kherr86

Ok, I had some issues finding an ECU for this car and finally found a p28. Now I was reading and according to some people it should be a p28-A02. I have a p28-A01, does this make a difference? And does it have to do with why my vtec isn't engaging? I already cleaned the cylinoid and checked the oil and wires.

HondaPartsHero

Is your check engine light on? What does the engine rev to?

crazyhouse2011

IIRC, the a02 and a01 are essentially the same, manual trans ecus. you would need to be worried if you had an a51 ecu, which is automatic, which i have in my manual EJ1 and somehow works with no CELs ever.

kherr86

It's revving to redline, which is 6500 but I don't feel any pull at 4800 at all. No check engine light is not on. I was told its a smooth transition but I would think I'd feel it pull a little.

kherr86

after reading up on stuff, ppl actually push it past 6500????? To me thats insane cause I don't wanna blow something up. And my performance tach does read different then the stock one....why would that be?

crazyhouse2011

Its a smooth transition, but you definitely feel it pull. Don't listen to any potential twin-cam members coming in here saying "blah blah blah single cam is weak blah blah". because i hit vtec at least once a week, and yes, the engine note does get richer (i have the same engine), and you feel the torque building up. it's really enthralling because youre used to shifting below 3500 revs in most daily situations, so when you finally climb the revs and get to the torque peak it feels like your car is really fast. And D16Z6 redline is 7200 with a fuel cut at 7411 rpm. There is a certain set of criteria that must be met in order for the ECU to "clear" the VTEC engagement. I'm gonna list as many as i can remember:
Vehicle speed must be greater than 20 mph
Coolant temperature must be [not sure of exact temperature, but engine has to be warm]
Throttle Position must be 100 percent
No CELs

I think there's a criteria related to oil pressure too, but i can't be sure. I'm sure RonJ can chime in on this.

crazyhouse2011

The stock tachs on these civics are notoriously inaccurate, especially at high revs. My EJ1 tach read over 8000 revs when i was trying to hit my fuel cutoff (7411 revs), and i didn't even hit it yet! I was scared so i didn't try it again. I bought the Omni Power replacment tach, it goes right where the OEM one sits, and is really neat. It's also incredibly accurate. Once I put mine in, i took it for a redline run, and the fuel cutoff kicked in when the gauge indicated roughly 7400 rpm. I'm quite pleased.

And as for blowing something up, i wouldn't worry too much. An occasional trip to redline won't hurt anything, there's a reason people say these honda engines are bulletproof.

ej1b18c1

If the valve adjustment is too far off it will not engage. Also if the temp is not warm enough it will not work. MPH plays a roll as mentioned above. Oil pressure, so you got to have enough oil as well, I've seen dirty enough oil cause it to not work. Poor ignition timing.

Do you have a CEL or know that for sure the CEL works? Have you opened up the ecu to make sure nothings burnt? How do you know it's not working, sohc vtec does not get as loud usually.

A properly tuned vtec engine should have a smooth transition into vtec. Don't listen to fanboys that say my vtec cracks hella hard YO!

HondaPartsHero

I would say hook up a test light and see if it comes on at the VTEC point but if it revs to 6500 (probably its higher but the tach is inaccurate) then VTEC is working. I've never driven a SOHC VTEC that "pulls" at VTEC.

crazyhouse2011

You can definitely feel it pulling harder when you reach VTEC on a d16z6 IMO.

doctorake

Also this? Does your CEL light up when turning the car on.

HondaPartsHero

Ha not a twin cammer at all since waaaayy back when but I can tell you every SOHC VTEC, Civic, Accord, etc VTEC is barely noticible. Either way do the light test as above and see if it lights up.

kherr86

Cell light doesnt come on and ok i'll check the light. Thanks for all your posts

B serious

iTrader: (1)

You guys can "feel" single cam VTEC? Y'all got imaginations.

It will be a smooth transition. Single cam VTEC only engages on the intake lobes. So if you have an exhaust, it will drown it out. If you have an intake, it will magnify it a bit...but you won't hear it all the time.

IIRC, rev limit is 7200 or 7500. I would recommend revving it that high at all times. You won't break anything.

Vladglad

what if its not a smooth transition then what ? on my miniswap when vtec hit i could feel the enganement but on my freinds Gsr you can hear it and its a hella smooth transition just curious why

B serious

iTrader: (1)

Usually, GSR VTEC (4400RPM) is smooth and you can barely hear or feel it...unless you have an exhaust. You definitely hear AND FEEL the intake butterflies open at 5700RPM. People mistake those for VTEC on B18C1's.

Twin cam VTEC operates on the intake and exhaust side. So usually its more noticeable.

Typically, VTEC is more dramatic and noticeable when it's set at a higher RPM and/or there is a bigger difference between low cam/high cam profiles.

SOHC engines engage VTEC at a relatively low RPM. The cam differences are not quite as big between high and low cam. And only the intake profile changes. So...it's less noticeable than DOHC VTEC.

Ideally, you want a smooth transition that makes a lot of power anyway. But...with a stock cam on DOHC VTEC engines that actually make power, they give you an idle/emissions friendly, semi-torquey motor at low and mid RPM...and then a big *** high cam that can fill the cylinder at high RPM. So...the transitions are more dramatic.

TomCat39

Looking at Dyno runs, there shouldn't be a major difference in feel when vtec kicks in on the SOHC motors. On the graphs it's just a nice smooth climb.

The difference will be is it just keeps climbing in power over the non vtec that just caps out and doesn't give you any more after a certain rpm.

To feel a difference you have to have a pretty sizable spike in power (which is obviously not linear) which would also be a major spike on the graphs. What the dyno's show is a pretty linear climb, the vtec stops the plateu affect and gets you more climb on the power graph, but pretty linearly with the SOHC engines.

NotARaCist

iTrader: (1)

It should be linear with all motors, not just SOHC motors. A "peaky" dyno graph is the sign of a bad tune, or a peaky aftermarket cam. You shouldn't "feel" it, especially not on a single cam motor.

crazyhouse2011

I don't care what all you are saying, at roughly 4800 rpm my car pulls harder. Not rocketship harder, but you definitely feel it in your butt dyno. The pull is there for me. you just gotta relax and let yourself become part of the car.

HondaPartsHero

That's cool bro, either way

https://honda-tech.com/forums/hybrid-engine-swaps-18/%5Bfaq%5D-%22my-vtec-doesnt-work%22-1812135/

Vladglad

That's explains my Freinds GSR why it's so loud at 5700 made me think it was VTEC enganement