vvti problems

[FGrob]

P1349
Condition (a) or (b) continues for after the engine is warmed up
and engine speed at 400 – 4,000 rpm :
(a) Valve timing does not change from of current valve timing
(b) Current valve timing is fixed.

If you have a problem with the VVTi, How do you explain the Absence of a Code?..  

Cap

Because he running a PFC

[Cap]

using the pfc we replicated rising and falling rpm and the ocv didn't budge. We even tried it with the oem ecu ... no difference.

Looks like the ECU did not toss a cell..

Cap

[ChrisGB]

Hi Nic

Looking at the dyno graphs posted in the N/A thread, looks like the problem started when you had the stage 1 cams fitted. The torque curve is showing exactly what I would expect from vvti not working. It could also be a result of increased valve overlap from the cams dropping mid range torque, but I would expect that from stage 2 or 3 cams.


This has made me worry about fitting my stage 1 cams that iv purchased    s:shock: :shock: s:shock:

The stage 1s will give a pretty much standard shape torque curve, just more of it. If Nic has got a set of stage 2 or 3 cams by mistake, that sort of mid band performance could result. Looking at the curve though, it starts to drop off quite quick near the red line. Stage 2 or 3 cams would still be pulling hard at these rpms. My guess is either a locked acutator or duff ocv.

Chris

[ChrisGB]

VVTi paranoia seems to have set in with some folk  s:lol: :lol: s:lol:   The easy way to test your vvti actuator and ocv system is working properly would normally be that the CEL would come on if it was not. The inlet cam has a positional sensor lobe and corresponding sensor in the head. If the cam is not where the ECU thinks it should be it will throw a CEL (and a P0341 code if I have understood it correctly). For anyone running the standard ecu, this should set your mind at rest.

A few things to consider for those newer to the MR2. First, this is not a Honda Vtec sort of device. Basically the 1.8L engine is rated at 138bhp. This gives a specific output of 72bhp/L. To achieve this, the engine is running maximum valve overlap above around 4500rpm. The OCV is doing nothing and the vvti controller is fully "off". The vvti performs its work lower down the rev range where the controller is able to advance the inlet cam reducing valve overlap and allowing the engine to produce a very plump torque curve relative to a non vvti engine of the same specific output. What you don't get is a "kick" at any sort of engine speed. The other function of the vvti system is to produce enough inlet valve advance, that under some circumstances, for example light load cruise, some exhaust gas is forced back into the inlets and then re ingested by the engine. In this way, the car does not need an EGR (Exhaust Gas Recirculation) valve.

Under most low load conditions a (eg, revving it up without driving under load), the vvti probably does nothing at all, only coming into play when some egr functionality or midrange valve overlap reduction is needed. The easy way to test if the system as a whole is working electromechanically is simple. Put 12v across the OCV. This will fully open the OCV causing the engine to try and recirculate exhaust gas at idle. This will make the engine stumble or stall completely.

If this test shows the electromechanical side to be functioning, then the error can only be the wiring or ECU output. Scope will show the PWM waveform, but failing that, a 12v indicator should trigger under conditions where vvti is activating. I would not advise use of an ordinary LED though as standard ones are generally 5v. If the electromechanical side is not working, it could be a duff OCV, or a locked actuator, or worst case, a blocked / gummed up actuator.

I have only seen a limited number of genuine vvti problems on the forums. Usually they are accompanied by an ECU light, but in Nics case, with the PFC, it looks like the dyno has found a problem.

Hope this helps put people minds at rest a bit!

Chris

[Cap]

Now you've done it!!..

... bringing facts to the Discussion..

[FGrob]

So what's the outcome Nic.

[Wabbitkilla]

Well, I was very busy at work yesterday, not feeling too well, and the tank had a fuel/octanebooster mix in it from Scotland so I cancelled the run.
Once I'm feeling better and cleaned the tank out with V-Power I'll revisit the rolling road.

On my run around Scotland I didn't seem to be lacking power so I'm assuming it's a lot better - will be good to know for certain.

[FGrob]

Well, I was very busy at work yesterday, not feeling too well, and the tank had a fuel/octanebooster mix in it from Scotland so I cancelled the run.
Once I'm feeling better and cleaned the tank out with V-Power I'll revisit the rolling road.

On my run around Scotland I didn't seem to be lacking power so I'm assuming it's a lot better - will be good to know for certain.

OK - None of my local Shell garages sell V Power any more - had to swop to Tesco  s:shock: :shock: s:shock:  

Rob.

[tasc74]

The old engine in my 2 ate my vvti controller when it blew up, got a new one being delivered to me tomorrow. Can i just install it or does the engine have to be in a certain position? TDC ? Will it do any harm if I dont?
many thanks
tom

[Wabbitkilla]

You can just put it straight in, no problem.

[ChrisGB]

The old engine in my 2 ate my vvti controller when it blew up, got a new one being delivered to me tomorrow. Can i just install it or does the engine have to be in a certain position? TDC ? Will it do any harm if I dont?
many thanks
tom

If it is the Oil Control Valve (OCV) on the back of the block, you can just swap them over with the engine in any position. If it is the actuator (the bit on the end of the inlet camshaft) then the engine timing marks have to be lined up, so it is one mark on the crank timing chain pulley lined up with the appropriate mark on the block and the two timing chain pulleys on the end of the camshafts have to have the alignment lines opposite one and other inboard. I cannot remember where the yellow link on the timing chain goes.

Chris

[manchestermatt1986]

yet another day i missed out on due to work, i will be not be missing ding day thou!

[Anonymous]

slightly off topic started to use the vvti on my new engine when the light came on. its p1349 vvt system fault bank one. toyota say its the actuator or controller. anyone got any ideas?

[Wabbitkilla]

I think your first port of call is to check the vvti ocv valve filter, it sits behing an bolt top just below the ocv valve on the back of the engine.
Check if it's clean or blocked.

If it's clean I would check the plug is ok on the ocv, then try replacing the ocv itself.
After that it's into the engine to look at the actuator on the end of the intake camshaft, but i doubt it'll be that as it's a pretty simple device and not prone to problems.

How's your oil?
Plenty of it and decently clean?

[muffdan]

After that it's into the engine to look at the actuator on the end of the intake camshaft, but i doubt it'll be that as it's a pretty simple device and not prone to problems.

Just to mix it up a little, I've had 2 failed actuators. I got my last (current) one 2nd hand from Rogue who had a box full of them on the floor left over from engine swaps they'd done. They tested each one in the box by applying air pressure through it and it turned out that half of them weren't working.

Makes you wonder how many people are driving around with no vvti and just don't realise.   s:? :? s:?

[Wabbitkilla]

Hmmmm ... good point, I have a spare I might get tested then and see if it's easily done in the engine.

[Anonymous]

ok i will check those bits i also heard a knock b4 it went woulx that change things. also if the actuator went would driving it cause damage?

[ChrisGB]

ok i will check those bits i also heard a knock before it went woulx that change things. also if the actuator went would driving it cause damage?

Should not do any damage to run it, but I cannot imagine anything in the vvti system that would knock.

Chris

[ChrisGB]

Just to add, knocking and that code could be an indicator of intermittent oil pressure.

Chris

[Anonymous]

na just the one knock and then no vvt going to look at it next weekend but im thinking it will be the actuator but will look at the other bits first. other than no vvt it pulls like a train lol.