5.3LS won’t rev?

[iamtherealJayy]

I’ve read so many different forums about this and everyone seems to lean towards abuse mode. Revs to ~1500 and just stops then revs back up etc so on. I’ve talked to my tuner and he said he didn’t touch anything related to it so I sent him a couple forums to inform him of what people are saying. He warned me in the beginning he doesn’t do many manual harnesses, I’m just hoping to get this resolved sooner than later

 

[Camar068]

That is probably your issue.....pin 34. I don't know if there is anything in the tune to tell it that it's a manual trans. See link below and look at what it says for pin 34.

Mine is an automatic so pin 34 is connected to the steering column safety switch with the trans range sensor removed.

LT1swap pinout

 

[iamtherealJayy]

Would that you think make the truck always think it’s in park or neutral though and make the rev limit really low? I don’t plan on revving it really high I just need it drivable

 

[Camar068]

Would that you think make the truck always think it’s in park or neutral though and make the rev limit really low? I don’t plan on revving it really high I just need it drivable

dont know the answer to that one.

 

[iamtherealJayy]

Yolo, I’ll ground both pins and see what happens

 

[iamtherealJayy]

I did not get around to grounding pin 34, but I did finish the vss and cut the exhaust back off and just clamped some 90° bends on coming out under the door. Drove all around the yard without issue, revved the truck and then it cut and started doing the issue again. Does this sound like I’m triggering a limp mode by revving it? I don’t have an accurate tach so I don’t know what the rpms are turning but it’s a good rev before it seems to start doing it

 

[Ricko1966]

^^^ @SquareRoot shitcan it put an sbc in it.

 

[iamtherealJayy]

It had a 350 that was getting ready to settle down, it would’ve cost the same to build a decent small block as I’ve got in this swap lol I’m under ~2500 and I replaced a lot more than just the engine. I’m all for a 350 but I needed this truck to be reliable and get decent fuel mileage/power ratio so I went with a 5.3

 

[Camar068]

What do you mean you finished the vss? You've been trying to drive it w/o a vss signal? That will put it into limp mode and should pop a code. Where's your vss mounted? In the trans or transfer case or after both?

Also, if you've got a scanner tool, it will show rpm's. If you don't have one, I suggest getting the BAFX bluetooth model that will work with your phone then download torque. Then you can see your rpms's and any codes your getting.

 

[iamtherealJayy]

I’m running a 4 speed manual, people have been 50/50 whether or not the vss was needed. It’s a Dakota digital pass through sender on the tcase. Never had any codes related to it. I’ve got a code reader but that’s about all it’s good for, I’d like to get a fancier one

 

[Camar068]

ah....so the speedometer cable hooks up to it? Back to the drawing board.

Did your tuner tune for the passthru Dakota digital adapter? Link below to read up.

DD pass thru tuning

 

[iamtherealJayy]

Yes tuned for an 8k pulse. Speedo cable connects to it. Speedo doesn’t work I have to redo it but the sender is on fine but I need to re route my Speedo cable so it reaches

 

[Camar068]

at a loss.....don't know where to go from here except google. If you get more info, I don't care to help search.

 

[CalSgt]

https://www.holley.com/products/fue...tor_x_and_x_max_ls_kits/terminator_x_ls_kits/

 

[CalSgt]

Also…. I was under the impression that “E” transmission’s absolutely need a VSS signal to operate correctly but the LS itself does not. If the PCM programing hasn’t been changed to know it is a manual that would cause all kinds of problems. It can’t communicate with the transmission so it can’t determine if engine RPM’s are appropriate for gear selection based on final output at the tail shaft.

Just a theory…. You had mentioned the programmer said they haven’t done a manual swap. Perhaps something was overlooked.