VTEC won't engage for D15b (three stage VTEC)

[D15Bee]

i have a JDM D15b with OBD2 P2j ECU. i can't get a VTEC sound anywhere after 3K RPM. i've checked the connectors to the solinoids ... no power... should i suspect just the wiring or is there anything else to consider??

[TurboMedic]

V-tech is dangerous stuff son....Best leave it to the pros or this could be you.....
My ex had a D15b, and I can't say I EVER noticed anything resembling "v-tech" at any RPM.....My vacuum made more power
http://i106.photobucket.com/albums/m244/MazTech/V-tech.jpg

[Datsun-Fever]

Any CEL's?

[89s1]

You can't "feel" d-series vtec on a stock cam.

Really can't hear it either. If you're checking for poewer at the solonoid you would need to be checking it when vtec is supposed to be on (ie: not at idle)

Need more info from you OP, help us help you. Ignore the dicks, there will be alot of them in a thread about hondas.

[Mr_ET]

Originally posted by D15Bee
i have a JDM D15b with OBD2 P2j ECU. i can't get a VTEC sound anywhere after 3K RPM. i've checked the connectors to the solinoids ... no power... should i suspect just the wiring or is there anything else to consider??

Doesn't mean because you don't get the VTEC sound VTEC is not engaging...

Does the engine fall on its face past 3k or it still pulls normally?

[Sebasshole]

Original Post Removed. (Please read the Forum Rules and Terms of Use (http://forums.beyond.ca/articles.php?action=data&item=1) before posting again, or risk getting banned).

[mugenmclude]

My friend down the street has a z6 and you can "feel" the cross over. Its a diffrent cam lobe, why could you not? Same goes for all vtec sohc and dohc one iv been in and owned.

Go through all cel and go from their. Search. Lots of smart honda guys around.

[ShermanEF9]

check your screen. check your oil. whens the last time you changed it? i had issues with VTEC, changed my oil and it works fine

[D15Bee]

Thanks a lot guys for the responses. ... i had an engine check light (for idle control valve) before so i guess it was masking the VTEC problem as well... i got a new ECU which fixed the Idle control valve problem....
Now for the VTEC... well we started the trouble shooting in a stardard way... i've checked the oil pan for any dents.. the oil's topped up...
i did rev the car upto the redline... but the VTEC doesn't kick it... cuz i had wire attached to the VTEC solinoid with a bulb to check... interestingly i now do get a checklight when the engine revs back from above 3K to round about 2K.... i guess i'll have to see what code is it.

As for the feel... well i saw a stock D15 B video on Utube that shows how the VTEC kicks in.... you can definately see it on the Rev meter... my car revs up but you dont feel the power trasferring.....

[D15Bee]

here's the Utube link.

http://www.youtube.com/watch?v=V4mN5YQhTZQ&feature=related

[ShermanEF9]

hahah, don't think VTEC does that. EVERYONE will put their foot to the floor at the vtec engagment point.... unless my B16 just sucks?

[LilDrunkenSmurf]

That youtube link... yea... That's a TURBO D15!!

Look at his other vids.. "Turbo D15 run"

[J-hop]

.

[TurboMedic]

That was the point of my post.....haha

[ShermanEF9]

Originally posted by J-hop
lol that clip was pretty good, vtec definitely doesn't work like that, people expect vtec to throw you back in your seat when it engages... not even close :) .

haha, i love when people are lime OMG VTEC *cream*


Nah, i can feel it pull harder in my car, but its definately nowhere close to that

[jdm_eg6]

check that your using the right ECU. I am using a P08 for my JDM D15B and vtec works great. and you wont notice a huge jump in power especially for a D. try taking it under a tunnel and 2nd gear usually works best to hear it. silence what ever exhaust and if you dont hear it then chances are it doesn't work. then try a P08 ECU maybe thats what is wrong.


Edit: i guess your running OBD2, unless that will plug into the OBD1 P08 dont try it i guess it would be a waste of time. Otherwise test the connection to the ECU

[mr2mike]

V-Tec doesn't = turbo.

Trying to dyno test with the seat of your pants is almost useless with the gain that v-tec is going to get you.

Used to be a 10second car and now it's only a 12 because v-tec not working?

[jdm_eg6]

Originally posted by mr2mike
V-Tec doesn't = turbo.

Trying to dyno test with the seat of your pants is almost useless with the gain that v-tec is going to get you.

Used to be a 10second car and now it's only a 12 because v-tec not working?

uggh, honda hate.. Just like herpes that shits annoying pointless and it always seems to come up.

anyway...

just for comparison.
Normal D15B w/o vtec =98hp
D15B w vtec = 130hp
although some things are DEFINATLY different because vtec does not add 32hp but it does something or honda wouldn't put it on their cars! Buddy just wants his car running right.

[rage2]

Originally posted by ShermanEF9
Nah, i can feel it pull harder in my car, but its definately nowhere close to that
If you can feel vtec engage, it's not set at it's optimal point and you're making less power over the revrange than optimal.

The optimal point is the TQ crossover between low cam and high cam. So if you set it up right, there's zero TQ transition, feel absolutely nothing.

[ShermanEF9]

Really? interesting. i may have to have you look at my car haha

[D15Bee]

yea ppl i take it that the video dosn't really say anything about the VTEC.... my diagnosis of my VTEC not working is based on the fact that i did a test where i extended wires and light indicator to see if it switches on when it should.... and it doesn't....
i agree the the VTEC won't throw me back in the seat... but i need to know if its working at all... cuz reving the car to 6K with only the three valve operations is useles....

[D15Bee]

There is more bad news i'm afraid.... the water level is going down by an inch everyday in the bottle.... i have tried locating any leaks but there are none i can point to.... i did check the radiator for any bubbles but none.... i am suspecting this has something to do with the gasket... i'm going to have it checked.

[texasnick]

blown head gasket?

edit::

Here you go.

http://www.honda-tech.com/showthread.php?t=830163



I think we should get some info together and post up some common problems, and maybe even have people post in here that have had problems in the past and how they fixed them, it just seems there are alot of people doing swap or that are just having problems getting it to work correctly

i will start gathering some information but i got some work to do, in the mean time if anyone has info to add please post

Problems and causes i have run into before:

Problems usualy brake down into 2 categories and sometimes include both: mechanical and electrical. the first thing when wiring in a swap or diagnosing a problem is to check and recheck and check 50 trrilion times your wiring, and run new wires if you have to, its very important that electrical is right first. mechanical problems can sometimes be the hardest to diagnois, but there are ways of testing certian issues

*CELs and LIMP MODE, any number of things can throw you into limp mode and you definatly won't have vtec. most likely if you have a CEL fix that first then worry about VTEC. CEL can be a great indicator as to whats going on, and that light is lit for a reason. even when people say, "i have a CEL but thats a different issue" fix that FIRST, then worry about vtec. many codes that are set have alot to do with why vtec isn't working. and if your car is most definatly not acting right take apart the dash and check that your CEL light is not burnt out. it should light up when you first turn the key on.

*VSS/ SPEEDO if your car loses its speed reference vtec will not engauge. the ecu will see it just as if you were sitting still reving the engine, no vtec

*TACHOMETER i have seen a case where there was a problem with a persons tach, and i don't know where the wiring problem was, but if the ecu doesn't have a tach reference , then how is it going to know when you reach proper rpm.. exactly

*OIL, if you don't have the correct oil presure no vtec: possible causes: dented or damaged oil pan (as members have said before) , not enough oil, or oil is so old and crappy it is thin as water

*VTEC OIL PRESURE switch, The vtec oil presure switch is what feeds back information the the computer to tell it wether or not the opening of the solinoid has alowed high presure oil into the vtec oil gallerys. Once the solinoid opens oil shoud presurize the vtec oil ways pushing the locker pins into place while the oil presure sensor right next to the vtec solinoid feeds back info to the ecu.

*TEMP, the cars coolant temp needs to be at a certian temp for vtec to engage, if any of your temperature sensors are screwed up that is another possibility to look into

*VTEC SOLINOID GASKET/screen, i have heard and seen many cases where a cloged or dirty screen that is part of the vtec soliniod gasket caused vtec to not engage or be intermitant.

*THROTTLE POSITION, if your throwing a code for the TPS being bad or wacky this can also cause intermitant or no engagement, from my expermiments, whether vtec engauges or not is throttle position dependent.


Testing the mechanics of VTEC

*You want to check are that you have the appropriate oil presure at head when approching the rpm vtec engauges. I have seen motors where their just wasn't enough oil press and it doesn't throw any CEL but vtec just doesn't work and you hit the 6500 rev limit. The way to check is take the 10mm bolt out of the head that is on the front left if you are facing the motor. This bolt gives you access to the oil way of vtec, this is the same bolt that you remove to do the air presure test listed below. But anway you need to get a gauge that screws into the oil port. Now from here you have two choices. once you have the gauge installed you can either raise the car up and run the car in gear in order to simulate the speed so the vtec solinoid will open and then measure the presure OR you can disconnect the 1 pin connector from the vtec solinoid and aply batery voltage tot he solinoid in order to open it so oil can/should flow into the vtec oil gallerys. The test has to have the motor reving at least up to if not beyond 5000rpm in order to get an accurate oil reading. now what ever way you shose to get the solinoid to open with the car runing is up to you but at 5000rpm you should read a minimum of 60 psi of press at that port. if you do end up having enough oil press i would investigate a bad vtec oil presure sensor. Also not having enough oil presure can also account for "Late" engaugement, where you reach the apropriate press after the preset engaugement point and then the ecu alows vtec to engauge because the required oil presure has been met.

*Secondly you want to make sure that your solinoid is opperational, take it off and using a 12 volt source and a ground make sure that the solinoid operates quickly and smoothly when 12v is applied. this is the valve and if it isn't working vtec won't either

*Third if all else fails you can check that vtec mechanics work by using air presure(this test should then be followed up by the oil presure test) Take off the valve cover, take the plug out of the front of the head next to the header, either find a fitting that you can adapt your air hose to screw in the head or get a blow gun with a rubber tip. with another person you have to block the bleed hole on the 5th cam cap and while applying 40-60 spi of air presure , slowly crank over the motor using the main crank pully and watch to see that all 3 rockers lock togther and start to follow the middle lob, the VTEC lob. you may even hear a tiny click as the pins in the rockers lock the 3 togther. also you will be able to tell that the vtec lobe is being followed as the lift or how far the valves are pushed down is much greater. with the appropriate air presure and if everything is workign corectly every valve should be following the vtec lob. make sure that you have a good air compresor that can keep up with keeping a presure of 40-60 psi. if you don't have luck try raising the presure a littlbe bit, but i wouldn't go much hiogher than 80 psi.

once you have verified that all the maechanics are working : vtec solinoid, oil press, and valve assembly then you can move from there and see where the problem lies in wiring.

Other Info

things i haven't seen but are possible are, a faulty vtec solnoid, vtec oil presure sensor, and if your ecu is not detecting the RPM signal.

more vtec presure switch info: the vtec presure switch is jsut that , a switch , its on or off deppending on the oil presure. the ecu sends out about a 10v signal from 1 pin and runs it thru the presure switch back tot he ecu. if the presure is to low the switch stays closed and the ecu "sees" this by the 10v returning, after the vtec solinoid opens the ecu is expecting to see that the switch is opend by the oil presure and for its 10v feed back to disapear.
THE JUMPER WIRE THEORY:if you just jumper the wire your simulating a switch that never opens, on the flip side however if you just disconnect it i think the ecu is smart enough to know that before the engaugement point it wasn't "seeing" its 10v feedback so it throws a vtec malfunction. doing some testing you can get a multimeater: remove the 2p connector from the vtec presure switch , measure voltage with the ignition on between the two pins on the plug you should measure about 10v, this will indicate the wires to the ecu for the vtec presure switch are good, then turn the key off and measure for continuity between the two terminals on the vtec presure switch. seeing as this is a switch its natural state is closed you should measure close to no resistance thru the switch. now this info just means the switch is good if you read continuity thru it but that doesn't mean that the switch is opening when it is supposed to. i would investigate the presure switch further if the oil presure tests are done and found that the correct oil presure is indeed there.

also where you car is hitting its rev limiter can give away even more information, if you can only rev to 6500 and then hit a fuel cut then your not in limp mode but one of the requirements for vtec to engauge has not been met.. such as temp, oil press speed, etc..

IAB solenoid activates on a P13 (91-96) at 4600, and 4900 on a P5M (97-01)
VTEC solenoid activates on a P13 (91-96) at 4900, and 5200 on a P5M (97-01)

but if you car is only reving to (i think limp mode if 5000 rpm) then you have something seriously prohibiting the car, and most likely almost definatly your CEL should be on, and like i said fix and present codes befor eyou worry about VTEC.

and NO vtec does not engauge if you sitting still in your car and reving it, the secondary runners will open up, but the vtec soliniod will not open.

which brings me to another point, part of what makes vtec work well is the fact that right before the secondary cam profiles engauge the secondary runners in the intake manafold open up to accomadate the engines greater demand for air flow when in VTEC. some times there maybe something wrong with the wiring that tells the IAB soliniod to remove vacume from the diaphram that holds them closed. If anything is wrong with the IAB system then that can cause vtec to feel like it is not engauging. The Iabs are rpm dependant only, and the do open if you reving the car in neutal. THe Iabs are held closed when the car is idling by vacume and continue to be held closed by vacume stored in the small canaster under the intake manifold so you will have vacume to the required rpm even at WOT. With key off and no vacume the IABs open due to a spring. so once vacume is removed they just go to their rest state which is open.

[D15Bee]

thanks for the details... the web link for the gasket above is not available.. but nevermind....

now for the VTEC... well i checked the car by reving it all the way... it does hit the cutoff... so no LIMP mode.... i hit the check-light actually when i'm reving down from above 3K.... the light actually comes on when the car is decelerating. It might be telling something about the VTEC operation failing...
The soliniods are fine becuz the the engine check-light should come on immediately after strating the car as the ECU checks the solinoid for availability....
However, the oil pressure switch, the VSS and throttle positioning have to be investigated.

[texasnick]

The link above is just to honda-tech to a thread about the possible reasons VTEC won't engage.

If your head gasket is blown and as a result you have low oil pressure, VTEC will not engage. A leakdown test will determine whether or not the gasket's blown. Even if there are no tell-tale visible symptoms, you can still have a blown gasket.

I would definitely check your oil pressure switch, VSS, and TPS first though.

Oh yeah, do you have enough time when the CEL comes on to catch it? That would help you out a bunch if you could find out what code is being thrown.

[D15Bee]

There isn't enough time for me to catch the CEL but that's not a problem, i'll find out.. ..

As for the gasket, well i haven't had the time to check it... i understand that it can be blown without all the obvious symptoms.... except that the water level (in the bottle) keeps going down everyday... no oil in the plugs, no bubbles in the radiotor, no milky oil....

[LilDrunkenSmurf]

The ECU should store the code if it is a legitimate code. Even if the light doesn't stay consistently on, you should still be able to pull the code.

[ShermanEF9]

Originally posted by LilDrunkenSmurf
The ECU should store the code if it is a legitimate code. Even if the light doesn't stay consistently on, you should still be able to pull the code.

yeah it should tell you whether the CEL is on or not.. i believe it stores codes for a while

[S-FLY]

What kind of car is this in? and did vtec work then stop working or did it just never work?

[ShermanEF9]

Originally posted by S-FLY
What kind of car is this in? and did vtec work then stop working or did it just never work?

I REALLY hate to be a bastard.... but D series and VTEC really kind of point to Honda civic.... cause really.... who puts a D in anything but.