22 spoon chip and raise the redline and all that stuff. Well, we did that and the motor still redlines at 6500rpm. The a/f ratio seem like they are working right on the motor but the redline still sucks ***... At first we thought the chip had problems so we tested the p14 ecu on an h22 accord, the car ran fine and was redlining at 8500rpm which was what the chip was meant to do... We also tested a p13 ecu on my friends prelude and it was still redlining at 6500rpm..which is way below stock... Does anyone know what the problem could be? I think something is not wired right... Maybe a sensor is not wired right? Oil pressure, knock sensor?? Or does it have anything to do with the fact that h22's are dual stage intake manifold's and the switch only activates the primary runners?? any help would be appreciated...thanks

Jason kiDD

Okay there are only a few reasons why vtec would not be working on most engines. First of all if you have a CEL light that is NOT a soft code vtec will not activate. You have to make sure that the wiring to the Pressure switch and/or the solenoid is correct. Or if the solenoid is even functioning at all, which can be done by giving it power and you can usually here it click or you can use a voltmeter and check for continuity.. Also if the car has not reached operating temperature or your oil pressure is low it will NOT activate. Check out those things and then retest again..

If you have a pulse sensor on your IM then disconnect that. It has been found out that this also may cause malfunctions..

blackedoutcivic

yeah, i would have to say the prelude is in "limp mode" since vtec will not engauge and you are getting a 6500 rpm redline. i had that problem, too. pull youre CEL codes and see what the business is.
-shane

Mentat Ghola

ANd after you fix a wiring problem, unplug the battery for a minute to reset the ECU.

chidoks

k...we finally fixed it.....we were using an h23 harness so there were some vtec plugs missing on the harness, it turns out the oil pressure sensor was not hooked up at all...we pulled an oil pressure plug from a vtec harness and ran the wires to the ecu, and then drove the car, it ran so much better...it was so different....this thing pulled...