u2slow

I bought one of my cummins D250s (5spd) for $1000 because it had a shredded rear end.

My NV4500 parts truck (4wd DRW) cost me $500 after I sold off the cummins. 400,000km on the ticker, but I can afford to rebuild it at that price.

This stuff doesn't have to be expensive if you go about it the right way.

thrashingcows

That is a very good point...never thought of that connection.

Take a look through my build thread as well....I documented my 2wd to 4wd conversion on my crewcab there as well.

StorminN

Hi guys,

I got the truck back from the tranny shop today. They cleaned the screen and swapped the fluid, but I had them hold off on any other work, I'm still trying to decide what to do. The truck actually drove a bit better on the way home, it didn't try to start in 3rd gear. It has never slipped on me.

I've got a question about the TPS... if the signal from that is not right / consistent, could that make the overdrive never kick in?

while the truck was in the shop, i was talking with a friend about it, and he said on his Dodge, all overdrive problems have been related to electronics. Then I remembered that the PO had said something about "cleaning" the TPS with contact cleaner... he had drilled a hole in it for just this purpose, and plugged the hole with a screw... when he was telling me about the truck's idiosyncrasies before I bought it, he mentioned the TPS... take the screw out, squirt some contact cleaner in there... but I can't remember what he said, and the poor guy had a massive heart attack and passed away about a month after I bought the truck, so there's no asking him now...

Thanks,
-N.

j_martin

Yes, if the TPS isn't working, you will not have any overdrive. They're not being produced any more, and the price is getting to be way high for a new one. There's several workarounds from a couple of resistors to fix a shift point, to a dash mounted pot, to a couple of ways to mount a gasser TPS and get the job done.

thrashingcows

Yeah the TPS can cause all kinds of issue with the OD function. The fact that he drilled a hole to spray cleaner in there....that would be a major clue to TPS issues.

Take a look through teh sticky and do either the potentiometer, or the GM V8 TPS conversion...I think this might solve some of your drivability issues.

StorminN

Thanks guys, I'll check out the sticky. A dash-mounted pot or a different pot where the TPSis now sounds pretty easy...

never2much

As for the water leak, I had a leak at the top of the windshield between the gasket and the frame, after a new windshield and gasket were put in.

At first it was coming through the floor, as only the floor was wet, but when it took off the interior moldings I could see that water had been running down to the floor via the moldings.

I used a tube of urethane (what my windshield was installed with) between the gasket and the frame to fix it.

My neighbors joke that I spend enough time working on my truck that it should be brand new by now, but it is nice to have a vehicle that I can actually work on without needing a garage full of tools.

Cheers,
N2M

StorminN

Well guys, I checked the TPS according to the instructions in this sticky:

Dodge Diesel - Diesel Truck Resource Forums - FAQ: 12 Vavle - 1st Gen - Engine and Drivetrain

The "at rest" voltage of mine was 0.233 VDC, and the WOT voltage was 2.390 VDC... it seemed like it had a smooth transition, no jumps, etc. I measured with a Fluke 87 meter, it has a little bar graph display to visualize the changes.

I see that my voltages are lower than the range mentioned in the sticky, but according to the sticky, a lower voltage will cause it to shift to OD sooner? I'm confused.

Thanks,
-N.

j_martin

I'm willing to bet that if you pulled your CEL codes, you'd get a code 24. Grab a 10-mm wrench, slip it onto the flats below the TPS, and adjust the tps voltage.

Is your alternator driven by the PCM, or has the PO rigged an external regulator?
To pull the codes, turn your ignition switch on, off, on, off, on.....then count the flashes of the CEL.

j_martin

Actually, the adjustment is critical to a couple tenth of a volt on the low end. Yer way below that. Grab a 10-mm wrench, slip it onto the flats below the TPS, and adjust the TPS voltage.

Is your alternator driven by the PCM, or has the PO rigged an external regulator?

Pull the engine fault codes. Let's see what the PCM is dealing with. To pull the codes, turn the ignition switch on, off, on, off, on.......then count the flashes in groups of 2.

StorminN

Ok, I pulled the CEL codes, and now I'm more confused than ever.

The first time I pulled the codes, I thought the CEL blinked 2 4 5 6 5 5.
Of course, I was looking for the 24, so I might have glanced down at my notebook at the wrong moment. It also seemed like they were blinking with different pauses in between, because my heater packs were on. (Are we supposed to do this after the truck is warmed up? Shut it down and then pull the codes?)

Anyway, I tried pulling them a second time, to confirm the first... and I got 3 4 5 6 5 5.

I tried it a third time, because I had gotten two different results... and I got 3 4 5 6 5 5. I tried it a couple of more times and seemed to get the same thing.

So my question is, what he heck is a code 56?

Then I tried to measure the voltage at the TPS again, and my voltages were really low... I didn't think I was getting a good connection, until I tried to start the truck and realized it wouldn't start... the battery was low from six or seven cycles of the heater packs coming on (that hasn't happened before... a new problem with this truck – imagine that!)... so I've got a charger on there now...

Thanks,
-Norm.

patdaly

Charge it and check it again, are you positive it wasn't a 46?

I know of no code 56.

StorminN

I'm pretty sure it was 56, but it's on the charger now overnight, I will check the codes again in the AM.

I didn't understand what was said about the alternator being controlled by the PCM vs. external regulator... the alternator has a small black box on the back... is that considered external, or are they more of the traditional firewall-mounted style? Sorry for the poor pic, it was the best I could do with a flashlight, in the rain, with a toddler tugging at me...



Thanks,
-N.

KRB

If it has an external regulator it will look just like the old gasser ones. Probably on the firewall in the center by the wiper motor.

j_martin

Stock, the alternator field is driven by the PCM. Sometimes when the y have trouble with the PCMl folks will install an external regulator and bypass the PCM.

Here's the connection. If the alternator is wired stock and working, the CPS is working.