Only one fuel injector, um, injecting.

my350tpi · 10-02-2006, 06:41 AM

Hi all! I've got a 1992 silverado 2wd with a 305 tbi in it and only one of the two injectors are working. It'a an electrical problem as switching the leads to the injectors will move the problem from one side to the other. On the blue wire (passenger side injector), I have no ground. Does anyone know where the ground comes from for this lead? Thanks!!!!

P.

wojeepster · 10-02-2006, 08:52 AM

I am not certain but usually the computer controls the ground circuit. If you get a good wiring diagram you should be able to trace it. Even if the wire goes straight to your computer it does not mean your computer is bad it just may be one of the grounds to the computer. Some cars have 4 grounds to ecm.

mudseeker · 10-02-2006, 06:26 PM

this should help. the pink wire goes to a mini-fuse under the hood labeld ecm-1.

wojeepster · 10-03-2006, 06:31 AM

You can see the wire for both injectors goes up that usually indicates Vcc ( 12v.) Next I would look to find which wires for the ecm go to ground and clean with sandpaper and install toothed electrical washer if it doesn't already have them. Still not absolutely certain but it does look like ecm is controling the ground to the injectors. You can also check the voltage at each of the two wires connected to the ecm while they are connected and car is running. If it is acting as a ground voltage should be quite low (.2v )or so on digital volt meter. If you read higher then you have a poor ground if you read 12v you have no ground, or I have it *** backwards and the ecm is supplying 12. Measure the injector line that is working first that should tell you how it works. Good luck let us know what you find. Do not use analog (needle) voltmeter.

mudseeker · 10-03-2006, 07:11 AM

forgot to add the pink wire is constant hot.

10-02-2006, 06:41 AM	#1
my350tpi Junior Member Join Date: Oct 2006 Posts: 1	Only one fuel injector, um, injecting. Hi all! I've got a 1992 silverado 2wd with a 305 tbi in it and only one of the two injectors are working. It'a an electrical problem as switching the leads to the injectors will move the problem from one side to the other. On the blue wire (passenger side injector), I have no ground. Does anyone know where the ground comes from for this lead? Thanks!!!! P.

10-02-2006, 06:26 PM	#3
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 6,375	this should help. the pink wire goes to a mini-fuse under the hood labeld ecm-1. Attached Thumbnails __________________ i'd rather be hunting

10-03-2006, 07:11 AM	#5
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 6,375	forgot to add the pink wire is constant hot. __________________ i'd rather be hunting

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10-02-2006, 08:52 AM	#2
wojeepster Senior Member Join Date: Nov 2005 Posts: 92	I am not certain but usually the computer controls the ground circuit. If you get a good wiring diagram you should be able to trace it. Even if the wire goes straight to your computer it does not mean your computer is bad it just may be one of the grounds to the computer. Some cars have 4 grounds to ecm.

10-03-2006, 06:31 AM	#4
wojeepster Senior Member Join Date: Nov 2005 Posts: 92	You can see the wire for both injectors goes up that usually indicates Vcc ( 12v.) Next I would look to find which wires for the ecm go to ground and clean with sandpaper and install toothed electrical washer if it doesn't already have them. Still not absolutely certain but it does look like ecm is controling the ground to the injectors. You can also check the voltage at each of the two wires connected to the ecm while they are connected and car is running. If it is acting as a ground voltage should be quite low (.2v )or so on digital volt meter. If you read higher then you have a poor ground if you read 12v you have no ground, or I have it *** backwards and the ecm is supplying 12. Measure the injector line that is working first that should tell you how it works. Good luck let us know what you find. Do not use analog (needle) voltmeter.