Help....post tune codes

**97txaggie** · 06-08-2010, 04:07 PM

Okay - I did the whole Frost tune, and honestly it does seem to have more get up and go, but I still have bad missing at WOT. It threw codes about 2 blocks from home after re-installing the computer, but I didn't get to check it until I got home today after about 150 miles of driving it and a couple times of getting on it, in hopes it would just "fix itself"

ha ha. Anyway -
0300
0134
0154
0137

That's what I got -- multi-misfire, O2 sensor, O2 sensor, and knock sensor I believe....any ideas? I had suggested to me before the tune either bent push rod or broken valve spring. Would just the O2 sensors being bad cause it to run this bad? What sensors did you guys recommend if using LTs w/ ORY? (seemed like it was a corvette version, but anything particular?)

Any advice or help would be greatly appreciated -- I live in the midwest, so not a lot of speed shops or anything nearby!
Thanks!!!
Jay

**basballny2** · 06-08-2010, 04:28 PM

have you tried contacting frost? a bad o2 sensor and knock sensor will cause the car to not run right

**0rion** · 06-08-2010, 04:32 PM

300 is a random misfire, 134-154 are insuff. activity, and 137 is a rear sensor. Frost deletes those rear codes I think unless you tell him not to...not sure why that one is there.
Have you checked your fuel pressure and how many miles are on your fuel filter? Stock MAF and do you run a K&N filter? If K&N when was the last time you cleaned your MAF?

**97txaggie** · 06-08-2010, 05:20 PM

i do have K&N....never cleaned MAF, only had the car for about 2 months...not sure on fuel filter or pressure either...thanks for the ideas !!! i may be off on theone code too...pretty sure it said knock sensor and pretty sure Frost deleted the rear O2s. I did not contact Frost yet.....didn't want to be a pest

**0rion** · 06-08-2010, 05:22 PM

it sounds and most likely is mechanical......dirty MAF, low fuel pressure, vacuum leak. Something along those lines. Could even be bad O2's but I doubt it...sounds like it's from going WOT and running lean in which case the O2's aren't functioning. Clean your MAF and check fuel pressure and then go from there ( fuel pressure should be ~58psi).

**Frost** · 06-08-2010, 05:52 PM

Jacob L.? Is that you? If so...

0137 is disabled in your cal. For your boltons car, the rest of those codes are legit problems. The misfire(s) are real. That needs to be resolved because a hard misfire can cause O2 errors.

**Frost** · 06-08-2010, 05:53 PM

Knock sensor codes will cause the car to always be down 4 degrees of timing at WOT (max KR), so they hurt performance past the point of their lost protection.

**97txaggie** · 06-08-2010, 06:04 PM

Steve - not Jacob..this is one of the ones that Jones sent from Iowa. My name is Jay - their cousin. I probably wrote the code down wrong - I'm sure it was a knock sensor.

So could the low fuel pressureor MAF problem be the culprit for the misfires then? Sorry for all the stupid questions!!

**97txaggie** · 06-08-2010, 07:32 PM

looked at my notes again.....last code was 0327, not 0137.

**LETHALxLS1** · 06-08-2010, 09:48 PM

Dude- don't feel like your questions are stupid! These guy's are all cool people who like to help.

**0rion** · 06-08-2010, 10:20 PM

327 is for knock sensor 1 ( front sensor). The knock sensors ( 2 of them) are under the intake in the valley cover. I would recommend changing both since you'll be there anyhow. Normally it happens from moisture getting under there and killing the sensor so if you wash your engine down with a garden hose then stop doing that.

Gmpartsdirect will probably have the best price on those sensors. Swapping them is pretty straight forward and a fairly easy job if you're at all mechanically inclined. Step by step instructions for pulling the intake can be found at LS1howto.com under the intake swap link.

Check your fuel pressure and buy some MAF cleaner ( available at any parts store). CRC makes it and it's specifically for cleaning the MAF. I would probably personally change that fuel filter since you don't know the history of the car.....could be the original filter. It's located on the drivers side frame rail just in front of the back tire. Pretty easy job and cheap to do.

Post back up if you have any other questions.

**Frost** · 06-09-2010, 07:04 AM

For misfires, plugs and wires are culprit #1

**0rion** · 06-09-2010, 08:10 AM

Originally Posted by Frost

For misfires, plugs and wires are culprit #1

I guess my train of thought was that misfires from plugs/wires wouldn't show lean like that?? I've been wrong before though....many times actually.

**97txaggie** · 06-09-2010, 02:18 PM

Even though I didn't put them in so I have no idea how many miles they have, we did pull the plugs and wires - they look to be good..NGK plugs in great shape by looks anyway - no visible arcing while dark or wet for that matter from wires either.

I hope to get the fuel filter tonight and see if I can find someone to check my fuel pressure before and after. I'll keep y'all informed in case it doesn't seem to be any different so we can move on from there.

BTW - is there a way to disable the knock sensors, or is that major no-no?

Thanks again for all the advice,
J

**Frost** · 06-09-2010, 02:21 PM

Originally Posted by 0rion

I guess my train of thought was that misfires from plugs/wires wouldn't show lean like that?? I've been wrong before though....many times actually.

Any misfires 'look' lean to the O2s. Unburned intake air passes right out of the exhaust valve and over the sensor.

**Z28Thunder** · 06-09-2010, 02:22 PM

Originally Posted by 97txaggie

Even though I didn't put them in so I have no idea how many miles they have, we did pull the plugs and wires - they look to be good..NGK plugs in great shape by looks anyway - no visible arcing while dark or wet for that matter from wires either.

I hope to get the fuel filter tonight and see if I can find someone to check my fuel pressure before and after. I'll keep y'all informed in case it doesn't seem to be any different so we can move on from there.

BTW - is there a way to disable the knock sensors, or is that major no-no?

Thanks again for all the advice,
J

Major no-no. The knock sensors prevent damage from detonation. I know many people run them but I would remove the NGK's. I know they are prone to foul and/or go bad.

**97txaggie** · 06-09-2010, 06:31 PM

The NGKs seem to have pretty good reviews on here -- what do you run Thunder? I had a 95 Z several years back and I always just ran the AC Delco plugs...but times change I spose.

J

**0rion** · 06-09-2010, 07:08 PM

Originally Posted by Z28Thunder

Major no-no. The knock sensors prevent damage from detonation. I know many people run them but I would remove the NGK's. I know they are prone to foul and/or go bad.

I've never had problems with NGK's. Even when I was learning to tune the car and was running questionable tuning they held up just fine.

**JayTA98** · 06-09-2010, 07:24 PM

If you do need to replace the knock sensors, be careful not to break the oil sender unit (oil sensor). Is behind the intake manifold and the electrical wire is looped around the brake booster line. I broke mine while changing my LS1 intake for LS6. Be sure to unplug the electrical plug that goes to the sensor and remove the brake booster hose if you can. Most instructions on removing the intake online don't mention about the oil sender unit. just my 2 cents.