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View Full Version : 4.3L, both injectors fire at idle?

RSBlazer
02-17-2007, 07:42 PM
Hello. My first time posting here, can nomarlly find me over at stangnet.

I just bought a 91 S10 4x4 Blazer with the 4.3L V6, fuel injected of course. The guy I bought it from thought the fuel pump was bad, so I did some checking, and turned out that the ECM fuse kept popping due to the green injector wire being pinched. I fixed that, and bought a new injector.

Are both injectors supposed to pump fuel at idle? The reason I ask is, it's running very rough with no power. I haven't really had time to troubleshoot anything else, I just bought it and limped it home today. Any help would be greatly appreciated.

-- Rick
RSBlazer
02-17-2007, 07:46 PM
Another quick one, is there a way to manualy pull the ECM codes on these trucks?
Sparky
02-17-2007, 08:18 PM
To check codes on 1991 Chevy check here

http://autorepair.about.com/library/ts/obd-i/bl-dtcs-94.htm
RSBlazer
02-17-2007, 11:14 PM
Anyone know about the injectors?
Kordog
02-18-2007, 01:55 AM
Yes, both injectors fire at all times when the engine is running. How the ECM controls fuel flow is by how long or short the injector is held open. Korey
RSBlazer
02-18-2007, 05:38 AM
So if this 1 injector is not firing, even though it's new, where should I start looking for the culprit?
drperry
02-18-2007, 05:54 AM
Fuses, relays, and wiring, in that order, I'm not 100% sure, but I think the injectors might each have their own fuse and relay...
Kordog
02-18-2007, 01:59 PM
Well you said that you fixed one of the injector wires, I would check the other wires by the injectors. It is possible that the injector driver in the ECM got shorted when the wires got pinched. This is a pretty crude FI system. Not allot there. The injectors have constant power from the ECM fuse that kept blowng, then they are supplied a ground by the ECM. I would check the integrity of the wiring from the injector to the ECM. I would also just make sure that the new injector is not bad, I have seen that before. To check the injector driver and circuit quickly, with the injector disconnected, install a test light between the two terminals, and crank the engine.If the test light flashes then it is most likely the injector, but it still could be the driver, because the test light takes less power to fire then the injector. HTH Korey.