Here's a letter from a reader who had no-start problems with his 88 Dakota pick-up
I recently had a experience with my 88 Dodge Dakota truck that caused me some grief for a few days. One morning the truck wouldn't start so I check for spark which there was then I checked for fuel which there was. After some other investigating I tried to start it and it started. The next day it wouldn't start again so my son and I checked the throttle body for fuel injection which there was none. After some troubleshooting we determined that there was no 12V supply to the injectors, fuel pump or coil.
We noticed that the fuel pump would run when the key is in the run position for about one second and then it would stop which is correct. Just to make sure that the fuel pump is good we checked the fuel pressure which was at 14 lbs. which is correct. We then took apart the wiring harness to see if there was a bad connection going to the injectors and the coil. The connection was good.
The 12 volts goes through the auto shut down relay and after checking all the wiring from the computer to the relay several times we decided that maybe the relay was intermittent. So I jumped the 12V through the relay and the truck started. We bought a relay the next day and put it in that night and it worked.
The next morning Brant my son went out to start the truck and it wouldn't start. That night we checked all the grounds on the engine and frame. Still no start. We replaced both battery cable connections as they were deteriorating. Then it started.
Next morning no start. Then we decided with great apprehension we bought a used computer. Installed the computer and now the fuel pump would not run at all and when I called the junk yard they said there was no warranty. We repeated our steps all over again and arrived that the computer was bad and so was the used computer so we bought a new computer. We installed the new computer and still no start.
At this point I was getting just a little tired of this problem and upset at spending $300 dollars for computers and the problem was still not fixed. I tried to think of what input to the computer would cause the computer to shut down the fuel system and coil but I couldn't think what it could be. Also another unanswered question was what caused the fuel pump to stop after about one second when the key is turned to the run position.
After looking at the shop manual some more I found a note that said that the computer will not energize the auto shut down relay if no tach pulses are seen from the computer. Then I knew what the problem was so I jumped the auto shut down relay again and checked for spark again and there was none. I removed the distributor and removed the electronic pickup to notice that the rotor under it with the six vanes for the cylinders was loose and they were rubbing on the electronic pickup which had taken out the pickup. We got another distributor complete with electronic pickup and the truck works fine.
Also I remembered a few months earlier when I was setting the timing that the marks were bouncing all over and I knew that the timing chain and sprockets were good so what was causing this. Now I know. What I learned was that fuel and spark are related and you need to check both.
Bruce Larsen Lindstrom Minn.
Message me at BobHewitt@Misterfixit.com
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