After the tranny shop rebuilt my 48RE tranny and replaced the TC (after less than 1,000 miles) there were a few problems with the truck. One was that the tachometer didn't work - that turned to be a sensor that somehow been obliterated. But the biggest problem is a significant loss of power.

The batteries had been disconnected for about a week and when they tried to start it the first time it would not start, but after a quick charge it did.

I re-programmed to Smarty Jr #2 but that didn't help.

I re-programmed it to Stock and it drives the same as it did with #2.

In fact it seems to be slower than stock, there's accelleration until you get about half way into the pedal, and there is no more. It used to a rocket ship on which putting the pedal to the floor was a scary experience requiring your complete attention, now it's no big deal.

So, what could happen that would negate the Smarty programming. Do I need go out and get a fuel pressure gauge?

Peter

Well Wait a minute here, Where is this sensor at? If its on the side of the crank shaft and its black and it has one bolt holding it in Thats the CPS. Maybe thats why there is no tach and no power, You would probably have a CEL if you had a light in the dash.

How would the truck run with no CPS? Would it run at all? I'll take a look. I'm pretty sure what I replaced was just for the tach, but if it was destroyed by something, there's a good chance the CPS was damaged too.

Peter

Check the CPS, it is still there and does not appear to be damaged. Anyone know what code it would throw? I checked the codes and there is nothing new, just the 3 transmission codes that it throws because of the ATS tranny controller - anyone know how to get rid of those?

Peter

OK, should I post this somewhere else? I need some help here. Is fuel the only thing that can cause a power reduction, or is there anything electronic I can check - other than the codes which I have already checked.

Peter

Fuel pressures would be the first thing to look at, a quadzilla rail pressure gauge with the fuel pressure option (for the lift pump) would be a good choice. What are you using for a fuel pump? Can you hear it running? Try changing the filter?

Thanks, I'll get the quadzilla.

I can here the FASS running - should I also be able to hear the pump on the block running? I will also change the filter, havn't done that yet, it looks impossible to get at on my truck, plus I need to acquire the 'tool' for it - we'll see.

Peter

OK, I got the Quadzilla installed today. It max's out at about 1800+ psi at about 40% throttle - lost power to the ScanGauge so I can't see the exact TPS position. Is there a table or a curve somewhere that shows what PSI to expect for various rpm and/or TPS positions?

Peter

OK, I should have said 18,000 psi, the Quadzilla reads in 10's. And I can get low 19,000. How are those numbers? I searched for a description of correct psi readings for the fuel rail but couldn't find anything.

Peter

Sounds ok, idle should be between 5k and 7k, cruising down the road 10k to 14k, wot 24k to 26k.

Lots of things affect the rail pressure. You need good lift pump pressure for one. If your injectors are leaking, I've read it will limit max rail pressure. Also, if you run any performance boxes or large injectors, you essentially can drain the rail of pressure when called upon. So if you get on it hard, the rail pressure will spike up and then drain down as rpms come up. The cp3 can't maintain the pressure due to larger injectors or longer duration from a box.

Any codes?

Thanks for the info. that's helpful.

No, codes, stock programming, stock injectors. I idle/cruise at 6,000, as I run up to 50% to 60% throttle the pressure rises to about 19,000 but never exceeds that. I have no increased acceleration after about 60% throttle and 19,000 psi.

Peter

OK, changed the fuel filter today to see if that was contributing to the problem - but no, pressures only seemed to go up a couple thousand psi. From maxing in the low 19,000's I am not hitting 20,000 occasionally. It's kind of hard to see what is exactly going on since, as I read elsewhere, the pressure spikes and then drops off as the engine uses the fuel. That would seem to imply to me that the max pressure isn't that important.

This is all happening in front of the regulator - right? What psi does the regulator regulate the pressure to?

Now that I know my pressure and have a clean filter installed, what's the next step in diagnosing a loss of power above 60% throttle?

Peter

That pressure (20,000 psi for example) is the pressure in the fuel rail, directly attached to the injectors. No regulator on it. The engine monitors this pressure and has the FCA (fuel control actuator) (little round thing on the cp3) adjust how much fuel is allowed to enter the cp3 to increase or decrease this pressure as needed. The FCA can't really decrease the pressure, but if it doesn't let any more fuel in, the injectors firing will cause the decrease...

Did you have to feed a speed signal to your ECM?

5.9, thanks for that info - that's very helpful. I don't know how it was wired, it was done by Autoworld in Montana. My impression was that the speed sensor was only going to the ATS controller. And it wasn't really speed it was off the driveshaft. Does the ECM need speed? And where on the big connectors would it be connected? And what flavor speed input would it require. My understanding is that the ECM is only looking at TPS and RPM - but as I have already proved, my understanding is very, very crude. Without this site I'd have given up on this truck a while ago.

The tranny was recently worked on and I wonder if the speed sensor got hooked back up incorrectly. The loss in power coincided with the tranny work exactly.

Peter

Without looking at the 05 wiring manual I won't be much help, but some years required the signal or the engine would defuel. The ford speed signal is output to the ABS system, the speedometer, the cruise control, etc. so there are many places to tap into it and then it is fed to one of the ECM inputs.

Scott at Destroked.com would be a great resource to talk to. He has all the wiring manuals for diff years and could tell you what color wire to look for to find it or where it should be connected on your engine wiring. Hope that helps...

Will it currently rev like normal? I seem to remember if no speed signal is present, it won't go above 2000 rpm maybe...

This truck is a '68 so there's no speed signals behind that comming off the Dodge transfer case. It will rev and I can get it above 2000, but not much - maybe that's the issue. I'll play with that today. Scott willing to just give advice for free?

Peter

My mistake, I was thinking you had a newer F250, guess I should have looked at your signature...

If you are limited with rev's then I'd bet that is your problem. The speed signal is not connected or doesn't have a good connection. It sounds like they mounted something on the driveshaft to create the speed signal. The ECM just needs to see a pulsed signal (frequency of the pulses doesn't really matter as I understand it). So I'd look at the sensor on the driveshaft, check the connections, usually those sensors need to be mounted within 0.020" or so to work properly. Maybe the shop put it all back on but didn't mount the sensor close enough to the driveshaft? Is there a tone ring on the drive shaft? A ring with notches in it?

I think you are right about being rev limited. I have two ways to judge RPMs and I don't have 100% faith in either. I have a ScanGauge II connected to the ODB II port, but I'm not sure what it is getting from the EMC - a pulse stream or a number. It reads 2,300 max. My AutoMeter tachometer shows higher. It is reading a 4 tooth sensor on the front crank, but I don't think AutoWorld calibrated it when they put the Cummins in and it probably thinks it is still connected to the V8. I have an email into AutoMeter to figure out how to set it up for the 4 tooth sensor.

My speed sensor is on the tailshaft of the Dodge transfer case. I'll have to trace it to where it is connected. Unfortunately it runs on top of the tranny forward and I may have to open up my tunnel to see where it goes.

Thanks for the help.

Peter

Just an FYI, on my excursion, it uses a tone ring in the rear diff and a sensor mounted in the differential housing. It has two wires which ran up to something (may have been the ford pcm, can't remember) that converted that signal pulse into the speed signal pulse output that went to everything else (abs, speedometer, cruise control, etc). I originally tried using the signal from the diff to my ecm and it didn't work. So you need to make sure you get the actual speed signal after it's been converted. I'm sure autoworld had to use something to do this.

However, I'd lean towards the problem being related to something the tranny guys touched (since that is when the problem started)...

good luck

There is nothing in my differential, and other than the cam sensor and the crank sensor the only other thing is the speed sensor on the transfer case. I assume the tranny guy just did something wrong putting the tranny back in, but finding it may require taking the tranny back out.

Peter

Do you know what model of transfer case it is? Any pics of this sensor on it? Did it come with the 05 cummins, and 48re? If so it would be a 271 if manual shift or a 273 if electronic shift. Neither of which have a speed sensor from the factory, I'm kind of curious how they adapted one...

It's a manual shift Dodge that came with the 48RE. The sensor is in the tail housing and looks like any speedo sensor I've ever seen. I'll try to get a picture posted today.

Peter

Here's a tailhousing off a dodge 271/273 on the right. On the left is a tailhousing off a ford 271/273. Neither of them have a sensor, nor doss the shaft have a tone ring.

http://i94.photobucket.com/albums/l110/jdnedde/transfer%20case/DSC01354.jpg

Are you sure you aren't talking about the speed sensor in the back of the transmission? It's on the drivers side (in the overdrive section of the tranny), angled downward right infront of the crossmember mount? The overdrive section of the trans bolts onto the main transmission case, so I can see someone confusing this with the transfer case.

Here's a pic that shows the speed sensor I'm talking about. It's under Ethan's left hand.

http://i94.photobucket.com/albums/l110/jdnedde/Excursion/DSC08287.jpg

Finally got under the truck today to take a picture. Not sure where AutoWorld found this. My first suspicion is that this didn't get put back together right.

Peter

Well, that's not a 271 or 273 transfer case. Looks like a 241 maybe (out of a 2nd gen dodge)... Regardless, that's the sensor they would be using for the signal. Check your connections where the tranny shop would have disconnected it...

Is 241 a manual version of the 271/273?

Peter

So Ethan's doing the trans work, well it should be a good runner then:)

So Ethan's doing the trans work, well it should be a good runner then:)

????????????

Peter

Just kidding[laugh] My boys used to help me work on my Diesels when they were young, now they both work on them for a living! Ethan looks like he could be a convert already.....

There are a few flavors of 241 cases. 241DLD and 241 DHD, the DHD has alittle stronger parts in it (heavier duty). These came in the 2nd gen dodges up to 02. The 271/273 cases are alot bigger (in all aspects) and can take more torque. Rated alot higher.

Grey Wolf,

Yea, Ethan does all the tranny work. My next oldest boy Matthew is the transfer case specialist. Here's a shot of him in action replacing the input shaft I tore up in my old 241DHD case...

http://i94.photobucket.com/albums/l110/jdnedde/Dodge%20Truck/DSC04643.jpg

http://i94.photobucket.com/albums/l110/jdnedde/Dodge%20Truck/DSC04431.jpg

Yeah, that brings back some memories[laugh] Looks like you may have a couple of future mechanics in the family too, anyway your sure to have help on future projects:cool: Nice build too, thanks for sharing!

So I finally got time to get under the truck. I pulled the speed sensor and took a look at it and there were not obvious problems. How tough is it to find the other end of that sensor and check the wave it is producing? Does someone make a "cheap" scope these days?

Peter

OK, so we finally tracked down the problem. It was in limp mode.

Althoug the speed sensor may have been partially to blame, the primary culprit was the fact that my ECM was for an automatic and as part of the converison the PCM was replaced with an ATS stand alone controller. The ECM just wasn't happy that all those tranny parts weren't there.

Bob Wagner at Smarty sent me a new ECM file (something Dodge couldn't even do) for a manual version of the engine and that solved all my problems.

I am down to 2 trouble codes now (from 8), one related to the fuel sensor which isn't there and one related to the lift pump that isn't there either. I may spend some time figuring out how to hook these to the appropriate inputs on the ECM to get rid of these as well.

In addition, ATS pointed out an interesting fact. When converting to a truck that is older or doesn't have ABS, you often end up getting your speed input from the tailshaft of the tranny or transfer case instead of the rear axel as on the original Dodge truck. This means it turns 3 to 4 times slower than the original. You can use the ATS stand alone controller (really a PCS) to take the existing input and program a new output at the approrpriate pulse rate. This affects least the cruise control and I'm not sure what else. I haven't tried it yet and will post here what I find out.

Peter

Maybe its a long shot, but you miss 100% of the shots you dont take. Try recalibrating your TPS by disconecting both neg. batt terminals for at least 30 min. Reconect cables and turn key to run, but do not start. Slowley and smothly depress accellator pedal to floor, then slowley and smothely back to idle position.

Hope it helps.