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Rodsrsr Rodsrsr is offline
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Join Date: Jul 2006
Location: Nor Cal
Posts: 4,230
There are a few guys on this forum who can explain the hypothesis to you in great detail, scarceller is one of them. He knows everything there is to know about the Motronic system and he's walked me through extensive troubleshooting a few times on my Motronic based car. Based on this experience I can tell you that sensors can sometimes ohm within specs but still be defective. Being that your's are pushing 30 years old it only makes sense to replace them anyway because at that age they can fail at any time. If I bought a 30 year old Carrera, the first thing I would do is change them even if it was running fine because I dont want to be stranded. If you're not getting spark to the plugs, and the ICV is vibrating, the DME is powering. If the relay is working, the most likely culprit would be a speed/reference sensor. Having said that, there is a very systematic method to troubleshooting these systems and this has been covered many times before. I would search the old threads under "motronic /no start". It may be something else but in order to find out you'll need to go through the entire process. Both sensors are the same BTW. I believe the BMW part just has a slightly longer cable as opposed to the Porsche one. Dont know the part number but search will tell you that as well. Good luck. Make sure you dont get the sensors crossed if you end up replacing them, that will certainly cause a no start.
To GI or not to GI.....
Fear the Heel Hook

1976 Turbo Coupe 3.2
2009 Carerra S (997.2)

Last edited by Rodsrsr; 03-05-2017 at 09:25 AM..
Old 03-05-2017, 09:22 AM
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