96 Dodge, Wont start

Tiny
MIKECOLE2011
  • 1996 DODGE RAM
  • V8
  • 4WD
  • AUTOMATIC
  • 160,000 MILES

I have a 96 Dodge 1500 4x4 turns over but wont start, its not getting any fire and the fuel pump not working, when I checked the ECU it's just reading (link error) I changed the coil, pick up, crank sensor and wires. Is it the ECU, loose wire or does it have a fusible link I can check?

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Thursday, February 24th, 2011 AT 4:22 AM

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Tiny
CARADIODOC
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Did you have a paper spacer on the end of the new crank sensor to set the air gap? Has the Check Engine light turned on? The best place to start is by measuring the voltage on the dark green / orange wire at the ignition coil, one of the injectors, or either small terminal on the back of the alternator. You should see full battery voltage there for just one second after turning on the ignition switch. It should come back when the engine is rotating, (cranking or running). If it doesn't come back during cranking, we have to look at the cam and crank sensors.

Caradiodoc

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Thursday, February 24th, 2011 AT 4:48 AM
Tiny
MIKECOLE2011
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The check engine light was on before it quit running, now its off. I run a scan while it was running and one of my oxygen sensors are bad. I didn't know about the paper spacer on the crank position sensor. What would cause the fuel pump to quit working at the same time it quits firing? And also the truck was running fine the day before, never missed or died once. Would a fusible link cause this?

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Thursday, February 24th, 2011 AT 5:22 AM
Tiny
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The crankshaft position sensor can have a thick paper spacer stuck to the end that sets the gap. It slides off the first time the engine is started. Some aftermarket sensors have a thin plastic rib molded to the end to set the gap. It will partially wear away over time so to reinstall a used one you must cut the remaining rib off, then install a paper spacer. If you don't use any spacer it's possible the sensor could go in too far and be broken from the flex plate hitting it.

The camshaft position sensor lives in the distributor. Both sensors are powered by a regulated 8 volt supply inside the Engine Computer. It doesn't happen often, but it's worth mentioning that if that orange wire to either sensor becomes shorted to ground the computer will turn that power supply off to protect it. Once the short is gone, the ignition switch must be cycled off and back on to reset the supply.

When the Engine Computer receives pulses from both sensors it turns on the automatic shutdown (ASD) relay. That relay sends current to the injectors, ignition coil(s), alternator field, oxygen sensor heaters, and fuel pump or pump relay. Since the fuel pump and ignition coil are tied together in the same circuit it is necessary to check both of them for a no-start condition. If you have spark OR the pump is running, (which can be hard to tell), you know the two sensors are working. That's when you must troubleshoot the dead circuit. When BOTH are dead, that's when to look at the sensors. The sensors cause a lot more trouble than the pump or ignition coil.

In addition to turning on the ASD relay when the engine is rotating, the computer also turns it on for one second when you turn on the ignition switch. You will usually be able to hear the pump hum for that one second but it's hard to hear it during cranking because of the noise from chimes and the starter.

The most reliable test is to measure the voltage from the ASD relay. That's the dark green / orange wire at the coil, injectors, or either terminal on the back of the alternator. You can prop up a test light so you can see it from inside the truck or you can jump the starter relay from under the hood. I can describe two ways to do that. If you see battery voltage for the first second after turning on the ignition switch, you know the wiring and relay are okay and the computer has control of it. Whether or not the voltage returns during cranking will determine where to go next.

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Thursday, February 24th, 2011 AT 6:38 AM
Tiny
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I forgot to mention that since the Check Engine light came on there is at least one diagnostic fault code stored in the Engine Computer. In the future when you have an intermittent problem it is important to read those codes as soon as possible. If the problem doesn't come back the codes will erase automatically after 50 starts. Disconnecting the battery will erase the codes too, then that valuable information will be lost.

You can read the codes by cycling the ignition switch from "off" to "run" three times within five seconds, then watch the flashes of the Check Engine light, ... Or, starting with '96 models the codes should be displayed one after the other in the digital odometer.

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Thursday, February 24th, 2011 AT 6:56 AM
Tiny
MIKECOLE2011
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I'm getting a reading on the ignition coil and alternator, I've already replaced the computer so thats not the problem either, where should I go next?

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Sunday, February 27th, 2011 AT 8:42 PM
Tiny
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If you have voltage on that wire during cranking you are missing either spark of fuel. For spark, the coil is the most likely suspect. If fuel is missing, the most common problem is the fuel pump fails to start up. Often banging on the tank while a helper cranks the engine will get it going. It will continue to run once it has started.

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Sunday, February 27th, 2011 AT 9:21 PM
Tiny
MIKECOLE2011
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I'm not good with these multimeter's so I might have done it wrong I'm still not getting fire on the coil, the coil is new also, and the fuel pump is not working. I just tried to read the meter again and its not doin anything on the coil or the alternator. Which setting should I use to test the coil wires correctly?

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Sunday, February 27th, 2011 AT 9:45 PM
Tiny
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Use the 20 volt DC scale. That will read anything up to 20 volts with one space after the decimal point. The black lead goes to the battery negative post or any paint-free point on the engine. With the red lead, poke it through the rubber seal on the back side of the connector for the coil or any of the injectors.

Prop the meter up in front of the windshield so you can see it or have a helper run the ignition switch. You should see a voltage reading when you turn on the ignition switch but it will disappear right away so you might miss it. What is important is it must come back steady while cranking the engine.

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Sunday, February 27th, 2011 AT 10:34 PM
Tiny
MIKECOLE2011
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Ok, I got a reading of 0.28 with the switch on, then 0.32 cranking, on coil and alternator, both were steady readings

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Sunday, February 27th, 2011 AT 11:01 PM
Tiny
MIKECOLE2011
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There's one fuse under the dash that's not getting any kind of reading, its the #9 fuse its marked engine. I changed the fuse, nothing. If u could help figure out what it goes to maybe I have my solution. Thanks

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Monday, February 28th, 2011 AT 5:53 AM
Tiny
CARADIODOC
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Was that fuse blown? That circuit feeds the automatic shutdown and fuel pump relays. If there's no voltage to that fuse, suspect the ignition switch. If you remove the plastic cover to get to the electrical connector, measure the voltage on the dark blue wire. It must have 12 volts in the "run" or "crank" positions.

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Monday, February 28th, 2011 AT 7:00 AM
Tiny
MIKECOLE2011
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That fuse wasn't blown. I checked the Ignition switch its reading 11.87 volts. I guess that's good. When I first got the truck a couple weeks ago the starter wires were loose, so I took it off and cleaned the wires, put it back and tightened it up good, now its cranking good. Is it possible that it could have shorted something out when it was loose that would cause my problem? And one more thing, Under the hood theres a 40amp fuse that goes to ABS Pump, It only has one prong going into the fuse? Thanks for the help!

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Tuesday, March 1st, 2011 AT 12:09 AM
Tiny
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There's multiple circuits in the ignition switch. You have to look for voltage going in on at least two wires and coming out on at least two wires when it is in the "run" position.

If there's just one terminal for a fuse that means that fuse isn't used in your truck.

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Tuesday, March 1st, 2011 AT 11:01 AM
Tiny
MIKECOLE2011
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There's voltage on all 7 out of 8 wires.

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Tuesday, March 1st, 2011 AT 11:21 PM
Tiny
CARADIODOC
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I only have a '98 service manual but it should be the same circuitry. Fuse #9 feeds the Engine Computer. It gets its voltage from the 10 gauge dark blue wire from the ignition switch. If you have voltage on that wire when the ignition switch is turned to "run", it must be on fuse 9 too. If not, pull the fuse out and measure right on one of the terminals in the socket.

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Tuesday, March 1st, 2011 AT 11:54 PM
Tiny
MIKECOLE2011
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I think I might have it figured out, Not sure what I did but I was cleaning some of the mud out of the control box under the hood and the check engine light came back and the fuel pump is working, still not firing. So I took the distributor cap back off and the rotor button is broke. The guy that replaced the pick up must not have noticed it was cracked. So he's gone to get one now, hopefully this takes care of everything. Let u know soon. Thanks for your help. And The engine fuse is good, finally figured that one out!

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Wednesday, March 2nd, 2011 AT 1:09 AM
Tiny
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I'm stuck again. The fuel pump's working and it's getting fire. But I can't get the timing set, I can't get the ignition rotor rod to turn, could that mean that something's broke in the oil pump? It just seems like it would be easy to turn.

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Saturday, March 12th, 2011 AT 9:29 PM
Tiny
MIKECOLE2011
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Distributor

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Saturday, March 12th, 2011 AT 9:42 PM
Tiny
CARADIODOC
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Hold on a minute. You have spark but the rotor won't turn? That's not possible. A spark is produced when the reluctor on the distributor shaft turns inside the pickup coil, so if you have spark, the shaft has to be turning.

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Saturday, March 12th, 2011 AT 10:36 PM
Tiny
MIKECOLE2011
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The rotor turns when you crank the engine. When we was trying to set the timing we had to take it apart to reset the distributor and ignition rotor, It's not like most distributors with the gears, you can just sit it down in there and line up the rotor with the #1 cylinder. You got to turn the rod that goes down in to the oil pump but it's not turning easy like I've been told it should. In the picture you can see where the distributor sits in the slot, it should turn with a screw driver so I can line up the ignition rotor to get the timing right?

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Sunday, March 13th, 2011 AT 7:08 AM

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