Does someone know what is the differential pressure regulator max current in open loop mode in 9A or ACE engines /KE-Motronic/? Mine is about 2-3mA from 4000rpm to the redline and I think there is somethink wrong, should it be more?
Thanks, on that site there is only idle current 0-5mA. What is the value of full throttle enrichment current? Anyone?
I don't think you will find a value anywhere for full throttle whilst running, because you would need to view it whilst driving. The values given in rubjonny's link are the ones I have always used. The official VW literature does not show anything other than that. What prompted you to think there us something wrong and start looking into this?
I've made some tests while driving with test harness connected to the DPR and the ampermeter on the pasenger seat and the results are: cold start: 30mA gradually decreasing to 5mA /when engine temp became 80C/ hot start /80C/: bump to 20mA then stabilises at 5mA driving in 3rd gear /steady spead/ and giving part trottle: bump to 7-12 then stabilises at 5mA full throttle at 3000rmp: bump to 7-12 then stabilises at 2-3-5mA??? I think full throttle enrichment do not enrich more than idle speed? Enrichment operates in 0-100mA range. 2mA is soo minimal, close to zero... I need to compare with other car. Nevertheless the car run smooth to the 7000.
From what I understand, the electonic control of the fuel pressure using the DPR is only used during closed loop lambda operation for very fine ECU controlled adjustment of the fuel mixture to keep it within the specified range around the stoichiometric mixture (14.7:1 AFR). This is ideal for good economy and applies to zero throttle and part throttle conditions. KE-Motronic has a narrow band lamba sensor which is only useful very close to stouchiometric mixture. For full throttle, a richer fuel mixture is required to provide maximum power and avoid lean running of the engine. The fuel mixture is ideally somewhere around 12.5:1. The narrow band lambda sensor is no use at this mixture, so at full throttle the closed loop operation using the DPR is not used, hence no emrichment current. At full throttle which the ECU recognises from the input from the full throttle switch on the throttle body, you are back to a basic fueling setup running as the previous K-Jetronic system would. It is possible to adjust the fuel mixture at full throttle by removing the DPR (2No. cap head bolts) and removing the small cheese head screw, which has a very fine thread from the face which joins the side of the metering head and turning the adjuster screw which you will find after removing the cheese head screw. You will need a very small allen key to turn the adjuster screw, and the adjustment is very fine. If you do decide to do this, make sure the ignition is off when dismantling and be warned that when you unscrew the DPR petrol under pressure will spray out momentarily as you split the joint. Do not loose the 'O' rings. The adjustment of the screw will alter the differential pressure, and is evident by the base current setting with the ignition on, but the engine not running. I adjusted mine down to give a current of 90mA which is the rich end of the scale, and then adjusted the fluctuating idle value back to 2.5mA +/- 2.5mA as advised.
Thank You Phil, sounds very easy. I thought in WOT conditions ECU boost DPR current to enrich mixture, my mistake. Have you measure AFR or put yor car on rollers?
It's fairly straightforward,, finding out the information was the hard bit. I have fitted a wide band lambda sensor and AFR gauge. At normal running temp, idle and part throttle fluctuate around 14.7:1 AFR. Full throttle richens up to around 12:1 at around 2000rpm, leaning off to about 13.2:1 at 6500rpm. It drives well, but made 154bhp and 148Ibft recently. For it's spec that isn't too good. 2008cc, 11:1 compression, Shed Head, KR cams, Magnex cat back, matched 42mm inlet, tidied exh mani, lightened flywheel, airbox mod, foam filter. Over the winter I will be converting to Megasquirt, hoping to end up between peak 170-180bhp, with good uabel torque.
