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VTC Control not working FT450 K20

Variable Cam Control Tuning

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Discussion and questions related to the course Variable Cam Control Tuning

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Hello all,

I'm currently working with a K20z3 powered a FT450 but I cannot get the cam control VVT/VTC to do anything for me. Then, it randomly will jump up to 50° out of nowhere without me touching anything. Anyone ever experience something like this?

It's wired to OP #5 (blue output) since this is the one that has the built in diode. I disabled the cam control before I adjusted the sensor position angle until I got the cam angle to 0.0° to 0.2°. Now when I try to target 10° or so, the cam angle doesn't seem to change. I then trying to dial in the PID settings, but again nothing changed (I ended up changing them back to ft's standard settings).

Not sure why I can't figure out how to attach a log or map here, but here's a screen shot of the log. Appreciate any help everyone

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[img="blob:https://www.hpacademy.com/20d0f0db-2f89-4592-9506-eefabd789957" alt="" alt="" ]

Then here is where is goes from 50* down to 0* with no adjustments being made

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I haven't worked on the engine, but as I understand it, the VTEC is rather sensitive to oil pressure and/or viscosity.

What oil are you using, and do you have a log of the oil pressure when the VTEC is in the cross-over region, preferably with it operating and not operating?

The folks that know the engine may find that useful with helping you diagnose the issue.

I assume you've already checked the wiring continuity and the connections, for electrical issues?

Yessir, checked continuity at the VVT/VTC solenoid. It seemed to check out.

Currently I'm running 20-50 convention oil. VTEC crossover seemed to work normally. Oil pressure has been 30's-40's at idle and was 74psi during thos WOT pull.

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It would seem that a 10-30 is recommended, might be worth trying that?

I might be mis-reading the initial post, but there are at least two issues?

a/ when you tried inputing different degrees there was no change in the cam' timing to match what was requested?

b/ when you say it's randomly changing by 50 degrees when you don't make any changes, when is this happening - at idle, when it should change it sometimes does and sometimes doesn't change? Had you requested the 50 degrees, or does it do that regardless of what was requested? Does it happen when the solinoid(s) is/are disconnected?

Is the PID even trying to do anything? The PWM is always 0%, that should be trying to move the cam one way or the other. Are you sure the ECU has the correct crank/cam settings?

Yeah, those are the two things I've noticed but I think they're related issues. I can definitely try the different oil weight, but I still feel like it should do something at idle/or even just the power on.

That is a possibility I do not have something right. I followed the steps in the FT manual around the crank/cam. Originally set to 330*, started the car and adjusted the BTDC until my timing light was fixed on the locked 20*. Then when I set the cam angle degree, I disabled the cam control and adjusted the angel until the cam was at 0*. I think that's haltech's guidance but I feel it should be similar. Then when it was steady at 0* I enabled the cam control and tried to test it. Nothing :(

I agree, adjusting the PWM definitely should have done something but I didn't see any movement

How is the wiring done? Honda OEM wiring has high-side drive for VTEC, I often need to flip polarity with aftermarket ECUs. I don't remember the VTC, but it could be similar.

The point being, perhaps "disabling" cam control, actually advanced it to the max, instead of retarding to the maximum. So setting the offset was incorrect. Also, sometimes angles are in CAM degrees, and sometimes in crank degrees, but you can usually figure this out by advancing / retarding to the max. Try disconnecting the VTC connector, you know that should go to full retard in the intake cam.

I made the wire harness from scratch following the ft450 wire diagram. So I tried to swap the two wires for the VTC and see if that changed anything, but same results. I'm going to start my map from scratch again and see if I'm over looking something within the settings

Swapping the wires won't change the polarity, normally the solenoid valves don't care which way the current flows. On your VTC valve, is one side tied to +12V or the ground? The ECU needs to control the opposite side. Normally most ECU want to control the low (ground) side, so the wiring needs to have the other side of the valve tied to +12v (ignition switched power). Have you verified there is 12v on one pin, and ground on the other when either 0% PWM or 100% PWM?

Oh I see, yeah I triple checked the 12v. I'll check the output again to see, but I believe these outputs are grounds like you said. I pulled the cluster back out to make sure I was getting continuity the ECU plug to the VTC connector. Mean while, I must have changed some of the settings for the intake cam sensor, because that stopped reading. I must have change the sensor tolerance, idk. It's reading now.

Anywho, I am seeing PWM now, but still seeing the weird over shooting. I spent sometime today adjusting the PID again, but it didn't seem to fix anything

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At the moment, these are my settings

Cam sensor:

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VTC:

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Where did you get those cam sensor settings? (base map, measured with oscilloscope, tech support?) Are you sure it's correct for your engine?

So those are close to what fueltech suggests. It changed when I locked & verified the ignition timing. Then they suggest to disable cam control and adjust the BTDC for the intake cam until you see 0.0° or as close to. From what I gather, a good indication is the intake cam BTDC should naturally be greater than the crank BTDC

Crank BTDC was 347.8° (ft suggests to start at 330°, the verify)

For what it's worth, using a MoTeC on a K24, for running the solenoid at 120hz, the 'base duty' (what is required to maintain a cam position) is 40% when maintaining the high side control strategy.

Mechanically:

- Have you checked the VTC screen isn't blocked?

- Have you tried removing the VTC solenoid, and checking with a 12v supply that then the solenoid is powered that the plunger assembly moves and isn't gummed up/sticky?

The cam gears have a locking pin in them, so they need a bit of duty to unlock. I have no knowledge of how they fueltech strategy works, but this could be coming into play as well.

Oh nice, thank you sir.

When you say high side strategy, is yours controlled by the 12v output?

Yeah, screen was cleaned very recently, but I can always double check. I can hear it while running the test circuit throught the ft software

Okay update, I changed to 120hz, and the base duty at 40% and its actually somewhat trying to move towards the target.

I'm going to attempt to adjust PID settings to see if I can get it smoothened out.

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