1997 Dakota 3.9 5 speed No spark or fuel pump power

1151 Views 71 Replies 2 Participants Last post by immattj, 7 d ago

knisleyharlan08

Discussion Starter · 2 mo ago

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?

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immattj

· #21 · 2 mo ago

Well, to continue troubleshooting this I am pretty sure you are going to need to get a hold of a multimeter--cheaper than taking it to a shop. Harbor freight ought to have some reasonable prices on meters.

knisleyharlan08

Discussion Starter · #22 · 2 mo ago

If my alternator was going bad before all this happened, would that also play a factor? Wife just reminded me about that.

immattj

· #23 · 2 mo ago

knisleyharlan08 said:
If my alternator was going bad before all this happened, would that also play a factor? Wife just reminded me about that.

I am not qualified to give you a definitive answer, but looking at the schematic for the charging system, I don't think so. (The operative word being 'think'.)

The PCM does have a 'generator field driver' and a 'generator field source' connectors for the alternator, so as far as that goes, the alternator is related to your other problems in that they all are controlled by the PCM, but I don't see any other tie in. There is a 140A fusible link in the PDC between your battery & alternator, but I don't see it being involved in any other circuit.

I did see a SB from GM once that was warning NOT to disconnect the alternator without FIRST disconnecting the battery due to potential harmful voltage spikes to the PCM. And, I have heard that these Dakota PCMs are finicky about having a good battery with a good charge (but I do not know that to be a fact or not).

So no, except for the PCM in common, I cannot see a relationship between a bad alternator & your coil not putting out & your fuel pump not energizing.

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knisleyharlan08

Discussion Starter · #24 · 2 mo ago

Maybe i should try to energize the asd relay with a jumper and see if she starts

immattj

· #25 · 2 mo ago

That sounds like it might tell you something. I don't know for absolute certain if anything could be harmed by doing that, so I won't advise you to do it, but if it was me & I didn't have a meter, I think I would personally try it.

However, the critical power through the ASD is to your injectors and your coil. It shouldn't be tied in to energizing your FP relay. I believe what it has in common with your FP relay is that if the PCM does not get a valid signal from your cam & crank position sensors, the PCM will deenergize both of these relays.

knisleyharlan08

Discussion Starter · #26 · 2 mo ago

The cam sensor is one componenti have not replacedbut the cranksensorisnew

immattj

· #27 · 2 mo ago (Edited)

knisleyharlan08 said:
The cam sensor is one componenti have not replacedbut the cranksensorisnew

Whoops! When I read your OP I was thinking I saw that also. My vision is deteriorating & sometimes I miss things when reading a computer screen.

Well, okay, I am pretty sure I covered this in my plethora of responses, and I'd also direct you back to one of the links to a thread I posted (which I think referred to reply 32 & 37 of the thread)

but the cam position sensor (cmp) lives under your distributor cap. (In one of the PDFs I posted there is a schematic showing its relationship to the PCM.) BOTH the crank (ckp) & cam position sensors (cmp) need to get 5 volts from the PCM in order for them to function, and then the PCM needs to get a valid signal from both in order for it to send a trigger signal to the coil (and I THINK but am not positive, to energize the fuel pump relay).

So if you have a good coil getting battery voltage through the ASD relay AND ALSO a good trigger signal, it should produce voltage. Which doesn't automatically mean spark at the plugs, but it starts to narrow it down.

So if you go back to that thread link I posted for you, reply 32 & 37 come from someone way more knowlegeable than I & are spelled out better than I did. I think he also provided a method to test both sensors, but you will need a meter.

Personally, at this point, I think you may as well throw a new cam position sensor at it.

ON EDIT: THIS thread, & it looks like it was reply 32 and 37:

www.dakotaforumz.com

coil is not putting out spark

Hello everyone!! I am brand new here with a 1996 dakota 5.2 and the coil is not sparking..Unplugged the plug and only getting voltage on the green/orange wire when cranking..That is it.....Is that normal? Brand new coil, distributor, cam crank sensor...Where do I go from here? Thank you greatly

www.dakotaforumz.com

www.dakotaforumz.com

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knisleyharlan08

Discussion Starter · #28 · 2 mo ago

I will look into it further when I get home

immattj

· #29 · 2 mo ago

knisleyharlan08 said:
I will look into it further when I get home

I forgot to tell you that for your Dakota the cam position sensor may be listed as the distributor pickup coil. It is the same thing.

knisleyharlan08

Discussion Starter · #30 · 2 mo ago

Jump wired the asd relay, no luck. Had the wire to the distributorfrom coil pulled off to try the test light method, no light. Idk

immattj

· #31 · 2 mo ago

knisleyharlan08 said:
Jump wired the asd relay, no luck. Had the wire to the distributorfrom coil pulled off to try the test light method, no light. Idk

Okay, just to clarify, what you did was to backprobe the black/gray wire at the coil with a test light while having the engine cranked?

If that is what you did and you did NOT get a flashing light, this is wht it would seem to point at:

1) faulty camshaft position sensor &/or crankshaft sensor. I know that you have already replaced the crank position sensor. I'd suggest either just throwing a new camshaft position sensor (also known a the distributor pickup coil) at it or doing the checks on that sensor with a meter.

2) a fault in the circuits betwen the PCM and the crank position sensor &/or the camshaft position sensor. Back a few posts ago I put up a PDF of the crank & camshaft position sensor circuits that tells you what wires are involved. After doing a god visual, you would then need to use a meter & do a continuity check.

3) IF you have a good crank & camshaft position sensor AND circuits from those sensors to & from the PCM which are intact with continuity BUT the test light backprobing the black/gray wire AT the coil does NOT flash when you crank the engine, this would seem to highly suggest (to me, anyway) that the fault was in the remanufactured PCM you bought.

But change the camshaft position sensor (distributor pickup coil) first . . . that's the quickest & easiest thing to do.

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knisleyharlan08

Discussion Starter · #32 · 23 d ago

Update, black/gray waire gets 9.70 v and the green/orange wire gets 12.45v

immattj

· #33 · 22 d ago (Edited)

knisleyharlan08 said:
Update, black/gray waire gets 9.70 v and the green/orange wire gets 12.45v

The 12.45 v at the green/orange means you are getting battery voltage traveling through the ASD relay to the coil. At the black/gray wire, the test that I did on mine was with a test light while cranking & if everything works the test light is supposed to flash while cranking, meaning trigger signal to the coil. I would assume that 9.7 v would indicate a trigger signal, but I don't know that for sure & I will repeat that I used a test light, NOT a voltmeter. (Was the 9.7 volts that you read pulsating or was it a steady 9.7?)

BUT: assuming that 9.7 volts does mean a good trigger signal, & since you do have battery voltage at the coil, IF it is a good coil it would be producing voltage (as voltage & trigger signal is what the coil needs to operate). When you say "no spark", where did you test for spark? From the coil or at a spark plug?

knisleyharlan08

Discussion Starter · #34 · 22 d ago

Spark plug, I'll try at the coil

knisleyharlan08

Discussion Starter · #35 · 22 d ago

And the test that I did is with the key on not trying to crank it

immattj

· #36 · 22 d ago (Edited)

knisleyharlan08 said:
And the test that I did is with the key on not trying to crank it

Well, first of all, if you scroll back through the posts on this, the test I described to check for trigger signal was to back probe the black/gray wire going to the coil, with a test light, while cranking. The test I described stated that a flashing test light while cranking indicated a trigger signal from the PCM to the coil.

As far as testing for voltage/spark, the first place I would check would be CAREFULLY from the coil. If you didn't have voltage output from the coil, to me, that would mean a bad coil or upstream of the coil. Voltage output from the coil but no spark at the plug would mean to me that one of your problems was somewhere between the coil & the spark plugs.

immattj

· #37 · 22 d ago

immattj said:
Well, first of all, if you scroll back through the posts on this, the test I described to check for trigger signal was to back probe the black/gray wire going to the coil, with a test light, while cranking. The test I described stated that a flashing test light while cranking indicated a trigger signal from the PCM to the coil.

. . . that was back on post #6 to this thread.

knisleyharlan08

Discussion Starter · #38 · 22 d ago

Ill recheck when i get off from work

immattj

· #39 · 22 d ago

knisleyharlan08 said:
Ill recheck when i get off from work

I think what you really need to check first is whether or not you are actually getting voltage out of the coil when the engine is cranked. BE CAREFUL WHEN YOU DO THAT.

If you are not getting voltage from the coil, then I think what you need to next check is whether you are getting a trigger signal TO the coil FROM the PCM when cranking.

knisleyharlan08

Discussion Starter · #40 · 21 d ago

What wire comes from the pcm?

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