So I bought a 91 Civic with a 94 GSR swap. Vtec will only work if directly connected to a toggle switch and will bog in and out of vtec at around 6k +. Always done this since I've had it. Any ideas?


Things changed/checked.
Oil is fine.
Rewired vtec and other sensors.
Changed vtec selonoid.
Tried other virgin/chipped ecu's.
Running str8 pipe, so no cat.
And only CEL on throwing is 6 Engine coolant temp sensor, and thats because it's not plugged in.


Things that I think can cause the problem.
Preety bad dented oil pan.
Don't know the condition of either oil pump or oil pick up.
And maybe fuel, even tough fuel gauge reading 50 at idle.

Please help..

 

its because of that sensor u have unplugged cuz vtec will only work if car is at running temp...and ecu can tell if the motor is at running temp if thats not plugged in....and make sure ur speedo works cuz that can cause it not to work either

 

Speedo is always working. So it could be just that sensor and not bad oil pressure?

 

yea i positive its that sensor cuz the same thing was happening to mine then my homie told me cuz that sesnor...just plug it in reset ecu and it should work withou a switch if u have the right ecu

 

but why would it bog in & out of vtec??

 

idk wat ecu u runnin it could be cuz u had it hooked to a switch

 

Chipped p28. And i've tried 2 other chipped p28's and a gsr ecu and still the same.

 

i would just plug that sensor in reset ecu wire vtec to ecu instead of switch and see if it makes a difference

 

Bump...wired up the sensors so no more CEL. But it still does it.

help..

 

Also vtec works propely now, no more vtec button.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 91EF_Si &raquo;</TD></TR><TR><TD CLASS="quote">but why would it bog in & out of vtec??</TD></TR></TABLE>

because the ECU doesnt want you in VTEC because of your temp. you are overriding what the ECU is telling it to do.

 

now when i get on it alot CEL 22 comes on and hits rev limiter at 6500. changed oil and tried 2 other vtec oil pressure switches...and still bogging out of vtec. going to change the oil pan and oil pick up and see what happens...

 

have u tried switching vtec seloinoids just an idea

 

yep.

 

is the ground for the vtp sensor good cuz i read somwhere that if the ground isnt that good it will bogg in and out of vtec

 

yea all grounds are good.

 

have you checked your timing? valve clearances? injectors?

 

Nah haven't checked the timimg or valve clearance. I noticed 1 cam gear is +1 and the other is -1. But I don't think that will make vtec turn on and off..or would it?


injectors are clean.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 91EF_Si &raquo;</TD></TR><TR><TD CLASS="quote">So I bought a 91 Civic with a 94 GSR swap. Vtec will only work if directly connected to a toggle switch and will bog in and out of vtec at around 6k +. Always done this since I've had it. Any ideas?


Things changed/checked.
Oil is fine.
Rewired vtec and other sensors.
Changed vtec selonoid.
Tried other virgin/chipped ecu's.
Running str8 pipe, so no cat.
And only CEL on throwing is 6 Engine coolant temp sensor, and thats because it's not plugged in.


Things that I think can cause the problem.
Preety bad dented oil pan.
Don't know the condition of either oil pump or oil pick up.
And maybe fuel, even tough fuel gauge reading 50 at idle.

Please help.. </TD></TR></TABLE>

What do you mean by bogging in and out of vtec. Do you mean vtec is engaging and disengaging? You may have a bad ignition module or something else other than a vtec problem.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by all-mtr-teg &raquo;</TD></TR><TR><TD CLASS="quote">

What do you mean by bogging in and out of vtec. Do you mean vtec is engaging and disengaging? You may have a bad ignition module or something else other than a vtec problem.</TD></TR></TABLE>


Yes.

 

How do you know vtec is engaging and disengaging? You can barely hear vtec on a GSR motor, most of the time all you can hear are the secondaries that engage at 5850 RPM.

 

Becuase you can actually hear vtec kick then turn off and on...

 

Are you refering to the sound at around 6K rpm? That's not vtec. Stock GSR vtec is at 4400 rpm.

 

Im running a chipped ecu that kicks vtec at 5200 rpm. Once it kicks it will start to act up.

 

What cams and other mods do you have?