ls pedal no responce at full throttle
 

I need some help with my 79 with a 6.0 lq4 its throwing these codes po507 idle to high.. po0332 knock sensor right side and po101.maf . I checked the wiring for the maf sensor and it checked out and I even unhooked it .the problem stays the same I can push down the throttle pedal to the floor and it doesn't raise the rpms at all but it does speed up using half throttle but nothing pass full throttle.

Re: ls pedal no responce at full throttle
 

If all three codes came on at the same time, the problem is likely common.

I can't even begin to guess how your setup might be wired, but here are a few suggestions...

If you have access to a decent OBD2 scanner, check the throttle response. It should report throttle position.

Check power to the MAF, knock sensor and pedal. Most pedals have 6 wires, 2 power sources, 2 signals, and 2 grounds. Check each power source. Keep in mind that some of this stuff is powered by the ECM/PCM so some of it will be 5 v. Also check the throttle actuator on the engine. The knock sensor, actuator, and MAF are all relatively close and could share a common power or ground wire. Look for signs of abrasion on the wiring or where it might be pinched. Check fuses too.

Check your GROUNDS! Poor grounds often lead to weird issues, and this sounds like one of those times. This can be done by measuring resistance from ground points back to the battery. Anything over a few ohms isn't good. May need to do a voltage drop test on ground points with the engine running. Ideally all ground points should show 0 all the time, but with higher loads there can be a few volt drop back to the battery.

Re: ls pedal no responce at full throttle
 

Is the truck actually idling high, or is it just reporting that code off a normal idle?

Re: ls pedal no responce at full throttle
 

no it just revs up when I first start it then it smooths out and idles normal all within a few seconds

Re: ls pedal no responce at full throttle
 

Check your GROUNDS! Poor grounds often lead to weird issues, and this sounds like one of those times. This can be done by measuring resistance from ground points back to the battery. Anything over a few ohms isn't good. May need to do a voltage drop test on ground points with the engine running. Ideally all ground points should show 0 all the time, but with higher loads there can be a few volt drop back to the battery.

__________________I checked every wire for the grounds and all the other for power. and I cant find out what it is causeing my problem.. I have the metal pedal . I am gona buy a new one and try that.

Re: ls pedal no responce at full throttle
 

Is the no throttle response a new problem, or has it always done it? When you floor it, do you loose all response to the pedal?

Re: ls pedal no responce at full throttle
 

its has done this since I installed the engine a few months back I have replaced the throttle body and the maf sensor. and even have tried a different ecm with no luck . when I push down on the pedal to the floor it does nothing if I let off it will drive and slowly raise the rpms but it still doesn't have full pedal ..

Re: ls pedal no responce at full throttle
 

Sounds a little like a DBW component mismatch, but usually that will throw its own code and limp the throttle.

Re: ls pedal no responce at full throttle
 

I had to buy the pedal and tac module and ecm it was supposed to be off a 2004 suburban with a 5.3. The engine and harness I used was from a 2007 h2 hummer it has the blue green harness . I wonder if I can get a plastic pedal and tac and see if that will work ??

Re: ls pedal no responce at full throttle
 

07 would have been Gen IV (except 06.5 classics), but I'm not sure if thats true for the Hummers as well. That wouldn't usually interchange with the GenIII stuff, so my assumption is the 07 Hummers use the late GenIII style stuff... I gotta find clarification on that though.

Re: ls pedal no responce at full throttle
 

I am pretty sure this engine I have is the last of the gen 3s .when gm changed to use the e38 ecms .I also have a 5.3 that was removed from a 2007 Silverado 1500 classic that is the last of the gen3s

Re: ls pedal no responce at full throttle
 

Then it would be the plastic pedal style, is that what you have?

Re: ls pedal no responce at full throttle
 

no I went with a metal pedal. the h2 wiring harness is the blue green and the hummer pedals are metal . so I am just gona try the plastic pedal next.

Re: ls pedal no responce at full throttle
 

You likely have the wrong TAC as well. What is the part number on it?

Re: ls pedal no responce at full throttle
 

12573059

Re: ls pedal no responce at full throttle
 

I will check in the morning and see what my 06-07 TAC part number is.

Re: ls pedal no responce at full throttle
 

I checked both my 2006 and 2007(Silverado Classic) TAC modules and they are part number 12590008. The one you have is for a 2003-2005. You can either get the correct TAC for your tune or you should be able to change the tune to match what you have.

Re: ls pedal no responce at full throttle
 

ok thanks for the info..i am gona find a tac and plastic pedal that is a matched set .

Re: ls pedal no responce at full throttle
 

I just put in a 06 plastic pedal and tac 12590008 I hooked the pedal up to see if was working and it was doing fine until I got done making a mount to mount the pedal that took 2days to faB UP . got in the truck today to test it out and it just barely made it out the end of my driveway when it went it to limp mode. now it will not go past idle . I took the battery cable off and it reset .but its still doing the same thing i hooked up my code reader and tried to get a code but the scanner said NO ignition power so I just don't know of any more things to do to it .