High RPM Sputter - PLEASE HELP!

[Steven Johnson]

What's going on everyone? I recently bought a 1998 Civic EX with a D16Y8. It has 195,xxx miles on the car and it's a 5 speed manual transmission. I'm having an issue that's driving me insane and I need to get it fix before going on a quick vacation that I need to drive the car 4 hours.

ISSUE:
Car drives no problem, until I cross over into vtec/high RPM. The car feels like it's slightly sputtering. Since I'm currently tight on money, I'm trying to take it from the cheapest fix possible, then work my way up.

WHAT I'VE DONE:
I've changed the oil - 5W30 Mobile 1 High Milage Full Synthetic
Changed the spark plugs - basic NGKs
Changed the spark plug wires - OEM replacements from Advanced Auto
Cleaned IACV
Cleaned Throttle Body

Haven't done anything else, however, I do have a CEL on and it's the P0325 code - knock sensor. Could this be causing my issue? Regardless, I already have the knock sensor, just need to install it. Previous owner bought it and didn't install it before selling to me.

I'm thinking that maybe I need a new fuel filter? Possibly clogged and not getting enough fuel for the higher RPMs....or could it be my solenoid? I'm lost and don't know where to start next. Any input is greatly appreciated.

 

[Steven Johnson]

Later on this evening, I should be changing out the Knock Sensor. Gotta go pick up a new 27mm deep socket, can't seem to place my finger on my larger socket set. Oops. I'll keep everyone updated to see if that helps my issue.

 

[XpL0d3r]

Replace the knock sensor. Knock sensor code will prevent vtec from engaging.

 

[Mr.Baker]

I'm thinking that maybe I need a new fuel filter? Possibly clogged and not getting enough fuel for the higher RPMs....or could it be my solenoid? I'm lost and don't know where to start next. Any input is greatly appreciated.

At what RPM does it cut out at?
Is the car in "limp mode"?
I'm just curious.
If it's reaching over 3k or so, it's prob not your vtec solenoid.
I'm just curious.

I doubt it's a fuel issue though, but on't over think it and start throwing money at it with parts that may not fix it.
If you have a code for knock sensor, and you have one, install it, clear the code and drive it in order for it to reset to see if that fixes the issue.

 

[XpL0d3r]

From what I got out of it, RPMs still climb but Vtec does not engage. This makes sense because Vtec wont engage unless it gets a reading from the knock sensor input to the ECU. No reading - no Vtec.

 

[Steven Johnson]

At what RPM does it cut out at?
Is the car in "limp mode"?
I'm just curious.
If it's reaching over 3k or so, it's prob not your vtec solenoid.
I'm just curious.

I doubt it's a fuel issue though, but on't over think it and start throwing money at it with parts that may not fix it.
If you have a code for knock sensor, and you have one, install it, clear the code and drive it in order for it to reset to see if that fixes the issue.

It starts to slight sputter around 5.5k-6k, so up there under heavy load. Definitely NOT in limp mode.

Replace the knock sensor. Knock sensor code will prevent vtec from engaging.

From what I got out of it, RPMs still climb but Vtec does not engage. This makes sense because Vtec wont engage unless it gets a reading from the knock sensor input to the ECU. No reading - no Vtec.

The vtec still engages right around when I start to slightly sputter, which is a bit odd by your statement. If I'm getting the P0325 code for the knock sensor and you say that it would NOT engage on a bad sensor, then why would it still be engaging?

Regardless of the fact, I'm getting ready to head to Lowes now to grab a new 27mm deep socket to get this sensor fixed. Wish me and my fat hands some luck in that tight sensor location!

At the end of the day, my main concern is getting this car to Vermont for my family vacation, and then back home. After that, I have some plans to eventually swap the K20 in her. I owned an 07 Si with 225 whp, so I'm extremely familiar with the K platform. Just had to get rid of the car because I had a son and lost my last job.

 

[lethal6]

According to Honda VTEC will NOT engage if a CEL is lit that has to do with the engine or any one of the sensors. Unless there is something that was changed or tuned in your ecu or you have some sort of aftermarket VTEC controller that is bypassing Honda's maps.

These are the main parameters that need to be met for VTEC to engage:

In order for the ECU to initiate the VTEC system, 5 engine conditions must be met.

1 - Temperature: The engine must have reached normal operating temperature.

2 - Throttle Position: The throttle must be open far enough to allow for increased airflow in VTEC.

3 - Vehicle Speed: The car must be in motion (wheels spinning).

4 - RPM: Engine must spin to the RPMs that the ECU has programmed for your specific motor to engage VTEC.

5 - Oil Pressure: The engine must be operating with normal and safe levels of oil pressure determined by the VTEC pressure switch.

Any of these not met, as well as the CEL being on for something engine related and VTEC is not kicking in.

 

[Steven Johnson]

According to Honda VTEC will NOT engage if a CEL is lit that has to do with the engine or any one of the sensors. Unless there is something that was changed or tuned in your ecu or you have some sort of aftermarket VTEC controller that is bypassing Honda's maps.

These are the main parameters that need to be met for VTEC to engage:




Any of these not met, as well as the CEL being on for something engine related and VTEC is not kicking in.

Hmm, pretty interesting. Thanks for the information. If this is true, then I'm lost in general. When I had my 07 Si and had a CEL for my O2 sensor since I was catless, I was still engaging?

On this D series, it certainly sounds and slightly feels like I'm engaging. So if what Honda says is true, then my latest two cars must be interesting to their own specifications.

 

[lethal6]

Don't know about the 8th gen as they are different motors altogether. K-series is in it's own world.

You aren't feeling vtec on a tiny single slammer anyway. They don't "kick" like a DOHC, b-series, or bigger engine. Hell my d15 non-vtec felt like it had vtec crossover when hitting higher revs and it was impossible with no vtec head. I have no clue what it is you are feeling. Perhaps the stutter makes it kick throwing a false impression.

 

[XpL0d3r]

How do you know for sure Vtec is engaging? It's not nearly as much of a kick compared to B/K series motors. I ended up wiring up a Vtec light when I did my mini-me swap. That way when I hit the crossover point I KNEW it was engaging. You can wire up a light to test it, but I would still replace the knock sensor first and go from there.

Vtec does not slightly engage -- it's all or nothing.

 

[Steven Johnson]

Don't know about the 8th gen as they are different motors altogether. K-series is in it's own world.

You aren't feeling vtec on a tiny single slammer anyway. They don't "kick" like a DOHC, b-series, or bigger engine. Hell my d15 non-vtec felt like it had vtec crossover when hitting higher revs and it was impossible with no vtec head. I have no clue what it is you are feeling. Perhaps the stutter makes it kick throwing a false impression.

The crazy party is, I swear it's crossing over and staying crossed over. I know my

How do you know for sure Vtec is engaging? It's not nearly as much of a kick compared to B/K series motors. I ended up wiring up a Vtec light when I did my mini-me swap. That way when I hit the crossover point I KNEW it was engaging. You can wire up a light to test it, but I would still replace the knock sensor first and go from there.

Vtec does not slightly engage -- it's all or nothing.

How do I know? Well, it's not my first rodeo with any Honda engine. You can still hear the crossover if all you have is an intake. You still can feel the slight power increase. Obviously it's all or nothing, I'm using the word "slightly" to help describe what I'm feeling.

 

[XpL0d3r]

But if the engine is sputtering at that RPM, are you sure you're not confusing that with Vtec engaging?

Go wire up a light and be sure. Get a LED and power to green/yellow on ECU.

.. after you replace the knock sensor, if the issue is still there, of course.

 

[Steven Johnson]

But if the engine is sputtering at that RPM, are you sure you're not confusing that with Vtec engaging?

Go wire up a light and be sure. Get a LED and power to green/yellow on ECU.

.. after you replace the knock sensor, if the issue is still there, of course.

Trust me, I'm not confusing it. Regardless, I'll keep you posted after I swap the knock sensor out. Ended up getting rained on yesterday, but today is looking beautiful.

 

[XpL0d3r]

Sounds good, let us know how it goes.

Also, for reference: http://honda-tech.com/honda-civic-del-sol-1992-2000-1/would-knock-sensor-cause-vtec-not-work-1907936/

 

[Steven Johnson]

Sounds good, let us know how it goes.

Also, for reference: http://honda-tech.com/honda-civic-del-sol-1992-2000-1/would-knock-sensor-cause-vtec-not-work-1907936/

Hmm, I'm going to go check out my wiring. According to this dudes problem, as well as some confirmation in the thread, vtec won't engage and it will go limp at 5k and won't rev out. I'm able to rev all the way to redline and it DOES engage. So....idk. Let me go see if the solenoid is being bypassed through the ECU or not.

 

[Steven Johnson]

Time for a good ol' update, because I'm not a happy camper.

As I was under the car, I noticed I was leaking oil from my drain plug. Fine, let me tighten it, no problem....right? WRONG! The drain plug is the wrong size. Guess my friend didn't realize this when he changed my oil. Thought he knew cars, guess not. I'll be doing everything from now on.

Ok, as I was under the car, for some reason, I decided to check out my transmission to see if I was leaking trans oil. I've been grinding third every time on cold start. Needless to say, I found out the flywheel cover is missing, so my flywheel is open to the environment. That's not normal, I don't assume. LOL

Well, that got me thinking - did I buy a swap car? Let me go check some other key signs.

The bolts holding all the motor mounts are different bolts, some seem new, some seem like new threads. Also noticed a lot of things were just thrown in the car and barely tightened. So, I've come to the conclusion I have a swap car. Awesome....

Regardless, I plan on swapping with a K or B in the near future. Just needed to get this car to Vermont. Don't really trust driving it there with my flywheel open like it is. Also, my wheel bearing is going on the driving side. When I had the car jacked up, it had a lot of play. Doesn't feel safe to put my girl and son in the car and drive for 4.5 - 5 hours.

Ok, so let's talk about this knock sensor.

So this picture below, you see that green thing. It has the EXACT same connector as the knock sensor. First impression, I thought this was the knock sensor until I dove into the engine and found it on the block. That's when I discovered that the original knock sensor wasn't plugged in....at least not to a wire. It had the connector on the plug, but the wire was missing.

So, here's my question. What is this "green" sensor in the picture? Did the guy bypass the knock sensor?

I installed the new knock sensor and plugged the connector that was in the green sensor into the new knock sensor and the check engine came right back and the car feels NO different. So, now I'm scratching my head.

 

[Steven Johnson]

Anyone have an idea on what I should do next? Do you have this cover piece for my flywheel?

 

[Killa_CiViC]

D16Y8 has an aluminum oil pan... it's very likely your drain plug is not the wrong size, it's very likely stripped out. I've seen this issue a lot. At 190k+ miles, I wouldn't doubt this a bit. You can either replace your pan, have a helicoil or time-sert installed, or just find a longer bolt the same thread pitch.... there are often enough threads left deeper in, that a longer bolt works ok.
You are also missing the flywheel cover, and a bracket. It's not the best idea to run around with the cover missing, but it's not what's causing your issues.
Problems at higher RPM... did the same knock sensor code come back after you installed it? Knock sensors have to be installed at a specific torque to function properly, so did you torque it to specifications?

Also... go here. Download this and study it, if you haven't already. http://www.manualslib.com/manual/464698/Honda-Civic.html

 

[Steven Johnson]

D16Y8 has an aluminum oil pan... it's very likely your drain plug is not the wrong size, it's very likely stripped out. I've seen this issue a lot. At 190k+ miles, I wouldn't doubt this a bit. You can either replace your pan, have a helicoil or time-sert installed, or just find a longer bolt the same thread pitch.... there are often enough threads left deeper in, that a longer bolt works ok.
You are also missing the flywheel cover, and a bracket. It's not the best idea to run around with the cover missing, but it's not what's causing your issues.
Problems at higher RPM... did the same knock sensor code come back after you installed it? Knock sensors have to be installed at a specific torque to function properly, so did you torque it to specifications?

Also... go here. Download this and study it, if you haven't already. http://www.manualslib.com/manual/464698/Honda-Civic.html

I'll probably just end up replacing my pan, makes more sense and probably better to know it's all new. Same code came up after I installed the sensor. Never heard that I needed to torque the sensor to anything specific. Literally, first time I've EVER heard that. I still think the previous owner bypassed the sensor and messed it up.