4g VTEC's water temp indication query

[chrismc]

Just wondering what is considered a 'normal' water temp indication for a 4g vtec?

Our UKDM seems to only ever have a maximum 2 segments lit up when up to temp (even on track) & occasionally this drops to the 1 little triangle by the letter 'C' on the road

To my mind a normal indication should be halfway between the C and the H (3 segments lit)

Just wondering if I have an iffy temp sender? The blowers warm up quickly & I have no reason to suspect the thermostat....

Chris

[littlefeller]

if it doesnt reach norm,(as you say 3 segies) then vtec would not engage. so if you have vtec then guage is knackered

[Pushki]

Mine has always sat directly in the middle when up to temp. It's never gone higher or stayed lower.

[chrismc]

Yup VTEC works even when it drops to a single segment- (though I don't think it actually has to be up to full temp to allow vtec in any case)

Guess I need to find out what sensor the gauge uses as its pickup then!

[jjmartin349571]

Mine has always sat directly in the middle when up to temp. It's never gone higher or stayed lower.

Same here, mine sits dead in the middle at halfway. I have no issues with VTEC engaging. As for it dropping lower sometimes, my Golf does this if you drive at high speeds in low revs, it's usually just the cooling effect of greater airflow over the rad. My Golf's thermometer sometimes goes into the 'warm up' segment if you hold 60 odd in 5th long enough

[Vtecmec]

Guess I need to find out what sensor the gauge uses as its pickup then!

I think its the one under the dizzy, with a single push fit connector.

[chrismc]

Yup think you're right!!

It seems there are 2 sensors

A 2 wire sensor to feed coolant temp to the ECU, & a single wire sender to run the dash gauge

Time for a wanted post now! Cheers all

[littlefeller]

my vtec doest work unless there is 3 segments lit (it will still rev past vtec point but no vtec), as you say there are 2 temp signals, one for ecu and 1 for guage, if temp was falling while driving then it should stop vtec from engaging, so temp to ecu must be ok, i think your on the right track with the second temp sender.

[si import]

i thought it was the oil temp which allowed vtec to work not water temp

[littlefeller]

there are quite a few musts before vtec is allowed, the ones that i know of are as follows
1. oil pressure
2 minimum speed (this is debatable as to how slow you can go while still having vtec available, this was descused quite recently and the outcome was something like 19mph or was it 16mph,this is why the delimmited jdm ludes loose vtec in 1st gear - there not going fast enough, although you can buy a delimiter that gets around this problem, there just a little more expensive)
3. engine temp must be up to normal before it is allowed too, however i have seen some chips that allow it at a lower temp on other honda forums, but as std it has to be upto normal.
4 throttle position is also checked before vtec, this doesnt really effect autos to much, but it does on a manual, like for instance if you just feather the throttle as you cross vtec point it doesnt engage, on the auto it will just simply shift gear before then. the vtec point does also change depending on throttle position.
i have also noticed that if any of the above are not met at vtec point, not only does it not give you vtec but the ecu also lowers the rev limit.
all the above are there to protect your h22 motor, you wouldnt want your h22 going into vtec if your not moving but just reving your engine

these engines can do some real odd things at times, like when then run low on coolant the idle revs become unstable, not sure why they do this.

supose it may be a faulty guage too, and not the sensor. if you have a multimeter i can tell you what results you should get from an electrical test of said sensor

oh yeh almost forgot number 5, if you dont have lsd then both hands need to be on the steering wheel at vtec crossover in 1st gear