stevefoster Posted May 5, 2001 Share Posted May 5, 2001 No spark! Weber Alpha 3d fitted to a VXC. Checked power and earth to the ECU, traced all loom cables from the plugs back to the ECU plug. Everything is fine. Crank sensor is giving low voltage through to the ECU on cranking. Tried the apply half throttle trick that another Weber Alpha fitter told me about. No joy. Reconnected the old MBE unit... starts first time! Apart from a faulty ECU or Weber perhaps not having loaded the map in what can it be? The supplier assures me that it will work with my existing VXC crank sensor and coil pack. Any help glady received. Edited by - stevefoster on 6 May 2001 18:34:48 Link to comment Share on other sites More sharing options...
StewartG Posted May 5, 2001 Share Posted May 5, 2001 Try speaking to Peter White at Webcon he really is very helpful and knowledgable. He did tell me that Vx have used several different types of crank sensor over the years but I've forgotten the details. Have you checked the throttle pot for 5 volts and set the idle/throttle closed voltage? It should be .75v some of the instructions say .65v but stick to .75v but I don't think this will cause total starting failure. How have you connected the tacho? try dissing the tacho feed and see if that's the problem. Are you sure you've not got the +ve and -ve sides of the coil confused? Sorry to sound patronising but sometimes we can't see the wood for the trees. E-mail me off line with your phone number if I can help. Link to comment Share on other sites More sharing options...
stevefoster Posted May 6, 2001 Author Share Posted May 6, 2001 Hi Stewart, How do I see your email addr from here? The system is all compatible with the existing Bosch coil / crank sensor plug wise. I can't wire the coil pack up wrongly unless Webcon have done it for me already. I have traced the contacts end to end and all seems right regarding the position of the power feed to the coil. On the Bosch 3 pin plugs thi is two -ve and the +ve in the middle. The crank sensor voltage is low. So low that I can really measure it.... The instructions talk about original VX parts.... There is nothing in the blurb about setting throttle pot voltages but that does not mean I should not do it I guess. Can you explain how this is done? Link to comment Share on other sites More sharing options...
StewartG Posted May 6, 2001 Share Posted May 6, 2001 You can find my E-mail address by clicking on the head icon on any of my postings or E-mail me direct by clicking on the pages icon next to it or to save you that my e-mail address is stewart.gray@btinternet.com sent me a phone number and as I said I'll do my best to help. Link to comment Share on other sites More sharing options...
stevefoster Posted May 6, 2001 Author Share Posted May 6, 2001 Thanks Stewart. Clever stuff. Pretty obvious clicking their wasn't it really. I have updated my profile to my home email which is more read over weekends etc. Link to comment Share on other sites More sharing options...
Roger King Posted May 6, 2001 Share Posted May 6, 2001 Steve, We had one Vx Alpha kit that wouldn't give a spark and it turned out to be a reversal of the wiring to the crank sensor. Just a small manufacturing error which was easily sorted when identified. Sorry, but I don't have the details of wire colours and pin numbers to hand to advise further. Worth a look though if nothing more obvious turns up. Link to comment Share on other sites More sharing options...
stevefoster Posted May 7, 2001 Author Share Posted May 7, 2001 Thanks Roger, I will add that to the list of check items. Will the standard Bosch (black pentagonal shape) coil pack mounted on plate at the end of the right hand cam really work with the ignition? I was advised it would but am now having doubts. Stewart called me last night and we went through his Dizzy and coil installation. I will check to see if I am getting 5V out of the ECU to the throttle pot... It is a sign of life. If all this fails today then I will call Peter White at Webcon tomorrow. Link to comment Share on other sites More sharing options...
stevefoster Posted May 7, 2001 Author Share Posted May 7, 2001 Ok here's what I've got. +5V coming out of the ECU to the throttle pot sensor plug (so that looks ok) Coil pack plug on loom has (as viewed left to right with wire clip at top) when traced back to the ECU plug the following:- Left pin = Ign sig output1 (green/purple wire) Middle pin = 12V (white wire) Right pin = Ign sig output2 (orange+black band wire) Crank senor plug (as viewed left to right with wire clip at top) Left pin = Engine speed sensor input (red wire) Middle pin = Engine speed sensor ground (blue wire) Right pin = Braided wire going to pin 24 on the ECU plug that is not designated The coil pack I have is B 0221503001 The crank sensor I have is GM 9045 1441 Link to comment Share on other sites More sharing options...
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