venomzz

Sup fellas I did do a search on this and found several threads showing the EXACT same problem Im having with several identical setups but no one has posted what the fix was. I checked the plugs not black at all in fact they look a little lean. All new sensors no cel.... fuel filter is fine fuel pressure is fine just changed the oil timing is perfect. Here is the kicker....when I was throwing a cel for sensors and it was running limp I was getting 270 to a tank now that everything is cool Im getting like half that.....so its gotta be the vtec solenoid right? I ve almost got this thing running perfect could someone post what there fix was before I go throwin more money at this thing

yoffer

Why would the vtec solenoid have anything do with the gas mileage? If it wasnt working properly, you would have a cel.

venomzz

in other threads a couple of people said that there vtec was engaging way too early and that the solenoid needed replaced also none of them where getting a cel with this specific problem. A bad solenoid is the only thing that makes sense being that my gas mileage cut in half as soon as I got the vtec working again. I know several others have had this same problem if you have please post your fix


Modified by venomzz at 7:31 AM 12/6/2007

Probot

do you drive foot-heavy?? and if you think your vtec solenoid is engaging too early, drive with the radio off, windows up, pretty much as little noise possible..and even have another person in the car and listen for the vtec change over. if it goes off before 5500rpm and i mean significantly..at like 4000 we'll say, then that MIGHT be your problem. do you have any mods done to the car???

venomzz

Actually Ive been driving light the the last two tanks shifting at 2500 and the vtec never even sounds like it engages at 4400-4800 another reason why I think it may be already engaged the car is moded but nothing significant.

other thread same problem
https://honda-tech.com/zerothread?id=2156356
https://honda-tech.com/zerothread?id=2130651


Modified by venomzz at 8:01 AM 12/6/2007

Probot

i once heard that vtec wont engage unless you're at full throttle (meaning pedal to the floor, not top speed) - but i dont know how much (and i doubt alot) truth that holds. and if you have atleast an intake on the car you'd probably hear the change over. try a solenoid from a different civic?

BryanM.

iTrader: (1)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Probot &raquo;</TD></TR><TR><TD CLASS="quote">i once heard that vtec wont engage unless you're at full throttle (meaning pedal to the floor, not top speed) - but i dont know how much (and i doubt alot) truth that holds.</TD></TR></TABLE>

100,000% untrue. You just can't hear it engage very well unless you're at like 1/2-3/4 throttle.

BryanM.

iTrader: (1)

Maybe you have a FI stuck open. Or 4 of them. Would not set off a CEL.

Probot

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

100,000% untrue. You just can't hear it engage very well unless you're at like 1/2-3/4 throttle.</TD></TR></TABLE>

yea, i figured that full throttle rumor was false - but i can hear my vtec engage when im at full throttle and im running d16y8 with just an intake.

MustWonder

It's a single cam just unhook vtec you shouldnt be racing anything with it anyways. unless you have some nasty setup unhook it and go back to 270 a tank.

MustWonder

also maybe check your injectors is it possible you bought this motor used and someone had swapped out injectors with bigger ones. or yours or just totally clogged.

Probot

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MustWonder &raquo;</TD></TR><TR><TD CLASS="quote">It's a single cam just unhook vtec you shouldnt be racing anything with it anyways. unless you have some nasty setup unhook it and go back to 270 a tank.</TD></TR></TABLE>

this whole thread has NOTHING to do with racing.
try reading next time
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by venomzz &raquo;</TD></TR><TR><TD CLASS="quote">Actually Ive been driving light the the last two tanks shifting at 2500 and the vtec never even sounds like it engages at 4400-4800 another reason why I think it may be already engaged the car is moded but nothing significant.</TD></TR></TABLE>

BryanM.

iTrader: (1)

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

yea, i figured that full throttle rumor was false - but i can hear my vtec engage when im at full throttle and im running d16y8 with just an intake.</TD></TR></TABLE>[QUOTE=Probot]

Honestly Probot, I have never heard VTEC engagement on a D motor. I really thought you were refering to B motors. The reason, I believe, is that D VTEC motors only have extra camlobes over the intake valves. With a B VTEC you get that dramatic exhaust note change.

venomzz

I pulled this off another thread

If the diaphragm on the FPR has ruptured, raw fuel will leak
into the intake manifold and cause a rich condition affecting
fuel mileage and hot engine starts. If ruptured it will act
much like an applied choke on a carburated engine
(aiding cold starts and hindering hot starts).
To check it, simply pull the vacuum hose with the engine
running (or key on, engine off) and look for fuel leaking
out of the nipple. There should be none.

Someone also had this exact problem with a non vtec d15
Another person tapped into there FPR vacuum line to hook up cruise and had a similar problem I appreciate your help guys if you come across anyone who was gettin 15mpg on a D16 will you post what there fix was I am starting to think fuel pressure regulator.

Probot

hmm, id say check that out then venomzz

and yes, vtec on a d series is audible, you just have to listen for it. and if anyone says they dont hear then perhaps they dont know what they are listening for or have other **** in the background. is it alot easier to hear on a b series?? of course, but it is audible on a d series.

its more emphasized on d series when you have an intake - i have the password jdm cf intake and i can hear it fine. its just alot more audible on a b series because of the cams.

BryanM.

iTrader: (1)

Very easy to hear on any dual cam VTEC motor, especially with I+E. The loudest I've ever heard is H22 and it had zero mods.

venomzz

Hoping someone with the same prob will see this

SilverCG

it is audible in a D its not as noticeable or dramatic as in a B tho. lol you just have to listen for it windows up and no radio.

The Lobster

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SilverCG &raquo;</TD></TR><TR><TD CLASS="quote">it is audible in a D its not as noticeable or dramatic as in a B tho. lol you just have to listen for it windows up and no radio.</TD></TR></TABLE>

you can hear it in a D.

its all in the cams. I have stage 3 cams and trust me i can hear it and feel it in my SOHC.

anyways back on topic im sorta at lost with all these off topic conversations.

you are asking why your fuel consumption has gone to **** right?

did you check your PCV valve? if its clogged youll get **** for mpg also.

venomzz

Ya as soon as it stops fkn snowing I am gonna check the pcv valve and the fuel pressure regulator before I go messing with the vtec ....its hella cold out...I hate Kansas

RYNO48

Like he said PVC is a good one. Same with any other hoses. However when I was getting poor performance and gas mileage it was a clogged cat. When you take it off hold it up to some light and if you all you see is darkness then its time to get a new one.

venomzz

No cat just straight pipe no emission checks around here I do run a silencer but I don't think that would have anything to do with it unless my muffler or straight pipe got clogged up some how

SilverCG

i know this might be a stupid question. but im just trying to learn and i know i will most likely be flamed. but where is the pcv valve located. Im also getting shitty gas milege in my D16y8.

mortificationrock

In for some answers or suggestions my **** has same problem! Gas mileage sucks about150-170at best per tank!

96 EX

Ok for gas mileage you need to check everything you normally would air filter ect ect ect an go from there. How longs it been since you did a tune up? As for the vtec on a SOHC you can hear it w/ just an intake its nothing big but you can hear it.