fastblueheeler

Need some advice on how to proceed with this problem. The 20A ECM B fuse blows after about 3 to 5 sec from turning key to start. and of course it won't start. After cranking (before I checked fuses) I noticed the "battery", "security" and "low fuel" lights flash in sequence. Also the indicator light for gear selection won't come on(not the P R N D etc, just the little square that tells you what gear you're in)

Then I discovered the blown fuse. There is about 50 ohms of ground on the cold side of the fuse plug. After replacing fuse the first time, the car started and ran about 5 sec before blowing the fuse. .but it will blow even if you don't crank the engine. Bad wiring? Bad fuel pump? Does anybody have any experience with this problem and some advice?
2001 Tahoe with about 90K miles.
Thanks

fastblueheeler

OK, it was the fuel pump. $800 at the dealership. There goes my guitar money.

viperjuice

NO WAY DUDE.. fuel pump doesn't do that, i've never once seen it do that. and i work at a chevy dealer. I have on the other hand, on 2 occasions, seen a shorted wiring harness by the motor mount right behind the l/f tire.

fastblueheeler

Well do me a favor if you can viper- If you have access to a wiring diagram where you work, tell me what that ECM B fuse feeds. Thanks

viperjuice

it feeds a gray wire that goes from the under hood fuse block to the fuel pump, but i have never seen a fuel pump blow the fuse. if it shorts, it causes and open. Although I have seen a guiy at my old job replace a fuel pump and then go looking for the short, they won't tell u that of course cause then you could say that the fuel pump was neevr the problem.

fastblueheeler

Thanks man, I appreciate the info. I did read on another forum that there's a problem with the wiring harness at the fuel pump. It rubs against the frame and shorts out. You've got to replace the pump when this happens, it's the wires that come out of the fuel pump. I'm the kind of guy that would be tempted to just separate the wires and wrap tape around them though. The service guy says this wasn't the problem, the ground I was reading was the winding on the bad fuel pump motor grounded out. What are you gonna do - you're at the mercy of doctors and mechanics.

bhartner

I have a 99 Yukon (~160K miles) that just started to blow the ECMB fuse a week ago .... fastblue, any chance they replaced the connector at the fuel pump when they replaced the pump (that you may not have needed) ? The reason I asked is I called GM service about my Yukon, he suggested it was probably the fuel pump, I explained it was replaced a year or two ago, he then suggested they probably didn't replace the connector at that time... I am going to replace the connector (65$) at the fuel pump in the AM, at least now it is DEAD, blew 4 ECMB trying to start this AM, where it was sporadic during the last week or so.

-Bill

fastblueheeler

I've wondered if the pump was really bad and not just the connector. The service guy assured me it was the pump but........?
When this thing went south it wasn't sporatic at all. I'd just towed an old Volvo we bought 600 miles, parked the Tahoe in the garage and the next morning-no start! Checked fuses and found the ECMB blown. Boy was I happy! Thought I'd replace the fuse and go on my merry way. Went through 4 or 5 fuses before reality set in. Within 2 seconds of trying to start, the fuse would blow. Good luck with the connector!

fastblueheeler

Sorry, forgot to answer your question. They told me no problem with the connector, they didn't replace it. I asked about this since I'd read some models had a problem with the wiring harness.