Lude Generation

Scott560 wrote: ↑

Mon Aug 24, 2020 4:11 pm

How strange! Can you describe the intermittency?

To answer your questions.

1. No CEL lights, the car's up to temperature before I even take it to the VTEC cross-over.
2. Duly noted, will have a closer inspection.
3. I have several cars that I drive regularly, but what tells me that VTEC is not engaging is that there's no noticeable change in engine note at 5k, there's no noticeable change in urgency or power delivery either. My 4g, you'd feel the 2nd cam and the engine note would change, that was quite a pronounced difference that the 5g doesn't have. I drove the 5g for a few days in December 2019, put it away for 18 months and then only recently did the restoration work on it. However, the 4g only sold in March and I was driving that regularly so I'm fairly sure I can still remember the cross-over into VTEC.
4. It will go to the red-line, but the power delivery is completely linear from 0rpm through to 7k, there's no change when going into VTEC.

What "might" be an issue is the elbow inlet pipe, which was knackered on mine, so I used them same pipe from a 2.0 but expanded the inlet/outlet flange to fit the larger TBs/venturi on the 2.2. The oil pipe was knackered, splits etc.

I think it's working fine then based on what you say.

I found my h22a5 had a noticeable sound and jump in feel at 5250rpm, but the h22a8 is very linear/flat power delivery, hardly any change in torque. If you can get naturally and quickly to the red line, then its fine. When its not working, you would struggle to get to 7k. Unclip the vtec connector and go for a spin - it makes a happy car very old

The split intake wouldn't do much unless it is considerably reduced in diameter compared to the original.

Also I'm talking balls about the CEL - a momentary drop in oil pressure doesn't affect the CEL - otherwise i would have triggered one on most of my track days coming out of the chicanes. Im getting confused with a B16 motor which noticed low oil pressure whilst in vtec and threw the CEL.

Scott560 wrote: ↑

Mon Aug 24, 2020 4:40 pm

I think it's working fine then based on what you say.

I'm wondering if it's the wrong oil viscosity, early Zetec engines are notorious for not liking anything but Ford-Only oil! What spec are you using in yours?

Scott560 wrote: ↑

Mon Aug 24, 2020 4:40 pm

I think it's working fine then based on what you say.

What I should also add is, since the restoration work the throttle response is body lemonade-poor from cold; my ATR had a similar problem, down to the throttle body being coked, but that cleared as soon as you stamped hard once. The Prelude has poor throttle response all of the time; it gets better as it gets warmer, but it's still poor for a Honda. It didn't have this problem 3 months ago when I started working on it.

It feels a bit like a vacuum issue but I was going to sort the VTEC issue first.

If you are seeing 7k rpms, vtec is working. I suggest the other issues you have need looking at.

Have you checked the distributor - take the dizzy cap off and have a butchers

Yeah, also check the plugs and leads and overall timing.

Scott560 wrote: ↑

Mon Aug 24, 2020 4:11 pm

How strange! Can you describe the intermittency?

Right, the update thus far:

There was definitely a change in cam note at 5250rpm, and a noticeable change in power; this happened twice on the way to the MOT last week, it was being driven by a friend that does most of the heavy work on it. When he tried to engage VTEC on other occasions, on the same journey, it wouldn't engage VTEC. So, we know there should be noticeable change. The day of the MOT was the first time it'd been driven since all of the service work was doing, including the oil change below.

It's running Shell HX7 10w-40w, on further inspection I'm reading that it should be 5w-10w. These VTECs are dead-head engines so I'm wondering if something has made it's way into the channel for the VTEC oil feed, or, the wrong weight is affecting the VTEC solenoid. There was only oil on one side of the plunger when we had it off, so that'd suggest that it's not passing through. The engine should still rev to 7k, whether VTEC engages at all, all the solenoid is doing is raising the cam inlet profile.

I've used 10W40 with no issues on my 5g

10w40 is the recommended oil.