nikpro Posted January 17, 2006 Share Posted January 17, 2006 The screw is just to adjust the initial position of the butterflies. If you use this to adjust the idle speed it will upset the ECU map. Basically at idle the throttle position site should be at 0 on the throttle index (voltage 0.69-0.71 on Westfield map), as you adjust this screw it will increase the TPS voltage and hence move the throttle site to 1 or higher. If you then adjust the TPS back to site 0 you will be running lean as the throttle body will 'pull in' more air as the butterflies are opened yet your TPS will be at site 0. This isn't explained very well cause it's late and you really need easymap to understand it. If you have easymap and you play with the fueling and timing you can raise or lower the idle speed but it should be 900-950 RPM on an 1800 Zetec. Quote Link to comment Share on other sites More sharing options...
Ian Podmore Posted January 17, 2006 Share Posted January 17, 2006 Exactly - need to be an Engineer to point his out Let me know when you find one Quote Link to comment Share on other sites More sharing options...
Flappa Posted January 17, 2006 Share Posted January 17, 2006 The screw is just to adjust the initial position of the butterflies. If you use this to adjust the idle speed it will upset the ECU map. Basically at idle the throttle position site should be at 0 on the throttle index (voltage 0.69-0.71 on Westfield map), as you adjust this screw it will increase the TPS voltage and hence move the throttle site to 1 or higher. If you then adjust the TPS back to site 0 you will be running lean as the throttle body will 'pull in' more air as the butterflies are opened yet your TPS will be at site 0. This isn't explained very well cause it's late and you really need easymap to understand it. If you have easymap and you play with the fueling and timing you can raise or lower the idle speed but it should be 900-950 RPM on an 1800 Zetec. I kind of understand what you are saying, but surely you can't actually alter the idle speed in the ECU without physically adjusting the butterfly position to match those settings. The situation that we have is a pre-prepared map that we need to match up to. When we balance the ports to the specified air flow, this produces the required idle speed. To do this you need to adjust the idle screw, the centre link screw and probably the individual by-pass screws as well. You then reset the TPS position. Quote Link to comment Share on other sites More sharing options...
nikpro Posted January 17, 2006 Share Posted January 17, 2006 I kind of understand what you are saying, but surely you can't actually alter the idle speed in the ECU without physically adjusting the butterfly position to match those settings. The situation that we have is a pre-prepared map that we need to match up to. When we balance the ports to the specified air flow, this produces the required idle speed. To do this you need to adjust the idle screw, the centre link screw and probably the individual by-pass screws as well. You then reset the TPS position. With a carb, as you open the butterfly the increased airflow causes a pressure differential in the venturi and this allows more fuel to be 'pulled' into the mixture (it is actually pushed in by pressure differential) so the mixture stays correct within the limitsof the idle jet. With the throttle body the only way of increasing the fuel flow is by the engine map, therefore if you just open the butterflies by the 'idle screw' then adjust the TPS back down to throttle site 0 (0.69-0.71 Volts) the mixture will be lean. If you allow the throttle site to increase by not re-adjusting the TPS back down to 0 the map will be wrong because at site 1 and above it is mapped for an engine under load. Yes, you can't fully controll the engine revs by the Map alone but you can change approx + or - 150rpm. The correct Position for the Butterflies is very,very fractionally open and this is set by the 'idle screw' and it is this amount of air entering the engine that has the main effect on idle speed. The air bypass screws and other linkage is just to allow for manufacturing tolerances and hence to balance the Throttle Bodies. The idle bleed screws should be fully closed at the start then only opened to balance the TB's Quote Link to comment Share on other sites More sharing options...
Flappa Posted January 17, 2006 Share Posted January 17, 2006 So that's agreed then.. Quote Link to comment Share on other sites More sharing options...
bill shurvinton Posted January 17, 2006 Share Posted January 17, 2006 I knew there was a reason why I didn't like alpha-N mapping on ECUs. I won't torture you all with some screenshots of how you can use a wideband and logworks to spit out a new map after 10 mins of driving. Quote Link to comment Share on other sites More sharing options...
KerryS Posted January 18, 2006 Share Posted January 18, 2006 Oh go on! Kerry Quote Link to comment Share on other sites More sharing options...
MAT1800 Posted January 18, 2006 Author Share Posted January 18, 2006 Now I'm really confused..... Fingers crossed, I might get chance to have a look tonight. Quote Link to comment Share on other sites More sharing options...
nikpro Posted January 18, 2006 Share Posted January 18, 2006 Matt, don't be, just carefully go through the steps I laid out on page 4 of this thread! Quote Link to comment Share on other sites More sharing options...
jak Posted January 18, 2006 Share Posted January 18, 2006 I knew there was a reason why I didn't like alpha-N mapping on ECUs. I won't torture you all with some screenshots of how you can use a wideband and logworks to spit out a new map after 10 mins of driving. Do you know anyone that sells wideband sensors, then Bill John Quote Link to comment Share on other sites More sharing options...
bill shurvinton Posted January 19, 2006 Share Posted January 19, 2006 Sensors can be bought from any VW garage. Sod all use without a controller mind. Some MBE models have a good wideband compatible closed loop mode. Seems a lot cheaper than rollers for the fuelling. But I never was a chequebook racer. Quote Link to comment Share on other sites More sharing options...
nikpro Posted January 19, 2006 Share Posted January 19, 2006 Sensors can be bought from any VW garage. Sod all use without a controller mind. Some MBE models have a good wideband compatible closed loop mode. Seems a lot cheaper than rollers for the fuelling. But I never was a chequebook racer. Bill, do you know which MBE ECU's are good for this, I currently have a 956e? Quote Link to comment Share on other sites More sharing options...
KerryS Posted January 19, 2006 Share Posted January 19, 2006 The MBE datasheet for the 967 here says it will run closed-loop lambda control. Is this the same as Bill's description? The 941 ECU says same but a whole heap more. Kerry Quote Link to comment Share on other sites More sharing options...
Gavin Posted January 21, 2006 Share Posted January 21, 2006 Hi guys, Any of you had problems with the connections on the loom being different to what is on the car ? For example the plug on my main loom for the ignition etc is a 12 pin plug but on the TB loom I was supplied it is a 4 pin plug.Also the lambda sensor plug is different and will not fit together allthough on this one I can rewire it by buying a new sensor. Have I been supplied the wrong loom for my car do you think ?? Help appreciated, thanks guys. Gav. Quote Link to comment Share on other sites More sharing options...
MAT1800 Posted January 21, 2006 Author Share Posted January 21, 2006 Dunno what's up with your kit Gav? Mine seemed to all fit properly. The 4 pin to 12 pin plug us a bit worrying, can't see how that will work.... I presume you've tripple checked it all? Quote Link to comment Share on other sites More sharing options...
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