I swap the #1 wire clip to the # 3 and then the #1 doesn't work. Can the camshaft sensor affect 1 injector wire output? Thanks.

 

No; it's the same sensor for all the cylinder fires.

Time to do it olde skool - check the wiring.

FIRST though; are you using a NOID light to check?

After you do the swap, do you mean the injector on the #3 clip isn't firing no matter if it's the #1 or #3 injector, or the #3 injector isn't firing no matter if the #1 or #3 clip is attached? (I'm thinking the former, but you really aren't specific enough.)

If the former; time to see if it's lost the 12V supply or if it's lost the firing signal (the ECU grounds the ECU side to fire the injector.) Then it's time to NOID at the ECU to see if the ECU is even firing the injector; if it isn't, it's a bad ECU. If it IS being fired at the ECU end, it's probably a bad wire in the harness.

Do note: "bad wire in the harness" can be as simple as oxidation in a connector, not necessarily the wire itself bad. So my next step would be to disconnect/reconnect the ECU side and all intermediate connectors five or six times to allow the contacts to self-polish and see if that fixed it. (Either way, each connector may need some "dielectric grease" or "bulb grease" to help keep the contacts from oxidating.)

RwP

 

Thanks RwP,
You were correct, the injector sounds like it's working fine when I plug the #1 wire into it.
I don't have a noid ligbt just yet. I'm not sure how (where) to unplug the ecu side connection.
Just a little more info I forgot to mention, I replaced the ecm a year ago bc the truck would die intermittently. I know those can be bad new or go.bad any time. But it ran fine afterwards. I gave the truck to my Dad soon after that.
He just got a new one and I got the Dakota back in this condition.
I will try to do some more checking in the morning.
Thank you again.

 

You might be able to rent a noid light set from your local parts store. Check and see if the PCM is actually firing the number 3 injector. If it isn't, just follow the wire back to the PCM, see if there is a break. (one of the wires will be the power feed, power feed is the same color at each injector. So, see what colors you got, check any other connector, and the one that has a same color as the connector in question, will be power feed, the other end will run back to the PCM to actually control the injector.)

 

Thanks Hey You and RwP.
Please forgive my ignorance, I know there is some reason everyone says to use a noid light, but I woke up early and eager and went to the Dakota with a multimeter.
The common positive reads the same on the injector wire that is'nt working as the one beside it that is working.
i found the pulsing negative (I think) at the ECU and with the multimeter got the same reading as the others (pulsing negatives at the ECU). I do realize I may have been peeing in the wind by using the multimeter and that's where my ignorance comes in to play.
Anyone who can tell me if what I did was pointless please do so.

Thanks,
Georgia Boy

 

The NOID light is a quick visual; an analog multimeter can do the job also; most digitals, however, will just flicker the voltage, plus they don't load the system down enough by themselves.

So, we have 12V on #3 connector.

The pulsing at the ECU says the ECU is firing; did you get pulsing at the injector? Maybe using the - on the meter to the ECU side, and + to the 12V side?

Also, the Factory Service Manual will say which wire is which at the ECU; I don't have the 1993 manual, but for 1995, which SHOULD (but may NOT) be similar, it's the 18ga yellow/white wire on pin 14; with power off, you should be able to ohm that wire back to the injector.

And if it's open, there's your problem.

If, however, it has continuity, check the 16ga dark green/orange wire back to the splice; your multimeter may not be loading the circuit down enough to see a high enough resistance to keep the injector firing You can cheat some; check continuity between dark green/orange wires from Injector 3 and, say, Injector 1. They both splice together at splice S132 for 1995 (again, YMMV to the exact splice # for a 1993 ... )

As an aside, on Ebay, they do have a 1995 FSM for as low as $30 shipped as I type this.

RwP

 

Thanks RwP,
New update, I took the wiring harness off the ECU to check the wire between the ECU and the injector wire.
Ended up taking it off and on about 4 times, finally got a reading thru the wire. I hooked the harness back up and cranked the truck to see if the repeated off and on of the harness had helped make a connection as one of you had mentioned.
I checked the injector in question and it WAS firing woohoo, then it quit while I still had the ole ear to it. I went over and wiggled the ECU box (not the harness) went back and checked and it was working.
I shut the truck off, cranked it back up and the check engine light came on, checked the injector and you guessed it, not working. My son went over to the ECU and gently gave it a bump while I had my ear to it (injector) and it started working again.
I shut it off, unhooked the negative battery cable, waited a couple of minutes, hooked it back up and cranked the truck. The check engine light stayed OFF so I checked the injector again, still working. We jumped in and drove it up the road and back, no problems.
I guess we will soon see if it was the connection or the computer. After spending $300 on the computer a year ago(Advance Auto no warranty) I sure hope IT isn't the problem. I'm not really counting on it though. If it does turn out to be the ECU where do y'all suggest buying one from?
Thank you fellows for the help. Any other advice is welcomed. Now on to the #7 brake light fuse that keeps blowing.
Georgia Boy

 

One more thing to check - disconect the battery, and carefully remove the connector from the ECU connector housing for the #3 injector. Tighten it up some, and reassemble.

It may have just sprung loose.

If that's all it is, then you probably should go through and do all the others on the ECU connector housing also.

(I would not be surprised if that was what was wrong when you replaced the ECU; there's a LOT of "part is bad, swap, new part works' that's just connectors in the electronics industry!)

RwP

 

Are you saying to pull the wire out of the connector?

 

Basically, yes; there's instructions on how to do that in the factory service manual, which if you're going to work on your truck, I feel like you need even more so than a set of combo wrenchs, ratchets, and torque wrenches.

Attached are the instructions from the 1995 FSM; your 1993 should be similar.

Also, the "special tools" are available on Ebay et al for a LOT less.

RwP