Guest suprastar Posted October 3, 2007 Share Posted October 3, 2007 I'm posting this as I think it might help others with a similar problem. The throttle On the VVTi runs using a drive by wire system. There are 2 sensors, one on either side of the throttle body. Looking in under the bonnet, the one on the right very rarely ever gives a probem, but the one on the left that has the cable attached quite often does. If the VVTi has an achilles heal this is it. I'm on my second one (but then I have had the car 9 years) I had the engine management light come on pretty much most times when I kicked down (it's an auto tip tronic) I couldn't be bothered to mess around so I replaced both sensors, HA! but the problem was still there. The fault was such that it never got logged and you could only read the fault number when it had actually happened and then you'd limp back to the garage for them to read the fault while the engine was still running. The number that came up just refered the fault to the throttle (Great help....not!) I decided to take off the throttle body and see what could be done. 4 bolts, 3 small hoses and 3 connections to unplug and it was off.one side of the butterfly was caked in black carbon that needed a good carb cleaner to remove it. I then set up the butterfly with both the throttle and the traction control. there are 2 grub screws, one for each on either side of the body, back off both screws until the butterfly is shut completely, then screw down one at a time until they just start to open the butterfly. With both screws just touching and the butterfly still closed, tighten the lock nuts. PRESTO!! job done. Just fit it all back, start the engine and the management does the rest. Idle has NEVER been so good, fault light has not come on since and it punches the air on a gear change like a F1 car. I hope this helps someone. Quote Link to comment Share on other sites More sharing options...
Mike B Posted October 3, 2007 Share Posted October 3, 2007 thanks for writing this.. what did the car do when the light go on... did it go onto limp home mode... ie 1/4 throttle or something? or does it just hesitate sometimes before it will let you have full throttle? I like the dbw throttle for engine safety reasons (det detection) but do fin it intrusive sometimes. Quote Link to comment Share on other sites More sharing options...
Mike B Posted October 3, 2007 Share Posted October 3, 2007 and you mention the grub screws... what position were they in before you adjusted?? Quote Link to comment Share on other sites More sharing options...
Guest suprastar Posted October 4, 2007 Share Posted October 4, 2007 Hi, Yes i was just left with a small amount of throttle, just enough to limp home. There was no hesitation. The grub screws were screwed a good way in and after i cleaned the carbon build up away i refitted the body and the car idled at over 2K and also started "hunting" so off it came again, that's when i backed off the screws and started from scratch with resetting the butterfly. The setting is quite critical when you're calibrating the butterfly with both the throttle and the traction control. Mine was so far out that it caused the engine fault to come up. I also had a feeling of resistance on the throttle peddal just before a gear change.... all that has gone now Quote Link to comment Share on other sites More sharing options...
styggen82 Posted October 5, 2007 Share Posted October 5, 2007 I'm posting this as I think it might help others with a similar problem. The throttle On the VVTi runs using a drive by wire system. There are 2 sensors, one on either side of the throttle body. Looking in under the bonnet, the one on the right very rarely ever gives a probem, but the one on the left that has the cable attached quite often does. If the VVTi has an achilles heal this is it. I'm on my second one (but then I have had the car 9 years) I had the engine management light come on pretty much most times when I kicked down (it's an auto tip tronic) I couldn't be bothered to mess around so I replaced both sensors, HA! but the problem was still there. The fault was such that it never got logged and you could only read the fault number when it had actually happened and then you'd limp back to the garage for them to read the fault while the engine was still running. The number that came up just refered the fault to the throttle (Great help....not!) I decided to take off the throttle body and see what could be done. 4 bolts, 3 small hoses and 3 connections to unplug and it was off.one side of the butterfly was caked in black carbon that needed a good carb cleaner to remove it. I then set up the butterfly with both the throttle and the traction control. there are 2 grub screws, one for each on either side of the body, back off both screws until the butterfly is shut completely, then screw down one at a time until they just start to open the butterfly. With both screws just touching and the butterfly still closed, tighten the lock nuts. PRESTO!! job done. Just fit it all back, start the engine and the management does the rest. Idle has NEVER been so good, fault light has not come on since and it punches the air on a gear change like a F1 car. I hope this helps someone. you got some pictures of this? the 2 grub screws? haven`t had any problems on my car yet but you never know:) Quote Link to comment Share on other sites More sharing options...
TRD3000GT Posted October 5, 2007 Share Posted October 5, 2007 VVTI throttle bodies have a single grub screw for adjustment.. It works about 50% of the time but the ECU keeps trying to correct the idle rpm so 50% of the time it doesnt work. I played with mine years back (nightmare) raised the ide to 700RPM and all was good for about 5 starts then the ecu went mad and the idle was 5500 rpm.. I took me about a week of playing to get it where it originally was so Id say leave it ;-) Quote Link to comment Share on other sites More sharing options...
Guest suprastar Posted October 12, 2007 Share Posted October 12, 2007 mine definately has 2 screws. the one on the side of the traction control is at the back next to the sensor connector, the other is on the top next to the throttle control. ooh i'd not try and set it with the engine running as the management will be working the butterfly and i'd imagine it would make it imposible to set. The body Has to come off so you can see inside properly to set it. I've set this up just the once and it's been perfect ever since. Quote Link to comment Share on other sites More sharing options...
Alex Posted October 12, 2007 Share Posted October 12, 2007 I personally tried the upper one, but never the lower...interesting theory, hope it pans out long term. Please bump this thread after 6months and let us know if it's still going well. Quote Link to comment Share on other sites More sharing options...
Guest suprastar Posted October 20, 2007 Share Posted October 20, 2007 It's been nearly 3 weeks and the idle is still perfect! Quote Link to comment Share on other sites More sharing options...
Alex Posted October 20, 2007 Share Posted October 20, 2007 Glad to hear it!! Will save people buying new TB's in the future. Quote Link to comment Share on other sites More sharing options...
Ewen Posted October 20, 2007 Share Posted October 20, 2007 Glad to hear it!! Will save people buying new TB's in the future. Oops. Quote Link to comment Share on other sites More sharing options...
Alex Posted October 21, 2007 Share Posted October 21, 2007 Oops. We're all learning - have you still got the old one?? You could try it out!? Quote Link to comment Share on other sites More sharing options...
Ewen Posted October 21, 2007 Share Posted October 21, 2007 We're all learning - have you still got the old one?? You could try it out!? :)I replaced the TB in the knowledge that there may obviously be other things that could be tried first...at that time I was just happy to get it working. An expensive fix perhaps in hindsight, but as you say little tweaks come up all the time. I've still got the old TB, still with the two sensors attached. I was going to send it to CW for him to play with but I never got round to it. Its still here if someone wants to autopsy it. I'd rather leave mine well alone as its running just fine now. Also, my old TB was very clean...non of the deposits described by the thread poster, so its not a given that the same fix would have worked ? Quote Link to comment Share on other sites More sharing options...
Guest suprastar Posted November 21, 2007 Share Posted November 21, 2007 21st November and it's STILL sweet ...... I love this car!! What could I ever buy to replace it? Quote Link to comment Share on other sites More sharing options...
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