GUIDE: VVTI Misfire, Automatic High Rev and Idle problem SOLVED - Finally - Pics att.

[adnanshah247]

Well after weeks and weeks of issues trying to get my Aristo functioning properly I finally cracked it! and learnt a lot about the VVTI system along the way. I will explain everything in detail so that it could possibly help other owners. I may make some term/spelling mistakes so i apologise in advance but this is taking a fair amount of time for me to type up.

 

So in total the Symptoms of my car:-

 

Problem 1 - Suddenly, on a cold start, I would start the car and the car would jump and hold at 3000rpm regardless of me putting my foot on throttle. I would have to switch the car off and pump the throttle and then it would start and idle at its normal level.

 

Problem 2 - I started to realise that on idle sometimes the engine would stutter, as if its miss firing. I would drive and it would go back to normal on and off. On boost it was perfect.

 

Problem 3 - Very temperamental miss-fire at higher boost setting.

 

 

Common Problems that I checked before finding the solution, i would highly recommend that all of these are checked prior to getting worried:-

 

 

Check 1 - First of all check your spark plugs, the technical FAQ page on the forum is amazing that Alex wrote up, if your running the wrong plugs expect issues and its so easy to think 'ow there brand new' and ignore them. For my car the plugs i had were correct but the spacing wasnt 0.7 hence why at boost it would misfire (problem 3)

 

Check 2 - Check the Coil Packs and Ignitor. Nobody can shell out £350 overnight for new coils etc. so what i did was found a friend who had a similar car and asked to use his coils for a few seconds, bought him a drink later but all you need to do is swap and drive to see if the issues still there, very easy job, all you need is a 10 spanner.

 

Check 3 - Fueling and Vacuum Lines - if you have a fuel pressure regulator, make sure its moving on the gauge that shows your pump is working, the pump on my car turned out to be a replica walbro but at the time was function fine, changed it for bosch 044 from Lil Num that was genuine just for the peace of mind. At this stage ensure all vacum lines are checked, dont just look at them, purposely take the off, turn them into S shapes and look for splits, recconect them with new clips or strong cable ties, you wont believe how many times members along with myself have had issues down to a loose or split vaccum line.

 

Check 4 - Fuel Injectors, sadly i checked these much later down the line, my injectors were crappy ebay skinny injectors, supposedly 650cc that previous owner had fitted but running genuine sard 650cc injectors now the difference is massive, put it this way the power i was getting at full boost is equal to the power im getting on low boost now with the proper injectors!

 

Check 5 - Crank Shaft Sensor, Trigger wheel and Timing. Getting to the Crank Sensor is a PITA but in doing this job seen as you have the front of the car apart its easier to hit 2 birds or should i say 3 with one stone. Its relatively easy to get things on and off, all the bolts are accessible. Once you have the covers, fan belt, alternator and crank pulley off be sure to get the CS sensor out and check the trigger wheel is attached to the pulley, as you can see on mine it was welded on but these are known to come away so imagine the big back bit not spinning and the front spinning, the back bit is what gives the CS sensor the reading so it sparks at the same time. Its a common issue and that part can be supplied from Whifbitz full welded etc for around £150. Also before all of this check all the marking on the CS Pulley and top pulleys to make sure your timing isnt out. Pics attached to try help:-

 

 

 

Check 6 - here comes the most hilarious find the actual solution to my problem 1 & 2, i had changed the throttle body and had exactly the same issue, what needed to be adjusted was the throttle position sensor on the right side of the body and a tiny bolt on top of the body that adjusts the pedal. Genuinely this is all it was. All my hard work for 2 tiny things, that is the magic of the 2JZ. Problem 1 and 2 Solved! As you loosen and tighten and move the two things you will figure out were to position because the car will respond to your re-positioning, were its back to normal and your idle is fine, tighten and then sit swearing at toyota for the crappy fly by wire throttle rubbish! Pic attached:-

 

 

 

Check 7 - finally my car started and wouldn't automatically rev its nuts off, RESULT and PROBLEM SOLVED, due to the change of injectors and a slightly jumpy idle i took my car to Torque Developments who gave it a fresh new map, expensive but the car runs beautiful, the power is intoxicating, much better fuel economy and also so smooth up and down boost. Idle is also perfect. As a final check for a single turbo etc get it 75% there running good the rest can be cured by a remap, anyone running a stock ecu simply do your adjustments, switch off the car and restart so the stock ecu can register changes and wait a few minutes to see if the ecu learns and sorts itself out.

 

 

And thats it folks, i hope this write up is helpful for guys running VVTI's and any issues similar to this dont hesitate to PM me, its taken me 5 weeks almost to get this far and can appreciate how frustrating it can get

Edited October 14, 2015 by adnanshah247 (see edit history)

[James]

You can also do an ETCS-i reset by turning the key 2 clicks, pressing the accelerator to the floor for ~30 seconds (you can hear a whine/beep), turning back off, then turning the car over. This sorts out some niggles if the idle has been funny or the car is choking at higher revs or WOT.

 

I was worried about needing a new TPS, throttle body etc. but did that first - ideal.

[adnanshah247]

You can also do an ETCS-i reset by turning the key 2 clicks, pressing the accelerator to the floor for ~30 seconds (you can hear a whine/beep), turning back off, then turning the car over. This sorts out some niggles if the idle has been funny or the car is choking at higher revs or WOT.

 

I was worried about needing a new TPS, throttle body etc. but did that first - ideal.

 

yup thanks for that!