WilloW

Hi everyone. I have a problem with my VTEC where I can hold it all the way to redline where I can hear the crossover without any problems. However, if I hold the RPM within the VTEC range I would hit the 6500 RPM wall as if the car wasn't warmed up as soon as I shift to the next gear.

This is a bone stock F22 with AP1 ECU since my original F20 died. With the original engine I've never had this problem so I'm thinking that I may have damaged a wire during the swap process but I don't know where to even start at.

What I have done so far:
1. Swapped in a known working VTEC solenoid from the old engine.
2. Changed both VTEC filter and upper gasket.
3. New VTEC oil pressure switch.
4. Repaired a exposed spot of wire on the VTEC solenoid plug (soldered and heat-shrinked.

What I haven't done:
1. P0411 from the missing air-pump. Got the Izze delete.

Thank you for your time an any inputs!

Spartarus

Wait, you're running a 2.2 liter engine on 2.0 liter tuning? That's a thing you can do? You can run an engine with different cams and different displacement without changing the Speed/Density ECU ?? I heard these engines were pretty forgiving of bad AFR's, but I'd expect you're running leaner than stock over most of the rev range, until the rich spike at the top end, right about the same time the AP2 cams are giving up... Then you're probably richer... Anyway, that's not the root of your problem, but it's god damn crazy..

Ok, back on topic... I'm not sure I follow your description...

So, you can run it up to redline, and you hear the VTEC crossover... Good...

Then, during acceleration, you shift from somewhere in VTEC, but not redline... and the revs land below 6500... And you continue accelerating... And then you hit a mystery rev limit at 6500?

Is that correct?

That is a god damn mystery.

Have you checked the coolant temp sensor and its wiring? And taken the throttle position sensor through a sweep to check for dead spots? Do you have the Pre-TSB MAP sensor?

Those are 3 good starting points.

WilloW

Thank you for your reply.

Yes I am running a 2.2 with 2.0 ECU.

Basically if I were in 3rd and floored it all the way to 8500 I would hear the crossover without any issues reaching 8500-9000. Shift to 4th and as soon as I arrived at 6500 I'd hit the rev limiter as if I didn't warmed up the car. This would only happens if I were to HOLD the revs above 6500 rpm. If I were to just wring it to redline, shift to the next gear then I would still be able to go past 6500 without any problems.

rpg51

I don't understand your description of what is happening. So in your example if you shift to 4th are your rpms dropping below 6500? And then you are unable to rev up past 6500?

WilloW

That's correct.

Edit: Sorry for the terrible description. I was going crazy and posting on my phone.

Scenario 1 - I'm in 3rd gear, I've just crossed over in to VTEC at 6500 rpm and moving towards redline. I'm finally near the rev limiter at around 8500 rpm and shifted to 4th. I worked my way towards redline again, without any problem. In this case I can come to a complete stop, gets moving and can still hit VTEC.

Scenario 2 - This is what I am experiencing now. I'm in 3rd gear, I've just crossed over in to VTEC at 6500 rpm and moving towards redline. I'm finally near the rev limiter at around 8500 rpm and stays around there for about 5+ seconds then up shift to 4th. I worked my way towards 6500 rpm. The moment I hit 6500 the rev limiter kicks in. This would stay with the car until I do a restart.

In both scenarios I have completely warmed up the car to three bar on the gauge.

Fried ECU?

flanders

Redline on a AP1 ecu is at 9000rpm and it's a really bad idea going that far if you have a F22 engine.
It doesn't sound like your ecu is fried but I suggest you replace it for an AP2 anyways.
Have you checked your oil level by the way?

Spartarus

Well, the VTEC oil pressure switch would throw a DTC and turn on the CEL.

This sounds like either the classic MAP sensor TSB, or the coolant temp sensor being loose / intermittent. either way, vibration from staying at high RPM would cause both of those problems, and issues with either of those sensors would cause mysterious hesitation at high RPM.

It is possible you have a pre-tsb sensor. I have one, and I'm about the throw it away because it's causing hesitation issues.​​​​​

https://www.s2ki.com/public/library/...-073/index.htm
​
Read the TSB, and imagine the same scenario happening if you had damaged or stretched the coolant temp sensor plug, and it gets strange resisrance with vibration... all of a sudden the ECU sees an intermittent temp value below the warm threshold and kicks on the rev limiter... Its just a 0-5V analog input.
​​​

windhund116

Sorry for the ignoramus question... but, will the AP1 ECU allow the AP2 engine to redline at 9K r's?

Thanks!

Spartarus

The AP1 ECU doesnt know the difference. It thinks it's spinning an F20c. Yes, it'll rev the engine like it's an F20.

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WilloW

I usually don't. It's more of an annoyance than anything.
My paranoia from having an oil burning F20 has resulted with me checking oil on the weekly basis so it's always topped off.

I do have the pre TSB MAP with a ziptie around it. Looks like I will be purchasing a post TSB one soon. As soon as I get the car back from the painter I will check the coolant temp sensor.

What you are saying makes sense. Thank you.