Yes, VSS and every other sensor is fine. Car runs perfectly without VTEC.

Yes, I tried with a wire from battery to solenoid while engine was running. Same symptoms.

ECU is what I haven’t tried yet.

I took out the engine and disassembled rocker arm and everything. Checked every single pin and mounted back everything. I tried to lock vtec with air pressure and that worked. Every single rocker arm engaged. So I’m going to put the engine back and see what happens.

One thing I saw was when everything was disassembled is that the first pin on the rocker arms, they needed a lot of air pressure to come out. When they first “loosened up” and I put them back in, they came out with a lot less air pressure.

 

I will have to try that out too. I had an old head that I know for sure vtec engages and this head I have now as soon as I try to go into vtec it’ll fall flat on its face until it lowers out of vtec then do it again. But sometimes it’ll run without vtec up to 8k no problems. I’ve did all what you’ve did too except the 12v while engine is running.

ive also checked the vtec pins too and have them all. So what I’m goin to try is swap all the pins from my old to the new head.

also I got s300 and when I enable the secondary table it’ll go into vtec... I know that’s used for different fueling type etc. but why would it engage when I enable it boggles my mind.

 

Well, it still doesnt engage. I'm totaly out of idea. A friend of mine will send me his ecu with hondata and I'll try that.

 

So, I'm totaly clueless now.

- We checked signal to vtec solenoid with oscilioscope. Its a stable 12v when vtec engages.
- Oil pressure on vtec solenoid when it engages is 70psi ++
- With air pressure, vtec engage. Had the engine out and put it on a stand and pressurezied the system.
- Solenoid is working.
- Have checked everything in the head, every single pin and rocker arm.

I have no clue why it doesnt work.

 

Ok, It's one thing I'm wondering; Do I need the skunk2 LMA?

 

LMA's have nothing to do with VTEC engagement... they help keep the engine quiet when NOT in VTEC.

 

My gsr in my old hatch ran perfectly as well, but just wouldn't go into vtec....problem was..... the VSS. It's probably a sensor or computer issue. I remember my old hatch being a hack job from the person I bought it from, and wiring connections and sensor issues had vtec not working on more than 1 occasion. If you're keeping the car, you may want to just go through it and replace all sensors...it isnt that much.

 

I have had the car for 10 years now, and when I bought it was pretty much original. The wiring is fine. Hondata is reading VSS fine, speedo is working fine. I have even set the vtec parameter to activate even when VSS is 0, so I pretty sure my problem isnt there.

 

I'll add to this and say you might **think** the VSS is fine; i.e. speedo working, BUT... I had a similar problem and couldn't rev past like, 4200 rpm and no CEL, speedo was working, ECU wasn't in limp.. I was confused. I saw in a datalog that during this time, my VSS voltage was reading 0. I don't know HOW my speedo was working during this time but, hey, Honda.. Anyhow.. I removed the pigtail and cleaned the connections real good and problem resolved..

 

I believe he bypassed the ECU and tried manually engaging the solenoid by touching it to power while driving. That leaves the problem either being a defective solenoid or something in the head

 

Hmm.. Thought he checked the solenoid and broke down the head. If everything has been checked and checks out fine, this is a problem that just can't be resolved it seems.. Lol! The only other possible option I could think of would be the oil orifice in the block.

 

Something low cost to try would be checking grounds. You could also add 3-4 extra grounds in the engine bay, run 1 to distributor (1 of 3 bolts), 1 to the rear of engine consolidation ground point, and pick another point. Clean battery terminals and cable ends. Bad grounds, weak grounds, and electrical issues can cause strange intermittent issues.

 

So I added extra ground and still same problem. I just got tired, so I installed ITR cams, and still same problem....

I will find an adapter and monitor oil pressure at solenoid when I'm driving.

 

New video which shows how it struggles under 5000rpm

 

I know it's a lot of work... but swap your old cams back in. See if vtec comes back.
if everything else is the same and u only changed a few things, go back a step and see if that fixes it.

 

I acutally did that last weekend, swaped to ITR cams, and It's still same problem

 

Ok so.. You've checked everything mechanically, tested the solenoid multiple ways, and swapped ECU. Leaves the tune or software. Otherwise, you've got the only VTEC Honda that should work, but doesn't.

 

I totally agree. I cant see anything wrong with mine tune either and the software worked last year. Only thing av changed, which I havent reversed yet is my injectors. I went from ID1000cc to ID1700cc.

 

In my experiences with Honda is to expect the unexpected. I mean, hell, I've had things work fine as well then, out of the blue, POOF.. My injectors, for instance. Worked fine before my car sat for 8 months. Fuel system was depressurized during this time. Bam, found out injectors were clogged after going again. Ecu was working perfectly, then BAM, it decided to Peter out. **** happens at the drop of a hat and can't be explained. I'd seriously look into your tuning hardware and software at this point.

 

Well guys, I solved the myth.

It was my oil. Yes, your read correctly. It was the stupid oil that caused these problems. I used to run Gulf racing 5w-50 oil, but I switched to Gulf competition 15w-50, ester-based oil. Today I changed the oil back to 5w.50, and bam, vtec is on, without ANY issues. Runs like it did last year.

 

If the oil pressure was there at the solenoid previously, I'm begging for an explanation as to how this would be the case.. If the problem is resolved, that's fantastic but, I feel you've just opened pandora's box for troubleshooting..

 

So here is the story.

I hooked up a standard workshop manometer on the head and checked the oil pressure, and as stated it showed 70psi +.

After I had tried everything, I called my friend, who learned me tuning, and explained him how I have tried everything. He told me then to be 100% sure if it mechanicle or electric problem. The way I should do that was to deactivate the vtec in hondata and add an switch to the solenoid with power straight from the battery. In this way I could rule out the electric issues completly. And also add 20% more fuel from certain rpm on the non vtec map.

I did that, and I had the same hesitation, when I activate vtec before 5000rpm, and almost non vtec after that.

I wanted to try the last 2 things before I took out the engine. 1. Hook up an oil pressure gauge on the head and monitored the pressure while driving and 2. change the oil to the 5w-50. When I did that, all kind of hesitation vanished. But the vtec felt a bit weak. But it was solid. But hey, I have lived without vtec for almost a year, so I had big hopes and dream how the engagment should be xD

Today I decided to upload my map from last year, change the fuel injector from 1000cc to 1700cc in hondata, adjust the dead times(same I have been running this year with the new injectors), and added a 5% more fuel to the maps to be sure. The AFR was almost spot on before and after vtec. Keep in mind that this was the map I drove the whole last year when everything worked fine. And everything is the same other then 1700cc injectors.

So the only real change was the oil. And yes, I dont understand how that made the difference. Maybe I will try to swithc back the oil just to see If i get the problems.

 

Hey,

Your saying its showing 70psi at the head, but at what rpm? I know for my LsVtec I'm at or around 100 psi while in vtec or over 3 to 4k rpm

 

Hi,

At the meassure point, it dosen't read anything(0psi) before the vtec engages. So the reading of 70+ psi is as soon as the vtec engages, which is the point I set, and it was 4500rpm. So from 4500rp the oil pressure is 70psi and climbing as rpm increases.

 

I had a friend who was having a similar issue on the dyno. We ended up manually activating Vtec from the battery to the solenoid, still was not kicking in. Some people there thought Vtec was activating but it was really just the fuel maps changing to the vtec maps. Ended up being a bad oil pump causing the issue. Now I know you said you replaced it but seems to me its a mechanical issue.

But that aside,you said its fixed now, since you changed the oil grading, which I don't see how that will allow vtec to kick in.