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Steve
Steve, Service Manager
Category: Dodge
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Experience:  25+ Years experience as a professional working automotive technician; ASE L1 master technician
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1989 dodge: dakota..firing..the coil to the distributor

Customer Question

i recently purchased a 1989 dodge shelby dakota. i having a problem with the firing.i cannot geta spark thur the coil to the distributor. i have asked several dealers, parts stores and a few mechanics and no one has came up with a solution. the previous owner said they had the the computer checked and it was ok.i have tried about everything to my knowledge nad can''t figure it out. please help me.
Submitted: 8 years ago.
Category: Dodge
Expert:  Dr. Hamman replied 8 years ago.


On your 1989 Dodge Shelby Dakota 5.2L, the Control Module for the ignition is located under the hood, on the driver side of the upper engine area, above the wheelwell, mounted on the fenderwell. This module could easily be your problem. You should also check and clean all connections dealing with the ignition. When you turn on the key, and it is real quiet. Do you hear the fuel pump come on for a few seconds. When you get the ignition working of coarse you will need the pump to work. But for now It is a good sign if it comes on because the base wiring isn't hacked, it shares the same base root circuit as the ignition. For your reference the Engine Control Computer is located under the hood, it is mounted on the air cleaner housing.


I hope this helps, good luck with your truck, and Thanks.
Customer: replied 8 years ago.
Reply to DR. Hamman's Post: Thanks for the reply. But, For the first answer. I know it says in the book that the ignition module says it on the driver side. but its not there. i have looked everywhere in the engine compartment and can't find any wire connections or any place on the fenderwell that it would be bolted to. i did clean the connections on the firewall that leads to the fuse panel. Theres no noise from the fuel pump. but when you connect a wire on the relay connector the fuel pump activates and get juice to the coil but theres not a spark. I knew where the computer was at and i have checked the wires from the fuel pump relay to the computer and didn't find a open. I know that theres not any power coming out of the computer to the coil when you turn over the engine and/or theres not any power coming out of the relay to coil. Some reason the contacts inside the relay is not closing.
Expert:  Dr. Hamman replied 8 years ago.
Ok, I have been looking for some good electrical reference for you, and I found the motherload. It for a 90 it should work just fine. Check out this link, this is good it has enough details to wire up an ignition module if yours is gone.

http://www.jameskowalski.com/Dodge/1990_Dodge_Dakota_Wiring.pdf

Another thing I wanted to bring up was a problem I see a lot in the Dakota's, it is failure (corrosion) of the splice that supply's battery power to the automatic shutdown (ASD) and fuel pump relays. It is more common on Dakotas newer than yours. Yours could have the same problem. If these relays do not get enough battery power your truck will start, and die. If it is not a weak connection, but a totally bad connection your truck will not be able to start. This could also create intermittent problems, or could possibly kill the truck when driving down the road. The splice is underneath the Power Distribution Center (PDC), it is the black box located behind the battery. Check out this link for a photo

http://www.dodgeforum.com/upfiles/948/40E4B5788A49433CAD5F8ADCB6682027.jpg





Customer: replied 8 years ago.
Did these 1989 shelby dakota come out with a ignition module and if it did why would it be gone. I know the parts store shows one for this truck. but why is there no place for it on the fenderwell or i dodn't see any wire connections anywhere. If it never had one how did it start before. Would it be in the computer. I don't know what the owner could have done before.There is power going in the ASD. Would i need to check for the voltage.I really appreciate the help.
Customer: replied 8 years ago.
I couldn't get the links to come up.
Expert:  Dr. Hamman replied 8 years ago.
I just tried them again and they both worked for me.

Good luck and thanks.
Customer: replied 8 years ago.
Somehow i found the wiring diagram. But its the same as i have and it doesn't show a ignition module. On the engine compartment figure it doesn't show a area for the ignition module. It suppose to be somewhere aft of the battery and forward of the relays. This is very confusing. Because at the parts store when the clerk looks up the ignition module for 1989 shelby it comes up with the part and the place it goes. Why doesn't the diagrams shows it in the circuit.
Expert:  Steve replied 8 years ago.

Hello!

I see the previous expert has opted out, so I thought perhaps I can help you here...

Although the wiring diagram may show an ignition module, this model does not have a separate ignition module. The ignition module function is an internal feature of the SMEC engine control module (computer).

Lets go back to the beginning; you stated there is no power to the ignition coil. The computer does not provide power to the coil; the computer grounds the negative side of the coil to turn it on and off. Power to the coil comes from the ASD relay, which also powers up the fuel injectors and oxygen sensor heater.

Basic checks:

(1) Check for power at the coil + terminal when the engine is cranking.

(2) Check to see if there is power present at the fuel injector(s) when the engine is cranking.

(3) Use a logic probe or noid light to check to see if ground is being pulsed off and on at the other (not hot) wire of each fuel injector while the engine is cranking.

(4) use the logic probe or a test light to check to see if ground is being pulsed on and off at the coil negative while the engine is cranking.

Do you have access to a scan tool (DRB-III, DRB-II or equivalent) for this vehicle capable of displaying live engine data?

 

Customer: replied 8 years ago.
OK, The ASD has power going to it but doesn't close the relay to send the power to the coil and when you put a jumper wire on the connector it sends power to the coil. But doesn't send a pulse to the distributor. But i will check these items and get back with you. thank you
Expert:  Steve replied 8 years ago.
The ASD relay is commanded on when the computer sees a crankshaft position signal. Do you have access to a scan tool to be able to view engine RPM data from the ECM?