Hi guys. It has happened before but now almost every day when I reach higher rpm about when Vtec is actuated, my car cuts out and feels like a rev limiter, very violently. I have searched this problem but it looks like its more common in honda 4 cylinder engines. I have no engine codes so far and I checked with my scanner. I do not know when my valves were adjusted so I will do that very soon. It is not low on oil and it isn't due but Im probably going to do that also. This is a manual car so it is not the transmission. Any help is appreciated and my apologies if I skipped over any previous threads but I could not find any like mine. Thanks

 

at what RPM does it fuel cut at ?

 

Right about 5500 id say, maybe a little lower. I am new to vtec but Ive read there is a solenoid that may be to blame. I only use 93 octane btw

 

just confirming it is indeed the vtec cutoff and not the 7200 fuel cutoff.
Have you researched the APP sensor? Accelerator Pedal Position..a bad APP can put the car in limp mode, preventing you from accelerating past 5000 RPM

 

I have but I didn't think it would be that with no CEL, but I will research that now. I get a decent deal on Honda parts so I'll ask my friend.

 

I believe some have had good luck changing out the APP, while some say it didnt make a difference...
anyway; we've got you closer to the suspected parts...either the vtec solenoid or the APP sensor

 

Okay awesome, I will research both, Im sure the app is easier and less expensive. I was just making sure it wasn't anything internal. Ill report back after I replace APP

 

research first!!!
another test is to see if you can recreate with cruise control

 

Sounds good, you mean set cruise then accelerate with cruise controls to the high rpm? Not a bad idea

 

So Ive realized that if I gently roll into the throttle it will not cut out but if I stab the throttle from a stop it will break up about 5k. Also on the way to work it threw a CEL so I will scan it after work and see what it says.

 

So I checked the codes and all cylinders except 1 and 3 are misfiring and also p0134 came up. Im going to check a couple plugs and see how they look.

 

could also be coilpacks...

 

With misfires it could be spark plugs, coils, or injector. Usually if I only one misfire I switch around the coils and see if it moves. Could a bad o2 cause this?

 

^^^ No, another thing that easily got over looks is that possible that your MAP/MAF sensor is on its way out.

 

I didn't think so either. I know there is an issue with one of the cats because the car smells pretty bad when driving harder. I really need to adjust valves and replace all the plugs, Id replace the plugs before but the seals are bad so I wanted to do all the gaskets at once when I tear it apart for the adjustment. Ill see if theres a way to test the MAP sensor.

 

unfortunately no, my Lexus has a bad MAF and I tried all methods prior replace it with a Denso one. Symptom is similar to yours except it much more consistent when hot and around 4k I got similar "fuel cut" funny thing is it never throw a CEL either.

 

Ill try and clean the MAP sensor later, at least Ill take off the inlet tube to TB and see how dirty the TB is. It's a damn shame when your Honda can't hit VVVVTTTTEEEECCCCCCCCCCC

 

^^^Especially you have MT

 

Yup haha car is a lot of fun. Hopefully I figure it out soon

 

So I feel really dumb because Ive been wrenching and modding cars for a while but last time I checked my oil it was within the lines, I checked yesterday and had to add almost 2 quarts of oil. Now it goes to redline no issues and runs fine. I go to Honda for oil changes because nowadays its just so inexpensive, plus they use oem filter. I always check level after I go. Its been about 4,400 miles since last oil change. 2 quarts of consumption is not horrible for a high mileage car but was wondering your guys' thoughts. Anyways Im doing the valve adjustment in the next week or two and Im also going to change the pcv valve and spark plugs. Thanks

 

Maybe the low oil level caused some sort of issue with the VTEC solenoid at high RPM's. That's odd that it would throw a misfire code though.

2 qt's of oil in 4,400 miles isn't ideal, but I wouldn't sweat it too much either. I might have missed it, but how many miles do you have?

 

Yeah I think theres still something else going on also. It has 183k miles, TB and WP service done about 160k miles. I asked last owner about spark plugs and he did not know if/when they were changed. When I checked a couple they were full of oil from the valve cover/spark plug well gaskets being rock hard. All of this will be replaced soon.

 

My '07 TL Type-S 6spd just started doing the same thing today! I have not yet done anything to diagnosis the issue, but this thread has been helpful as a place to start. 90foxnotch, did you resolve the issue???

 

 

That's great to hear, I bet it will be the same for me! Yeah I miss hearing her howl! Thanks for the reply!

 

 

Lol, confirmed. If your oil is low, but not low enough to register as a warning light on the dash, Rev limit is reduced to 5,500 rpm.

 

Exactly this. VTEC activation requires proper oil pressure (as many of you know)

 

It's not that it's low oil pressure it's low oil volume. Even a temporary loss of oil pressure, or low pressure, would trigger a flashing oil indicator on the dash. The reduced rev limit is caused by a lack of oil volume since the VTEC System is actuated with oil acting as a hydraulic fluid. If there is not enough extra fluid to activate the VTEC System the ECU triggers the reduced rev limit.

 

smh.....

 

Honestly Ive never had a car do that to me, my Fords will be a quart or so low-during a 3-5k oci- and they have never cut out at high rpm. This motor is pretty cool that it will try to prevent some damage due to low oil.

 

Vtec works base one engine oil pressure and with modern car the PCM got involved as well, its common for you not experience that since ford doesn't use any variable valve timing until mid to late 2000s (its doesn't call Vtec but its similar concept)

 

That's pretty cool stuff. Ive got a few things to learn about on my coyote. It will be the most advanced engine Ive had in the notch

 

yeah the Coyote has variable valve timing and adjustable cam shaft on intake and exhaust, A lot of Mustang fan making fun of Honda Vtec but they fail to realize Ford utilize the same technology.

The 2018-2019 GT 5.0 motor actually use the same technology found in Lexus ISF (07 IS350, GS350, GS460 and LS460 using the same concept) where it feature 16 injectors total (8 for direct injection and the other 8 for port injection) depend on engine load and speed it can switch between DI or Port injection, lead to better fuel economy and solve the issue of carbon deposit on the back valve in DI car.

Ford is the ONLY domestic company adapt foreign technology and so far they doing pretty good. DOHC and dual injectors tech explain why Coyote motor out perform LS series (HP/ litter) every time.

 

Yeah man the VVT is pretty cool stuff, the direct injection Im not very familiar with but I know tuners are a lot more comfortable with it now than when cars started coming out with it like the mazdaspeed3's. Yes Id say Ford is doing awesome but then I also heard terrible things like the new gt500 not being offered with a manual. Shelby would be furious haha Along with the great fuel injection they are now making the new engines capable of a safe and somewhat reliable 900hp. The new 10 speed is also a great addition