Crank, no start

Tiny
OX1
  • MEMBER
  • 2000 DODGE RAM
  • 5.9L
  • V8
  • 4WD
  • AUTOMATIC
  • 106,000 MILES
It is a 2500, gas engine. Cranks, but will not start.
Borrowed advanced scan tool (Autel). In live data section, can see state of ASD and fuel pump relays, they both turn on during crank. Can see injector PW during crank. Ran diagnostic on PCM/TCM, both passed. Checked codes, none. Removed ignition fuse, can hear a relay click when fuse put back in (ignition on). Fuel pump cycles when ignition turned on. Spark good off coil, but weak off spark plug wire.
Sprayed start fluid in intake, still no start. I am a Ford guy, working on truck for friend. Is there really a crank sensor near flex plate that you have to remove transmission to get to? Is there a way to test pickup coil in distributor (think Dodge calls it cam sensor? ). Thanks
Friday, November 30th, 2018 AT 5:28 PM

5 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,826 POSTS
Someone is pulling your leg. The crankshaft position sensor can be a little hard to get to, but it slides right in behind the right cylinder head. The air gap was critical on older models. Those used a thick paper spacer glued to the end to set the gap. Many aftermarket replacements used a thin plastic rib molded onto the end. With those, if the sensor needed to be removed and reinstalled, you were supposed to cut the remaining part of that rib off, and use a new paper spacer. By 2000, that sensor just bolts in with no need to worry about the air gap.

You have already gone through most of the diagnostic steps, and the fact the ASD relay is turning on proves the crank and cam sensors are okay. Since you hear the fuel pump run for one second when you turn on the ignition switch, you should have fuel pressure, but you might want to verify that. Since spark is weak after the distributor cap, check the carbon button inside it, and the rotor. Do not overlook bad gas too. We had two in a row with that. After lots of frustration, it was finally observed that a sample of gas dumped on the ground would put out a lit match.
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Friday, November 30th, 2018 AT 8:08 PM
Tiny
OX1
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Thanks. But it is a Dodge, my first one, a 1963 Polara had those left hand threaded wheel studs (on only one side of course), LOL! Is it true that the cam sensor is primarily for injector timing (read that here or there)? Did find a corroded terminal on the ignition coil connector. Tried to repair, but no go and had to order new pigtail. Battery voltage was down to about 12.1 from cranking it so much, but coil voltage during cranking was only about 10.5. Ohmed out coil and it was 2.2 and 8800. Seems out of spec from everything else I read.
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Saturday, December 1st, 2018 AT 3:58 PM
Tiny
CARADIODOC
  • MECHANIC
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I have never bothered to measure resistances. Those are listed in service manuals mainly for training purposes to provide typical values. You will find perfectly-fine working items that measure out-of-specs as often as you will find non-working parts that measure fine. Ignition coils can arc internally, which has nothing to do with the resistances you measure with an ohm meter that only puts 6 to 9 volts on each winding.

About 95 percent of crank/no-starts are caused by a loss of spark and fuel, but you already observed that is not the case here since the ASD relay is turning on during cranking. That leaves a loss of fuel only which causes maybe four percent of these no-starts, and loss of spark only, which accounts for the least of them. You are going to find the cause of this no-start is bad fuel or no fuel pressure, no spark at the spark plugs due to fouled plugs or a problem inside the distributor cap, or a problem with timing, meaning a jumped timing chain.

Also, have you checked the diagnostic fault codes? Chrysler made doing that yourself much easier than any other manufacturer. Cycle the ignition switch from "off" to "run" three times within five seconds without cranking the engine, leave it in "run", then watch the code numbers show up in the odometer display. You can go here:

https://www.2carpros.com/trouble_codes/obd2/p0200

to see the definitions, or I can interpret them for you.
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Saturday, December 1st, 2018 AT 4:15 PM
Tiny
OX1
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Hooked up an 1980's, EEC-IV (Ford) coil I had lying around. Fired right up, the first shot.
Still waiting on a replacement coil pigtail. Appreciate all the help!
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Saturday, December 8th, 2018 AT 9:33 AM
Tiny
CARADIODOC
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Dandy. Let me know when it's done and you're ready to buzz off, ... I mean "buzz off into the sunset"!
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Saturday, December 8th, 2018 AT 3:13 PM

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