Hey guys, very long time lurker here..

I recently bought a car that has me stumped. It's a 95 accord ex (f22b1) auto, it's all stock. It has had an issue where it'll run out of steam as 4k rpm approaches. Initially it threw a code for oil pressure but I then determined the head gasket to be questionable so I replaced it, along with the coolant, oil, t-stat and associated gaskets.

Again, threw code for oil and still no power past 3800ish.. I bypassed the oil pressure sensor since I knew the oil was good and full. This time, no code, but also no improvement.

I have cleaned the gasket screens and tested the solenoid (clicks, not ohms) also.

I'm also noticing that when I try to push it past 4k, it'll get all nasty and stinky on me, but won't continue revving.

I don't know where else to turn other than bad ecu? Well any input from the pros will be more than helpful. Thank you in advance.

 

IF the oil pressure sensor is leaking then it may be faulty. If it throwing a code due to low oil pressure do not override the switch.
It is designed to prevent damage to the engine if there is low oil pressure. Albeit with inadequate oil pressure even with everything bypassed the VTEC system may not properly operate.
Verify with a pressure gauge that the oil pump is putting out enough pressure.
Also verify that the VTEC solenoid screen is not coated in junk. If it is oil will not pass to activate the rockers/high lift lobe.

 

The sensor itself isn't leaking. I only bypassed the sensor to verify that it wasn't a bad sensor, since I know its not that, I reverted the bypass. I'm going to check the oil pressure and report back.
I read somewhere about a plug in the head that deverts oil? Maybe someone took that out at some point and didn't put it back? Idk.. I'm also going to have to check the passages between the head and vtec solenoid assembly. The screen is clean.
I took off the solenoid itself to see if that screen was clogged, and there's no screen. But one thing that I noticed was that there's no plunger either. Is that normal for this motor?

 

Honda Automotive Parts

There should be spool valve and spring. The unmarked parts inside #9 are missiing?
If the spool valve is missing then I would think the VTEC would be on constantly, if not a constant oil leak. Although this would cause rough running at lower RPM and the engine would be able to rev freely above 3K rpm.

Verify that the VTEC spool valve base has not been plugged/modified to prevent oil passing through it, this would prevent VTEC actuation.

 

What exactly are the codes it is throwing ?

 

Correct, those parts are missing. It idles pretty good for being close to 200k miles. I wasn't able to work on It today but hopefully tomorrow will be more productive.

 

It throws code 22.. And it's only when I'm getting on it pretty good, the RPM's will get close to 4k and the car will just float there.. Then the code pops up, I let off the gas slightly, it up shifts and begins pulling again.

 

Okay, upon further inspection. I'm only missing the top spring from the plunger assembly..

 

I wasn't able to do an oil pressure check, but i changed the oil and filter again, completely cleaned the vtec assembly, used a wire to check the passages for blocks... There's no oil leaks or coolant leaks. Tried again this am and it climbed to about 4200rpm and then floated, cel, let off the gas and that was that. Pulled the code and again 22.
I don't think the oil pressure is to blame, in the am when it first starts I only see the oil light for a half a second then it's gone. There's no knocking or valve tapping noise whatso ever. Would someone "adjusting" the valves cause this issue?
I've read places about a plug in the head the routes oil, where's that plug at? I don't mind replacing parts, just don't wanna aimlessly throw parts at it. I am thinking of ordering a new vtec assembely tho..

 

Update: today at work it was slow, so I decided to hook up my multimeter to the ecu pin A6? (Vtec solenoid) and went to get lunch. Whattdaya know, 12v almost instantly under load..
So then I thought, maybe it's cutting off at higher rpm.. So again, I got on it and watched for the 12v to turn off, and it didn't. At 4200 rpm, it wouldn't accellerate anymore, so I backed off the throttle, as soon as I did, the car up shifted and the cel came on. At the stop light, I could smell the exhaust all nasty like.
My thinking now is, if the ecu is allowing 12v to the vtec solenoid, then my oil Pressure and sensor must be good right? So it's gotta be the spool valve that's not working right??

 

Okay, I'm lost.. Vtec is in fact working. I was able to get the trans to stay locked so I could use torque to climb up an on ramp and sure enough, I was able to actually feel the engagement point. So I know it's working.
Why would it lose power around 4k and throw a code 22? Anyone think ecu is bad? Or maybe my intake has obstructions? Or maybe my o2's are bad and the A/F is off? Or maybe my exhaust is clogged? I'm really lost and have almost decided to just keep it below 3500 and start saving for an h22 lol.. Any more info/help is much appreciated. Thanks!

 

If the exhaust smells 'nasty' there is either a problem with A/F, catalyst is damaged/partially blocking flow, or the exhaust has a restriction.
If it was a burnt rotten egg smell that is most likely the catalyst is buggered.

Get it up and look for physical damage to catalyst.

 

It's fixed.. It turned out to be that little upper spring (in the diagram). It's more of a button with a hole in it. Well that was missing so the plunger was free to open and close so it threw the oil code. Works fine now.

Thank you Mike for helping out and showing me that pic. Appreciate the help. +1

 

Yup, the car will definitely run in limp mode with that code being thrown.