6.0 swap poor pedal responce

[bigdaddy4x4]

ok my 79 with a lq4 6.0 has no pedal response after pushing the pedal half way down it just falls off its ass I have had 2 different ecm replaced and it still just wont go any ideals it has no codes

[mongocanfly]

welcome...
dbw or dbc?

[nsb29]

I’m still learning about these motors but I would wonder about fuel pressure

[ls1nova71]

Is it just bogging down or actually losing pedal response? If it's losing pedal response then it sounds like you have a mismatch in components.

[bigdaddy4x4]

Originally Posted by ls1nova71

Is it just bogging down or actually losing pedal response? If it's losing pedal response then it sounds like you have a mismatch in components.

its dbw 2006 6.0 with the blue green harness .it first had a metal pedal and it did the same thing bought a matched plastic pedal and tac .it started and ran better with the plastic pedal but it does the same its does ok at half pedal but when I push it past half pedal it just doest have any response but if I keep to the floor it does gradually speeds up .

[BR3W CITY]

^x2 Start and run, but when it sees the pedal sweep it will cut throttle input if their is a DBW component mismatch.

[BR3W CITY]

Take a look at the wires on the throttle body servo (IIRC yellow and dark blue or purple), give them a little tug/jiggle and look at the connectors. Sometimes they fray or break and cause DBW issues, tho they usually trigger a code.

How was the truck tuned, you mention multiple ecms.

[bigdaddy4x4]

Originally Posted by BR3W CITY

Take a look at the wires on the throttle body servo (IIRC yellow and dark blue or purple), give them a little tug/jiggle and look at the connectors. Sometimes they fray or break and cause DBW issues, tho they usually trigger a code.

How was the truck tuned, you mention multiple ecms.

I had one from ebay ecm with it the truck had trouble starting and running had to undo the maf sensor for it to stay running and it didn't run past half throttle .either .. then I got a ecm from Brendan at lt1 and installed the plastic pedal and tac I have checked the wiring and even got a new throttle body and new maf sensor

[thehata1]

It may be a dumb question, but have you cleaned the throttle body? In the donor, my throttle response was sluggish until cleaned it.

[nsb29]

Originally Posted by thehata1

It may be a dumb question, but have you cleaned the throttle body? In the donor, my throttle response was sluggish until cleaned it.

He replaced it

[BR3W CITY]

Grab the pedal pinout and see if you can read the pedal sweep in voltage (it should have 2 pin combinations that work, on the plastic pedal one will read 0-10v and the other will read 10-0v cross referencing each other). If there is a dead spot, hold in voltage, or crazy mismatched inverse voltage (i.e. both read 10v at the same time) then the pedal or its wiring are probably the issue. I know you mentioned replacing the pedal, but I'm tossing the idea up for the sake of troubleshooting.

If you have access to the tuner, you can watch pedal % and throttle %. It might also be worth verifying that the Ecms being used match the pedal/tac year, and that a bad tune file isn't just being copied across all the Ecms. Commanded throttle % is also viewable in HPt or EFI Live scanners.

[bigdaddy4x4]

I don't have axcess to a tuner gona call around and see who has one. here is a you tube video that you can see what I am talking about https://www.youtube.com/watch?v=2C1ke6idzJM if let off and get back on the throttle the rpms just graduly go up real slow

[mongocanfly]

I really got nothing...but I'd blame it on the dog.....haha

[bigdaddy4x4]

Originally Posted by mongocanfly

I really got nothing...but I'd blame it on the dog.....haha

oh yeah he always has something to do with it .

[04ls1gto]

Corvette pedal and truck pedal have different pinouts. I had to re- pin my Corvette pedal. Found the directions on the painless LS swap harness directions