[kienai22]

The speedometer and VTEC stopped working while driving.. What could it be?? We replaced the sychros and put a new radiator in.. We did everything carefully step by step.. It was running fine last night.. What could it be?

[taoh]

The speed sensor on the tranny might be bad or not properly connected.

Look for a wiring diagram and troubleshoot with a multimeter.

I'm surprised whoever replaced the synchros doesn't know to look at the speed sensor.

No idea why VTEC wouldn't kick in, I've never worked on Hondas.

[kienai22]

Nevermind.. The speed sensor wasn't making a good contact with the harness clip.. We didn't think that was the problem though..

Thanks anyway..

[DaRkViEt73]

No idea why VTEC wouldn't kick in, I've never worked on Hondas.

probably because VTEC relies on the speed sensor to operate. But that's just a guess.

The 300ZX's rely on the speed sensor AND speedometer for the HICAS system as well as power steering. If either one goes, so does your HICAS system and your power steering. Safety fallback mode probably... cuz you don't want sensitive steering when you're driving at 100+mph and lose control.

[i haet piza]

u need moar vtek sticker

[marvinoppa]

ok vtec is not activated by any speed sensor, its activated by oil pressure. namely the vtec solenoid is activated by oil pressure.

[DaRkViEt73]

^ from what I already know about VTEC, yeah I know that oil pressure plays a role in it. However, I was guessing that perhaps VTEC is actually ECU controlled instead of being a purely physical valve like a thermostat. It would explain why VTEC controllers can adjust on-the-fly when VTEC kicks in. So I googled it and this is what I found. http://www.pgmfi.org/twiki/bin/view/Library/VtecSolenoid According to them, the VTEC solenoid that physically opens and closes allowing the oil pressure to go from the low to the high cams... it's actually controlled by a +12v signal from the ECU. Now the question is, does the ECU require input from the speed sensor in order to send the signal that activates the VTEC solenoid? I honestly do not know, but I'm guessing it might since that might explain why the topic starter's VTEC wasn't functioning.

[tinyt]

The speedometer and VTEC stopped working while driving.. What could it be?? We replaced the sychros and put a new radiator in.. We did everything carefully step by step.. It was running fine last night.. What could it be?

you might want to check you oil level and the vtec solenoid harnass connection.

here's the helms manual that should help. it's for 96-00 honda civic. this manual should gave you some idea. it has the civic si and ex in it. these model has vtec. the SI is a B series engine and the EX is a D series. hope this manual helps. your ITR is a B series so it's the same as the SI.

this manual is 69 mb.

Helms manual :96-00 civic

[kienai22]

Thanks everyone for the help. I appreciate it..