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Author Topic: 1991 Dakota 3.9L No Power to Coil & ASD Relay  (Read 4404 times)

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Offline ChrisKD

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1991 Dakota 3.9L No Power to Coil & ASD Relay
« on: February 1, 2010, 10:06:18 AM »
Got a 91 Dakota (3.9L / 5-Speed / 2WD) on the Rollback, No Power to the Coil & No Power to ASD Relay.

I seem to recall seeing this mentioned before on the RC's & D/W Trucks,  What was the most common issue that caused the problem?  That way i have an idea where to start looking.

It's a little too cold to just start checking wires without a good idea where to start, Can't bring it in the garage, there's a Skidloader in the one bay with the engine removed, and a Neon in the other bay that has the head removed (bad gasket)
76 Ramcharger 318/727/203
48 Dodge Pickup
83 Scamp GT 2.2 Turbo AWD
92 Dakota 5.2/518/231
84 PW50 273/727/100/203
74 Duster 6-71 Blown 340/833/D60
73 Duster 340/727/8.75
73 Dart Sport 340/833/8.75
73 Dart Sport 340/727/8.75
71 Duster : Viper V10/6-Speed/8.75
71 Demon 8-71 Blown 540 Hemi/833/D60
72 Demon 340/833/8.75
65 Cuda 273/904

Offline v737d

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Re: 1991 Dakota 3.9L No Power to Coil & ASD Relay
« Reply #1 on: February 1, 2010, 02:30:40 PM »
OK I will dive in but I have ZERO experience with the V-6 or Dakotas

If it was your RC I would say your Hall effect sensor is not working.  Computer shuts down power to fuel pump (after a 1-2 sec prime), coil etc if it does not "see" the engine turning via the Hall effect sensor. 

You can try jumping the relay for the ASD just to verify the pump is working.  You should be able to hear it.  I do not know of a way of testing the Hall effect sensor. 

BTW it is in the distributor.  Should have a three wire triangle or half circle look plug coming out the dist.  Only a couple of screws to replace but sometimes those screws are not fun.

Again, this all base on RC V-8 experience.  YMMV


Cheers

Chris
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Offline s ǝoɾ

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Re: 1991 Dakota 3.9L No Power to Coil & ASD Relay
« Reply #2 on: February 1, 2010, 04:50:18 PM »
You say no power to ASD relay. If there is no power going in, you have a bad wire.

If you meant no power coming out, that could be a bad wire, bad relay, bad hall effect, or bad pcm. That is the order I would go in as well.
Avoid replacing any part that you have not proven to be faulty through extensive testing.

Offline ChrisKD

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Re: 1991 Dakota 3.9L No Power to Coil & ASD Relay
« Reply #3 on: February 1, 2010, 05:07:14 PM »
You say no power to ASD relay. If there is no power going in, you have a bad wire.

If you meant no power coming out, that could be a bad wire, bad relay, bad hall effect, or bad pcm. That is the order I would go in as well.

Sorry typo on my part. No power coming out of  ;)

First thing i tried was swapping in a known good relay. Same thing. it's fa-fa-farkin cold out there with the wind blowing  :-[

It's supposed to be warmer tomorrow so i'll check the wiring
76 Ramcharger 318/727/203
48 Dodge Pickup
83 Scamp GT 2.2 Turbo AWD
92 Dakota 5.2/518/231
84 PW50 273/727/100/203
74 Duster 6-71 Blown 340/833/D60
73 Duster 340/727/8.75
73 Dart Sport 340/833/8.75
73 Dart Sport 340/727/8.75
71 Duster : Viper V10/6-Speed/8.75
71 Demon 8-71 Blown 540 Hemi/833/D60
72 Demon 340/833/8.75
65 Cuda 273/904

Offline s ǝoɾ

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Re: 1991 Dakota 3.9L No Power to Coil & ASD Relay
« Reply #4 on: February 1, 2010, 05:45:23 PM »
You DO know you only get power for 2 seconds after turning the key right?

Which means by time you get out of the truck and back under the hood, even a perfectly working system will be in "sleep mode".

Bypass relay by jumping terminal 30-terminal 87.
Avoid replacing any part that you have not proven to be faulty through extensive testing.

Offline s ǝoɾ

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Re: 1991 Dakota 3.9L No Power to Coil & ASD Relay
« Reply #5 on: February 1, 2010, 07:14:35 PM »
The fastest way to test this is with a PowerProbeIII. A cheaper alternative is a logic probe.

Since you are a professional, 1 or both is a must-have.
Avoid replacing any part that you have not proven to be faulty through extensive testing.

Offline ChrisKD

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Re: 1991 Dakota 3.9L No Power to Coil & ASD Relay
« Reply #6 on: February 2, 2010, 06:04:58 AM »
You DO know you only get power for 2 seconds after turning the key right?

Which means by time you get out of the truck and back under the hood, even a perfectly working system will be in "sleep mode".

Bypass relay by jumping terminal 30-terminal 87.

Had my dad sitting inside the truck, while i was under the hood  ;D

The fastest way to test this is with a PowerProbeIII. A cheaper alternative is a logic probe.

Since you are a professional, 1 or both is a must-have.

I'll have to check, i know my dad bought some kind of probe. Its somewhere in the garage (probably near the unused TIG and the Plasma Cutter that's never been opened)  It was in a Case that kind of reminded me of one of those Portable Toolkits (you know, the ones that have a few wrenches and a bunch of sockets)
76 Ramcharger 318/727/203
48 Dodge Pickup
83 Scamp GT 2.2 Turbo AWD
92 Dakota 5.2/518/231
84 PW50 273/727/100/203
74 Duster 6-71 Blown 340/833/D60
73 Duster 340/727/8.75
73 Dart Sport 340/833/8.75
73 Dart Sport 340/727/8.75
71 Duster : Viper V10/6-Speed/8.75
71 Demon 8-71 Blown 540 Hemi/833/D60
72 Demon 340/833/8.75
65 Cuda 273/904

Offline s ǝoɾ

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Re: 1991 Dakota 3.9L No Power to Coil & ASD Relay
« Reply #7 on: February 2, 2010, 02:20:51 PM »
A logic probe has 2 or 3 leds and usually a clear handle. Has 2 battery clips as well.

You back probe things like hall effect sensor and start cranking. The LED flashes like a noid light. So it will work with injectors or coils or anything that rapidly pulses. Cost like $15.
Avoid replacing any part that you have not proven to be faulty through extensive testing.

Offline offroader_dodge

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Re: 1991 Dakota 3.9L No Power to Coil & ASD Relay
« Reply #8 on: February 3, 2010, 10:11:07 PM »
i have experienced similar issues with vehicles in that era,although they were front wheel drives,the chrysler products shared similar wiring functions. fuel and spark were controlled by the asd,which the computer controlled.3 times i have seen a computer crap out and the asd driver circuit was bad.
i use a long jumper from battery+ to positive on ign coil and crank it.if it fires up its asd,wiring or comp.if it dont,check for fuel pump operation and spark,it could very well be the hall effect /pickup in the dist.i have the power probe 3,its an awesome tool for anything electrical.a must have for any auto electric diagnostics/electrical accessory installer
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Offline s ǝoɾ

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Re: 1991 Dakota 3.9L No Power to Coil & ASD Relay
« Reply #9 on: February 3, 2010, 10:43:33 PM »
I got your "jumper wire"  ;D  :o

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Avoid replacing any part that you have not proven to be faulty through extensive testing.

Offline ChrisKD

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Re: 1991 Dakota 3.9L No Power to Coil & ASD Relay
« Reply #10 on: February 3, 2010, 11:03:34 PM »
Well i managed to track it down. Bad Hall Effect.  To be honest i didnt track that down, my dad did. I was picking up a head at the machine shop (for an '04 Neon, head is wasted)
76 Ramcharger 318/727/203
48 Dodge Pickup
83 Scamp GT 2.2 Turbo AWD
92 Dakota 5.2/518/231
84 PW50 273/727/100/203
74 Duster 6-71 Blown 340/833/D60
73 Duster 340/727/8.75
73 Dart Sport 340/833/8.75
73 Dart Sport 340/727/8.75
71 Duster : Viper V10/6-Speed/8.75
71 Demon 8-71 Blown 540 Hemi/833/D60
72 Demon 340/833/8.75
65 Cuda 273/904

 

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