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Wont vtec

PostPosted: Mon Mar 15, 2010 5:08 pm
by Jk147kx
Hey guys im having a slight problem with my car it doesnt want to vtec any more im running a b16a2 engine vtec used to kick in at 5500rpm and u could feel it now it almost feels as if the choke is on when it gets to 5500rpm and its jus not pulling properly ive noticed it happens when i take the car out for a cruise and im sitting in neatral the rpm will idle and just over 1000 rpm were as once its warm it usually idles under 1000rpm its really anoying me now friend said it mite be the engine coolent temp sensor i had it cheked its not that what else could it be im stuck? maybe the vtec solonoid? any help would be really good guys cheers... p.s i have a exhaust system in my house for the car which im planning on putting on and getting a remap but want to get the car vtecing properly first cheers....

PostPosted: Mon Mar 15, 2010 7:30 pm
by teal_dx
moving to B series since this doesn't have to do w/ hatchback chassis :thumb:

low oil pressure will cause vtec not to happen

PostPosted: Tue Mar 16, 2010 9:42 am
by Jk147kx
thank you buddy, i had the oil replaced last week and still nothin..any ideas on what could be the cause :?

PostPosted: Tue Mar 16, 2010 9:53 am
by tom_eg_vti
check your oil level , what oil are you using ?

PostPosted: Tue Mar 16, 2010 12:41 pm
by forcefedEG
heres a few things to check first

1. Oil level
2. Vtec Selonoid Assembly screen (unbolt the assembly from the head with the 3 10mm bolts on the side of it some oil will run out so have a towel)
3. Check the harness ground on the back of the block
4. Check all plug-ins for corrosion or moisture

and heres a few obvious things it could be if all this other stuff checks out

1. Vtec oil pressure switch
2. Vtec Solenoid
3. ECU
4. A broken wire in the harness somewhere (check with a continuity tester :thumb: )

PostPosted: Tue Mar 23, 2010 9:05 pm
by Jk147kx
hey cheers guys checked every thing its all good oil levels good plugs clean ect checked it all the car only vtec's when it wants went out this morning it was pulling hard in vtec stopped to buy some breakfast then it just didnt want to vtec atall v weird think it may jus need remapped personally..

PostPosted: Wed Mar 24, 2010 3:41 am
by Apexracing
if its on and off, most likely you have a bad connection, ive heard that the vtec connecter can corrode on the inside pull it apart and check for continuity like suggested earlier. and until you get it fixed, take it easy on her.

PostPosted: Wed Mar 24, 2010 12:29 pm
by forcefedEG
Apexracing wrote:if its on and off, most likely you have a bad connection, ive heard that the vtec connecter can corrode on the inside pull it apart and check for continuity like suggested earlier. and until you get it fixed, take it easy on her.


x2 :thumb:

PostPosted: Thu Mar 25, 2010 7:13 pm
by Jk147kx
Hey guys thanks for the advice iv not had the car for long i always just cruise if i kno the vtec's not gonna kick in.. im not 100% sure on what wires to check if im honest i used to be an electrician so checking for continuity is no problem its just what wires to check, if some 1 could kindly tell me or even put a pic up that would be great! i have an exhaust system waiting to go on the car but i want it to be tecing properly before i do anything to it... 8)

because we all kno having no vtec is like having a cheese sandwhich with no cheese its not right and i got to sort it out a.s.a.p

PostPosted: Fri Mar 26, 2010 12:07 am
by Apexracing
Check the harness plug that connects to your vtec cylinoid(spelling) and check that first for continuity

PostPosted: Fri Mar 26, 2010 4:54 am
by kylenjdm93
the ecu also checks coolant temp in order to engage vtec. is your temp sensor working properly? do you have enough coolant?

is your oil pressure up to par?

HOW OLD IS YOUR B16A2?

How many miles??






(4 years honda certified mechanic)
cityracingmotorsports

PostPosted: Fri Mar 26, 2010 4:59 am
by kylenjdm93
ahh, i forgot!!


if your knock sensor is going out, vtec will not engage, there are some b16a2's that will not engage vtec and will NOT throw a CEL code.. usually the check engine light will come on if any sensors go out, "usually" but, if you have not done a tune up or are running cheap ampm gas, your b16a2 will not run as good as it should, resulting in some combustion ping and knocking at certain rpms,

combustion ping also known as "detonation" will cause your knock sensor to put the ECU in a "semi-limp" mode, thus will not engage vtec

but listen to these other guys first before you start diagnosing a knock sensor, they usually run from 130-280 for one,

you could chip your factory ecu with crome and kick the knock sensor out of your engine completely...

PM me if you have any questions.

Kyle

PostPosted: Fri Mar 26, 2010 8:34 am
by Jk147kx
Hey thanks for the help guys i had the engine coolent temp checked by honda as the engine seems to stay cool for ages unless its jus sat idleing... they changed the engine oil so i kno thats all good, im going to check the continuity of the wire that goes into the vtec solonoid and the solonoid itself the engine has 75,000 miles runs sweet i kno the battery needs replacing soon but i didnt think tht would hav anything to do with it.. thanks alot for the help and advice guys ill keep you all posted..

PostPosted: Fri Mar 26, 2010 12:43 pm
by forcefedEG
kylenjdm93 wrote:ahh, i forgot!!


if your knock sensor is going out, vtec will not engage, there are some b16a2's that will not engage vtec and will NOT throw a CEL code.. usually the check engine light will come on if any sensors go out, "usually" but, if you have not done a tune up or are running cheap ampm gas, your b16a2 will not run as good as it should, resulting in some combustion ping and knocking at certain rpms,

combustion ping also known as "detonation" will cause your knock sensor to put the ECU in a "semi-limp" mode, thus will not engage vtec

but listen to these other guys first before you start diagnosing a knock sensor, they usually run from 130-280 for one,

you could chip your factory ecu with crome and kick the knock sensor out of your engine completely...

PM me if you have any questions.

Kyle


he has a great point there :thumb: when we first got my friends jdm b16 in we didnt wire the knock sensor, and it had a cel light for the knock sensor, it would hit vtec good about 2 times and throw the light, then vtec would "half way" come it, you could hear it kinda come in but it wasnt as strong... knock sensor wouldnt be a bad place to look :hehe:

PostPosted: Fri Mar 26, 2010 3:53 pm
by suspendedHatch
Staying cool to long could indicate a bad thermostat or sometimes a stupid ricer (previous owner) will remove it. In some cases the ECU will not allow VTEC if the coolant temp is too low. I don't know that for sure for your ECU.