VVT Problems!??!

[Sportmax]

Anyone ever had any problems with the VVT on the BT 20V??? Im having this weird intermittent hesitation and misfire. Im thinking it is the VVT sticking on.

So this isn't a help me diag it, I will figure that out. My question is if it is the VVT actuator, Can it be rebuilt instead of replaced? Has anyone ever done that? Looking at it, its pretty nasty, there is grease coming out of the front along with rubber(im guessing that its the internal seal). Theres enough rubber coming out i could see it getting jammed on. The Solenoid is dry but could still be an issue too.

Anyone ever delt with this before? And ive always read not to go with adjustable cam gears unless im running huge cams which im not!

Thanks
Kirk

[yoshimitsuspeed]

I have always wanted to get my hands on an extra one to do a little R&D on rebuilding and also on changing cam timing. Unfortunately it is nearly impossible finding them.

[Duy-]

are we talking about the cam gears themselves or the solenoid?

[Sportmax]

Intake cam gear. The actual acctuator. I disconnected my control valve and it drives perfect so I know its the VVT, just need to figure out what part it is if not both. Oh and I already opened my ECU-it looks brand new inside!

Lithia Toyota can get both parts but its Expensive for both
Yoshi.... Im going to swap out my friends control valve and if that doesnt fix it I'll pull my acctuator and take it apart. If I do I will take good notes and pictures to see if I can rebuild it before I order a new one.

[yoshimitsuspeed]

DUY was kind enough to send me some gears for R&D.
Unfortunately these are sealed units unlike many others I have seen that can be unbolted.
It looks like it will be possible to press them apart but a new way of fastening them back together will need to be created. This shouldn't be too hard.
The other issue is some of the internal seals are not basic o-rings but it may be possible to find another alternative.
I have a good understanding of the internal components now. Can you take a pic of the rubber bit sticking out?
I could possibly exchange you gears with one of the healthier looking ones I have now but I would not be able to guarantee their form and function just yet.
I should be getting an extra head in. At which point I should be able to mockup a way to test the gears and check for function and leaks.

[Sportmax]

I actually cleaned up all the rubber that was sticking out, it was annoying me LOL. I just purchased a used one "in good working condition" so ill swap that out next week and see if it fixes the problem(hope so because I have a race next saturday)!
I was looking at pictures of a taken apark actuator and it did look like a proper seal, not a simple o-ring like you stated.
I swapped out ECU and oil control valve last weekend with a buddy and the hesitation was still there so I know it must be the Actuator.
If they need to be pressed apart I guess I wont mess with mine. I don't have a press at home. Always thought about getting one tho.

[BoostJunky]

Exact same problem with mine. runs perfect with the vvt solenoid unplugged. I replaced the VVT gear already but no luck. I wonder if theres a clog somewhere on if the solenoid is sticky?

[Sportmax]

Exact same problem with mine. runs perfect with the vvt solenoid unplugged. I replaced the VVT gear already but no luck. I wonder if theres a clog somewhere on if the solenoid is sticky?

What setup are you running on your engine??

I just swapped the cam actuator and no change. My friend and I are thinking it is a ECU logic problem. Short open velocity stacks, bigger then stock cams and a thinner head gasket. There is to much flow of air for the amount of gas when the vvt is actuated.
My wideband goes FULL LEAN(off the gauge) when it happens. Guess its time to start saving for a Standalone.

[onnaj]

Maybe for the time being you can use a fpr and some supra injectors i believe?

[yoshimitsuspeed]

Maybe for the time being you can use a fpr and some supra injectors i believe?

FPR or injectors will change the fuel delivered all the time. This means when now it's running properly it would be running too rich with more injector.

[yoshimitsuspeed]

Exact same problem with mine. runs perfect with the vvt solenoid unplugged. I replaced the VVT gear already but no luck. I wonder if theres a clog somewhere on if the solenoid is sticky?

What setup are you running on your engine??

I just swapped the cam actuator and no change. My friend and I are thinking it is a ECU logic problem. Short open velocity stacks, bigger then stock cams and a thinner head gasket. There is to much flow of air for the amount of gas when the vvt is actuated.
My wideband goes FULL LEAN(off the gauge) when it happens. Guess its time to start saving for a Standalone.

What sized cams are you running?
Does it do the same thing at the same load/RPM every time or is it intermittent?

I would do a run with the VVT unplugged and then a run with the VVT jumped to ground to keep it on for a full pull.

Monitor your AFRs on both and see how it does.

[BoostJunky]

Exact same problem with mine. runs perfect with the vvt solenoid unplugged. I replaced the VVT gear already but no luck. I wonder if theres a clog somewhere on if the solenoid is sticky?

What setup are you running on your engine??

I just swapped the cam actuator and no change. My friend and I are thinking it is a ECU logic problem. Short open velocity stacks, bigger then stock cams and a thinner head gasket. There is to much flow of air for the amount of gas when the vvt is actuated.
My wideband goes FULL LEAN(off the gauge) when it happens. Guess its time to start saving for a Standalone.

YES! same here. wideband shows full lean at part throttle. I wired the vvt actuator with a rocker switch so I can turn it on and off easily. Full throttle is usually ok and part throttle above 4k rpms is ok too. Just the lower rpms I have the issues. My setup is BT w/ open stacks, higher fuel pressure (fpr), oem manual ecu & COP.

[Sportmax]

Im running Tomie Pon Cams 264/256. It usually happens all the time right about 3k rpm. It only does it at 50ish % throttle. Seems to be worse when warm as when its cold the VVT is not actuated.

At this point I really don't care about it. I can drive it on the street around it, just have to be precise on my throttle control. I had a race saturday and it did not affect the performance. Full WOT acceleration would no hesistate and I was above the 3k rpm range the whole time so i wont worry about it untill next winter when I get a stand alone and go Sequential Ingition.

As for bigger injectors and FPR, that will just cause it to run rich all the time. Ive always read the Black Top runs rich but my AFRs seem Perfect with the stock ecu. I have not looked at WOT AFR yet but I will next time I drive it.

[BoostJunky]

Your issues are exactly like mine. If you ever find a fix for it, please do share. Yes bigger injectors wouldnt help imo as well. My afr's are bang on even with the higher FP. I havent driven the car in months but before I took it off the road, I was getting misfires around 7800-redline. My only hunch at this moment, maybe my vvt solenoid is sticking?

[yoshimitsuspeed]

So just to verify, this issue doesn't happen at all when the VVT is unplugged?
This issue doesn't seem to me like it would be VVT related at all. The VVT should transition at the VE crossover point which means AFRs shouldn't change when it activates.
I would suspect ECU or sensor input such as TPS, or MAP.

[BoostJunky]

Correct, when the vvt is unplugged, it works fine. Ive ruled out the sensors at this point as they checked out fine when I tested them a while back. I thought it mightve been an ecu as well but no difference when I swapped in a working one.

[onnaj]

Those are not the most expensive sensors. I believe around $90. So absolutely worth a try imo. Too bad i threw away my old sensor cause the housing was leaking, it would have been ideal for you

[riddleyo]

Subbed.

[Sportmax]

Correct, when the vvt is unplugged, it works fine. Ive ruled out the sensors at this point as they checked out fine when I tested them a while back. I thought it mightve been an ecu as well but no difference when I swapped in a working one.

Exactly this. unplug the vvt and it goes away and drives perfectly. if you accelerate hard passed 3k rpm you dont feel any problems, runs great. its right at the time that vvt actuates at partial throttle(60%ish).

[yoshimitsuspeed]

Correct, when the vvt is unplugged, it works fine. Ive ruled out the sensors at this point as they checked out fine when I tested them a while back. I thought it mightve been an ecu as well but no difference when I swapped in a working one.

Exactly this. unplug the vvt and it goes away and drives perfectly. if you accelerate hard passed 3k rpm you dont feel any problems, runs great. its right at the time that vvt actuates at partial throttle(60%ish).

What if you leave the VVT activated by jumping the neg to ground?

[BryceWSJ]

Hey Guys,

Minamoto asked me to post in here as well. I'm having the exact same issues as you guys. I recorded a video of it doing it with my a/f gauge and it looks like it's going SUPER lean. like off the charts lean. However, if you floor it, the afr's balance out to 13 where they are supposed to be. i've checked all connections, i've upped my fuel pressure, turned it down, all same basic results. i drove without my o2 sensor and it got WAY WORSE. it doesn't misfire, just bogs really bad.

Also, when i disconnect VVT, the problem is totally gone. i can drive all day without VVT and it's perfect. It feels like it's happening right at the point VVT engages. I'm wondering if it's a bad O2 sensor?

[Sportmax]

Its amazing how many of us are having the same exact problem. I really want to see somone with this problem put in Stand Alone and see if it solves it. My 02 sensor is brand new so its not that.

yoshimitsuspeed: Have not tried that but I see it causing even more issues. I may give it a try tho and see what it does.

[yoshimitsuspeed]

Its amazing how many of us are having the same exact problem. I really want to see somone with this problem put in Stand Alone and see if it solves it. My 02 sensor is brand new so its not that.

Is it a BT denso sensor? If not then what is it. Many people have had issues that for whatever reason were solved by using the proper sensor.

yoshimitsuspeed: Have not tried that but I see it causing even more issues.

It will help narrow down possibilities.
Does it go lean with it left on but not with it left off?
Does the problem disappear with it on and it off?
These things will help us try to decide what to look at next.

[BoostJunky]

Ive got denso oxygen sensor on mine. Ive also tried ngk, no difference. Im running bung type but really wouldnt be an issue. Its always narrowed down to when the vvt activates at part throttle for me which would mean its when its in closed loop mode. Swapped in a known good tps & map but no luck.

[BryceWSJ]

exactly what boost junky is saying. right when VVT kicks at partial throttle. mine is worse when it's around 160 degrees vs 185.

[BryceWSJ]

any luck? i adjusted my TPS, just by moving it, driving it, moving it, driving it, and i can honestly tell you the problem is almost 90% gone. LOADDSSSS better than it was. i will do some more messing with it another time.

[yoshimitsuspeed]

any luck? i adjusted my TPS, just by moving it, driving it, moving it, driving it, and i can honestly tell you the problem is almost 90% gone. LOADDSSSS better than it was. i will do some more messing with it another time.

Interesting.
I would love to hear where it is compared to spec.
When I swapped my BT in and got it running on my GZE ECU I had a bad tip in stumble off idle. I had to tweak the TPS as tight as I could get it while still keeping the idle circuit tripped at idle.
Pretty sure that was largely due to the GZE ECU being used to a very large volume of air between the TB and head.

[Sportmax]

any luck? i adjusted my TPS, just by moving it, driving it, moving it, driving it, and i can honestly tell you the problem is almost 90% gone. LOADDSSSS better than it was. i will do some more messing with it another time.

Interesting.
I would love to hear where it is compared to spec.
When I swapped my BT in and got it running on my GZE ECU I had a bad tip in stumble off idle. I had to tweak the TPS as tight as I could get it while still keeping the idle circuit tripped at idle.
Pretty sure that was largely due to the GZE ECU being used to a very large volume of air between the TB and head.

What he said. Im really curious. i may have to try that myself one of these days.

[onnaj]

Couldn't it be the iscv? I have also problems like that and i'm suspecting the iscv. I didn't try to disconnect the vvt sensor yet.

[Sportmax]

Couldn't it be the iscv? I have also problems like that and i'm suspecting the iscv. I didn't try to disconnect the vvt sensor yet.

Are your talking about the Idle Air Control Valve!?!?! That has nothing to do with how the engine runs off idle.