Engine/Transmission (1998.5 - 2002) Intermittent Lockup in O/D

[Dirks]

I have spent the last few hours searching the forum for my specific problem but only could find the more typical symptom of the torque converter going in and out of lockup at freeway speeds. My problem is a bit more unique!



My problem is that at speeds around 60 mph about 50% of the time the TC won't easily go back into lockup after letting off the gas pedal, coasting a bit, and then re-applying the gas pedal. When the problem occurs, it just goes and goes in 4th with no lockup. I can eventually get it to go into lockup after pushing down on the pedal, letting off, and doing this a couple of times. This is never a problem at speeds below 55 mph, when O/D is off, or cruising around town. I have completed the procedure for resetting the TPS (APPS) this morning with no change in behavior.



This problem only started after I had my 53 series cracked engine "reblocked" and a BD T/C installed since the engine was out. Or after I replaced the fuel lift pump; it's hard to tell since all this work was done over a very short period of time.



I have not had the dealership upgrade the PCM by flashing new software since the dealership and I really got into it over the 53 series block crack. I really don't want to go there. I am wondering if it is noise on the TPS signal, maybe I need an upgraded valve body since I have the BD T/C, flash the PCM, or install a "Happibox".



I know it is not the lockup solenoid since the T/C does go into lockup everytime with O/D off and at lower speeds in O/D.



What do you all think?

 

[CumminsAholic]

Could be a lot of things. Bad tps (apps) or it could be interference from the alternator. Could also be a bad ground. The list goes on. Call BD and see what they suggest. I just started having this problem with my truck. I have a noise filter on the way and I'm going to reset the tps per Bill K at DTT. If that doesn't work I'll go from there. I think mine is mainly because I barely have to push the throttle to go 60 with all my upgrades. Before the power upgrades I had to push thee throttle down a lot further to go 60. Your problem sounds a little different, but could be the same problem. Good Luck



Corey

 

[Dirks]

Thanks "CumminsAholic" for the input. This is what I was looking for from this forum; others who have experienced a similar problem.



I reset the TPS yesterday and it didn't help. I liked what I saw from the forum searches I did reading about the "Happibox" since it seems that this will eliminate any future noise problem on the TPS signal. Therefore, I going to order one of these and give it a try.



Good luck with your efforts and I would be interested in your results of the reset of the TPS.

 

[DJWyckoff]

I replaced my tps, gov. and transducer also jumped the trans relay. find someone with a snap-on code scanner and have them take a ride and see what it says. good luck!

 

[OPoole]

Sounds like you need a noise from DTT 1 866 504 4002

 

[CumminsAholic]

Checked my tps voltage today... WAY LOW. 256 mv. Should be 516 mv, or . 516v . I adjusted it as far as I could (per Bill Kondolay's instructions), got it to . 483v, WOW what a difference. No more hunting issues at any speed and it shifts way better. I think it's been low since I got the truck, I just noticed it now after the power upgrades. I always had a problem with it not downshifting like I thought it should ( it'd never downshift into first without coming to a complete stop for a few seconds and didn't downshift into second if I had slowed down for a sharp corner unless I got on it more than I thought necessary). Not anymore, it downshifts like it should. The voltage is still low (I may need a new tps) so I'm going to call Bill tomorrow, but I cannot believe the difference it made, I'll update as I drive it more.



FYI, I did the battery disconnect reset a couple of times, never made a difference at all. This made a huge difference. I don't think I need a noise filter, but I have one coming already anyways. Also the torx screws are a PITA. Mine were really tight. I couldn't find the socket torx (had every one but the 20... figures) so I had to use a screwdriver one and a pair of vice grips. I recommend having the socket torx on a ratchet.



Corey

 

[Dirks]

Thanks again Corey for the very helpful status update. I'll pull out the factory manual tonight and look up the procedure for testing/adjusting the TPS voltage.



In addition, I'm going to compare the wiring diagram on the TPS to try and get an idea if the installation of the "Happibox" assures a more constant 516 mV signal to the ECM. This may take a call to the folks at Happibox to find out if the TPS voltage is supplemented with a conditioned or amplified voltage of its own from the Happibox to better provide a clean signal to the ECM.



It would be good for me to know if a low TPS voltage can be corrected by the Happibox installation alone or does the Happibox rely on having the design 516 mV signal in the first place.



Thanks again for keeping this thread alive!



Sincerely,



Paul

 

[CumminsAholic]

The voltage isn't constant. It changes with throttle position. The further down the throttle is depressed the higher the voltage. I don't know what a "happibox" is, but I'm guessing it's just a noise filter.



Corey

 

[Will Manchester]

Give this a shot, it will probably fix your problem!



https://www.atsdiesel.com/PDF/120505/4th hunt 46 47 RE.pdf

 

[Dirks]

Thanks Corey & Will:



Corey: I checked the voltage of the APPS (TPS) by measuring it at the LB/BK (that's the light blue with black tracer) wire when the pedal was at the resting (no load) position and got 404 mV (0. 404 V).



Is this the same voltage test point you refer to when you said it sould be 516 mV?



Also, could you describe how to adjust this voltage; easily?



Will: I checked out the link and since I'm getting the "Happibox", it seems the box will do a better job of providing a clean signal connecting at the similar location for the APPS and PCM. Check out www.madselectronics.com for more on the Happibox.



Paul

 

[CumminsAholic]

I tested the orange wire with the dark blue tracer. There's a tag on the back of your apps that says the voltage it should be. Mine said . 516 It's not too hard to adjust it. I know I seen the instructions in another post, but can't find it. I'll send you a pm with my phone # and I can try to explain it.

Corey

 

[Dirks]

OOps!



The website I posted was for the SMARTY box. The HAPPIBOX website is www.happibox.com. Sorry.



Paul

 

[Will Manchester]

Will: I checked out the link and since I'm getting the "Happibox", it seems the box will do a better job of providing a clean signal connecting at the similar location for the APPS and PCM. Check out www.madselectronics.com for more on the Happibox.

Paul

No experience with the Happibox, and unfortunately can not get the link to open right now.



The URL I gave you was actually derived from a Dodge TSB, service tip, ... something like that. It was very confusing, ATS cleaned it up A LOT. Basically, you have a nice clean signal leaving the APPS going into the ECM. The problem is on the APPS output at the ECM going into the PCM - there is nose on the line. A spike in voltage looks like your nailing the throttle (TC unlocks over 70-80% throttle), a big enough drop in voltage looks like you take your foot off throttle (TC unlocks at 0% throttle). A biggie that really seems to help and many over look is adding the redundant ground wire to the APPS gound line.



So, the procedure described in the URL is basically feeding a clean signal directly from the APPS to the ECM and the PCM - you are totally bypassing the ECM passthough signal and eliminating the problem. As long as the Happibox is doing something along those lines, you should be fine. A "box" or a fliter really shouldn't be needed to fix this problem!

 

[Will Manchester]

Finally got the Happibox website to load. Check out the install instructions: http://www.happibox.com/id8.html



They are doing the exact same thing. They probably have some sort of a noise filter to clip the spikes - but in my experience, the spikes are all post ECM. I suggest adding the ground wire that I mentioned earlier as just feeding the PCM a dedicated signal is not always enough.

 

[Dirks]

Thanks Will.



I agree the ground wire looks like a good idea. I took some voltages yesterday and noticed that I had a slightly higher (i. e. , 15 mV higher) voltage on the APPS position sensor signal wire (LB/BK) to battery ground versus to the APPS position sensor ground wire (BK/YL).



This slight difference indicates to me that taking that BK/YL wire and teeing it to the battery ground will get the best overall voltage reference.



Based on Kris Patrick's explanation in his website, I believe his Happi Box is using some "smart" filtering with added electronics over a simple R/C filter circuit from Radio Shack. I get this from the analogy of the "traffice cop" for my throttle position sensor signal. I will post the results of the installation in about a week after the device arrives.



BTW the Happi Box is also post ECM because it separates the signal from the ECM to PCM for the APPS and runs it through the H box while monitoring (i. e. , teeing off of) the APPS to ECM wire.



Paul

 

[Dirks]

Just an update since installing the Happi Box:



From what I can tell, the problem has been cured by the Happi Box! I took it for a test drive after the installation and the lockup seems to be acting like what I remember it to be before the problem. The challenge, though, is that I am now hyper sensitive to when the T/C goes into lockup since this problem started and did notice that on the test drive a couple of times the T/C did not go into lockup right away after coasting and reapplying power. When the T/C had a problem, it would take letting off on the pedal, punching it, and repeating this several times before it would go back into lockup. Now, after the Happi Box, it will eventually go into lockup without this procedure especially on a light pedal application which is what I seem to remember how it worked before.



The bottom line is that there has been a significant improvement with the installation of the Happi Box.