86 s10 blazer keeps blowing ECM B fuse - The 1947 - Present Chevrolet & GMC Truck Message Board Network

75chevyeyesore · 04-22-2005, 02:14 AM

Every once in a while when I start the Blazer I turn the key and it runs for about 2 seconds then dies, then will not start back up, due to the 10amp fuse marked ECM B. I also get no trouble code from the diagnostic mode.
This seems to happen randomly once a week or so out of nowhere. I have a 1986 2.8L V6 S10 Blazer. If anyone has any idea how i can narrow down the problem, there are tons of sensors and relays and crap. Could it be the oil pressure sensor? It also has TBI and a manual trans, 4x4. thanx

*bisquik65* · 04-24-2005, 12:35 PM

You need a new fuel pump...Ecm b fuse is tied into the fuel pump relay circuit... That should do it...S-10 wiring are a little funny to fix...I have run into this before..I have 6 blazers here for parts..

75chevyeyesore · 04-24-2005, 06:02 PM

wouldnt the thing not run right if it were the fuel pump though?

*bisquik65* · 04-24-2005, 06:16 PM

If you look at a wiring diagram,the ecm b fuse controls the fuel pump and the injectors. Thinking on it a while ,it may be in your distibutor too.. The fuel pump and pickup coil in the dist,wont set a code...Did you change the oil pressure switch?

Does your radio work fine? I know this sounds weird but check all the other fuses,if the radio fuse is blown too,change that fuse out.. It will backfeed into the ecn b fuse...Trying to help.

75chevyeyesore · 04-25-2005, 02:16 AM

my radio and stuff works fine. I am a little confused about the oil pressure switch, or where it is. On the drivers side of the block just under the oil filter there are 2 switches/sensors. One has 2 connection posts, the other has three. I assume one is the oil pressure swich, but witch one, and what is the other thing?, fuel pump/pressure regulator?

*bisquik65* · 04-25-2005, 08:24 AM

The 3 wire one is for the fuel pump. If your motor loses oil pressure it will shut the pump down,you may want to check oil pressure too.

75chevyeyesore · 04-26-2005, 02:37 PM

it is the oil pressure switch, if i unplug it everything works fine, except for the gauge anyway....

*bisquik65* · 04-26-2005, 03:47 PM

OK glad you found it,Later,Erick

75chevyeyesore · 04-26-2005, 05:57 PM

thanks for the help, if u are parting out some s10 blazers maybe i get some parts from ya....

*bisquik65* · 04-26-2005, 06:31 PM

Welcome to the board!!!Post your location so it will help you find stuff closer to you..

75chevyeyesore · 04-26-2005, 10:12 PM

guess im kinda far here in Reno Nevada

04-22-2005, 02:14 AM	#1
75chevyeyesore Registered User Join Date: Apr 2004 Location: Reno, Nevada Posts: 11	86 s10 blazer keeps blowing ECM B fuse Every once in a while when I start the Blazer I turn the key and it runs for about 2 seconds then dies, then will not start back up, due to the 10amp fuse marked ECM B. I also get no trouble code from the diagnostic mode. This seems to happen randomly once a week or so out of nowhere. I have a 1986 2.8L V6 S10 Blazer. If anyone has any idea how i can narrow down the problem, there are tons of sensors and relays and crap. Could it be the oil pressure sensor? It also has TBI and a manual trans, 4x4. thanx

04-24-2005, 06:16 PM	#4
bisquik65 Account Suspended Join Date: Apr 2004 Location: N.C. high country Posts: 6,107	If you look at a wiring diagram,the ecm b fuse controls the fuel pump and the injectors. Thinking on it a while ,it may be in your distibutor too.. The fuel pump and pickup coil in the dist,wont set a code...Did you change the oil pressure switch? Does your radio work fine? I know this sounds weird but check all the other fuses,if the radio fuse is blown too,change that fuse out.. It will backfeed into the ecn b fuse...Trying to help. Last edited by bisquik65; 04-24-2005 at 06:18 PM.

04-24-2005, 12:35 PM	#2
bisquik65 Account Suspended Join Date: Apr 2004 Location: N.C. high country Posts: 6,107	You need a new fuel pump...Ecm b fuse is tied into the fuel pump relay circuit... That should do it...S-10 wiring are a little funny to fix...I have run into this before..I have 6 blazers here for parts..

04-24-2005, 06:02 PM	#3
75chevyeyesore Registered User Join Date: Apr 2004 Location: Reno, Nevada Posts: 11	wouldnt the thing not run right if it were the fuel pump though?

04-25-2005, 02:16 AM	#5
75chevyeyesore Registered User Join Date: Apr 2004 Location: Reno, Nevada Posts: 11	my radio and stuff works fine. I am a little confused about the oil pressure switch, or where it is. On the drivers side of the block just under the oil filter there are 2 switches/sensors. One has 2 connection posts, the other has three. I assume one is the oil pressure swich, but witch one, and what is the other thing?, fuel pump/pressure regulator?

04-25-2005, 08:24 AM	#6
bisquik65 Account Suspended Join Date: Apr 2004 Location: N.C. high country Posts: 6,107	The 3 wire one is for the fuel pump. If your motor loses oil pressure it will shut the pump down,you may want to check oil pressure too.

04-26-2005, 02:37 PM	#7
75chevyeyesore Registered User Join Date: Apr 2004 Location: Reno, Nevada Posts: 11	it is the oil pressure switch, if i unplug it everything works fine, except for the gauge anyway....

04-26-2005, 03:47 PM	#8
bisquik65 Account Suspended Join Date: Apr 2004 Location: N.C. high country Posts: 6,107	OK glad you found it,Later,Erick

04-26-2005, 05:57 PM	#9
75chevyeyesore Registered User Join Date: Apr 2004 Location: Reno, Nevada Posts: 11	thanks for the help, if u are parting out some s10 blazers maybe i get some parts from ya....

04-26-2005, 06:31 PM	#10
bisquik65 Account Suspended Join Date: Apr 2004 Location: N.C. high country Posts: 6,107	Welcome to the board!!!Post your location so it will help you find stuff closer to you..

04-26-2005, 10:12 PM	#11
75chevyeyesore Registered User Join Date: Apr 2004 Location: Reno, Nevada Posts: 11	guess im kinda far here in Reno Nevada



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