so i bought a sub harness hooked everything up and bam..no vtec...although i am getting a code for the knock sensor....that's it. what should i look out for or do?

this is in my DC4..all obd1 gsr head with a blox intake manifold...and stock p72 ecu


Modified by I got a honda at 9:18 PM 8/20/2008

 

Get a new knock sensor.

 

Check to make sure you are full on oil. Does the speedo and coolant temp sensor work good?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CompanyFlow &raquo;</TD></TR><TR><TD CLASS="quote">Get a new knock sensor.</TD></TR></TABLE>

That's what I would do. Correct any errors you have first.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CompanyFlow &raquo;</TD></TR><TR><TD CLASS="quote">Get a new knock sensor.</TD></TR></TABLE>

would that really cause vtec not to engage?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by neardon &raquo;</TD></TR><TR><TD CLASS="quote">Check to make sure you are full on oil. Does the speedo and coolant temp sensor work good?</TD></TR></TABLE>

yea i was thinking maybe the oil..i know i was low few days ago and i added 1qt. i told my self i would do an oil change when vtec was hooked up...maaaybe that could be it...oh and yea the speedo coolant temp work normal.

 

fucc i went back and repinned the sub harness to the ecu..even better this time...double checked all the lines and re did them...checked oil level on dip stick...its at max levels...warmed up car took it out and still no vTaK..=[

and started to throw a knock sensor code again....?

 

you prob dont have a wire that goes to the knock sensor.if you old block didnt have it then you will have to run the wire to the knock sensor.i dont know if you had a vtec motor before. vtec will not engage without a knock signal.i had a b20vtec that i had to run a knock sensor wire for knock sensors suck. you could send the ecu and get it chipped to not look for the knock signal.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondaman1212 &raquo;</TD></TR><TR><TD CLASS="quote">you prob dont have a wire that goes to the knock sensor.if you old block didnt have it then you will have to run the wire to the knock sensor.i dont know if you had a vtec motor before. vtec will not engage without a knock signal.i had a b20vtec that i had to run a knock sensor wire for knock sensors suck. you could send the ecu and get it chipped to not look for the knock signal.</TD></TR></TABLE>

well the thing is i do have the wire hooked up to the knock sensor..it came all setup from a subharness i ordered...so its all hooked up....one thing though...my knock sensor is not screwed to the back of the block.....so really vtec will not engage while throwing a knock sensor code???

 

if the knock sensor is not screwed into the back of the block then it cant pick up the vibrations from the block.vtec wil not engage with a knock sensor code.the ecu will retard your timing and mess with the fuel mixture screw the sensor in the block and it will be fixed

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondaman1212 &raquo;</TD></TR><TR><TD CLASS="quote">if the knock sensor is not screwed into the back of the block then it cant pick up the vibrations from the block.vtec wil not engage with a knock sensor code.the ecu will retard your timing and mess with the fuel mixture screw the sensor in the block and it will be fixed </TD></TR></TABLE>

i know that might have sounded dumb but i heard that knock sensors were useless and that a friend of mine did a long time ago and it worked..meh who knows...well im going to go try out a chipped p28 with a base map for stock lsvtec and see if that fixes my problem..thanks again! ill keep this updated..

 

if you have a knock sensor problem and your vtec isn't working. Then your problem is to replace the knock sensor. Or at least make sure it is wired correctly. WIthout out your knock sensor connect properly. Your vtec wont engage. Had this problem when i swapped a gsr in my rs.

 

try a get your hands on a p28 just to give it a shot...they dont look for a knock sensor

 

well i just got back from tryin a chipped p28 and well of course it got rid of the knock sensor code BUT STILL NO VTEC!!...i dunno now....fucc

 

ok well my last thought would be a bad vtec soloiniod or a bad V-tec pressure switch

 

VTEC will not engage unless the car is under proper operation conditions. The fact that you were getting a knock sensor code is bad. Instead of using a different ECU, try actually fixing the problem thats FLASHING IN FRONT OF YOUR FACE

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtecb18c &raquo;</TD></TR><TR><TD CLASS="quote">ok well my last thought would be a bad vtec soloiniod or a bad V-tec pressure switch</TD></TR></TABLE>

yea i was going to swap out for another vtec solenoid next...

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CompanyFlow &raquo;</TD></TR><TR><TD CLASS="quote">VTEC will not engage unless the car is under proper operation conditions. The fact that you were getting a knock sensor code is bad. Instead of using a different ECU, try actually fixing the problem thats FLASHING IN FRONT OF YOUR FACE </TD></TR></TABLE>

did you not know that a chipped p28 does not EVEN look for a knock sensor? there for not having to CARE about the knock sensor??? AND when the p28 was hooked up there was NO code flashing in my face???.....

 

well he could mean not just the knock sensor being faulty. Maybe its picking up a signal?? but with the p28 in effect then. yea that shouldn't matter. so could be the vtec oil pressure switch or the vtec solenoid..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dc2_97teg &raquo;</TD></TR><TR><TD CLASS="quote">well he could mean not just the knock sensor being faulty. Maybe its picking up a signal?? but with the p28 in effect then. yea that shouldn't matter. so could be the vtec oil pressure switch or the vtec solenoid..</TD></TR></TABLE>


would i throw a code if i had a faulty vtec oil pressure switch or even for the solenoid?..

 

to be honest with you... i don't know... i believe it should.

 

Trying to run an LSvtec with a p72 was a dumb idea in the first place. Why spend all that money on a motor just to skimp out on a proper tune?

Back to the issue at hand. Some cars crossovers are really quiet. Does it run like crap over say about 5k? if not then maybe you just cant hear/feel it crossing over. Try the Pressure switch and the solenoid as well.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Horseofcourse &raquo;</TD></TR><TR><TD CLASS="quote">Trying to run an LSvtec with a p72 was a dumb idea in the first place. Why spend all that money on a motor just to skimp out on a proper tune?

Back to the issue at hand. Some cars crossovers are really quiet. Does it run like crap over say about 5k? if not then maybe you just cant hear/feel it crossing over. Try the Pressure switch and the solenoid as well.</TD></TR></TABLE>

well first off its not a dumb idea to run a oem ecu...im not building a race car...all i did was slap a vtec head on the block guy...and no it runs great through out at the rpm's and i think with an upgraded intake manifold and an intake im sure i could hear/feel vtec engage....that was with both the p72 and chipped p28...

 

well since you seem to know everything why even ask for help?

 

Your solution to the knock sensor code was to change boxes instead of fixing the problem. If everyone changed boxes when they got a code then problems would never be fixed. I'm trying to tell you that you're a half asser and you should fix the problem that you actually know is a problem before you continue to ask questions.

 

Company Flow Dont even try to help him. He seems to know everything there is. And I dont know why he needs our help or our opinions. I dont know very much either. But I do know that when you ask for help take everything with consideration.

There is no such thing as an OEM ECU that will run an LSV safely. You should have the car properly tune or at least get a basemap for it before you ruin everything.

Does it Run like poop after 5k? Cause my old y8 when my vtec wasnt working the motor wouldnt hardly operate after 5k or so. And i know the same is true with DOHC's.

Fix your knock sensor problem, see if you get any changes.

 

this thread is going nowhere....OP doesnt want to fix his problems by listening to what EVERYONE has to say than this thread should be locked...seems like a waste of time at this point