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I'm in a little over my head here, and looking for some advice, and possibly a wiring diagram if possible.

Mfgr date- 10/01, Ram 3500, 4x4, 5.9, 47RE. 667,000 miles

Was a super cab long bed dual rear, but was fitted with a small sleeper at some point.

Had some transmission problems previously, changed the servo/transducer and adjusted the band, solved the shifting problem for a while. It's acting funny again now, it doesn't always like to upshift like it should.

The throttle also acts funny, just off idle is fine, then it's not hardly responsive, until just before full throttle. ( I believe my father has adjusted the throttle switch a couple times trying to solve this)

Cluster did the No Bus thing once, a year or two ago, never did it again.

Temp related- at hot idle, it surges/ misses occasionally.

Will only turn on the CEL below 50*F.

With a cheapo actron scanner I can pull P1698, and P1693.

Blink codes I get P1694, P1693, and P1687.

Been researching those, but having trouble making it all fit together in my head. Have also been sniffing out and cleaning grounds.

Now, the real noggin scratcher, and the reason I'm here, and looking for a PCM wiring diagram.

Black PCM connector, closest to the engine, ( C1?) , On pin 23, Orange w/light blue tracer, someone has spliced in a resistor, and what appears to be a capacitor on a ground jumper.

Simplified- from the plug at the PCM, wire is branched through a resistor to the harness, and a capacitor to batt ground. ( See photo)

With a volt meter, at the splice, KOEO, PCM side reads .22 volts, harness side of resistor reads .30 volts. No continuity between the capacitor? and the ground jumper wire

Any ideas what this wire does? Any ideas what this modification was for?

Sorry for being long winded, but I tried to include everything.


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First got to mess with you a bit. You do not have a "super cab" that is Ford terminology, We have Quad Cabs with doors, Club cab without.
Now, tha wire modification is likely becaseu somebody either tried to fix a lockup issue or did "MPG Fooler". Either way for not remove ALL wiring Mods and replace them to factory.
Now other issues to check/fix.
What APPS is on it Factory, Timbo(only one with a 3" pigtail), or other?
Only thing adjustable is idle voltage on on some apps, no on Timbo.
When checking the apps you probe pin/wire3 of the plug and you want about .5 volts at idle and it should graduate smoothly to about 3.8-4 volts at WOT.
Alternator needs to be checked for high AC voltage. It should be under .03 to .05v when checked at the big hot wire with a good voltmeter with a 2v scale, not 20 or 200v scale.
Check all terminals and cables for corrosion and resistance.
So do all that, and remember start with removing mods. except extra grounds, they do not hurt.
Replace the trani speed sensor too. The others may be dirty and bad already too or if they were cheap ones no good from the start.
 

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Discussion Starter #3
Thank you sir! I'll start working through that list and see where we come out.

3rd generation Ford guy here, so there is a possibility it may get refered to as a super cab again, bear with me, or poke fun, I don't mind, but old habits don't break so easy haha.

I failed to mention, speed sensor was changed during transmission repair, since we were there we did it.

I see you put a lot of thought into your response, I thank you for that.

I'm still curious to know what that wire goes too though.......

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Ok, did a little testing on the " quad cab", ( evidence of rear door latches so I'll go with it).

APPS- not a TIMBO, looks stock, not 100% sure. Could use some education there, going to search a little, pin #3 was .30 volts, smooth transition to 3.42 volts at WOT.

Alternator- reading 13.87 volts DC after idling a few minutes, but was reading
.099-.100 volts AC. Good meter, 2 volt scale. So some cause for concern there.

I'm pretty confident in the battery connections, and our ground cleaning marathon turned out well.

Funky wiring mod is done away with.

Trans speed sensor was NOT changed as I thought, nor was the one on the rear diff. So I still have a little work to do, will take some time.

New symptom- I noticed this evening, the tach is not always steady. It wiggles slightly, hadn't noticed as I don't drive the truck often.

Thanks again.

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Start by rotating the apps by loosening the screws on back and adjust it to about .5 volts, not more than .529v and at least .48v. That may be part of the issues.
Your AC is way too high coming from the alt. at .1v it is fowling all your other electronics and may have or will damage the ECM and apps or more.
You need a quality alt with AC under ,05v, preferably under .03v. Nippon Denso and Napa are not good choices and are often high out of the box. If you can find a Bosch they are usually better. Aftermarket like Nations are also good. Rebuilding yours can be OK but you must have a quality rectifier put in it. Whatever you get always pretest it on a machine or check the ac upon instillation for under .03v. I think the wire is from the ECM or apps with idle voltage to the pcm, but check the colors on the schematic. Either way what is not stock should be removed and replaced to stock.
As far as the speed sensor , at least take it out and make sure there is not crap adhering to its magnet. If it is dirty at all, that dirt could have also fouled the the other sensor an solenoids, but I think they were replaced with the valve body and the electronics were cheap junk like mine were..
You can drop the valve body and replace all the sensors by your self in a couple of hours or so.
Can't prove it yet but I suspect that the idle and throttle issues are due to damage in the ECM from the AC. But start with adjusting the idle voltage. I suspect that the ECM damage is causing the throttle issues.
You can also monitor the apps operation voltage at all throttle positions by using probe pin and running jumper wires to the cam and a voltmeter and monitor it while running down the road.
 

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Thanks for the input. That AC voltage damage is scarier than the rumors I had heard previously. The alternator is actually a relatively new one, auto zone I believe, so there is more confirmation about being junk out of the box. However we did have these problems before the alternator swap. That's not saying the previous one didn't have the same problem though, never knew to test it.

I'm trying to remember exactly what was done in the transmission. I know the transducer was changed, but not the valve body. Band was also adjusted. I didn't do the work but was in the next bay working on a Ford, but I do remember how remarkably clean it was inside. I believe it was rebuilt shortly before we got the truck.

Any thoughts on shielding the main alternator wire? I've read claims that it solved the problem, or did it just delay disaster?

I'll see what I can get done and post it up!

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Quick question, haven't really seen this point discussed.

When testing the alternator for AC current, should it be checked right after starting, or with the batteries charged to capacity?

At idle or high idle?

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Does not matter when testing but it does increase with increased load, whether it is after starting , using fan or even rolling up a window.
NO. Shields, wiring mods, noise filters are all "fixes" that may help for a bit , but almost never permanently. They only help some with Lockup Issues, not damage to ECM and other parts. Nothing actually removes the AC. I most likely had issues on the prior alternator. Many trucks did. If you search it on Google you will find that many brands of car and trucks have had similar AC issues. It comes from poor quality, damaged or worn out rectifiers in many alternator manufacturers.
I repeat NO "fixes" are good and reliable. Most stemmed from attempts to fix the lockup issues before the real culprit, AC from alternators, was figured out by Mopar1973man, a user here with his own similar website now.

The AC level acceptable on most test machines is .06v ac, but that is a bit high. If you bought it and it has .1v, you could try taking it back for refund as defective. You will have to explain AC and its effects to them an show them on their own machine, maybe even take your voltmeter and show them while running on their machine. Good luck explaining anything to them.
 

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Thank you. I'll give that a shot. Thankfully I know some decent parts guys, if they don't know about a problem, they are usually willing to learn.

I mentioned it to some of my buddies on another forum, as I had never heard of it, and apparently a lot of heavy equipment is very sensitive to this as well. I'm a dinosaur myself, so this electric stuff is all pretty new.

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Ok, update. Alternator sorted out, now within acceptable limits. .037 volt AC.

Goofy noise filter thing removed from PCM harness.

Still the same symptoms, BUT, I haven't adjusted the APPS yet.

Been a mess around here this week, probably won't get to it for a spell.
@bigfish95971 thanks for the help, I hope you are well, hope you don't blow away in that wind!

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PGE mgt is a bunch of POS. I have trees hanging out over power lines in my own yard that can and do break off all the time. They trimmed them to 10 ft away but they still hang over the top of the lines. But I live in an area that is almost all cultivated crops/land so no wildfire hazard or cutoffs even in 40 mph+ winds.
037v ac is still a bit high, over .03v, but should be OK for not, but watch in the future for an increase.
Remember either or both prior alternators could very well have already damaged the ECM or more.
Check apps output voltage again before adjusting, see if it changed with removal of mods.
 

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On it, APPS voltage did not change, I'll attempt an adjustment when things let up.

I'm beginning to wonder about the transducer we installed. It was an updated one, supposed to be the "fix". I'm thinking it was a GM adapted to work. But again, I can test that later after other bases are covered.

As for power companies, well I won't start on that! But I will say, I'm no stranger to outages. Any wind over 30 mph, bad rains, snow, or when the crows start mating, at least we have some good linemen, they do good work with what they have. Electricity is more of a convenience than a necessity here.

I was in your neck of the woods after the fire, during the rain and flooding. Up at Oroville.

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What exactly were your original trani issues, both before and after the "upgraded" transducer? All of them, when how and where?
 

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As for the when, long story/foggy memory makes that difficult. The truck was purchased from a wrecking yard, had been purchased by the towing company as part of the bill. Transmission looked fresh, T case was new, but had never been filled with oil. A rebuilt transfer case and we were running. Resealed the tappet cover, fixed lights and such. Has always done the choppy hot idle thing.

Trans things- over a period of a couple years, it gradually started shifting at higher RPMs, then would only shift at higher RPM if you took your foot off the throttle, then would only shift at higher RPMs if you let off the throttle when cool. No load, just commuter duty.

Looked over harnesses, cleaned grounds, added grounds. Then started serious research, found the manual shift test for the 47RE, determined problem to be in the transmission. Researched possible causes, found the transducer to be a common cause of our symptoms. Dropped pan, found no evidence of a mechanical failure. Replaced the transducer, with one from my local auto trans parts supplier, adjusted the band, and it was fixed. Drove like a new truck. It even downshifted fine without coming to a complete stop, which it had never done while we owned it.

That was slightly more than a year ago I figure.

At that point the transmission worked flawlessly, but the goofy idle has always been there, and the funny throttle has always been there, intermittently, under 50* F ambient temperature.

Does the thread title make sense now?

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Does your wait to start light come on for an instant when you first turn the key on?
One of my previous trucks had a bad ecm, which was damaged by a bad alternator. No WTS light, and I had only 3.8v out of my 5v reference signal for the sensors, BUT no CEL or codes. It also had a weird chopping idle, and poor throttle response.

I gave up on 24v trucks and just got a 12v...
 

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That too is possible if power supply from is ecm to systems is bad.(related to voltage issues in sensors and apps).
Choppy idle could be the .3 volts idle voltage or maybe dirty worn injectors. Mine got to missing at about 500k from carbon build up and one worn injector.
 

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Sorry Killjoy I completely missed your post. I'll check out voltage to some of the sensors when time permits. The WTS light and related system has always worked fine . Thanks. Personally I have a 12 valve, so I see the sentiment. However my daily is a 7.3, my father drives the 12 valve more than I do haha! That little truck just has a sweet personality.

Bigfish, that's interesting, once we get the electrical nightmare figured out maybe I can talk dad into getting them tested, or a set of rebuilds or something. How many miles did you run your truck?

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