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Discussion Starter #1
Hey guys, need help with a few problems .... My truck is a 98.5 2500, already replaced the lift pump to a fass, shortly after that had to replace the injection pump. That was bout 5 months ago. Ok now the problems, here lately everyday or so its hard to start, have to let it crank a few seconds before it will fire. After that it runs fine. Then the other day stopped the truck an restarted it was hard to start after it started looked down an the tach was on 0. Shut it off an restarted it an there was a CEL but the tach worked. Went home an after a couple hours restarted it an the CEL was gone. Had the codes read an it gave these codes: P1693 and P1698. Sorry bout it being long winded , can anyone help???? Thanks
 

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Mopar1973Man.Com
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Hmmmm... Fuel pressure??? :w:
 

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Sounds like a crank or cam position sensor.

Also, the hard starting means you are loosing prime. When I put my Fass in it was hard to start for several weeks, then it just started firing up on teh first crank. Wierd.

Merrick
 

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I agree with Mopar man...he just helped me with the codes I was getting for my CSPS...when I installed my FASS... I never had a problem..my truck starts everytime....but I did an extensive leak check of every connection..before I tried to start the truck..when I had my problems...my stuck would cough..then the CEL would come on...but after a restart..it ran fine...with the CEL on...just replaced CSPS...the 1693 code is a companion code...as I learned recently..nothing to worry about...but the P1698...hmmm..I'm sure Moparman will chime in again..
 

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It's the crank shaft sensor. I had mine go out. It's easy to fix and only cost 100 bucks.
 

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Discussion Starter #6
So you think its the crank position sensor that is causing all these problems. What exactly does it do? Would it also cause the hard starts? Thanks
 

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So you think its the crank position sensor that is causing all these problems. What exactly does it do? Would it also cause the hard starts? Thanks
for one thing...it can be a direct cause of a tach going to 0....and hard starting...(cause ecm doesn't know how to schedule fuel without knowing what engine timing is) and the...seemingly dead pedal...if you have good FP and a good LP installed...if you are getting a IP timing code...then it could be a CSPS..I'd think...a logical solution...
 

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Mopar1973Man.Com
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I agree with Mopar man...he just helped me with the codes I was getting for my CSPS...when I installed my FASS... I never had a problem..my truck starts everytime....but I did an extensive leak check of every connection..before I tried to start the truck..when I had my problems...my stuck would cough..then the CEL would come on...but after a restart..it ran fine...with the CEL on...just replaced CSPS...the 1693 code is a companion code...as I learned recently..nothing to worry about...but the P1698...hmmm..I'm sure Moparman will chime in again..
P1689 (M) No Communication Between ECM and Injection Pump Module Data link circuit failure between ECM and fuel injection pump. Low power, engine derated, or engine stops.

Basically the VP44 is dead...:thud:​
 

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Discussion Starter #9
The codes were P1698 an P1693 not P1689. So what does that mean , I hope I dont have to change that pump again. Please tell me its something else please!!!!!!!! So moparman you dont think its the crank sensor? Thanks
 

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Sounds like a bad cam or crank sensor. When the cam or crank sensor is on the flake, it will throw a plethora of codes. The VP44 is telling the ECM that it's turning over and the cam or crank sensor is saying, we ain't movin' over here, so the ECM thinks, hey bad connection! The VP44 is freakin' out!! Sound the alarm!

The tach is run off the crank or cam sensor. After '99 there was no longer a crank sensor... only a cam sensor.

Well, that's my idea.

Merrick
 

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Sounds like a bad cam or crank sensor. When the cam or crank sensor is on the flake, it will throw a plethora of codes. The VP44 is telling the ECM that it's turning over and the cam or crank sensor is saying, we ain't movin' over here, so the ECM thinks, hey bad connection! The VP44 is freakin' out!! Sound the alarm!

The tach is run off the crank or cam sensor. After '99 there was no longer a crank sensor... only a cam sensor.

Well, that's my idea.

Merrick
...if only we could talk back to them sometimes.. :lol3:
 

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...if only we could talk back to them sometimes.. :lol3:
ohhh the things I would tell them. LOL.

ok MAP sensor, here's some dialectic grease, now, when I push the APPS down, I want you to instantly to tell the ECM you have 10PSI... Got it?

Ok, now crank and cam, what I want you to do is when we get close to 3,000RPM, I want you to tell the ECM that you are still turning 3,000RPM ok? just, kinda, stick it to the man? alright?


Now, wait, HEY, HEY Fuel Gauge! Yah, YOU!, I better not catch you lying again! Last time you told me I had 1/4 tank, and I was OUT! What the freak? You are lucky I didn't make you bleed the injectors!


And you ABS, just stay out of my business ok? I'm tired of you always putting your own ideas in when I am pretty sure I know what I want to do ok? I hope you just blow a fuse some day and turn into a distant memory. Infact, we are on such bad terms, I may file for a divorce from you in the near future..

Oil pressure gauge, now, stop falling asleep on the job, you are scaring me! There I am motoring down the road, and BAM, 0PSI oil pressure! but I know that ol' faithfull Cummins is still pumpin' oil, just,, uhm,, try to stay awake, ok? I'm going to have to replace you if you keep knockin' out on the job. When I turn the key, then you can nap...

Anyway.. That's all I got for now, LOL.

Merrick
 

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Mopar1973Man.Com
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The codes were P1698 an P1693 not P1689. So what does that mean , I hope I dont have to change that pump again. Please tell me its something else please!!!!!!!! So moparman you dont think its the crank sensor? Thanks
Opps my bad...:ah:

P1698 No CCD Messages received from PCM Bus communication failure to PCM. A​
Companion DTC was set in both the ECM and PCM.

You got a wiring issue between the PCM and ECM. Check all grounds and electrical connectors between the two...

I hope this helps...:w:

 

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Did you relay the FASS?

The FASS if wired straight into the ECM will burn up the fuel pump circuit and possibly more...

Merrick
 

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Discussion Starter #15
mcummins ,yes I used the relay that came with the fass unit. So where should I start to fix this.. The truck was hard to start every time today its getting worse.. So have you decided its not the crank sensor. Its only done the 0 tach reading that one time an that was the only CEL. What do you think?
 

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In my opinion if it's not a sensor, then you are loosing prime. I'd check by the tank. Or, in some rare cases, you might have to much pressure at startup. Let your fuel pressure fall to 0 before you crank 'er up.

Or, you can go back and check for any air leaks, especially suction leaks at the tank.

Merrick
 

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Discussion Starter #17
How will I know if its a sensor or not? Thanks
 

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Cummins CrAzY
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I am having a very similar problem, it is taking 20 revolutions to start up. It didnt start till I replaced my fuel filter, inline fuel filter befor the FASS, and oversized banjo fittings @ the FF and IP. It hasnt takent more than 2 revolutions to ever start before. Once it starts its fine. Im also not losinf prime cause I cracked the banjo @ the ip and cranked her and she spewed fuel! I also replaced my CSPS about a year ago.
 

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Discussion Starter #20
Does anyone know how i could find out if its a sensor or not? Thanks
 
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