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Tune, resistors and tcc

It's running and getting around which is awesome...but when I first put this tranny in the dragging feeling it's had for a long time went away completely, and it felt like it's old self again...but last to days it's coming back..I'm honestly at a loss as to what is causing it...I'm almost thinking that maybe the truck is running the tranny in limp mode. Cause it will be running great, then for no reason I can figure out it starts feeling like it's dragging a trailer or trying to take off in high gear. That's best I can think to describe it
 
ALDL is the PCM connector under the dash. I forget, is your's an obd1 or 2?

Edit: DOH! I didn't read your sig. OBD2 when you get a chance run it by the local autoparts store and ask them to give you the code read out. and we'll help try to diagnose it. if it's showing a tranny code it will be in limp mode meaning youll be taking off in second gear. other than that can you tell if it's shifting through all it's gears and in lockup?
 
Stoney said:
It's running and getting around which is awesome...but when I first put this tranny in the dragging feeling it's had for a long time went away completely, and it felt like it's old self again...but last to days it's coming back..I'm honestly at a loss as to what is causing it...I'm almost thinking that maybe the truck is running the tranny in limp mode. Cause it will be running great, then for no reason I can figure out it starts feeling like it's dragging a trailer or trying to take off in high gear. That's best I can think to describe it
Click to expand...
When You are driving, aftdr the engine comes to operating temp, You should be aboe to count the four gears of the transmission then a feel like another gear. It could also be three gears of the transmission, then the TC lockup and then another gear of the transmission.
See how that goes.
I too am wondering if maybe the brakes is locking up and dragging.
Once in a while, a grain of sand or some other comtaminate can get stuck in the return port of the front disk brakes and not allow them to release all the way.
If You have access to a infrared temp sensor, You might also try shooting the temps of the rear brake drums and the each front hub and see if there is any variances between each of the front and then each of the rears. Dont try temp differences between the fronts and the rears as they work differently between the fronts and backs and the temps will be different.
 
how many miles have you put on the newly installed tranny? I had a thought of maybe a tiny bit of varnish or goo in the valve body from sitting just breaking loose. I don't remember if you said how the inside looked when you first pulled the pan to do the new filter.

I remember Napa used to sell some stuff in a small clear glass bottle that you put into the trans to dissolve that stuff and it was designed to evaporate over a few days of driving. it works good without harming anything. Motor Purr tune up.

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I think I actually isolated the prob. And it's not the transmission...
I realized something today when I turned the key on to warm the glow plugs I didn't hear the lift pump running like I usually do...I didn't think much of it I thought maybe I had already cycled at the beginning and then stopped like it usually does and I just didn't hear it..
When I backed out of the driveway and went to take off it felt like it was dragging.. after a couple minutes I stopped at the stop sign going to take off and it was back to normal hauling ass good...
However there's something else I have noticed that I have not figured out... Say I'm driving down the road and I take my foot off the accelerator for a second...then I push it back in....( Keep in mind this does not happen all the time). Sometimes when I push it back in I don't get any response from the engine but if I take my foot off of it again and then put it right back in again then I do get response..... So I'm wondering how is the lift pump connected to the accelerator?? I know the pump works.. but maybe it's loosing signal from the accelerator at time...and at those times the i.p. is doing all the work causing it to feel like it's dragging and has no power..
Is this possible??
 
It could be you are loosing fuel pressure- the normal description people give is on the hiway, hard acceleration, etc. is the truck does “fish biting”. Like a fish randomly tugging on the line with no rhyme or reason.

Ya know what I am going to say: fuel pressure gauge tapped at the ip inlet.
Not enough cash at the moment? How it gets tested at the dealership is put in a plastic t in the rubber fuel line and run fuel hose from it to a gauge on the outside of the windshield held in place by the windshield wiper.
An Affordable gauge for this:
www.harborfreight.com

Fuel Pump and Vacuum Tester

Amazing deals on this Fuel Pump /Vacuum Tester at Harbor Freight. Quality tools & low prices.
www.harborfreight.com www.harborfreight.com
 
And that gauge can also be used for a boost gauge too, Meee thinks.
Long as the boost dont go over ten PSI.
I have one very similar. Very old, I dont rememer how many PSI it goes up to and, I too dont rememer the brand name of the thing. 🤷‍♂️😹
 
Just an idea, here, when I first read of the problem Stoney is describing it sounded like a fuel delivery issue. So as already mentioned it could be:

bad LP
bad OPS

I'm going to add to the list plugged fuel filter, that was my first thought

also going to throw out there bad fuel tank cap- If I recall correctly @Stoney has a custom fuel tank in the bed, if it isn't vented properly it could be under vacuum and also causing a starving for fuel condition
 
@DieselAmateur I've had this problem for a long time now. Before I did the custom tank. And I've changed the filter and lift pump multiple times. No change...
O.p.s. is possible but not sure how to check that..my other thought is that there's a intermittent electric problem causing the lift pump to work then not then start again.
But that's just a thought
 
Stoney said:
@DieselAmateur I've had this problem for a long time now. Before I did the custom tank. And I've changed the filter and lift pump multiple times. No change...
O.p.s. is possible but not sure how to check that..my other thought is that there's a intermittent electric problem causing the lift pump to work then not then start again.
But that's just a thought
Click to expand...
That too was My thought. AKDD mentioned that the ECM/PCM is capable of powering the LP even if the OP sensor is out.
I think best way to check will be with a fuel pressure gauge.
I have a cheap pressure gauge and got the pressure tap fitting from Leroy. Run the plastic tube into tje cab and have a FPG that I can monitor constantly.
I aint happy with the plastic fuel tube run into the cab, but for right now it is what I will live with and keep a very close watch out for the danger signs. Which includes visual and smell.
It also is mentioned to install a T between the filter and the IP and run a gauge off of that. I believe if I was doing that, I would use a brass T and barb tire both sides with the tube adapter, or electronic sending unit out the side port of the T.
 
@Will L. Brass or Copper? all the fittings on my remote fuel filter are brass and the filter head is aluminum. am I asking for trouble?

@Stoney the pedal position sensor doesn't effect the lift pump operation, but when you say at times you step on the pedal the truck does nothing as if your not stepping on it or are you feeling hesitation like the truck is trying but not responding well? the reason I ask is because I had a very similar issue where there were random times when I'd start to press the pedal slightly from a stop not trying to move very fast due to being inside my work (speed limit 10 mph) and my truck did nothing as if I wasn't pressing the pedal. no SES light ether. after it happened a few times I connected my laptop and saw there was a code for the sensor mounted on the accelerator pedal. I replaced it and never had that issue again.
 
Stoney said:
@dbrannon79 . What was the name of that sensor and how much did it run
Click to expand...
this is the one I bought from amazon, but this was before I learned how Dorman parts were junk! I would check on @RockAutoLLC to see if they offer the GM Delco part. plus the 5% discount for us as members of the forum :)

mine is a 95 model so your's may be different being a OBD2 system. check your codes for APP circuit and also look at the live data. this sensor is like three TPS sensors built into one. so there will be three readouts in the data stream showing, youll need to watch all three. if only one protion is not working it will set a code but not turn on the light. two or more and youll see both the SES light and "service throttle soon" light too.

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