secondary injector problems after service

boosted93 · 10-27-2009, 11:55 AM

I have stock computer and stock fuel system. I had the injectors serviced and it started and ran fine. When I started to build boost it would fall on its face. Turns out the secondaries where not firing. Took them out and sent back, they where stuck. Got them back and put in, took for a test drive. This time it wouldn't stall at boost, but it still isn't right, kind of like its still not getting all the fuel it should be. The best way I can describe is, it stutters. Could this still be my injectors or something else? Didn't have this problem when I took them out.
Is there a relay that puts more volts to the injectors at a certain load? And if so if that was bad would that cause this problem. Reason I ask is when I was testing the injectors I may have touched the wires together when trying to manually fire them with a 12volt supply.

dudemaaan · 10-28-2009, 09:13 PM

No there is nothing that changes the voltage at the injectors. They receive whatever battery voltage there is. It's just a coil that opens and closes the injector. The more often the injector is opened is what determines how much fuel they deliver.

I found a good way to clean injectors by soaking them in carb cleaner, then installing them in a rail with the return line capped off and the supply line gets pressurized with an air compressor. I then fill the rail with carb cleaner then pressurize the rail and pulse the injectors on and off. This will let you see the spray pattern and clean out any gunk.

You can test the injectors without completely removing them from the engine. To do this you have to pull the rail from the block, jumper the f/p to ground in the diagnostic area, and trigger the injectors manually with 12v. Look for fuel and watch the spray pattern.

How much boost are you running? Mods? Any other symtoms? Strange idle, overly rich or anything else? Studdering could be a several things unrelated to the injectors, or fuel system entirely. Could be ignition breakup caused by plugs, coils, wires etc.

10-27-2009, 11:55 AM	#1
boosted93 The Newbie Join Date: Nov 2008 Location: Glasgow, KY iTrader: (0) Posts: 7 Rep Power: 0	secondary injector problems after service I have stock computer and stock fuel system. I had the injectors serviced and it started and ran fine. When I started to build boost it would fall on its face. Turns out the secondaries where not firing. Took them out and sent back, they where stuck. Got them back and put in, took for a test drive. This time it wouldn't stall at boost, but it still isn't right, kind of like its still not getting all the fuel it should be. The best way I can describe is, it stutters. Could this still be my injectors or something else? Didn't have this problem when I took them out. Is there a relay that puts more volts to the injectors at a certain load? And if so if that was bad would that cause this problem. Reason I ask is when I was testing the injectors I may have touched the wires together when trying to manually fire them with a 12volt supply.

10-28-2009, 09:13 PM	#2
dudemaaan Rotary Fanatic Join Date: Mar 2008 Location: Brenham, TX iTrader: (4) Posts: 335 Rep Power: 17	No there is nothing that changes the voltage at the injectors. They receive whatever battery voltage there is. It's just a coil that opens and closes the injector. The more often the injector is opened is what determines how much fuel they deliver. I found a good way to clean injectors by soaking them in carb cleaner, then installing them in a rail with the return line capped off and the supply line gets pressurized with an air compressor. I then fill the rail with carb cleaner then pressurize the rail and pulse the injectors on and off. This will let you see the spray pattern and clean out any gunk. You can test the injectors without completely removing them from the engine. To do this you have to pull the rail from the block, jumper the f/p to ground in the diagnostic area, and trigger the injectors manually with 12v. Look for fuel and watch the spray pattern. How much boost are you running? Mods? Any other symtoms? Strange idle, overly rich or anything else? Studdering could be a several things unrelated to the injectors, or fuel system entirely. Could be ignition breakup caused by plugs, coils, wires etc. __________________ 500+ HP thanks to: Fast reacting IAT sensor thread! Mechanical Pre-turbo Water Injection Thread Dual Stock fuel pumps Thread T2 differential swap!