Rich Presthus

I thought I had my bases covered, researched before asking, but I'm at the point I need help. My truck intermittently would drop the tach and CEL would come on but after a while it would spin back up and all was good. Then more recently it would go dead tach, CEL, and no start. Sometimes it would start if the tach had come back. I replaced the crankshaft position sensor, no luck, alternator was showing bad diodes so it got replaced, no luck, then realized that my truck also has a cam position sensor, replaced it still no joy. it always starts with a shot of Ethier and runs decent and after the cam sensor the CEL goes off after the truck is shut off where as it would remain on the next time I tried to start before. all of this work was done over the weekend. any idea? I am about done in.

jrs_dodge_diesel

Kinda sounds like ECM or VP44 issues here.

What dashboard do you have? More specifically what type of odometer do you have, the tan colored one with black LCD digits, or the black one with green digits?

Reason I ask is that 99 was a transition year for the 2nd gen trucks with a revised interior. Some of them have the ability to show you what trouble codes are in the computers using the odometer if it is the one with green digits. Let us know what you have.

And please don't use ether for starting. Our engine do not have glow plugs. Instead they have a grid heater right under the air intake horn on the manifold to pre warm the air going to the cylinders. Some over the years have started a fire or have had the mixture explode inside the intake, damaging it in the process. Do be careful.

Rich Presthus

I have the black dash, green Odometer. After installing the Cam position sensor, I got it started and down to the parts store to have the codes read. P0336 CKPS. But it seems like that is really generic. is there any tests I can do? Voltage or resistance to the plugs? Am I understanding correctly that the truck wants to start off of the cam sensor and run off the crank? It runs decent, just will not start, when I do juice it to start it, the tach works for about 2 seconds and falls flat. I truly appreciate your help. My only vehicle besides the bagger so I'm riding rain and shine.

jrs_dodge_diesel

To pull the codes using the truck, you use your key in the ignition. You cycle your key three times between the OFF and the ON positions, with the third one staying in the ON position. ON here meaning ignition ON, the one click right before START. The sequence goes ON - OFF - ON - OFF - ON. Done correctly you'll hear the door chime once, and you watch the odometer display. You'll see it tell you the codes in two sets form both computers, the Cummins ECM and the Dodge PCM. You'll see it say P PCU, any stored codes, then P DONE and then you see P ECU, any stored codes, and then P DONE. Once the test is done you'll hear the door chime again and the mileage will show again on the odometer. It may show the ECM codes first, or the PCM, I don't recall which since it's been a while that I've done it on my truck. The reason it will say ECU instead of ECM is that there is no way to make an M on a 7 segment display like in our odometers.

If there are no codes stored in a computer, you'll just get a row of dashes ------- in place of any codes.

Now for starting, that is generally all on the VP44, though the ECM is on at the same time. The VP44 can function on it's own since it's base timing is set by being gear driven and it has its own internal position sensor. Once the engine starts, the ECM takes full control of engine operation and works with the VP44. It's rare for an ECM to go bad, but it can happen.

Strange that your engine has both a crank and a cam sensor. Older 24V engines got one sensor, and the newer ones got the other. Both sensors give the same output for the computers. Not often you see both on one engine. Now the ECM and PCM both use that sensor. The PCM mostly uses that to know if the truck is running or not. If it does not get a good signal from that sensor, it assumes the engine is not running and will shut off the alternator, the A/C compressor, cruise control, and the tachometer. The PCM runs all of the truck functions including the dashboard, the ECM runs the engine. Interesting to note that on the gas engine Rams, the PCM will also shut down the engine because on those trucks the PCM also runs the engine. Our Cummins will keep on running because of the ECM and VP44.

A bad sensor connection, or a wiring issue can cause problems. Weak batteries can cause odd issues as well. These Rams need good strong batteries in order to run well due to all the electronics, and age isn't doing them any favors. Especially when you consider that the "newest" 2nd gen Ram is now 17 years old.

Rich Presthus

That's what is throwing me. I have everything but the tachometer and ability to start (without starting fluid, used in moderation) It's charging well. I tried the code generator w the key to no avail. I think the motor has been replaced so it may be an earlier version. I did have an issue buying a fuel filter the first time. my canister was much larger than the filter offered

Rich Presthus

The key does not produce a Ding or codes. O'Reilly code reader gave me the P0336 ckp sensor

KATOOM

Have you checked your batteries for condition? Its easy to misdiagnose a bad battery in a dual battery system unless they're fully disconnected from each other and the truck. Also, hows the corrosion? Loose or corroded main connections and/or battery cables will cause all kinds of problems.
And if your tach is still not moving then a bad CPS or bad connections is all it could be. Does your wait to start light illuminate like it should when you first turn on the ignition key?

jrs_dodge_diesel

Some 99's could do the key trick, sounds like your is unable to. Pull your cam/crank sensor again and see if there is debris on it. They are magnetic and if there's debris stuck on the face of the sensor, that causes them to have bad readings or no reading at all. While your at it, check the teeth under the sensors and they are nice and clean too.

Yes, the WTS light is usually the first sign that the ECM is acting up. Should come on right away when the ignition is switched to ON for 2 seconds, longer when it's cold out. If it doesn't come on at all or, it hesitates for a few seconds and then comes on, then you may have an issue with the ECM.

Also, how's your fuel system and lift pump pressure? The OEM fuel lines on these Rams are not known for longevity. If your fuel system is losing prime, that can cause hard starts as well. I had to replace mine a few years ago when the supply line cracked.