i have a 91 crx hf with a b16 and when im drivin it it works great but when i turn on the heater the vtec quits working but only when the heater is on. Has any one ever heard of this?
Thanks

 

is the AC button depressed?
i know that Honda programmed the ECU to react differently in regards to VTEC crossover when AC is turned on...at least on some engines

 

i have the same problem i thinks it is cool it helps save gas

 

it doesn't have A/C

 

how is the engine temperatures? you might be overcooling your engine when you route the coolant flows through the extra heat exchange (the heater core).
stan

 

i do have the fan on all the time but it seems to happen as soon as you turn the heater on either hot or cold. I can be going down the road in vtec 6300 rpms and turn on the heater and the vtec instantly goes away.

 

Ride around with the heater on, then while above 5500 rpm turn it off.
You've got a TURBO BOOST switch now . LoL

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hahagasdcrx &raquo;</TD></TR><TR><TD CLASS="quote">Ride around with the heater on, then while above 5500 rpm turn it off.
You've got a TURBO BOOST switch now . LoL</TD></TR></TABLE>

hahahaha, that made me laugh!!!

But on a serious note, I have not heard of this problem before.

 

maybe when the heater is on the temp of the motor drops so much the ECU wont let it go into vtec??

i have had weird issues with this with a PR3 i had, i got the TODA program and it got rid of the issue

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by davidcrx89 &raquo;</TD></TR><TR><TD CLASS="quote">i do have the fan on all the time but it seems to happen as soon as you turn the heater on either hot or cold. </TD></TR></TABLE>

"fan" as in radiator cooling fan?

"heater" as in underdash blower motor?

Heater to me usually means turning the **** all the way to the right into the red zone as indicated on the climate control panel.

 

Ride around with the heater on, then while above 5500 rpm turn it off.
You've got a TURBO BOOST switch now . LoL


hahahaha, that made me laugh!!! ME TWO

 

hmmm.. very interesting.

Does it make any sounds like its trying to engage? If you have your heater on is it blasting hot air or is it cool air?

 

no sounds heater still works fine just simply shuts off vtec

 

Have you checked your wiring? Perhaps a wire is shorting or is connected up wrong.

 

the car has to be a certain temp for vtec to be engaged. My theory is that your fan blowing all the time (radiator fan?) and that fact that you turned the heat on cooled the car down so it wasnt at operation temp and bam vtec isnt working.

Josh

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by deftones0817 &raquo;</TD></TR><TR><TD CLASS="quote">the car has to be a certain temp for vtec to be engaged. My theory is that your fan blowing all the time (radiator fan?) and that fact that you turned the heat on cooled the car down so it wasnt at operation temp and bam vtec isnt working.

Josh</TD></TR></TABLE>


this would be true if it was an instant drop in temperature.

when you turn it on..does vtec still engage for a little while and then stops. or is it instantenous?

 

From the sound of it, it has nothing to do with temperature. He said it happens all the time no matter what. Even when he's in VTEC a press of the button turns VTEC off. That's not temp... that's a waredrobe malfunction or alteast something amiss with the wiring or the ECU.

 

how do you know it is turning off??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 4drEF &raquo;</TD></TR><TR><TD CLASS="quote">From the sound of it, it has nothing to do with temperature. He said it happens all the time no matter what. Even when he's in VTEC a press of the button turns VTEC off. That's not temp... that's a waredrobe malfunction or alteast something amiss with the wiring or the ECU.</TD></TR></TABLE>

I concur. As others have stated, it sounds like an electrical problem. Actual engine temperature doesn't instantly drop with a press of a button.

Are you running a PR3 ECU?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by limpy &raquo;</TD></TR><TR><TD CLASS="quote">how do you know it is turning off?? </TD></TR></TABLE>

 

well you can deffinatly tell when it turns off it doesn't matter whether it is hot or cold it has to do with the blower fan i can be in vtec flip it on low or high and it instantly shuts off i checked it out today the wiring seems ok. its almost like its steels the vtec power. so when the car was running with the heater on i gave the vtec sylinoid power under the hood and it works it just that the ecu wont give it power also the ecu hits vtec at 4500 rpms on a fast idle and on a slow one its 5200 and the rev limiter is 7800 i think its the ecu but im not sure??????????????

 

You are losing power/ground somewhere...

The first thing I would recommend,
Clean the battery posts and terminals..
I use a wire brush on a cordless drill..

When the terminals are bolted to the battery,
see if either will turn [with force] on the post..

If so that could be the problem..
A loose connection equals resistance..
It will create heat which expands the connection..

 

everything is clean and tight does anyone think it maybe the ecu is junk

 

hmm.. well the wiring of HVAC and the main harness come in at the firewall (I believe right next to each other) just at that point every where else it is seperate.

Perhaps there is a short near there. Also do you have a vtec controller or a vtec dummy light?

-shane

 

i used a test light