Fuel Injector not working?

Does anyone know why the electronic signal to a fuel injector would stop working?

The Check Engine light came on and the car started idling rough at the same time. Took it to a friend who has a computer and it said it was the fuel injector (don’t know the # but it’s the front injector on the passenger side). However, it wasn’t the injector… it’s something electronic??? It’s not getting a pulse to open (I guess)… the guy said it might be the ECU???

Any ideas????

Thanks,

Bill

[Beav]

It could be the ECU or a bad wire between the ECU and the injector connector. Check my locker for wiring schematic.

Thanks for the reply Beav…

I checked out the schematic in your locker… I didn’t realize that the positive (+) side of the injector is constant (with the key on) and is also bridged across all six injectors. The pulse from the ECU is negative (-).

Did a little Volt/ohm checking tonight… with the car running, the reading on the 5 good injector wires fluctuates between 10.75 and 10.82 VDC, and the reading on the bad wire is 14.35 VDC?

Now the rest of the story… the car was involved in a wreck and the connector to that fuel injector was broken and the wires shorted out…. Guess it screwed up the ECU! Anyone have a spare they’ll part with (for a 96)?

Bill

[Beav]

Originally posted by ALsvx
Thanks for the reply Beav…

I checked out the schematic in your locker… I didn’t realize that the positive (+) side of the injector is constant (with the key on) and is also bridged across all six injectors. The pulse from the ECU is negative (-).

Did a little Volt/ohm checking tonight… with the car running, the reading on the 5 good injector wires fluctuates between 10.75 and 10.82 VDC, and the reading on the bad wire is 14.35 VDC?

Now the rest of the story… the car was involved in a wreck and the connector to that fuel injector was broken and the wires shorted out…. Guess it screwed up the ECU! Anyone have a spare they’ll part with (for a 96)?

Bill

Yeah, I think every car is wired the same in that respect - hot with ignition and the ground is pulsed.

The higher voltage is a result of no ground signal. The battery voltage comes in on one leg, runs through the injector and you measure it as battery voltage coming out. If the ground pulse was present it would measure lower...

Most injectors are only around 12-16 ohms resistance, a shorted wire shouldn't kill an ECU. Also I've replaced a number of injectors that have shorted internally and ECU replacement wasn't required after replacing the bad injector. My guess is the wire is broken a bit further upstream. Try to check it at the ECU under the dash - if there's no signal there then I would probably condemn the computer.

Thanks Beav...

I'll try that (test it at the ECU)... Now the hard part, getting my fat butt contorted enough to crawl under the dash…

Bill

[Mr. Pockets]

Originally posted by ALsvx
Thanks Beav...

I'll try that (test it at the ECU)... Now the hard part, getting my fat butt contorted enough to crawl under the dash…

Bill

In my wife's Legacy and in my SVX, I usually fully recline the seat and then lay on it uspide-down. Granted, all of my blood flows into my head, but I consider it a better aternative than kneeling on the garage floor or gravel driveway.

PS I do this AFTER changing into clean clothes - I don't want to emulate one of those Fram (?) commercials that depict guys leaving big oily handprints on everything.

[Beav]

Originally posted by Mr. Pockets


In my wife's Legacy and in my SVX, I usually fully recline the seat and then lay on it uspide-down. Granted, all of my blood flows into my head, but I consider it a better aternative than kneeling on the garage floor or gravel driveway.

PS I do this AFTER changing into clean clothes - I don't want to emulate one of those Fram (?) commercials that depict guys leaving big oily handprints on everything.

And women usually complain that the blood is always flowing away from our heads, maybe you're on to something here...

[Trevor]

Good one Beav.

You not only wisely answer all the curly questions but come up with quality humour (humor for you up there) to boot! What is more you never let anything go to YOUR head.

Cheers will await the next one with interest, Trevor.