Intermittent tach + P1693 + miss @ idle + = what?

[jmadden]

Tried this earlier... but I don't think it took, so I hope this doesn't post twice!



Greetings all... and HELP!!!! Bear with me since this is my first post with what is bound to be many more to come. Unfortunately a "search" for help seems out of the question today... so here goes.



What I've got is a stock Y2K 2500QC 4x4 w/ Auto... nearing 73k miles.



What it has started to do in the last two days is: 1) an intermittent tach... becoming less functional... and when the tach kicks back in there is a sudden power surge, 2) MIL -- check engine light -- is on, 3) DTC is P1693 shows, 4) when the tach goes out is has a distinctly noticable miss at idle... does not appear to miss while applying throttle, although it is somewhat more sluggish than usual... and starts to miss when I let off the throttle, 5) will occasionally miss when the tach is back to functioning, and finally 6) after one bout of disfunctional tach I shut it down to shop and w/in 15 minutes went to start it and... it was a good 10-15 seconds of cranking the starter before it would run, the hard start has not since been repeated.



Any thoughts? Other than a no start is it likely to strand me... while I shop for a service provider (the 5-star that sold it is not a real option after 7 transmission services before 20k mi. -- I think the stars represent the cartoon stars used when a character takes a beating and finds themselves in pain)?



Thanks in advance for any & all assistance.





John Madden... but not THE John Madden.

 

[SnoKing]

crank sensor? Snoking

 

[Patriot Diesel]

Yep...Sounds Like a Crankshaft Output Sensor to me...

Yep... Sounds Like a Crankshaft Output Sensor to me...



had a similar problem, we replaced the sensor... fixed...

 

[jmadden]

Thanks for the insight... one little part causing so many symptoms... hope this is it.



In regards to snoke (smoke?)... it is pretty negligible but white when present w/ a little more at start up than previously.



I'll let you know the resolution.





thx, John

 

[jmadden]

The dealer called (pretty prompt since they've only had it a couple hours and they don't service too many Cummins) and... it's not the out-of-warranty $37 part (Crankshaft Position Sensor)... but supposedly the PCM (powertrain control module... sounds more expensive)... which is now on order and scheduled to arrive by Wednesday... . Truck is supposed to be ok to drive until then (per the dealer). On the positive side... the PCM is covered by an 8-year/80k mile warranty so it's failing just in time!



I'll post the result when the new PCM goes in.

 

[bbowe]

Same symptoms

Mine had symptoms #1-5 exactly (2000 ETC 60K miles). The weird thing is that they would usually happen in the same spot along my daily route. Pulled starter, replaced crank sensor, drove around, all fixed up .



Depends on how much you trust what the stealer does, but myself I'd have a new sensor hanging around . It took less than an hour to fix.

 

[zman]

jmadden - did the new PCM fix your problem?



I'm experiencing a a lopey miss that is most noticible at about 1000 RPM. You can hear it at idle and you can hear it at a high idle, but it isn't as noticible as it is at 1000 RPM.



I acts like a gasser with an intake leak. After installing a fuel pressure gauge at about 15k miles, I noticed that I had very low fuel pressure at idle, almost no pressure under load, and absolutly no pressure at WOT. I'm starting to wonder if the lack of fuel damaged the injector pump. The problem is getting worse as time goes by. No codes or MIL are being set.



I pulled the EZ off and it improved the idle somewhat, but it is still rough. The truck is going to the dealer Saturday morning. I'm guessing its the injector pump or the crank sensor. Anyone have any other ideas? TIA.



Steve

 

[Jhillmann]

There is one more possibility. On a y2k there a a cam posistion sensor as well as a crank position sensor. The cam position sensor is what fixed mine with similar symptoms.

 

[zman]

jhillman - Thanks for the reply, I'll add that to the list. What exactly were your symptoms?



Steve

 

[jmadden]

zman -- the PCM came in today, but the dealer can't install until Monday... but I'll let you know when they get it done.



On your fuel pressure... are you sure the gauge &/or sensor are/were working right? Maybe a bad gauge or sending unit... although there seem to be enough lift pump problems occurring. I can't wait to see what kind of readings I get when gauges go in the next month or so.



Good luck.







John Madden

 

[jmadden]

Well, here's the update.



PCM went in this morning... call from the dealer revealed the problem has not been resolved and the truck is not drivable. They believe the problem is electrical and now feel there may be a problem with the crankshaft position sensor, although someone suggested that it's the fuel pump... . A crank sensor was ordered (I offered them one from Cummins) and theirs will go in tomorrow. Hmmmm... perhaps I should have just replaced that before it when in for the PCM.



Could a bad PCM make the crank sensor fail? If a warranteed item makes something else fail do they fix that under warranty too? Is the fuel pump covered by the engine's 100k warranty? Would a bad PCM cause it to fail? Many thoughts and of course they have the warranty book with the truck.



Tune in again tomorrow for another exciting episode of "Diagnosing John's Truck"... I'll look forward to any thoughts.





John Madden

 

[RKohn]

Mine had the same symptoms...

it was the crank sensor. Sounds like the stealer is just yankin your crank for some extra labor $$$.

 

[jmadden]

Final Report

I feel so abused!



The final result is in. One new PCM @ no charge and one crank sensor @ $248. 30 for labor + the cost of the part... we are back to normal function.



In removing the crank sensor they snapped it off in the block because "it was seized" and had to get 2 techs working on it to get it replaced. Maybe if they just worked really slow they could charge extra too!



You all seem to know your stuff so next time I'll just listen to y'all and do it myself... even if I'm wrong it can't cost much more and I'll get more new parts.





John

 

[Mark_Kendrick]

You got shafted the crank and cam position sensors are part of the 100k engine warranty.



I hope you didn't pay for the labor or the part.



At 73k anything bolted to the motor is pretty well under warranty.

 

[RKohn]

DC says...

and Cummins agreed. We get screwed for those sensors. :{

 

[jmadden]

To quote the 2000 Dodge warranty book...



"Parts covered for 5 years or 100,000 miles

In trucks equipped with a Cummins Diesel Engine, ONLY the following engine parts and compenents are covered for 5 years or 100,000 miles, whichever comes first:



-cylinder block and all internal parts

-cylinder head plug assemblies

-core plugs

-fuel injection pump and injectors

-gaskets and seals for listed components

-intake and exhaust manifold

-oil pan

-oil pump

-timing gear drive belts and/or chains and cover

-turbocharger housing and internal parts

-valve covers

-water pump and housing"



Doesn't seem to cover the prone to failure parts... such as the crank sensor, lift pump, etc.



Mark Kendick -- if you know something about the list that gets them to cover the crank sensor I'm all ears... .

 

[Mark_Kendrick]

check the emissions warranty. It covers most everything else.



my lift pump was replaced under warranty at 36,500mi.



fwiw,

Mark

 

[americana]

i feel your pain

i had the same probs. dealer changed crank sensor and pcm at the same time and i've been trouble free (and money free, but that's another story) for 25kmi.



unfortunately for me i had to take it to the dealer hot and raise a big fuss (i'm greek so that was easy) to have the techs look at it with me over their shoulder. they didn't believe me when i dropped it off. engine had to be hot (op temp) for it to stumble. while i was looking it happened and i got all that work and parts under warranty.



mr. kendrick is correct. i think it should be covered under the emissions warranty. when the crank sensor/pcm goes bad it runs on a default fuel map which isn't as clean as the regular map (but at least the engine will run). the stumble you feel is the transition from the pcm to the default.



you should be good to go from here on out. aint this list wonderful?

 

[Bill H]

crank sensor?

Pretty much the same symptoms as jmadden. Tach, miss, P1693 and 73,400 miles. is the truck ok to drive? Is this something I can fix myself? Also have a light on in the instrument panel (outline of alt or starter)??





Thanks,

Bill H

 

[Mark_Kendrick]

Bill the cam position sensor is behinh the vp44. I think you could get to it w/an extension and removing the TPS assembly. . a PITA to sa the least.



The crank sensor is about the middle of the block on the driver's side. not hard at all to get to.



I'd check you codes to be sure about that idiot light though.



Later,

Mark