****I think for most people, who don't drive their cars that often, may have issues related to the fuel system after some of the issues I have had along with some of my GN owning friends and fellow fat, flatulent old people.. Old gas, water in the tank, clogged fuel filter from rust in the tank plugging it along with fuel tank pump sock, etc.. In addition, my own car had similar knock issues, with Siemens 60lbs injectors that I bought new but after several years or relatively little use, 3 showed poor flow and atomization, and the car ran like crap.
I have a fuel injector tester I bought on the internets that cycles various pulse widths and you simply disconnect the injector harness from whatever injector you want to test, with the car OFF, plug the tester in and listen to the clicking of the injector. If it sounds weak, or muted compared to others, the injector is plugged or something is wrong. I also have a noid light, but even if the injector gets power, doesn't mean it is spitting out any or enough fuel - this fooled me for a long time until I got pissed and pulled the injector rail, all of the injectors, and tested them with the tester on an injector with a pressurized solvent going through the injector to test atomization. After testing all of the injectors like this, it was clear 3 of my 6 injectors had noticeably poorer atomization even after cleaning them with concentrated solvent, etc..
I hope this post saves someone as ass load of time as it took me HOURS to figure out why my car was running poorly, with knock retard, but awesome fuel pressure, fuel pressure holding fine at the rail after shutoff (perhaps ruling out injector stuck open or FP regulator bad, etc..), new gas, new filters, lowered boost, and a TON of other crap I tried... (Cam sensor, crank sensor, checking wiring, grounds, ECM integrity, MAF)
Below is a pic of the tester, and I rigged up the leads to be longer, along with cobbling together a properly fitting fuel injector lead so I don't have to use alligator clips. Makes it easy to test all injectors quickly on the rail. If an injector sounds appreciably different (they should click pretty loudly...) or doesn't click at all the injector is bad, or at least clogged up. Sometimes it's fixable with a thorough cleaning using pressurized solvent (the white tube in the pic holds the injector in place so you can run pressurized cleaner (carb cleaner or throttle body cleaner, etc...in a can...the stuff you buy at auto parts stores....). In my case, I tested 3 injectors that came out bad, so had to pull the rail... to try and clean them, etc.. The white tube thing is interference fit with the O ring at the top of injector, and cleaner shoots in from other part of tube.. works really well... You can really see if an injector has poor atomization quickly.
Anyway, hope this helps someone avoid the nightmare I had starting my GN this season after it sat all Winter long. Noid light, FP testing, Cam and crank sensor testing, etc.... didn't solve my no start and then crappy running car. I did the no start flow chart and narrowed stuff down, but didn't figure the injectors themselves were bad after having proper noid light operation, spark, and wet spark plugs with cranking.
Max
I have a fuel injector tester I bought on the internets that cycles various pulse widths and you simply disconnect the injector harness from whatever injector you want to test, with the car OFF, plug the tester in and listen to the clicking of the injector. If it sounds weak, or muted compared to others, the injector is plugged or something is wrong. I also have a noid light, but even if the injector gets power, doesn't mean it is spitting out any or enough fuel - this fooled me for a long time until I got pissed and pulled the injector rail, all of the injectors, and tested them with the tester on an injector with a pressurized solvent going through the injector to test atomization. After testing all of the injectors like this, it was clear 3 of my 6 injectors had noticeably poorer atomization even after cleaning them with concentrated solvent, etc..
I hope this post saves someone as ass load of time as it took me HOURS to figure out why my car was running poorly, with knock retard, but awesome fuel pressure, fuel pressure holding fine at the rail after shutoff (perhaps ruling out injector stuck open or FP regulator bad, etc..), new gas, new filters, lowered boost, and a TON of other crap I tried... (Cam sensor, crank sensor, checking wiring, grounds, ECM integrity, MAF)
Below is a pic of the tester, and I rigged up the leads to be longer, along with cobbling together a properly fitting fuel injector lead so I don't have to use alligator clips. Makes it easy to test all injectors quickly on the rail. If an injector sounds appreciably different (they should click pretty loudly...) or doesn't click at all the injector is bad, or at least clogged up. Sometimes it's fixable with a thorough cleaning using pressurized solvent (the white tube in the pic holds the injector in place so you can run pressurized cleaner (carb cleaner or throttle body cleaner, etc...in a can...the stuff you buy at auto parts stores....). In my case, I tested 3 injectors that came out bad, so had to pull the rail... to try and clean them, etc.. The white tube thing is interference fit with the O ring at the top of injector, and cleaner shoots in from other part of tube.. works really well... You can really see if an injector has poor atomization quickly.
Anyway, hope this helps someone avoid the nightmare I had starting my GN this season after it sat all Winter long. Noid light, FP testing, Cam and crank sensor testing, etc.... didn't solve my no start and then crappy running car. I did the no start flow chart and narrowed stuff down, but didn't figure the injectors themselves were bad after having proper noid light operation, spark, and wet spark plugs with cranking.
Max
