Non SVX - Why would a fuel injector not inject fuel?

Crazy_pilot · #1 09-18-2009, 04:03 PM

My friend bought a 91 Chevy Tracker which will now not start. I've gone through the usual stuff. There is spark, fuel pump runs, fuel is flowing well at the fuel rail, timing is good, and it will fire if I'm spraying gas/starter fluid directly into the intake. It has single point injection inside the throttle body, so we pulled the injector to look for anything obvious, but all looks good from a visual inspection.

Because it's a single point injector, it wouldn't pulse like ours, right? I would expect it just sprays more or less fuel constantly depending on throttle/engine load.

Apparently (this is coming from people who don't know much about cars and can't really give me a technical description) it was running poorly and the gas pedal had to be pumped to make it run properly. *shrug*

Thoughts?

MadMaxSvx · #2 09-18-2009, 04:22 PM

Check the injector for continuity with a tester (ohmeter?), the mono point injector should have around 3-10 K ohms.
If there is no continuity, (o ohms) then the injector should be replaced.

Crazy_pilot · #3 09-18-2009, 04:26 PM

I'll check that when I see my friend next. I'm really hoping not to replace the injector, as they run in the $550 neighbourhood

.

MadMaxSvx · #4 09-18-2009, 04:31 PM

Also the first thing to check in those cases is:

The injector will have two wires,one is 12V(+) and the other is a pulse (-).

1- The injector MUST be in its place, or you can disconnect the fuel pump before continue.

2- Turn the key to the start position (when the dash lights lite)

3- Unplug the injector connection, and check the voltage in every wire.

4- One of them will have 12 volts or more, if there is no voltage, then maybe the EFI fuse is blown, or there is a bad connection.

5- The other will have a negative pulse when cranking the engine, you can check this with a LED light tester. If there is no pulse, then the problem may be harder to explain.

Good luck.