VTEC not engaging...? Tried everything I can think of...! Help!

Hi guys.

I've just picked up a 1995 DC2 VTi-R about 2 and a half weeks ago, and since I got it it's been running mechanically ok, VTEC was engaging fine until now.

Yesterday I degreased my engine bay and gave it a hose down. I did make sure to tie plastic bags around the air filter and the ignition when I hosed it down. Even after this, VTEC was still working fine, but then I get up this morning, go out to my car, warm it up as always, start driving, wait until it's up to running temp and went to hit VTEC and nothing...? The entire day VTEC has not been engaging at all. No change in noise. No boost of power, not even a small one. Even up at 7200RPM nothing.

I've read up about possible causes such as a CEL but the light isn't on. Here's what I've tried so far:
1. Checked oil level. Fine.
2. Checked ECU for fault codes. None. Light just stays on.
3. Reset the ECU. No effect.
4. Pulled off VTEC solenoid, checked the filter and it seems fine, however I still gave the inside of the housing and the filter a little clean before chucking it back in. No effect.
5. Cleaned out the wiring connections (power and oil pressure) to the solenoid. No effect.
6. Put external power to the solenoid via the battery and a 10 amp cable to test it and you can hear the click of the piston, so it must still be functioning properly.

Gah! I just don't understand! Could it be a wiring problem or something electrical? I would think if this was the case the ECU would throw a code or a CEL but it doesn't.

Another thing I tried was disconnecting different plugs and turning the ignition to ON(II) (not start) one at a time and the engine light stayed on for all (as it should) except the VTEC oil pressure switch on the solenoid. So I'm not sure if it's meant to be like that because its just a switch or what?

Please help! I don't wanna take my car to a workshop, every time I do I get my car back with some sort of damage... :(

Canberra mechanics are almost always dodgy and careless...

What makes you feel the vtec isnt working? It may just be that the dual runner intake is not switching around the 5800prm mark (i think) .You may have just popped off the vacuum line..(id check this first)
If not, have you had the rocker cover off to check the rocker gear? what is the oil like and has it at all tarnished inside? if it was bad enough it may of physically blocked up the vtec oil passages (this is a worst case senario)
Let me know how you go with it...

Well you can't feel any sort of power increase, and there's no change in sound, it's like driving my old DA9 but a bit more powerful and higher revving. Like it used to have quite a significant change in sound especially considering the intake is open air (no top of airbox). But now nothing..? I don't understand how it works one day, then fails overnight while it's sitting there and doesn't work the next day..?

(Please excuse my frustration)

Which vacuum line might this be cause I'm pretty sure they're all hooked up fine?

No I haven't gone as far as to pull the valve cover off yet, I don't think it's a serious mechanical failure so I'm gonna save checking that type of stuff till last.

Thank you for your advice I will definitely keep these things in mind! :D Anyone else got any idea's?

.....Did you leave the engine running while you washed it? Or at least let it sit and run for a bit directly afterwards?

Quote:

---

Please help! I don't wanna take my car to a workshop, every time I do I get my car back with some sort of damage...

Canberra mechanics are almost always dodgy and careless...

---

Stop taking it to places that work on lawn mowers then =P There is nothing wrong with Canberra mechanics, just depends on where you choose to go...

Well i left it for about 3 or 4 hours before i drove it, and as usual let it warm up heaps.

Yeah, i guess you're right that is a bit of a generalization, but i've been to a lot of different places and not one has really impressed me apart from Battalion Motors Honda (yes the place that also does lawnmowers haha :P) but they're expensive..

Hey, besides, it's always better to save some money and learn a thing or two by doing what you can yourself. :)

Did you pull apart the vtec solonoid unit? Check if the spring is ok and is springy when you press it, inspecting all bits for faults.

Try take it apart and give it a clean, replacing the smaller gasket that sits under the round solenoid if there's damage

Check the wiring and the plugs for damage etc.

On the side where your battery is. Look toward the manifold. There is a circular unit with a shaft under it that is connected to a return spring or pivot of some sort.
On the top there is a vacuum line.
Get someone to help you. Observe the position of that shaft. Start the car and it should move up (or in another term, it should be pulled)
This is because at atmospheric pressure (or WOT) there is a little unit that controls when that valve is to open. And on a dc2 its around 5800 or 6000rpm.

If you dont see any movement at all, with the engine running, remove the vacuum line from the top. This should immediately move the shaft. In this case, it should move down, opening the secondary butterflies in the manifold.
If in both tests the shaft on that goldy circular unit does not move. Put a vacuum gauge on the goldy unit, and it should pull that shaft. If it does. Check for a vacuum leak. If it doesnt move at all in any condition, either the diaphragm inside the unit is busted, or your secondary butterflies are seized.

If in any of those tests it does move (working). Block the vacuum supply of the goldy circular unit. And put a vacuum gauge on the vacuum line thats supposed to go to the goldy unit.
Drive the car, first gear shoul d be alright, get someone to monitor that gauge. Between idle and 5800 or so rpm at full throttle should be vacuum. Anywhere past 5800 should go straight to 0 on the vacuum gauge (atmosphere pressure).

If it stays at vacuum all the way passed 5800rpm and to redline, the unit that controls the vacuum on that line is faulty. ( forgot the name for that little thing).
If it goes to 0 straight after you put your foot down. That also means its faulty.

If everything is ok up to this point and youve checked everything on the vtec side. There is only one other thing on my mind atm that could have failed.
And that is the vtec cam follower. Which is apart of your rocker arm system. If you look at how a vtec system works itll give you a better idea of what im talking about.
Oil pressure is designed to lock the follower in place so the high cam (vtec) is engaged. Your solenoid may work, but if the followers are fooked it will never engage.
You could have a blockage in the system preventing pressure to get in there. Or maybe you have low oil pressure.

An easy check is to put an oil gauge on and monitor it. Find the specs at what the factory pressure regulator valve is set at and it should stay at that pressure on the high revs, well at least when vtec kicks in.


All seems very technical, but you never know. Could be something simple that was overlooked.

EDIT: One thing i didnt note down. You checked the solenoid for its function but you didnt check if there was supply.
Put a test light on the connector and take it for a drive. Make sure its on there good. It should light up at around about 4500rpm.
If it doesnt. You dont have supply to the solenoid. Though usually, things like that should throw a light.

Thanks for all your opinions guys I'll keep these in mind, and also reference them as I go through troubleshooting.

Ok so I took my car to a honda specialist today, he reckons the solenoids resistance is out by 1 or 2 ohms, and he thinks that'd be his best guess at what's causing it. So I guess I'll have to replace the VTEC solenoid then. But before I do, does anyone know if there is a way to fix this rather then replace it? I'm not very good with understanding electrics as you can tell and I'm just repeating what I was told. So I'm not sure if there is a way of restoring it's original resistance...

Thanks for all your help so far. :)

Ok I ordered another solenoid + housing from honbits in sydney and a new gasket/filter from OEM honda. hopefully they should arrive tomorrow, well, I've got my fingers crossed that they do haha.

Wish me luck that this works!

goodluck

thanks dude :)

And it's working again! :D Thanks for the help everyone!

what did the problem end up being?

Quote:

---

Originally Posted by moey

what did the problem end up being?

---

Have a read, he replaced the solenoid.

yeah it was the resistance of the VTEC solenoid, so i changed it and now it engages. :)

How did you **** up the solenoid?

90% of VTEC problems is solenoid related..

so a lesson learnt, if u wash ur vtec engine bay down, make sure u plastic bag the distributor, filter and most importantly VTEC solenoid.....

Quote:

---

Originally Posted by aznstyler

How did you **** up the solenoid?

---

The solenoid is an electromechanical device, so it does wear out eventually.

yep haha i'm scared to wash my engine bay again... and thats right, they do wear out over time anyway.