History of the truck.

Truck was purchased in 2002 with 43K miles.

Engine and transmission were stock except for a K&N drop in air filter.

Early 2003 installed a PowerMax programmer from TST which displays boost, transmission temp, and EGT.

Late 2003 installed a PacBrake, TripleLoc (three clutch disk) torque converter, and HP valve body from TST.

2007 spring had check engine light and intermittent hard starting local diesel shop diagnosed it as a fault between primary and secondary computer and cleared the code (don’t know what the code was). They checked my fuel pressure which was around 10 at idle and much less under static 2400 rpm throttle. He advised getting a new fuel lift pump.

Aug 2007 installed a fuel pressure gauge, engine oil temp gauge, FASS 95, and rebuilt VP44. Fuel pressure 17 at idle 14.5 at WOT.

July 2008 installed MagHyTech Double Deep transmission pan and 14CM turbo exhaust housing on the HX35.

December 2008 began experiencing hard starting when hot after sitting shut off for more than 5 minutes. Truck had check engine light P0336 CKP sensor. Took the truck to Lithia Dodge in Anchorage who kept it for a week and said they couldn’t find anything wrong and the CKP was fine. I told them to change it anyway. They wouldn’t do it and told me that I had to remove the Fass 95 and any other aftermarket items installed on the truck (Pac brake, converter, valve body, programmer, etc.) as they didn’t understand how they worked or could affect the diagnostic equipment. I told them where to put their dealership and where I would not purchase my next vehicle. Took the truck home and changed the CKP with one from Cummins. Hard starting problem solved.

I Installed 18” of clear fuel line at a high point before the vp44 to be able to check visually for air in the supply fuel line. (I have never seen any air)

July 2009 began experiencing hard starting when hot and sitting more than 5 minutes again along with stalling when shifted into drive from park or neutral. I Cleaned the Map and IAT sensors. No joy.

I installed a set of Edge 80 hp injectors, new connector tubes and O rings, and a CoPilot transmission controller for the PacBrake. I also soldered all connections for the PowerMax programmer and CoPilot. Starting and shifting problems went away.

Aug 2009 installed BHAF and 4” MBRP exhaust.

February 2010 Shifting and hard start problems returned. Truck starts fine after sitting overnight and completely cooling off, but stalls when shifted into drive. Engine does not idle smoothly seems to hunt for a idle rpm to settle into. If left idling for a longer period (30 min) the hunting grows worse until the tachometer is swinging 100 or so up and down. Revving the engine settles the hunting down a bit but the hunting continues.

When the engine stalls after shifting into gear it usually re-starts on the first try.

The stalling is worse when the truck is cold than when hot.

The restart problem is worse when the truck is hot than when it is cold.

Bringing the engine rpm up to about 900 will usually prevent the stalling when shifting. Sometimes after stalling several times and then getting on the road just idling along at 5mph or so the engine will suddenly go rumph, rumph, rumph, rumph, rumph quickly like it’s going to stall then catches itself and revs a little each time to prevent a stall.

I have checked the fuel return line, rear banjo bolt, and all fittings and clamps for fuel leaks and found none. I have replaced the VP44 fuel return check valve. I have re-calibrated the APPS memory.

March 2010 I noticed erratic boost pressure readings sometimes the boost pressure would read zero under partial throttle where it should have been reading12 or 14 lbs boost. Replaced MAP sensor and the boost reading problem went away.

April 1 2010 took the truck to Cummins Northwest to purchase a new IAT sensor suspecting the stalling problem could be due to a faulty IAT and the cold outside air.

While there a mechanic looked at the truck and noticed the sticker saying the last ECM program re-flash was in 1999. He thought a re-flash with the latest program might help the problem and I agreed. He re-flashed the ECM and kept his scan tool hooked up shut off the truck and restarted several times and noticed the IAT temp reading sometimes went to and stayed at 160. When it went to 160 the truck would not re-start until enough cold air came through to cool the IAT to below a 130 reading.

I went home, changed out the IAT with the new one from Cummins, and took it for a test drive.

Still have the stalling and hard starts but not as bad and the idle rpm hunting seems to have gone away.

Yes, I have checked the grounds on the ECM and PCM.

I have also cleaned all battery connections and used dielectric grease everywhere.

So I'm Kind of out of ideas here.

Today I'm going to get it up to operating temp then shoot the exhaust temps of each port on the manifold looking for enough variation to indicate a plugged injector or one that may have a lower pop off pressure.

If I can't find anything there I may pull the connector tubes part way out and rotate them so the O rings seat in different positions and see if that does any good.

I'm open to any and all suggestions to solve these problems.

Thanks

Jim

Your fuel pressure is supposed to fluctuate when starting. The power is pulsed to the lift pump.

---------- Post added at 12:39 AM ---------- Previous post was at 12:22 AM ----------

You could put a resistor in line on the IAT so the values did not change for the ecm and see what happens. It would make the car hard to start when it was cold outside but otherwise shouldn't cause any problems.

It only did the fluctuations on one start not on any subsequent starts (about a dozen before I got home). When it did it on the one start, it continued to fluctuate between 5 and 12 psi for as long as the engine was running. like the check valve was slamming shut then popping open again over and over until I shut it off.

UPDATE

I put a smarty program on the truck (#3) and took it out to see how it ran (normal driving - no wot or anything like it).

When I started it I noticed that when I turned on the key the fuel pump didn't run for 2 seconds like it always has before.

Once the starter engaged and the truck started the fuel pump came on and The pressure went to 17 psi.

I backed out of the garage put the truck in drive and it died (like always) put it into neutral and started it.

The fuel pressure gauge started going crazy (first time it has ever done this) the needle jumped from 5 to 12 back and forth never going under 5 and never going over 12 after about 10 seconds of this without stabilizing of going to the normal 17, I shut the truck off.

I restarted it and the fuel pressure went to 17 and stayed.

I don't know what that was all about, The only thing I can figure is maybe the return line drain might have stuck open????

It might of been the pressure regulator of the FASS pump doing that too. I've had that happen to me on my AirDog come to find out the plastic check ball has forced its way into the coil of the spring causing it to be lower in pressure then getting a piece of debris hung up between the check ball seat and the ball itself. Lord knows how the the debris got there but I know the squeezing into the coil of the spring I seen that twice now.

The hard starting when warm has gone away completely It starts every time now.

Then its not a torn diaphram issue... Unless your stil lgot the relay mod...

The idle hunting has also gone away, don't know if it cleared up from the injector cleaner or the new ECM program from the smarty. It idles at 745 rpm according to the scangauge.

The idle speed is low compared to mine at 880 RPMs and factory setting or programming is typically 850 RPM.

The last thing is if I let it idle for a minute or longer when warm, it does not die when put into gear.

You might consider changing the ATF fluid again.

I'm suspecting more and more that the VP44 has a torn diaphragm that is causing the problems over an electrical issue.

It's puzzling because the VP44 has never had low fuel pressure because I put in the FP gauge, FASS 95, and rebuilt VP44 all at the same time.

I guess it's possible that the VP44 re-builder didn't replace the electronics and diaphragm module when it was rebuilt.

As I said before If it's torn I'll live with it until the IP dies.

I still need to clean and check the ECM connection.

Hmmm... Comments in blue...

Hmmm... Comments in blue...

This smarty ECM flash don't let the LP run until the engine starts or is bumped and now the engine starts immediately (no initial fuel pressure, no more hard starts). That's what made me lean toward the torn diaphragm theory. So your saying that isn't an indication of a torn diaphragm?

I'm on the second tank of fuel with injector cleaner in it along with the 2 cycle oil.The stalling when shifting into drive has gone away, it no longer stalls warm or cold. The change was gradual after I put in the injector cleaner.The hard starting has also gone away. It stopped being hard to start when I put the smarty #3 program on the ECM and the fuel lift pump don't come on for the 2 second run when I turn the key on. It now starts immediately when the engine turns over hot or cold.Thanks everyone for the input.:thumbup2:Jim

This smarty ECM flash don't let the LP run until the engine starts or is bumped and now the engine starts immediately (no initial fuel pressure, no more hard starts). That's what made me lean toward the torn diaphragm theory. So your saying that isn't an indication of a torn diaphragm?

Even in the dodge FSM it notes that some ECM flashes do not bother with the inital burst of fuel pressure or the pump. But what is import in the starting pressure and the run pressure...

http-~~-//www.youtube.com/watch?v=NCJjMzRImpA

I'm on the second tank of fuel with injector cleaner in it along with the 2 cycle oil. The stalling when shifting into drive has gone away, it no longer stalls warm or cold. The change was gradual after I put in the injector cleaner. The hard starting has also gone away. It stopped being hard to start when I put the smarty #3 program on the ECM and the fuel lift pump don't come on for the 2 second run when I turn the key on. It now starts immediately when the engine turns over hot or cold. Thanks everyone for the input. Jim

Now... Wait till you run that tank out and load back up as a normal tank of fuel. I did the same thing trying to resolve a injector miss issues and guess what it all returned on the next fresh tank of fuel... So don't get you hopes up that injector cleaner resolve the problem in might come right back after the cleaner is gone... Reason being this occurs is because the injection cleaner is produce with either naptha or mineral spirits with have a VERY LOW flash point so now even if you have a bad spray pattern, weak pump, etc that littl extra boost in the flash point reducing will cause it to ignite easily (centane booster effect). So hence the problem goes away. But after you return back to normal fuel problem returns... So be aware of this...

Glad to hear youre makin some headway on this. Bein up in Alaska, you should look into the High Idle?

Glad to hear youre makin some headway on this. Bein up in Alaska, you should look into the High Idle?

All programs in the smarty have the high idle so I now have it turned on.

I loaded the smarty program #7 (catcher + added Timing) It's quite aggressive on the throttle and when I up the PowerMax3 it runs very well.

Hard starting when warm has gone away and it no longer dies when going into drive.

I have been reading this for awhile now with curious interest and noticed you cleaned the apps sensor if your problem occurs again that is probably where the problem lies my truck doesnt have neerly as many modsbut is the same in theory only being a 2500 instead of 3500 but had almost identical issues minus the fact that when you started mine it would throttle up and down until I put it in gear and it would stall finally after cleining all the sensor one at a time very tedious as you probaly already know and the apps made adifference enough to take it on the driveway out to the road and when I stepped on the gas it started missing and chugging scared like a little chicken I took it back and started over after talking to the dealer wher the truck was purchased it was reflashed and had the ground wire installed, well salt and dumb dumb mechanics (no offense to those on this site in that occupation there are plenty of good ones to) it wasnt doing much of anything but causing problems rewired that and where good for a few months I finally gave up about a year and a half ago and spent the 500 and replaced it the truck has done flawless since minus me having to redo the ground one more time due to a whoops in removing the battery. I thought I would pass this bit of insight along and I hope she keeps running strong for ya.

All programs in the smarty have the high idle so I now have it turned on.

I loaded the smarty program #7 (catcher + added Timing) It's quite aggressive on the throttle and when I up the PowerMax3 it runs very well.

Hard starting when warm has gone away and it no longer dies when going into drive.

Does the smarty high idle kick in if the trucks idling for a long time? Or is it just upon start up? I rarley see below 40*.

Does the smarty high idle kick in if the trucks idling for a long time?

No, it's temp dependent, you need mopar1973man's idle switch to manually trigger the high idle if that's what you want.

Or is it just upon start up?

It's on startup until the block temp comes up, then kicks off.

I rarley see below 40*.

If you rarely see below 40 degrees then it will not kick on to high or 3 cyl idle.

Answers in red above.

Does the smarty high idle kick in if the trucks idling for a long time? Or is it just upon start up? I rarley see below 40*.

The IAT temp must drop below 32*F to start high idle and drop below 15*F to start 3 cylinder high idle... Then the high idle is cancelled by engine temp reaching 175*F, brake pedal, transmission in gear (auto), movement, etc... Here is a quick video if it...

http-~~-//www.youtube.com/watch?v=il7iJCKfmaE

Even in the dodge FSM it notes that some ECM flashes do not bother with the inital burst of fuel pressure or the pump. But what is import in the starting pressure and the run pressure... Now... Wait till you run that tank out and load back up as a normal tank of fuel. I did the same thing trying to resolve a injector miss issues and guess what it all returned on the next fresh tank of fuel... So don't get you hopes up that injector cleaner resolve the problem in might come right back after the cleaner is gone... Reason being this occurs is because the injection cleaner is produce with either naptha or mineral spirits with have a VERY LOW flash point so now even if you have a bad spray pattern, weak pump, etc that littl extra boost in the flash point reducing will cause it to ignite easily (centane booster effect). So hence the problem goes away. But after you return back to normal fuel problem returns... So be aware of this...

OK. Mike you were correct, after I started using fuel without cleaner the problem with the truck dieing when shifted into drive returned. The hunting, surging, and hard starting have not returned. I don't know if this symptom is related or not. When the truck dies, I put it into neutral and restart it, as soon as it catches I shift it into drive before the rpm has stabilized and it will usually stay running. However, this is when the fuel pressure fluctuation (bouncing between 5 and 10/10 lbs on the gauge) starts to happen. I've found that if I shift it back into neutral the fluctuation of the fuel pressure stops and the pressure stabilizes at 17.5 lbs. Then when i shift it back into drive it dies again. However, if I give it some throttle and the engine rpm comes up to 1000 or so the pressure goes to 17.5 and the fluctuation stops. The only sensor I haven't replaced is the cam sensor, anyone think that could be the issue?. Anyone know what the function of the cam sensor on a 98.5 is? The CKP sensor was replaced not that long ago 12/08. Thanks Jim

When i had problems my overflow valve on the vp went bad.The pump was only 1 year old.It is only a few bucks.

Replaced the overflow valve in Feb. No change.

My truck is stalling when shifting into D or R but only when a/c is on any thoughts

Something is wrong with your ac compressor clutch.

My stalling problem is solved, turned out to be winter fuel.I got fresh summer blend fuel into it and the stalling is gone.I've driven from Anchorage to Montana and there is no longer a hint of stalling when shifted into drive.ThanksJim