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Discussion Starter #1
I have a 1999 Cummins 24v, 2500, manual transmission, 4x4.
I've been having an issue with my tachometer since I got the truck, 2 weeks ago.
When I first start the truck the gauge works, and the truck idles a little rough. Then after about 3 seconds, the idle smooths out, and the gauge drops to 0 and never comes to life again.
I've installed a cps form Orielly's with no success.
I've tested the cluster, it works fine.
My obd2 port isn't getting power ( I've checked all the fuses).
I may have a new vp44, I don't know if they wired it up correctly.
This is my first diesel truck, so I'm not sure how to fix it.
Any suggestions would be greatly appreciated.:D(y)
 

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What does your Wait to start light do? Does it come on immediatley every time you turn the key to ON? Does it start on very first crank every time? Seein as how your issue is in the first 5 seconds and you have already replaced crank sensor it sounds like the issue may be in teh ECM. It provides timing for the first 5 seconds. Sounds like the timing is being received by the ecm for runing but itis not transferroing to the tach, or the tach is broke. I would also check the wires to and from teh sensor for continuity and for 5 volts from the ECM for power.
 

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Discussion Starter #3
What does your Wait to start light do? Does it come on immediatley every time you turn the key to ON? Does it start on very first crank every time? Seein as how your issue is in the first 5 seconds and you have already replaced crank sensor it sounds like the issue may be in teh ECM. It provides timing for the first 5 seconds. Sounds like the timing is being received by the ecm for runing but itis not transferroing to the tach, or the tach is broke. I would also check the wires to and from teh sensor for continuity and for 5 volts from the ECM for power.
The Wait to start light comes on immediately, and it starts within 1-2 seconds every time.
I have considered the pcm(ecm,ecu)
But before I dive into the expensive side of it, I wanted to know if there was something else I could check. Like I said, I'm not familiar with these trucks yet. So I'm wanting to know all the components it could possibly be, then, weed out the ones I know it can't be.

Is there a way I can unplug the pcm and see if it still idles rough?

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Your last post is missing, SNAFU again I think. First there is both an ECM(engine control module) and PCM powertrain control module ECM controls engine, most sensors, fuel and timing and VP, PCM controls shifting(auto) and charging and some other functions. Both are associated with the Dash cluster. I have not had your particular issue.

The things you can do are:
Pull codes with a good scan tool and also check monitors available, Key trick does not work on 99. Keep doing it.
Check those wires.
Hot wire or repair the obd port, don't know if it is 5 or 12v. It is probably powered by the ECM, but I do not know.
Find a friend with a 98.5 or 99 and switch the ECM with them for a test. It won't hurt theirs. Computers on these trucks are not vin specific.
 

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PS VP44's are not "wired up". They are plug in only.
 

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Discussion Starter #6
Your last post is missing, SNAFU again I think. First there is both an ECM(engine control module) and PCM powertrain control module ECM controls engine, most sensors, fuel and timing and VP, PCM controls shifting(auto) and charging and some other functions. Both are associated with the Dash cluster. I have not had your particular issue.

The things you can do are:
Pull codes with a good scan tool and also check monitors available, Key trick does not work on 99. Keep doing it.
Check those wires.
Hot wire or repair the obd port, don't know if it is 5 or 12v. It is probably powered by the ECM, but I do not know.
Find a friend with a 98.5 or 99 and switch the ECM with them for a test. It won't hurt theirs. Computers on these trucks are not vin specific.
I didn't know there's both a pcm and ecm \(0_0)/ sorry, Makes sence tho.
I'll see if I can fix the obd. And I'll check the wiring.
 

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ECM is on left side of engine, PCM on firewall.
 

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Maybe but the reason I mentioned the VP is you said "wired up".
 

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About the only way to do that is screw up the key way alignment. No way to do that electronically so long as plug is together and latched. VP times the fuel injection on mechanics and electronic timing from ECM and CPS
 

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The repair manual is your friend and may shorten the guessing game.
 

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Discussion Starter #13
I found the fuse that was blown for the obd2. (It was the I.o.d. fuse)
So, I got the truck scanned I have a p0336. Crank position sensor code. (I had heard these trucks only had a cam position sensor \(0_0)/, I guess that didn't pertain to this year.)
I also have a p0236. Turbo boost sensor A. I'll have to look in to that.

Any suggestions on what brand cps I should buy?


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98.5 to 00 have crank and cam sensors both. Tach and ecm run mostly of Crank sensor on up to 00. So which sensor did you already replace? Replace it with a name brand only, store brands can be OK if it is there better version of 2 or more and has lifetime warranty. It is located beside the starter in the block. Common issue with your symptoms too.
 

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Told you about that fuse 11 days ago, glad you got it working. The sensor isn't available from Mopar any more but maybe Cummins. PDP has one and looks like you need the pigtail too. Edit: I think the pigtail is is for if you use this sensor as a cam sensor. Look at yours 1st and compare connectors.
P0236 can be from over boost. Do you have a tunner on it? Performance waste gate actuator?
 

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Discussion Starter #16
98.5 to 00 have crank and cam sensors both. Tach and ecm run mostly of Crank sensor on up to 00. So which sensor did you already replace? Replace it with a name brand only, store brands can be OK if it is there better version of 2 or more and has lifetime warranty. It is located beside the starter in the block. Common issue with your symptoms too.
I tried replacing the cam position sensor before.
I'm going to try to get a mopar cps, if I can find one.
 

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Never heard the 98.5-00 had cam sensors. 98.5-99 crank sensor 00 crank and cam sensor 01-02 cam sensor.
 

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Discussion Starter #19
Told you about that fuse 11 days ago, glad you got it working. The sensor isn't available from Mopar any more but maybe Cummins. PDP has one and looks like you need the pigtail too. Edit: I think the pigtail is is for if you use this sensor as a cam sensor. Look at yours 1st and compare connectors.
P0236 can be from over boost. Do you have a tunner on it? Performance waste gate actuator?
The guy b4 me had a redneck waste gate actuator. Literally a ball valve on the waste gate.
 

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P0236 doesn't clear?
 
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