How bad did I "F" up my ECU?

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Reeve · #1 Post by **Reeve** » Thu Feb 11, 2010 6:03 am

Well after some reading here I guess it's not a good idea to ground the fuel pump manually to prime the syster after a filter change. Whoops! I had done it a few times in the past with no problems but last weekend I had to change the filter because there was water in it. I didn't notice the water untill the battery was low from cranking it. I didn't want the battery to go dead from cranking and cranking again to get the pump to prime so I grounded it. After it was primed I took the ground off and the fuel pump kept running but at a much lower speed. I turned the key off and it kept running. By that time I knew I screwed it up. At that point I was pissed. I had been working on it for an hour and a half trying to get the water out of it so it would start so I grounded the pump again and cranked it. It started right up so I took the ground off and it kept running with only the stock wire going to it. I took it up the road a bit and everything was running fine even on full throttle so I rode it for a about 45 minutes (witch made me feel a bit better) After I shut it off the fuel pump was still running slow so I took off the ground wire and parked it. So is this somthing that is an easy fix? I have a couple friends that are very good with electronics. This is on an 02 Speed.

Lightman02 · #2 Post by **Lightman02** » Thu Feb 11, 2010 12:42 pm

QUOTE (Reeve @ Feb 11 2010, 01:03 AM) <{POST_SNAPBACK}>

Well after some reading here I guess it's not a good idea to ground the fuel pump manually to prime the syster after a filter change. Whoops! I had done it a few times in the past with no problems but last weekend I had to change the filter because there was water in it. I didn't notice the water untill the battery was low from cranking it. I didn't want the battery to go dead from cranking and cranking again to get the pump to prime so I grounded it. After it was primed I took the ground off and the fuel pump kept running but at a much lower speed. I turned the key off and it kept running. By that time I knew I screwed it up. At that point I was pissed. I had been working on it for an hour and a half trying to get the water out of it so it would start so I grounded the pump again and cranked it. It started right up so I took the ground off and it kept running with only the stock wire going to it. I took it up the road a bit and everything was running fine even on full throttle so I rode it for a about 45 minutes (witch made me feel a bit better) After I shut it off the fuel pump was still running slow so I took off the ground wire and parked it. So is this somthing that is an easy fix? I have a couple friends that are very good with electronics. This is on an 02 Speed.

Try:
http://cgi.ebay.com/ebaymotors/Cannondale-...sQ5fAccessories

Not bad if it works. As far as fixing your old one, not sure if you can get it apart in one piece, therey are pretty well closed up and the elctrioncs are potted to shield agains moisture etc. I would get a replacement and then try taking the other one apart. Or just put a switch on the fuel pump and turn the pump on and off manaully.

wistech · #3 Post by **wistech** » Thu Feb 11, 2010 1:47 pm

You ecu fuel pump driver is smoked and cannot be repaired. For safety reasons I would wire up the fuel pump to the tether circuit or get a new ecu. If you want to run your fuel pump independent of your engine you need to unplug it and run a jumper pos and ground to it to keep from frying the grounding diode in the ecu. This is a very common problem documented from day one with cannondales and unknowing fiddlers. I think Caniboomer might have the best prices on ecu's. You need to transfer over your maps and settings, hex code if you want to change it which also bring up the absolute need for a D@M kit for every owner so they can do it themselves.

Reeve · #4 Post by **Reeve** » Thu Feb 11, 2010 3:36 pm

Thanks guys. Live and learn . If I can't fix it I think I will just make it run when the key is turned on. Does the key switch close ground or supply power? I don't know what map is in there right now but it runs great. I don't think it's stock.

SlOoT · #5 Post by **SlOoT** » Fri Feb 12, 2010 9:56 am

Key supplies power.

Reeve · #6 Post by **Reeve** » Wed Feb 17, 2010 7:04 am

Thanks for the info. I am just going to hot wire the fuel pump to the key. I went out yesterday and started it up again. I just did a manual ground to the fuel pump to make it run full speed and I swear it started up with less trouble than it did when the ECU was in charge of the fuel pump. Do you think I am on to something here?