• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Tune, resistors and tcc

Stoney

Lock-n-load
Messages
1,956
Reaction score
3,772
Location
Elmira ny
Ok after much though and confusion my brain is spinning on a thought about my truck... I've had trouble with it for a long time now... When driving, some times it runs great takes off fast, acceleration is fast, shifts no prob couldn't ask for better...
HOWEVER. Other times it feels seriously sluggish. Like it's stuck in high gear at take off. Takes forever to get up to speed, no power, gotta push the pedal alit harder...it's about like it would feel if I was pulling a big heavy trailer....and it will go from running great to being sluggish back and forth constantly... It maybe do great and I stop at a light and when I take off it's switched to being sluggish...or vice versa..there doesn't seem to be any pattern as to when it switches back and forth between the two running quality's..
This started right after doing a brake job and tranny fluid and filter change and fuel filter change...I DONT KNOW IF THAT IS COINCIDENCE. ..
Facts that I know: when the guy was changing the tranny filter I rem him unplugging something on or in the tranny..I don't know what it was or if it was inside or outside the tranny...I do know he plugged it back in. But that doesn't mean he got it in right he was really incompetent..
I remember him having something happen with the seal that goes on the filter nipple that snaps into the tranny..don't know if it was cracked or broken or whatever or if he reused that one or the new one that came with the filter.. as I said he was a idiot..( I'ma idiot also for letting him touch my truck)
Also when changing one of the wheel cylinders on the rear he broke the brake line that goes to it from the "T"...there wasn't any brake line that size in the shop so he used a piece that was a smaller size to replace the broken one..
Other facts. My truck has never had a resistor in the pmd plug since I've owned it..and it used to run like a beast. when guys on her told me it was supposed to have one I bought both #5 and #9 ones..truck wouldn't start with either of them in so I took them back to the store...still no resistor in it...
I've noticed guys say that if the truck has a tune in it that it doesn't need a resistor. I don't know this for a fact but that makes me assume the prior owner may have put a tune in it... again I don't know that for a fact but don't know how the truck could run without a tune done and no resistor...
Is it possible that the tune got messed up somehow and that's causing the problem? Would that screw with the tranny shifting?? Or cause it to get sluggish at times???
I'm at a loss
 

Stoney

Lock-n-load
Messages
1,956
Reaction score
3,772
Location
Elmira ny
Oh I forget to mention. When he changed the fuel filter he threw out the little filter that goes down in the FFM..I didn't realize it at the time...I put a new one in last time I changed the fuel filter but there wasn't one in there for a long time...and another fact is that the fuel tank liner was pealing for a long time before I realized it...and I was finding flakes in the bottom of the FFM when changing fuel filter.
 

ak diesel driver

6.5 driver
Messages
17,020
Reaction score
11,840
Location
alaska
Since your truck is ob2 the PCM only reads the resistor when requested ie doing a relearn, why it dies with the resistor in place is another story. Is it possible that the extension harness has one in it already? maybe from a previous owner?
I would pull the fitting going into the IP as theres another screen there and see if it is clean.
Thinking maybe your intermittent problem could be a ground issue, the LP and the fuel tank sending unit share a ground back at the tank on the frame. When I redid the wiring harness along the frame I added another wire and ran it up to the engine bay to help keep it from corroding so much
 

Stoney

Lock-n-load
Messages
1,956
Reaction score
3,772
Location
Elmira ny
Would that ground by chance cause the fuel gauge to act like it sucks?.. only asking because I hadn't noticed that the fuel gauge will stick in one place and all of a sudden it'll drop down some like you all of a sudden had five less gallons of fuel in the tank...
 

JMJNet

Recruit
Messages
2,259
Reaction score
603
Location
Richardson, TX
Would that ground by chance cause the fuel gauge to act like it sucks?.. only asking because I hadn't noticed that the fuel gauge will stick in one place and all of a sudden it'll drop down some like you all of a sudden had five less gallons of fuel in the tank...
The fuel gauge in this truck is suck. Mine did it too and I know the ground is there.
Saw it when I replaced the wheel cylinder.

The only way to see if it has a tuned ECM is by taking it out from behind the glove box and do a visual inspection.
Usually the tuned ECM have a sticker on who actually provide the data inside the tune, unless the PO did it himself but to own one of those tool to put different tune is not cheap.
 

DieselAmateur

Diesel or Bust
Messages
218
Reaction score
401
Location
Upstate NY
Put an inline filter in before your lift pump, getting little flakes of tank liner in the FFM isn't the best thing for the LP. NAPA filter #3270 is a simple mesh screen filter that takes 3/8" hose. Just cut out a short section the hard steel fuel line before the LP and splice in the filter using 3/8" hose and hose clamps.

Wish I could be more helpful with the other stuff, sorry I don't know squat about the automatic transmissions. Also thought the resistors actually did something to increase fueling but I guess this theory has been debunked?
 

WarWagon

Well it hits on 7 of 8...
Messages
10,030
Reaction score
6,445
Location
AZ
Put an inline filter in before your lift pump, getting little flakes of tank liner in the FFM isn't the best thing for the LP.
That's a good way to walk. The cute little inline filters will clog from the tank lining coming through the bypass valve in the tank sock. Or on a cold day diesel fuel gelling can clog the inline filter. The first filter needs to be heated. The tank sock has a bypass valve rather than a heater. Gelling and wet dirty diesel fuel The USA is known for are two reasons the filters are HUGE vs. the small gasoline filters.

The lift pump working intermittently could cause a loss of power. It did for me as it went to "no power" and stalled the engine. Any loss of pressure at the IP inlet from a clogged tank sock, gelling, plugged filters, etc can knock out power.

So can a failing vac pump or related vac system and you get black smoke instead of turbo boost.
 

Stoney

Lock-n-load
Messages
1,956
Reaction score
3,772
Location
Elmira ny
@ WarWagon I don't use the regular tank anymore, it's trashed...I plumbed in a transfer tank that's in the bed of the truck..no filter in the tank at all so I'm Leary of not having the in line filter before the lift pump..I installed one when I hooked up the transfer tank..I put Howes anti gel in fuel in winter. Been putting tranny fluid in fuel all summer to lubricate.. not sure if that's best..
Vac pump has been deleted , built my own wast gat control.
I'm thinking that I should clean that ground to the lift pump by the fuel tank. And if I remember right y'all said there's a filter actually in the injection pump under the inlet nipple.. possible that flakes from the tank got there because of hole in the tank sock filter and the little filter under fuel filter being missing...
Actually thought about putting a tank heater in though
 

MrMarty51

Well-Known Member
Messages
8,043
Reaction score
15,862
Location
Miles City, Montana
PO had removed the tank sock on My truck afore I bought it from Him.
It has that little steel 3/8ths inline filter before the lift pump.
I change filters every other oil change.
Soon as temps start hitting into the teens, I start blending in number 1 diesel. Never have had a problem with gelling fuel. I dont know about the tank flaking out though. Maybe next filter change I’ll carve open that little filter and see what is in it.
I do have a real nice large filter system that has a heater installed in the clear water trap end of it. I would love to install that pre LP but it hangs lower than the frame rail and I would be in fear of beating it off on some rutted cow trail out in the hills.
And then also, how would a person be able to bleed the air from it being on the suction side and also tucked into the frame rail where it would be near impossible to dump fuel into it.
The little inline filter and precautionary measures to keep fuel from gelling, then installing that nice big filter on the pressure side just makes way more sense to Me.
 

WarWagon

Well it hits on 7 of 8...
Messages
10,030
Reaction score
6,445
Location
AZ
After wiping out a couple of Walbro's on bug infested fuel because I got tired of the big bowel screen plugging up and removed them ... Yes, no screen can ruin the lift pumps.

This is what I used for a filter before the lift pump: a CAT Water separator. It saved the injection system from bad fuel that destroyed the tank and injection system on my other 6.5 without this filter. In colder weather I would have added a heater to it.

cat.jpg
 

MrMarty51

Well-Known Member
Messages
8,043
Reaction score
15,862
Location
Miles City, Montana
This is the one I have. Now looking it over a little, I see there is no air bleed on this unit. Must just crack the filter loose a couple of turns then let it fill.
image.jpgimage.jpg

would this be a good candidate for a pre filter ? At one time I checked with NAPA for the filters for this and they do have them available.
 

Stoney

Lock-n-load
Messages
1,956
Reaction score
3,772
Location
Elmira ny
I had wondered about putting something like that on a 6.5. I figured if it's good enough for a bulldozer it's good enough for my truck right LOL... What system y'all think would be best to bolt right to the frame pre-lift pump.
 

MrMarty51

Well-Known Member
Messages
8,043
Reaction score
15,862
Location
Miles City, Montana
I had wondered about putting something like that on a 6.5. I figured if it's good enough for a bulldozer it's good enough for my truck right LOL... What system y'all think would be best to bolt right to the frame pre-lift pump.
I was searching around last night for some kind of a heated water trap filter system. Seems the marine industry has them for about 50 bucks.
I dont know if a person discards the entire unit or if filters is a available for them ?
 

Stoney

Lock-n-load
Messages
1,956
Reaction score
3,772
Location
Elmira ny
That's the sticker on top of the ECM.. not sure if they're supposed to be another one somewhere but that one looks like it got put over a different sticker.
 
Top