Hi
Here is the story
I had 91 Crx with swapped stock b16 in it.the engine itself did not have a knock sensor ,and I always had cel 23,but everything was working perfect including vtec.
Recently I swapped in a b20vtec(it is newly build engine with 1500 miles on it,it does not have a knock sensor ether),and now the vtec is working from time to time.When it is not working, the car would not rev past 7000.I have checked everything: oil pressure and level,vtec solenoid,ground,even checked for loosen pins in ecu,nothing seems wrong.Once when I checked vtec signal voltage from ecu,it was 11 something all the way from 0 to the red line,but just once. And just after I checked everything once again,the car started to run perfectly,but after one hour or so, vtec died again.What the hell could it possibly be? Any ideas?
Thanks.


Modified by nismo at 4:49 AM 4/2/2004

 

sounds like a loose or faulty wire.
try a different ECU, if that doesn't fix it, try running a new wire for vtec.

How did you run the oil line for vtec pressure? Are you sure you have proper oil pressure in the vtec gallery on the B20V motor?

 

CLEAN THE FILTER INSIDE THE VTEC SWITCH OR SWAP THE ECU. AND OBD1 CARS DONT READ KNOCK SENSOR,

 

probably a loose connection somewhere or a shorted wire.

i had an o2 wire that kept touching my shift linkage every once in a while and that threw my vtec out of whack. what happen was when i cut my 2nd o2 sensor wires, i electrical taped them individually and then taped it to the shift linkage, well when the exhaust got hot it melted the tape and the exposed wires would sometimes make contact with the linkage. so sometimes when i drove it and the wind would catch the wire, it would hit my linkage and short out, causing my vtec to sometimes not work.

 

Well,the pressure is good,it is an almost new engine

 

I have obd0 car,but I doubt that obd1 cars do not read KS,who told you this?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JUMPTHELIGHT &raquo;</TD></TR><TR><TD CLASS="quote"> AND OBD1 CARS DONT READ KNOCK SENSOR,</TD></TR></TABLE>

 

Thanks everyone.
The problem was in the loosed speedo cable,I would not even thought that this can couse vtec not to work.
Thanks again