no vtec??? hesitation? (i've searched!!)
 

I first want to say that I have searched for this topic, and the topics i have found really don't go into detail of what could be wrong, so.....

I have had my 1999 Civic Si 5 speed for about 7 months, when I first got it, it ran great, it still does, now I know that the DOHC has a nice song when Vtec hits, unlike the SOHC, but how do you really know when it engages? AND yes, it is the Vtec block, D16Y8, stamped on the block...

also, when i am starting out, if I don't rev the car up in the 2-3000 rpm mark before releasing the clutch, it boggggs under load until the revs get up there, then it jolts forward, it started to do this within the past couple months, 2 i'd say, and its now the cold weather, I always have to give er lots of gas to get going off the start, any reasoning?? besides replacing all the plugs, wires, dizzy, etc.etc? cause I have done that already....any help appreciated! thanks,

Kevin.

what size headers do you have? maybe ur just feeling some poor lowend power...
Im not a pro but it seems like its a bigger problem then just plugs n stuff, I think your clutch might be worn off a bit.

Is this your first 5spd or have you had experience driving 1 b4? I know these are pretty stupid questions but sometimes ppl tend to overlook the obvious...

i've been driving standard for a good 5 years now, so i know thats all good, it might be the clutch, im not sure...the headers are stock 4-2-1 headers, good size actually, i was impressed...but other than that, it just seems like to LITTLE low end power ya know? it bogs pretty bad...

mine bogs a bit, but I only have to bump it up to 2000 rpm to get it moving from a stop. Ive got pretty decent size racing headers...the bigger the pipe the badder low end power u'll get. How does it drive 100kms\hr+ ? Winter shouldnt really be the reason tho..Im guessing the clutch was just at the point of wearing out. btw...what rpm do you hit vtech on? just curious cuz Ive never tried hitting on my 95 si.

VTEC activation on a d16y8 or d16z6 should be right around 4500rpm provided the car is up to operating temperature. If your low on coolant or low on oil OR the screen on your vtec solenoid is clogged with sludge your vtec will not "activate".

As far as vtec is concerned on a d-series, with a stock intake it is difficult to hear(especially the 7th gen) but you should notice a bit more pull through the seat of your pants, especially if you've driven a non-vtec d-series.

A fewquick questions regarding the bogging issue:
1)How many KM are on the car?
2)Does your car flash any codes when you check the ECU?
3)When was the last time you changed the O2 sensor?
4)When was the last time you cleaned the throttle body?
Any of above listed could possibly make your car unresponsive at the low end, best of luck.

And Green_Gobblin, what do you mean you haven't hit 4500rpm?

would vtec not hit if the car is cold??

how do you clean this screen??

will the 02 sensor really do that much, how about a cat as well, how can you tell when they are clogged? or can't you? i haven't replaced the 02 sensor yet, i actually think it is stock, and origional...

177 km on car, runs 110% besides the hesitation, thanks for the response

kevin

well I just havent, I baby my car and dont try taking it above 3500 rpm, and my car revs pretty low surprisingly...I'll be on 3200rpm going about 130kmh...in 5th. and I usually shift up everytime Im on 3000rpm.

I think I may have gone 4000rpm once but I dont remember feeling or hearing the vtech kick in.

Id love to race n hear the vtech n all that jazz, but Id also like to keep my car for a while without having major issues.

i thought vtec crossover on SOHC VTEC was at 5500. Thats what i remember it to be when the stock d16z6 was in my car.
I couldn't really feel/hear a difference when vtec crossed over even with an intake and exhaust.
I wouldn't just clean the screen, i would replace it. Its only $20 from honda, if its clogged or really dirty then replace it.
In order to do so, all you have to do is remove like 3 bolts that hold the vtec solenoid (or spool valve as honda calls it) to the cylinder head. Make sure to clean all of the oil that spills out though and that the mating surface is nice and clean before putting it back on.
Brad, with a stock ecu, vtec won't x-over until it reaches normal operating temperatures. You can eliminate this by chipping the ecu and changing the option in crome/uberdata. But IMO its a good thing to keep it so that vtec won't crossover until its warm.

i had a 99 el and i could mildly hear the vtec kick in after i installed an intake pipe. as for the bogging issue, i'd maybe consider checking the map sensor as well as the other items mentioned in the above posts.

andrew your right, vtec hits at 5500 rpm on a d16y8.

and on a d16z6 b/c thats what used to be in my car.

ok, all sounds good, ill try all the different sensors that i need, ill replace them, as well as get a new vtec solenoid screen as well, ill see how that all works out for me! thanks for all the opinions, any other helf would be appreciated! thanks all,

kevin

reset ECU for as long as you can and then see if it persists.

will do, thanks all

game.

i had a y8 in my ek and 3.3rpm boom the vtec kicked in hard i duno what was done 2 te motor but i knew wen it hit:)

all of a suden it was if u woke up the motor from a sleap it would rev like **** and off u went :) then it blew up :( i spun a bearing and was never able 2 find out if the motor was stock or not i got ****ed on a swap with lucky star japan auto :( nasty people

then my y5 was installed and baghh pos motor i had vtec for about 2 weeks then it quit

AHAHAHAHAAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAH




BAH HAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHA

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