Monitoring VVT / VVT not working

[lukester 20]

Hi

I've been suffering from VVT issues I think. Last time it was at Fensport, Adrian said he'd seen it not "engage" (might have the wrong word) a couple of times. Recently it's just had no get up and go at all, a bit like its driver (but I'm a lot older than it is).

Anyway, following on from the supercharger-stopped-working thread, I've given DashCommand a go (only ~£6 for the app, another ~£5 or so for the Toyota PID package - worth a shot before ~£300 for ecutek...).

I'm a complete newbie with this stuff, but graphing a complete log seems to suggest that DashCommand is working OK for VVT. But not my car

This was a 10 mile steady drive (happened to be after having the battery disconnected for a while, so ECU was doing some relearning?). Looks like VVT stuck for pretty much the whole trip:

The return trip - variation to start with but gets stuck once off the cruise-control (about 15 mins in):

Assuming DashCommand was working properly (speed seems OK), this looks pretty bad I guess?

Thanks for any help!

Cheers

Luke.

[Bfranklyn86 52]

Luke, I don't know if I'm missing something obvious here, but surely it needs to just go back to fensport for Adrian to sort it out?

[nerdstrike 186]

Interestingly there's a bit of jitter when you turn the engine off, I wonder if it's oil pressure related? You should log that too!

If the VVT sensor readings are correct, then the valve timings are static after the initial wiggle. That starves the airflow under high power, and may reduce effectiveness at low rpm too, depending on what position it's sticking in. It's basically downgrading your engine to the 1980s. 

The "relearning" part will be fuelling adjustments for efficiency and shouldn't have any impact on the VVT.

I'd put your problem firmly into expert territory. Apparently oil viscosity and cleanliness can be a factor for VVT systems, and that's under your control, but everything else is probably going to mean pulling parts from the engine. Not sure how easy that is with the boxer recessed into the engine bay.

[lukester 20]

32 minutes ago, Bfranklyn86 said:

Luke, I don't know if I'm missing something obvious here, but surely it needs to just go back to fensport for Adrian to sort it out?

Well I dunno if it's really related to any Fensport work. The last job was the Cossie SC, which means heavier oil so I guess that could be making it worse - it occasionally felt sluggish before the SC but I have no stats to prove anything... Fensport suggested a new oil control valve first, but then off to Toyota for warranty work. Downsides of that are a) taking out the SC and later refitting (bit dent out of any warranty savings) and b ) I've only got 27 days left of warranty anyway

 

27 minutes ago, nerdstrike said:

Interestingly there's a bit of jitter when you turn the engine off, I wonder if it's oil pressure related? You should log that too!

If the VVT sensor readings are correct, then the valve timings are static after the initial wiggle. That starves the airflow under high power, and may reduce effectiveness at low rpm too, depending on what position it's sticking in. It's basically downgrading your engine to the 1980s. 

The "relearning" part will be fuelling adjustments for efficiency and shouldn't have any impact on the VVT.

I'd put your problem firmly into expert territory. Apparently oil viscosity and cleanliness can be a factor for VVT systems, and that's under your control, but everything else is probably going to mean pulling parts from the engine. Not sure how easy that is with the boxer recessed into the engine bay.

OK thanks! Actually the engine was on all through the log (via Android headunit, so needed to save the log before turning off). But yeah once stationary it does. Weird. Didn't think there was an oil pressure sensor though? Must see if DashCommand can do oil temp or needs the custom PID adding like Torque.

Oil should be OK (3 months old) so yeah. Downer. Maybe time for a trip to autotrader for some nearly new "kuokis", or carwow ...

[Kodename47 446]

No oil pressure sensor, so can't be read via OBD.

The obvious things to do are the OCV, check sensors etc. I don't see why Toyota wouldn't warranty it, you could always ask as the supercharger won't have any impact on the operation. Most of the components are on the front of the engine I believe, cam position sensors are on the outer housing but you'll need the front cover off the engine to get at the OCV and actuators. Better pics here:

https://www.revvolution.com/blog/2014/03/tearing-down-and-assessing-the-fa20-4u-gse

[lukester 20]

5 minutes ago, knightryder said:

No oil pressure sensor, so can't be read via OBD.

The obvious things to do are the OCV, check sensors etc. I don't see why Toyota wouldn't warranty it, you could always ask as the supercharger won't have any impact on the operation. Most of the components are on the front of the engine I believe, cam position sensors are on the outer housing but you'll need the front cover off the engine to get at the OCV and actuators. Better pics here:

https://www.revvolution.com/blog/2014/03/tearing-down-and-assessing-the-fa20-4u-gse

OK thanks, worth a go then I suppose! Don't fancy my luck at Bedford, they weren't interested in changing the battery (before it was the done thing) because I had "installed a shark fin aerial"

[Rich 378]

Might be worth running it up to RRG for a check, they should be able to sort warranty if it's not supercharger related.

From what you said at the Bedford track day, you were really down on power, barely hitting 100 on the back straight, which is slower than an NA by a good margin.

[lukester 20]

Just to hopefully complete this story... after the track day I had a very rattly exhaust. Was hoping it was the cat in the front pipe (~3 years old) rather than the one in the manifold (~5 months old!). Haven't made it up to RRG but was at Fensport recently so had it looked at - turns out it was the manifold It's nice and clean inside though...

What was left of the cat, squashing the cat in the front pipe (so that needed replacing):

Anyway, hopefully all my VVT issues are gone. Certainly the performance problems are fixed now there's decent flow  Not sure what to do about the manifold, it's JDL and they only cover cats for 90 days (plus the faff with them being US based)! It's too noisy for me now, wonder if that's because of the void where the cat was, the lack of a cat or the change from Berk -> Cobra front pipe (or a bit of all three)?

For info, Adrian said the next ecutek version in a month or two will have the ability to light the CEL if it looks like VVT isn't working (I forget what conditions he said...). Eyeballing it with DashCommand it's been OK (AFAICT) since fixing the exhaust.

Cheers (and thanks for the various advice!)

Luke.

 

[Paul 442]

That's the cat in the manifold?

[lukester 20]

Yes, sorry. Well ... it was supposed to be in the manifold The one in the old front pipe just got squished but was still in one piece.

[nerdstrike 186]

Aftermarket cats can be a bit dicey for both effectiveness and durability. I'm sad to see it caused you so much trouble.

[lukester 20]

18 minutes ago, nerdstrike said:

Aftermarket cats can be a bit dicey for both effectiveness and durability. I'm sad to see it caused you so much trouble.

Yeah - I'm sure I must've read about the 90 day cat guarantee on the JDL manifold before I bought it, and just figured it would be a non issue as my car is 99% a daily driver.  Then just forgot about it ... was a bit of a shock looking into the guarantee today. Lesson learned! Screw the planet? No that's not a good lesson.

 

[Paul 442]

If only we could all go full decat....

[nerdstrike 186]

In general it is a good thing that we're not all in a fug of lead-infused petrol vapour these days, some environmental regulation is good! It's just the low hanging fruit for performance gains which are hard to ignore.

Are there any other aftermarket catted manifold providers?

[Deacon 1357]

I wonder how much of the problem may be down to being supercharged. I know Dan's OEM manifold split and Mark at Abbey said they seen similar on other supercharged cars. Maybe the pressure was high enough in this case to literally blow the cat through?

[Paul 442]

Screw the primary cat and go with an HFC in the front pipe?

[Lauren 2259]

1 hour ago, Paul said:

Screw the primary cat and go with an HFC in the front pipe?

Yeah, I would do this. Or no cats at all. A decent manifold would be a good option too. Only problem is that the SC will make the exhaust a fair bit louder so you may have to look at a resonated exhaust if you haven't already got one. 

[Rich 378]

3 hours ago, Deacon said:

I wonder how much of the problem may be down to being supercharged. I know Dan's OEM manifold split and Mark at Abbey said they seen similar on other supercharged cars. Maybe the pressure was high enough in this case to literally blow the cat through?

More likely the extra heat from the supercharger overheated the matrix and caused it to break down.

[lukester 20]

21 hours ago, Rich said:

More likely the extra heat from the supercharger overheated the matrix and caused it to break down.

This suggestion could be The One...

[lukester 20]

23 hours ago, Lauren said:

Yeah, I would do this. Or no cats at all. A decent manifold would be a good option too. Only problem is that the SC will make the exhaust a fair bit louder so you may have to look at a resonated exhaust if you haven't already got one. 

I had a Berk front pipe and was worried that it alone wouldn't pass from what I'd read. Turns out it way well have done - MOT was a few weeks ago with the remnants of the manifold cat floating about and the Berk cat squashed and it made it through (just, after a couple of goes!).

[NJay 10]

I would agree with extra heat. Stock gt-86 at the moment but adding a rotrex to my gen7 celica increased exhaust temps alot as the fitter of my customers exhaust found out when he banged the cat to see where a leak was coming from and it melted right through his fleece. Well I did warn him it would be hot after a spirited 30miles 😂. The fitter who did my exhaust on it don't normally offer a lifetime warranty on a sports car if FI'ed (presumably due to this extra heat) but got them to agree to it 😉 

[Rich 378]

Be interesting to see what the exhaust temp sensors are reading on a FI car.

[Ade 517]

 

EGT is very tune dependant. A tune that creates high EGT even N/A can make the cat shit itself.

 

 

Rich there isnt a egt sensor but you can use the O2 heater in reverse to measure temp but its too far away.

 

 

Ive got the original H&S Cosowrth dev manifold. It has individual sensor taps on each primary where they measured egt accurately using thermocouples to make sure they were kept in check. So if lee was running the cosworth tunes I doubt egt should be an issue.

 

 

I suspect its a mixture of a poor quality cat and possibly the vvti issue causing high egt?

 

 

Ive done 8 trackdays supercharged with each session being a good 20-30mins. Plus cat driver training and 7k road and my cat hasnt shit itself yet (just passed mot).

 

 

 

 

Sent from my SM-G935F using Tapatalk

 

 

 

 

[Rich 378]

The O2 sensors give temp readout in torque and they are next to the primary cat, which is the critical point for EGT really if you're concerned about cat breakdown. I'm not sure if you can read both sensors, or just the front (or back) sensor.

[Mark@Abbey M/S 235]

The EGT readings that you can read on OBD readings is via the O2 sensor but this is the temp the element is running out , it is shielded from full exhaust gas flow so I would believe that temp.

 

SC car seem to run high EGT. Manufacturers CATS are far better quality than any of the CATS brick used on after market kits unless you spend a lot of money so they seem to last a lot longer when running on a FI car. Running the after market CAT as far away from the engine is the best way to make them last but this also causes issues with keeping them hot enough for MOT emission testing.

Thanks