GMC Truck Forum banner
1 - 20 of 33 Posts

·
Drive It Like Ya Stole It
Joined
·
6,656 Posts
Discussion Starter · #1 ·
Some of you might have ready my engine problems. Here is the deal now. I fixed the IAT sensor, it was bad wiring. Now my engine is still not running right. Its missfiring (SES blinks sometimes) and its still backfiring. No SES codes. Now I do have autotap, and can send a log to someone. I dont knwo what shit means. Should the fuel trim be teh same on both banks? Could a bad or goign bad o2 sensor be causing this?

BTW im running rear 02 sims
 

·
It's Jerry's World
Joined
·
3,573 Posts
maybe try ls1tech or ask allen, i dont think any of us will know how to Decipher the Values and whether or not they are right
 

·
HOT AIR BALLOON OWNER
Joined
·
14,932 Posts
Did ya try resetting the comp?

You talking S and L trims? :think:
 

·
To hell with BHO!!
Joined
·
2,645 Posts
OrangeCrush said:
maybe try ls1tech or ask allen, i dont think any of us will know how to Decipher the Values and whether or not they are right
Try BigTex or XLR8NSS on LS1Tech. They are big on the computer side of things. I dont see much of Allen on Tech.
 

·
internet bigot®
Joined
·
4,016 Posts
99Silver5.3 said:
Try BigTex or XLR8NSS on LS1Tech. They are big on the computer side of things. I dont see much of Allen on Tech.

thanks to flyer.. :anitoof:

anywhoo, what did you do to fix the wiring with the IAT??? tell me tell me...
 

·
heavy on the skinny pedal
Joined
·
1,732 Posts
do like i tolled you and go to allen and have your computer tuned for the headers you put on. I'm 90% sure that is your problem since your running rich.
 

·
internet bigot®
Joined
·
4,016 Posts
black4x4 said:
do like i tolled you and go to allen and have your computer tuned for the headers you put on. I'm 90% sure that is your problem since your running rich.

i really doubt the headers have anything to do with that. i put on new headers and had no problems.
 

·
Registered
Joined
·
1,816 Posts
I think de messed with the plug that goes to the IAT sensor, said it needs to be replaced. At least thats what I gathered from the static-y aim conversation :crazy:
 

·
heavy on the skinny pedal
Joined
·
1,732 Posts
onyx said:
i really doubt the headers have anything to do with that. i put on new headers and had no problems.
Yes but did you move the cats and remove the two rear o2 sensors. the reason i say its from the headers is because i use to frequent f-body forums and on ls1 equiped ones when you put long tube headers on you would have to move the cats farther back and run o2 censors and when people would do this it would cause the computer to make the car run rich and run like shit till they retuned. Maybe i am wrong thats why i said i was 90% sure, but to me it sounds like the same problem the f-body guys would have.
 

·
internet bigot®
Joined
·
4,016 Posts
black4x4 said:
Yes but did you move the cats and remove the two rear o2 sensors. the reason i say its from the headers is because i use to frequent f-body forums and on ls1 equiped ones when you put long tube headers on you would have to move the cats farther back and run o2 censors and when people would do this it would cause the computer to make the car run rich and run like shit till they retuned. Maybe i am wrong thats why i said i was 90% sure, but to me it sounds like the same problem the f-body guys would have.

thats only if they removed the cats. then it would be running rich. if the cats are still there then they are still doing there job of catching the Co2. unlike f-bodies though, when we put on longtubes, our cats stay in the same place and dont get moved.
 

·
Registered
Joined
·
1,816 Posts
DE's got moved though, and theres actually only one of them now. I don't see how that would change anything though, because as i understand it, the readings that determine the fuel stuff are taken before the cats from the front o2's, the rear o2's just tell the truck that the cats are there, which is why o2 simms work.

I also think that ASM would be smart enough to put the o2 sensor in the right spot to get the correct reading...

I think he has a bad 02 sensor.
 

·
HOT AIR BALLOON OWNER
Joined
·
14,932 Posts
Front O2s measure CLOSED LOOP A/F... Rear O2s are cat efficiency sensors.

That is all.
 

·
internet bigot®
Joined
·
4,016 Posts
Whifflebat said:
fuel stuff are taken before the cats from the front o2's, the rear o2's just tell the truck that the cats are there, which is why o2 simms work.

I also think that ASM would be smart enough to put the o2 sensor in the right spot to get the correct reading...

I think he has a bad 02 sensor.

:word: to all that... sounds good.
 

·
heavy on the skinny pedal
Joined
·
1,732 Posts
onyx said:
thats only if they removed the cats. then it would be running rich. if the cats are still there then they are still doing there job of catching the Co2. unlike f-bodies though, when we put on longtubes, our cats stay in the same place and dont get moved.
But if you would have seen the thrad were he said he only has one cat now and it is at the end of the y pipe you would now hes down one cat and has moved it. and i thought the o2 sims through the computer off not the cat because couldn't you remove the cat and leave the rear o2 censor and if the motor ran clean it would run fine. cause the back ones are for emmision and the front ones tell the computer if the motor is running rich or lean right.
 

·
HOT AIR BALLOON OWNER
Joined
·
14,932 Posts
If it does this crap at a COLD START I mean at like 80° coolant temp, it is NOT an O2 sensor problem. Those are off in Open Loop fueling (cold start and WOT).

I was under the impression, DE's MAF was a lil jacked up...
 

·
Drive It Like Ya Stole It
Joined
·
6,656 Posts
Discussion Starter · #18 ·
Well I did some invcestigating and work. I was misfiring bad in cylinenders 1, 7 and 8. Pulled the plugs and what do ya know, allll dirty and carbon covered. Bought some bosche platnums and oreillys wires and put them on. Nothinf fancy but at least as good as stock. Initial startup seems much smoother. In about 5 mniutes when Kailyn is done with her laptop im going to go hook it up and scan for misfires, clear the codes and do a test drive. I will post up what happens!
 

·
HOT AIR BALLOON OWNER
Joined
·
14,932 Posts
When I had the misfire due to bad plug wires, I got an SES after about 10 min and no TCC lockup due to that...

Odd there was no SES with that problem.
 
1 - 20 of 33 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top