Got a ? I HAVE A 94 BUICK REGAL V6 3.8. It’s been running rough. I started the car and unplugged the injectors one at a time. With 4 of the injectors there was a change in the motor when I unplugged them. I went and bought 2 new ones. I put them in and it still runs bad. And when I unplug the 2 new ones there is still no change in the motor it doesn’t bog down like the other 4 do when I unplug them. Any thoughts or comments on the matter would be greatly appreciated. Thanks
Lack of spark now something to check
One thing you don’t do is, unplug and plug back in the injector connectors while the engine is running.
It can take out injector drivers in the computer.
Please tell me why I’m reading a troubleshooting manual for this motor and it’s telling me it’s a cylinder balance test.
Does your engine have 3 coils? Are the 2 dead cylinders fed from one coil?
Spark plugs, wires, coils, etc should be a consideration before spending money and time on fuel injectors.
Your car has 3 coils, If both of the dead cylinders are on the same coil, see if the dead cylinders move after you swap that coil with one of the others.
Generally spark is tested before fuel injection because the ignition system wears out faster and has more maintenance requirements. Check for spark, you likely have a bad coil.
I can’t imagine what kind of manual you are looking at that recommends pulling injector connectors on a running engine. That’s just nonsense.
Agree with the others. Spark first. Check to see if the plugs are firing with an inductive timing light. If they aren’t swap coils and see if the problem follows the coil. If they are firing, pull the spark plugs and have a look at them to see if they are clean or oily. Run a dry and wet compression test. A compression test will tell you if the rings or valves or valve seals are shot.
If you don’t have the tools, borrow some. If you don’t understand what I just posted, take it to a mechanic or buy a book on how to work on engines because you don’t know enough to work on your car. I don’t want to be too critical but you just bought and installed 2 fuel injectors for no reason at all. Just replacing parts blindly will cost you lots of money and will rarely fix the car.
Sounds like it is either lack of spark at those spark plugs, or lack of injector pulses at those injectors. A good, new injector still won’t inject fuel if it isn’t getting its electrical signal from the engine computer. A gadget called a noid light is how shops test for that.