ECM probs...
- Thread starter cdezzz
- Start date
leroy
Donating Member
You could have fried an injector driver. The drivers can be replaced or upgraded. The ecm could also be replaced, but I'd be worried about what fried them to begin with. I like the idea of disconnecting things attached to the 439? circuit. You still have power to that fuse since it quit blowing them?
Not much help.
Jim
Not much help.
Jim
InvisiBill
Active member
Not to insult you or anything, but you have pulled codes before, right? Just making sure you're not mistaking the codes for "flashes constantly". I'm assuming you do know what you're doing and this post can be ignored, but I thought I'd throw it out just in case...
leroy said:
With everything hooked up, it doesn't blow the fuse, I pittled with it for a couple of hours yesterday aftrnoon. Never blew it once. It does have power at the fuse box. Not knowing if you had read my other post, the connector at the injector harness, has power. The pink/black wire had 12 volts, the green wire 5.5 volts and the blue wire nothing.
jwaller said:
Done that.
InvisiBill said:
No, offense taken. I have pulled codes before. It flashes, at the same speed all the time, no short or long ones.
Pink/black wire should be 12v, so that's ok. BOTH thegreen & blue wire should read zero; the ECM switches these lines to ground to fire the injectors. Check them @ the injector harness *and* @ the ECM - green is connector BC12, blue is BC11. If the readings are still goofy @ the ECM, an injector driver is fried. If ok @ the ECM, the wiring between the ECM & injector plug is bad. Drivers can be replaced, rather than the whole ECM, but I've never dont that. Used ECMs aren't *that* rare, go for around $40-$60 @ boneyard.
Barry
Barry
I just went through something exactly like this on my F150...
A pac rat got under the hood and completely shredded one of the injector pig tails(huge mess). The bare wires were shorted and it ended up killing the injector driver to one bank of cylinders. After fixing the wiring and a new ECU(250 bucks), I was back on my way.
When you have a chance, use an ohm meter at the ECU harness to check between the pink/black to green and the pink/black to blue. They should read about 5-7 ohms on each injector channel. If it happens to be lower, please find the problem before killing another ecu.
NOTE: Most of the cheaper multimeters are not very accurate at low resistances like this. To get a more accurate reading, connect the two test leads together from the multimeter, subract this from the measured value and you'll have a lot better indication as to what the resistance in the line is. My multimeter reads about .9 ohms with shorted leads.
A pac rat got under the hood and completely shredded one of the injector pig tails(huge mess). The bare wires were shorted and it ended up killing the injector driver to one bank of cylinders. After fixing the wiring and a new ECU(250 bucks), I was back on my way.
When you have a chance, use an ohm meter at the ECU harness to check between the pink/black to green and the pink/black to blue. They should read about 5-7 ohms on each injector channel. If it happens to be lower, please find the problem before killing another ecu.
NOTE: Most of the cheaper multimeters are not very accurate at low resistances like this. To get a more accurate reading, connect the two test leads together from the multimeter, subract this from the measured value and you'll have a lot better indication as to what the resistance in the line is. My multimeter reads about .9 ohms with shorted leads.