Reduced Engine Power write-up

[Eldiablo]

I think its time to build a better thicker harness for just the fly by wire circuit. Ill get on the phone with the painless guys and see what I can come up with D. I . y. that doesnt cost 800 bucks. I havent seen on anyones post of the testing for the pedal sensor? I did mine today, it failed first test, but passed the other two. So it has power and ground but the potentionmeter part failed. I think I shall remove it and carefully take it apart. I tend to do this with everything that is iffy. Do all my own alternators and starters.

 

[Fless]

A good scan tool will graph the various position sensor PIDs to see how they compare and if there are dropouts or non-linear tracking.

 

[Eldiablo]

A good scan tool will graph the various position sensor PIDs to see how they compare and if there are dropouts or non-linear tracking.

I did the testing on the pedal sensor, and it failed the first test. Also tonight I found not one set but two sets of connectors on the wiring for the throttle body. I cut all that out and soldered it up with heat shrink tubing. I was lining it out for the custom harness. I think it would be pretty simple. Pull the wires at the computer for the throttle body. Make a new set, I beleive there are 8 or 9 wires. Then pull the wires from the tac to the computer. Same thing make new ones and build a better set up going to the pedal sensor. Done. Probablly two hours once I have the schematic. ????????????Bet we could sell a bunch of them. Tomorrow the fuel injector connectors are coming. Ill get those installed and get er fired up. Oh and I ran a circuit breaker instead of fuse for that center red terminal on the fuse block. It only had.6 of a volt. Now it has 12 like the other two. That was probablly the problem. Thanx guys for putting up with me. When I have a problem like this, I research my butt off, and I learn very quickly. I am going to get that x tool d7 soon. I need it. Snap on sucks. lol.

 

[Fless]

Oh and I ran a circuit breaker instead of fuse for that center red terminal on the fuse block. It only had.6 of a volt. Now it has 12 like the other two. That was probablly the problem.

I may have missed it -- on what fuse block did you use a circuit breaker? Pics?

 

[tylopes3]

New to forum so thanks for any help. I have an 09 Yukon and have been dealing with p1516 and TPD sensor codes for years. Been reading this forum for days and appreciate the information. Does anyone know a mechanic in the Denver area who is familiar with this issue and will look at the ground issue instead of just telling me I need a new TB/ TPS?

 

[alpha_omega]

Oh and I ran a circuit breaker instead of fuse for that center red terminal on the fuse block. It only had.6 of a volt. Now it has 12 like the other two. That was probablly the problem.

*Bump on the info and photos @Fless asked about. You have piqued some interest.

 

[RobertRN]

Where are you selling this dedicated beefy harness for the throttle circuit? I want one. Ar 180,000 miles on my 04 Yukon xl alt with the 6.0 I decided to do some "preventative maintenance" because the idle was getting tougher and felt that was long enough on the plugs. So I put in new plugs, wires, the wire harness to the coils was crumbling so replaced both of those, engine block temp sender under #1 on the left, both t connectors at the fire wall for heater core, MAS sensor, canister purge valve, I did not have and the only check engine light I have ever had was replaced fuel cap. The engine has carried me anywhere any time. Well she is now making up for it. The idle seemed rougher, no warning lights, and fuel economy went into the toilet. So I was told the clean the throttle or better yet replace it. So I replaced it with OEM, the more I do it seems the worse it gets. Now I have reduced engine power. I reprogrammed the TCM it ran at idle for 15 min perfect. I stepped on the throttle and bag back into limp mode with P1516. So now putting in a new harness pigtail for the throttle body and going around and rewiring the ground on the left and right rear engine. The ground to firewall and to the TCM and splicing the black/white on the PCM. I got a grounding block and going to not only to their original places but to this block. We shall see what today brings. So much for preventative maintainence. I am an old school mechanic 1970s-80s and then the issue was vacuum lines. They were awful. But, this ain't a lot better.

 

[tomloans]

Where are you selling this dedicated beefy harness for the throttle circuit? I want one. Ar 180,000 miles on my 04 Yukon xl alt with the 6.0 I decided to do some "preventative maintenance" because the idle was getting tougher and felt that was long enough on the plugs. So I put in new plugs, wires, the wire harness to the coils was crumbling so replaced both of those, engine block temp sender under #1 on the left, both t connectors at the fire wall for heater core, MAS sensor, canister purge valve, I did not have and the only check engine light I have ever had was replaced fuel cap. The engine has carried me anywhere any time. Well she is now making up for it. The idle seemed rougher, no warning lights, and fuel economy went into the toilet. So I was told the clean the throttle or better yet replace it. So I replaced it with OEM, the more I do it seems the worse it gets. Now I have reduced engine power. I reprogrammed the TCM it ran at idle for 15 min perfect. I stepped on the throttle and bag back into limp mode with P1516. So now putting in a new harness pigtail for the throttle body and going around and rewiring the ground on the left and right rear engine. The ground to firewall and to the TCM and splicing the black/white on the PCM. I got a grounding block and going to not only to their original places but to this block. We shall see what today brings. So much for preventative maintainence. I am an old school mechanic 1970s-80s and then the issue was vacuum lines. They were awful. But, this ain't a lot better.

Be sure to solder the 8 new wires from your new throttle body connector. Very sensitive. Also be sure you have the correct gap on the plugs. It wouldn't hurt to run some seafoam in your engine oil to see if you can clear up the rough running issue. You may have more than one problem. Kind of need more detail to know the order of things. how it all went down. If you received the P1516 code straight after you installed the throttle body, you likely have a lemon throttle body or you jostle the connector that has a broken wire in it. Anyways some thoughts for you. Slow down and think through it.

 

[Fless]

Where are you selling this dedicated beefy harness for the throttle circuit? I want one. Ar 180,000 miles on my 04 Yukon xl alt with the 6.0 I decided to do some "preventative maintenance" because the idle was getting tougher and felt that was long enough on the plugs. So I put in new plugs, wires, the wire harness to the coils was crumbling so replaced both of those, engine block temp sender under #1 on the left, both t connectors at the fire wall for heater core, MAS sensor, canister purge valve, I did not have and the only check engine light I have ever had was replaced fuel cap. The engine has carried me anywhere any time. Well she is now making up for it. The idle seemed rougher, no warning lights, and fuel economy went into the toilet. So I was told the clean the throttle or better yet replace it. So I replaced it with OEM, the more I do it seems the worse it gets. Now I have reduced engine power. I reprogrammed the TCM it ran at idle for 15 min perfect. I stepped on the throttle and bag back into limp mode with P1516. So now putting in a new harness pigtail for the throttle body and going around and rewiring the ground on the left and right rear engine. The ground to firewall and to the TCM and splicing the black/white on the PCM. I got a grounding block and going to not only to their original places but to this block. We shall see what today brings. So much for preventative maintainence. I am an old school mechanic 1970s-80s and then the issue was vacuum lines. They were awful. But, this ain't a lot better.

If you're asking @Eldiablo that member hasn't been on here since last October.

 

[tomloans]

Where are you selling this dedicated beefy harness for the throttle circuit? I want one. Ar 180,000 miles on my 04 Yukon xl alt with the 6.0 I decided to do some "preventative maintenance" because the idle was getting tougher and felt that was long enough on the plugs. So I put in new plugs, wires, the wire harness to the coils was crumbling so replaced both of those, engine block temp sender under #1 on the left, both t connectors at the fire wall for heater core, MAS sensor, canister purge valve, I did not have and the only check engine light I have ever had was replaced fuel cap. The engine has carried me anywhere any time. Well she is now making up for it. The idle seemed rougher, no warning lights, and fuel economy went into the toilet. So I was told the clean the throttle or better yet replace it. So I replaced it with OEM, the more I do it seems the worse it gets. Now I have reduced engine power. I reprogrammed the TCM it ran at idle for 15 min perfect. I stepped on the throttle and bag back into limp mode with P1516. So now putting in a new harness pigtail for the throttle body and going around and rewiring the ground on the left and right rear engine. The ground to firewall and to the TCM and splicing the black/white on the PCM. I got a grounding block and going to not only to their original places but to this block. We shall see what today brings. So much for preventative maintainence. I am an old school mechanic 1970s-80s and then the issue was vacuum lines. They were awful. But, this ain't a lot better.

Would love to hear of what solved the issues