Fuel injector gone bad Options

[troth]

Vehicle was running great until I lost cylinder no. 2! Verified spark was good. Hmmm... must not be getting fuel. Swapped injectors with one of the good cylinders and was happy to see the issue moved with the injector.

I guess I'm going to shell out to have them all cleaned again. Even though I just did that less than 3000 miles ago. I say all because when I unplugged the injectors individually with the motor idling, each had varying effects on how it ran. So some of the others in addition to no. 2 may also be dirty?

But what could have caused them to go bad all of a sudden? One day it was good, but then the next day when I go to take it to work it's crap. I have read that letting the fuel level get too low can dislodge crud in the tank. It had about 3 gallons in it last time it was running well and it has certainly ran on less fuel than that before. Should the filter be replaced? Is it worth taking the tank out and cleaning it?

Lots of questions, but I am happy the immediate issue presented itself so quickly. I'm just trying to diagnose the root cause to avoid another $100 injector cleaning/test.

[timothy_nd28]

With the wires and connectors pushing 50 years on these cars, I would turn your attention to exactly that. Intermittent problems sounds electrical, atleast to me. I would buy 4 new injector connectors that have wire leads, and replace your old ones.

[troth]

With the wires and connectors pushing 50 years on these cars, I would turn your attention to exactly that. Intermittent problems sounds electrical, atleast to me. I would buy 4 new injector connectors that have wire leads, and replace your old ones.

I have a new set of connectors sitting in a box somewhere. It's not intermittent, but snuck up relatively suddenly. I unplugged the injector in question with the engine idling and it was getting a steady 12 volts on both connections. I'll go ahead and replace those connectors for good measure anyways.

I'm going to try soaking the injectors in that Chevron stuff to see if I can save myself from getting them professionally cleaned again. Is there any way to spray some carb cleaner or something through them as well?

I will say that I have never used anything other than Shell Nitro+ gasoline or whatever their highest octane rating is called.

I'm going to take a good hard look at the tank as well. I'm hoping to get some time next weekend to think about pulling it.

[Bartlett 914]

With the wires and connectors pushing 50 years on these cars, I would turn your attention to exactly that. Intermittent problems sounds electrical, atleast to me. I would buy 4 new injector connectors that have wire leads, and replace your old ones.

I have a new set of connectors sitting in a box somewhere. It's not intermittent, but snuck up relatively suddenly. I unplugged the injector in question with the engine idling and it was getting a steady 12 volts on both connections. I'll go ahead and replace those connectors for good measure anyways.

I'm going to try soaking the injectors in that Chevron stuff to see if I can save myself from getting them professionally cleaned again. Is there any way to spray some carb cleaner or something through them as well?

I will say that I have never used anything other than Shell Nitro+ gasoline or whatever their highest octane rating is called.

I'm going to take a good hard look at the tank as well. I'm hoping to get some time next weekend to think about pulling it.

I am pretty sure that the ECU provides a steady 12 volts to the injector. It then gives a pulse to ground on the other terminal to activate the injector.

[JeffBowlsby]

I am pretty sure that the ECU provides a steady 12 volts to the injector. It then gives a pulse to ground on the other terminal to activate the injector.

No. The injectors get a pulsed signal<3V. 12V will kill them. Ground is constant. If you are getting crud in there plugging the injectors it's not a bad injector. It's bad fuel or corrosion in your fuel fystem . A good fuel filter should prevent that.

[troth]

I am pretty sure that the ECU provides a steady 12 volts to the injector. It then gives a pulse to ground on the other terminal to activate the injector.

No. The injectors get a pulsed signal<3V. 12V will kill them. Ground is constant. If you are getting crud in there plugging the injectors it's not a bad injector. It's bad fuel or corrosion in your fuel fystem . A good fuel filter should prevent that.

I did some research on this. I have a bosch book that says they get 12 V but there's a resistor somewhere to drop it down to that 3ish V range. Jeff, I know you're probably one of the best sources for this. Is that resistor integrated into the injector itself or somewhere else in the harness? I was getting the 12 V reading right off each of the two prongs on the pig tail connectors to ground.

I pulled the tank this weekend. There's a decent amount of surface corrosion in there. And it looks like something took a dump in my filter. Just ordered the POR15 fuel tank repair kit. I imagine that's where the issue came from. I'll post up some pics soon.

[mepstein]

I am pretty sure that the ECU provides a steady 12 volts to the injector. It then gives a pulse to ground on the other terminal to activate the injector.

No. The injectors get a pulsed signal<3V. 12V will kill them. Ground is constant. If you are getting crud in there plugging the injectors it's not a bad injector. It's bad fuel or corrosion in your fuel fystem . A good fuel filter should prevent that.

I did some research on this. I have a bosch book that says they get 12 V but there's a resistor somewhere to drop it down to that 3ish V range. Jeff, I know you're probably one of the best sources for this. Is that resistor integrated into the injector itself or somewhere else in the harness? I was getting the 12 V reading right off each of the two prongs on the pig tail connectors to ground.

I pulled the tank this weekend. There's a decent amount of surface corrosion in there. And it looks like something took a dump in my filter. Just ordered the POR15 fuel tank repair kit. I imagine that's where the issue came from. I'll post up some pics soon.

Leave the por15 kit alone. Remove the corrosion and keep the tank topped off. Add some mmo- marvel mystery oil with each tank of gas.