Dakota Forumz banner

1997 Dakota 3.9 5 speed No spark or fuel pump power

4K views 143 replies 2 participants last post by  immattj 
#1 ·
I have replaced pcm, crank sensor, relays and fuses, checked wires for dmage, even went as far as replacing coil wires. No spark and no power to fuel pump. Also, fuse 9 on in the panel on driver side of dash has no power as well. Hooked up a jumperwire to fuse 9 and my guages come back. Im not smart in this department. Mechanicalis more me. Help?
 
#49 ·
Correct me if I am wrong, but doesn't the + battery cable go directly to a terminal stud in your PDC ("the fuse box under the hood")?
I am not an electrician & I could be wrong, but it seems like the only way you could lose power to the PDC is if your + battery cable was loose or connection faulty either at the battery or at the connection in the PDC or you had lost your ground?
Check your connections: clean your negative battery post & the terminal connector on the cable & make sure it is tight & check it where it grounds (I think on the engine block).
 
#53 ·
Well, if you truly have 12v at your battery, when you put your - voltmeter lead on the - battery post & you put your + lead on the positive terminal in the PDC where your + battery cable connects, as I see it you are essentially putting your leads on the battery posts themselves. If you are putting your leads at those two points & reading 0 volts, I don't see how that could happen unlless there is a problem with the cable from your battery to the PDC.
 
#55 ·
Are you anywhere near Western Pa.?

Anyway, put your multimeter on the ohm-meter function (looks like an upside down U) & check for continuity between the + battery post & the terminal stud in the PDC. You should measure very low resistance. If you read 0L that means an open & that would mean that the cable from + post on battery to terminal stud in PDC has a problem.
 
#56 ·
. . . just for the helluvit I went out & took some readings on my Dakota.
With key off I get 12.5 v at the battery from - to +
& from - post on battery to + in the PDC I lose maybe 0.01 v. Maybe not.
Checking continuity from + on battery to the + terminal stud in the PDC I am reading 0.7 ohms.
 
#57 ·
. . . assuming that the cable (from + on battery to terminal stud in PDC) does not ohm out good, maybe it's possible that it has had shaky continuity from the get-go & making a poor connection to your PDC all along? Maybe this is where your problems stem from?

I am kind of thinking not, but I just thought I'd throw that out there.
 
#60 ·
I believe i found the issue. After running the test you told me to, i kept the multimeter neg connected, and traced the positive cable where its slightly exposed on the pdc to the nut and bolt that hold it down and the volts and ohms fluctuated from 12.54 to 1.23 and stayed in between. Bad connection seems to be the issue
 
#61 ·
Okay, well, if I am understanding you correctly, that's too bad, because if there was something wrong with that cable or the connecting terminals on the cable & the continuity was intermittent from your battery + post to the stud in PDC where the cable connects, that would probably raise all sorts of holy hell with your electrical system & could certainly account for issues.

So if I've got you correctly, from the - post of battery to the + stud in the PDC you are now reading battery voltage. Checking from battery + to PDC + with for continuity should actually give you a low resistance reading (remember, mine was 0.7 ohms), but since you are now reading battery voltage from - to the + stud in the PDC, it goes without checking that you do have continuity.

Which doesn't solve anything, except that you should have power to your PDC.

Out of curiosity & to review past history, how did you make out on the other checks I previously recommended? Did you ever change your cam position sensor (also known as the distributor pickup coil)?
 
#66 ·
I'm up late trying to order parts for one of my rust buckets that is broken.
What a coincidence!
I live for moments like these!

Okay, I do not think that your OBD port has to be connected in order for your PCM to be powered.
I will not say that I know this to be an absolute fact, but I do recall a member posting about a Dakota with problems & she said she was not getting a CEL because her OBD port was disconnected.

If I am interpreting the schematic in the '97 through '99 Dakota Haynes correctly, it appears to me as if the PCM gets power through 20A fuse #1 in the PDC & goes to the PCM via a red/white wire & if my previous assumptions in a previous reply were correct it would be the C1 plug & pin #22.

And remember that I did preface this with the caveat: IF I am interpreting the schematic correctly.
 
#74 ·
???

I don't think that the '97s had a TIPM?

I am going by this, which was posted by oldmarine a while back ago,

"Beginning in 2005, the module (equivalent to the BCM for other manufacturers) is called the front control module (FCM), which is physically co-located with and mounted on the power distribution center (PDC -- the underhood fuse box), and together they comprise the integrated power module (IPM), sometimes called the totally integrated power module, the infamous TIPM."

But regardless, the ASD relay is accessible, & easily replaceable, in the PDC (power distribution center) which is the box under the hood with fuses & relays in it.
 
#78 ·
Remember: without receiving a signal from the crank & cam pos sensors (meaning the engine has to be turning) the ASD relay will only stay energized by the PCM for about 2 or 3 seconds after you turn the key to 'on', so you need to take that reading quick.

I thought that once upon a time in the tangled & twisted course of this thread that I had posted a schematic from the 97 through 99 Dakota Haynes of the ASD relay in the engine control system, but I guess that I didn't. So I'll attach that PDF now. Anyway, you will note that the ASD relay is CONTROLLED BY THE PCM. I am not convinced that the "remanufactured" PCM you bought was good. Also, did you ever test or replace your cam position sensor?
 

Attachments

#80 ·
You expressed the desire to bypass the ASD relay, meaning, I guess, to make the green/orange wire to the coil and the green/orange wire to the injectors always hot..

I make no claims whatsoever to be an electrician, so I don't think I'd do that, but it seems that theoretically using wires hot from the battery straight to those wires would accomplish that.

But personally, I don't know enough to feel good about doing that. It may be more complex than that.

I'll post a PDF of the fuel injectors from the same Haynes for you.
 

Attachments

#91 · (Edited)
Quite a while ago I found a neat little tutorial on relays and I took some notes and I believe that you should be able to do some troubleshooting at the slots where the ASD relay pins insert into.

First I'll identify the slots:
30 receives constant battery voltage.

85 is the relay's connection to ground.

86 is the power control side of the relay. I guess that would be the PCM.

87 (and 87A IF it is a 5 pin relay) go to whatever the relay controls. In this case I guess we are talking about the coil & the injectors.


So to start with, with the + lead of your volt meter in slot 30 & the - lead to a good ground (the - post on your battery, for instance) you should be reading battery voltage. If not, stop right there.

Check for constant ground to relay:
plug the - lead of your v-meter into slot 85 & touch the + lead to the + battery terminal. Again you should see CONSTANT battery voltage. IF THE VOLTAGE FLASHES: LOOK FOR A BAD GROUND WIRE TO 85.

If you have CONSTANT voltage:
check for quality of power to the switched side of relay:

plug the + lead of your VM into slot 86. Turn on ignition key and put the - lead of your VM on the - terminal of battery. IF VOLTAGE VARIES THE PROBLEM LIES IN WHATEVER IS SUPPOSED TO ACTIVATE THE RELAY (for example a switch, or, in this case, the PCM). Inspect the wiring/circuit for 86 & repair as needed; if you discover no damage, suspect the component that controls the relay (in this case, the PCM).

And you could also use this method to troubleshoot at your fuel pump relay.

And on a quick edit: getting back to the subject of bypassing or cheating the relay, I have also heard of people using a paperclip for a jumper and I guess as long as you could verify constant voltage at slot 30, you could jump across there to slot 87 & that should theoretically provide power to the injectors and at the coil.

Here is another relay tutorial, it's not the one that I took my notes from, but I like it also:

 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top