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Are These Symptoms of a Bad PMD?

D

DennisG01

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Location
Allentown, PA
Hi everyone. I feel a little lost. There is so much info on this site, it gets a little confusing to weed through, sometimes. I know enough about the PMD issues to have a basic understanding of the problems associated with it, but not enough to weed through all the info efficiently. I know this issue comes up a lot, but if you could bare with me to discuss this topic again, I'd appreciate it. :)

The engine quit on me yesterday. Background info: currently about 120,000 miles, IP (I assume the PMD, as well) was replaced under warranty 5 years ago at 89,000 miles. PMD is currently still on the pump.

Around December, I started having various issues, culminating in the quitting today. Here's the jist of the problems since early Decmember:

-- Occasional "Hiccuping" when warming truck up in the morning... but only when using the "high idle" settings. It seems to be better when the block heater has been used, but not perfect. After the coolant gauge needle starts to climb, it will run fine on high idle.

-- About 10 instances of stalling 15 - 30 seconds after the engine started fine. After, it would start right back up and be fine.

-- 5 instances of initial non-start. Engine would crank, try to fire once for a split second, but then just crank. This reminds of the time my ignition module (passlock?) was flaking out a few years ago. However, 4 times when this happened I would move the gear selector through the gears and back to park - it started fine, then. Once, it wouldn't start until about 15 minutes later (which I think is about the safety time built into the Passlock system).

Now, on to yesterday. The engine started fine after work. I drove about 7 or 8 minutes and started to merge onto a highway. I gave it about 3/4 throttle and the engine fell flat like the someone turned the fuel off. I let off the throttle and the engine stayed running. Tried again - same thing. I kept the throttle under 1/2 and it was fine. Started playing around and found if I pushed the throttle down past 1/2 way and KEPT it down, it would stall. Over the course of about 6 or 7 minutes and about 4 miles, it progressively got worse. Eventually I was on the side of the road, able to start the engine after about 30 seconds of waiting, but not able to start going as it would stall. After another minute or so, it wouldn't even start.

I called AAA and had it towed to a local, reputable shop that knows the 6.5's. Ultimately, they are probably going to do the work (time is not friend right now). But I'm very interested in learning more about this engine and it's idiosyncrasies.

Later last night, I stopped by the shop to put my key in their drop box. The engine started (a little reluctantly), but stalled after 15 seconds. It wouldn't start again.

By the way, after reading Buddy's response in another thread and again in one that Acesneight1 pointed me to, this may be of interest, as well: In October or November, I had an issue where I was losing battery juice big time. Turned out to be a loose alternator wire. BUT, in getting the truck running (after it wouldn't start because of the low juice), I did use a battery charger that had a 50amp "start" option. I think I used that feature a few times (maybe 20 seconds at a time).

Sorry for the long post! If you made it this far, thank you for obliging me!

EDIT: On the side of the road, I started to pull the fuel filter to check that, but I didn't have a spare with me so I stopped. I had pulled the filter enough to see what appeared to be clean diesel come spilling out. If that means anything, anyways. I only had a rag or two, as well.
 
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That sounds like it could be more then 1 issue. The pedal response fits perfect with no LP or restricted fuel filter / leak. Lack of LP could also be the culprit with the other starting issues. Easy to do the LP check...
 
Thanks, Crank. Yeah, I should've included more info.

I didn't test it, but the LP does run (it's a little grumbly when it's really cold, but it clears up fine and purrs). I bought it from Heath about 5 years ago. I always use a double dose of FPPF Total Power when I fill up.

Oh, just to clarify, yesterday when it was shutting down (or only shutting down to idle), it was happening super fast - it was just as fast as if I were lifting my foot off the pedal (actually a bit faster).
 
A known good PMD is the only way to check that.

I also think you may have more issues, Clean all the grounds, fuse spades(ecm and fsos)especially. Check fuel pressure while running. Change fuel filter and blow back through the lines into fuel tank.

This would be a good start.

The shutting down to an idle could be the APP.
 
What he said^.

The non responsive trottle cold start is prob IP related.I got that problem for a couple yrs allready.
It always clears up after a restart or longer warm up.
 
Good points on starting with a known PMD. Thank you.

APP: That makes a lot of sense, considering how quickly the throttle shut off - it felt like it was turning off like someone was throwing a switch. Does a failing APP always set an idiot light? I don't have one... at least not a visible one.
 
I have not had any APP problems Dennis but I think it would throw the "Service Throttle Soon" light.
 
I think NVW covered it, I have experienced PMD issues in the past. Stall is instant and progressively gets worse until no starts happen. I had one replacement that lasted two years and replaced under warrantee that would act like that only when cold, from one to multiple stalls but didn't happen when warm. The no problem when warm was consistent but given the stalling I didn't take any out of town trips to be on the safe side. Try a new one and get it out of the engine compartment, it never hurts to have a spare PMD around even if it doesn't fix it this time. And the one on the pump now is living on borrowed time anyways. Good luck
 
I have, I assume, the black box Stanadyne (mounted on the pump) since it was replaced about 5 years ago. I think the grey one is a relatively recent one?
 
UPDATE UPDATE UPDATE

Well, I got the initial prognosis from the shop. R&R the IP. Pulse Width is stuck at either 279.38ms or 0.00ms - nothing in between. They think the problem is the "solenoid on the back of the pump". Honestly, they were very informative, but I didn't write enough down so I might be mixing words there. They also said the crank position sensor might be bad, but they don't want to make that call until they get it running.

EDIT: Oh, there were no codes - none at all.
 
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That's the only thing that ticks me off a bit (and really, I must say, that these guys are really a good bunch of people). They don't have any good ones laying around. He said they let people borrow the ones they used to have and never got them back. I could buy one to use as a test dummy (and then keep it as a spare). He thought it wasn't necessary though, based on his findings. He's going to talk with the guy that used to rebuild pumps and we'll discuss this aspect again, tomorrow.
 
If it were me I would buy one as a spare to test with. The spare is good to have anyhow and is a lot cheaper than an IP.
 
I totally agree with Leo, Dennis ... if you need a new IP, chances are good you need a new PMD, also.

However, I'm still concerned about your fuel flow. Did you actually get fuel out of the line with the LP running? It's not uncommon for them to make lots of noise, and SOUND like they work, but be pumping nothing.

If your PMD was causing the stalling, the truck wouldn't have re-started itself when you let off the fuel unless you have a standard... but if you had 'bogging' (lack of fuel), the truck would appear to recover when you let off the pedal. Snotty sock can also cause those symptoms... and they would appear quite suddenly and get rapidly worse, if you got some bad fuel...

I would make sure I had full fuel flow making it to the IP with the key on, before I started changing either PMD or IP.

Then PMD (Like Leo said, everybody needs a spare), THEN (and only then) change the IP.

My thoughts, worth what you paid for them.
 
I've got a brand new never used PMD that the connector body was damaged in shipping. The little broken pieces of plastic are still here and could be crazy glued back on. Would make a great emergency spare PMD. I can't sell it for new, so would take $145 + $5 shipping for it. Has a brand new #9 resistor in it also. At this price I can't give a warranty on it.
 
AK you got it if Dennis passes on it. I'll give him first crack at it as a pay back. He turned me onto this forum in jan 09 and have been here ever since.
 
That sounds like a great way to go, Leroy - thank you! Have you been able to verify if the PMD physically works? As long as you tell me it works now, I've got no problems if it happens to crap out a month from now.
 
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