6.0 LS running poorly

Sawzall · Jul 27, 2015

KyTrash said:
Chris , do you have water standing around the knock sensors ?

That was the problem with mine. Timing would go to a -15 degrees under acceleration and the buggy would fall on it's face. It ran fine under light throttle. I built a silicone dam around the new sensors.

bighook · Jul 27, 2015

Knock sensor issue would effect both banks. I would be looking at o2 readings. Swap from side to side and see if problem moves

1tfrot · Jul 27, 2015

what harness are you using? I had a similar issue and it ended up being a voltage jump in one of coil packs that was messing with an injector.

good luck

wizzo · Jul 27, 2015

1tfrot said:
what harness are you using? I had a similar issue and it ended up being a voltage jump in one of coil packs that was messing with an injector.

good luck

Stock harness that I cut down. I'd like to hear more

1tfrot · Jul 27, 2015

wizzo said:
Stock harness that I cut down. I'd like to hear more

from what I understand (sorry for lack of technical terms), but I think he (tuner) stated that the pins were soldered and he thought it was arcing and causing the voltage issue. he repinned that one and then did some tuning. haven't had it out yet to really beat on it, but it felt like it was running pretty strong after that session.

it was causing the motor to run a little rough, mostly at lower rpms. it would seem to "clear up" many times once we got into the higher rpm range. hopefully it's good to go now. will find out soon.

I do know it was a voltage issue for sure since he told me what he found before that tuning started.

redneckengineered · Jul 27, 2015

wizzo said:
Stock harness that I cut down. I'd like to hear more

This may sound stupid but have you checked grounds? Does the issue happen when you're hitting rough terrain i.e. maybe a wire getting vibration

wizzo · Jul 27, 2015

redneckengineered said:
This may sound stupid but have you checked grounds? Does the issue happen when you're hitting rough terrain i.e. maybe a wire getting vibration

The off idle running issue happens in park sitting in the shop. The only issue that happens when hit rough terrain was the throttle response cutting out on hellavator. All I know is I had it pinned and it was acting like it was at idle. It is weird b/c i was hitting jumps at the fair race events and bounced the buggy pretty good a couple times on crack head so is this a separate issue that just developed as well? I'm going to go over all wiring and connectors also.

Bumpers · Jul 28, 2015

Re:

It really "sounds" like a fuel issue but you have covered those bases it seems. I would get somebody with me with a scanner and ride to see if you can get it actin goofy and watch it to see what exactly its doing timing/fuel ect.

Computers can go bad as well.. had that happen before.

Also i would think it would throw a code but possibly a cam or crank sensor goin bad

extremetownie · Jul 28, 2015

It seemed to be running good when it was launching skyward on Crack Head.

redneckengineered · Jul 28, 2015

wizzo said:
The off idle running issue happens in park sitting in the shop. The only issue that happens when hit rough terrain was the throttle response cutting out on hellavator. All I know is I had it pinned and it was acting like it was at idle. It is weird b/c i was hitting jumps at the fair race events and bounced the buggy pretty good a couple times on crack head so is this a separate issue that just developed as well? I'm going to go over all wiring and connectors also.

Have someone pull the air cleaner while you cycle the throttle body. Make sure it's not a DBW pedal issue.

wizzo · Jul 28, 2015

Re:

Bumpers said:
It really "sounds" like a fuel issue but you have covered those bases it seems. I would get somebody with me with a scanner and ride to see if you can get it actin goofy and watch it to see what exactly its doing timing/fuel ect.

Computers can go bad as well.. had that happen before.

Also i would think it would throw a code but possibly a cam or crank sensor goin bad

Only thing I haven't checked in the fuel system is pulling the injectors and fuel rails.

extremetownie said:
It seemed to be running good when it was launching skyward on Crack Head.

Yeah, that was part of the day when it was running pretty good with the MAP sensor unplugged. I was pretty happy to finally climb that obstacle. :driving:

yankster · Jul 28, 2015

zjtrey said:
have you checked for intake leaks? I know its a fairly common problem on these motors in the stock configurations so maybe its worth a quick starter fluid spray test… just a .02 thought

I had a 6.0 in a Yukon throw this code and the silicone rings on one of the intake gaskets had deteriorated and was sucking air.

muddinmetal · Jul 28, 2015

yankster said:
I had a 6.0 in a Yukon throw this code and the silicone rings on one of the intake gaskets had deteriorated and was sucking air.

That does explain the one bank lean condition, but surely he would have sprayed the intake too while checking vacuum leaks :dunno:

wizzo · Jul 28, 2015

muddinmetal said:
That does explain the one bank lean condition, but surely he would have sprayed the intake too while checking vacuum leaks

I sprayed what I could get to around the intake. It is pretty much impossible to spray underneath the intake. I may give it another go.

pholmann · Jul 28, 2015

Just a thought but have you checked for water in your fuel?

redneckengineered · Jul 28, 2015

Have you checked the tailpipe, for a banana?

Banana in the tailpipe!

pholmann · Jul 28, 2015

Fuel cells are awful for collecting water in the bottom.

muddinmetal · Jul 28, 2015

pholmann said:
Fuel cells are awful for collecting water in the bottom.

The first thing a coworker said when we were all brainstorming the possibilities :****:

wizzo · Jul 28, 2015

redneckengineered said:
Have you checked the tailpipe, for a banana?

No but you know the jokers I run with....... but I've worn Josh out about this issue, surely at this point he would have given in! or would he.........

pholmann said:
Fuel cells are awful for collecting water in the bottom.

Since this started in Harlan, I had thought maybe I got **** fuel there. But I've ran at least 10 gallons of fuel through it since then at this point. I've got a 15 gallon cell. Would water still be in the bottom of the cell?

I really do appreciate everyone's input so keep the idea's coming. I will post up what fixes it when I work on it and figure it out. I'm going to do my best to change 1 thing at a time.

zjtrey · Jul 28, 2015

are you running the foam under the intake? might prevent the fumes from getting in there…

on a side subject to most guys run the foam? I did when i had an LS. not sure if it would help or hurt the water in the knocks issue