Tally TransAm

iTrader: (17)

i just finished installing heads on my car this weekend and everything went together fine. started it up, oil pressure is fine, everything seemed ok

now for the problem

took it for a test drive and it is stumbling noticably at low rpms and part throttle. sometimes it gets past the stumble and will behave normally , sometimes it keeps stumbling. its not backfiring, it just stumbles around and looses all power and the exhuast note changes. sometimes at idle it will also drop to like 500 rpms and act like it wants to stall. it also threw an SES light

i had a buddy atap the car when it was at idle and it showed codes P0300 (i thought i had this taken care of with the tuning for the cam) and P1133 (says HO2S Insufficient Switching Bank 1 Sensor 1).

some atap things my buddy said stood out to him was at idle:
Lterm B1 was fluctating around 20-25% and Lterm B2 was fluctating around -13 to -15%. these would also both come really close to zero as i reved the motor. also the Inj pulse B1 was between 5-6 and B2 between 2-3. he said this struck him as odd (i dont know anything about atap at all) and he guesses intake leak or exhuast leak (fairly certain i dont have an exhuast leak though)

can someone help me please. after all this work to have this happen im kinda depressed.

mods:
pp stg2 5.3's milled .015
224/581/112
ls6 intake
just about every bolt on
M6

thanks

Tally TransAm

iTrader: (17)

another question, after searching around here ive found that p1133 is usually related to the drivers side front 02 sensor. now this sensor worked fine before the install, however during the install coolant got all over the exterior of the sensor and the plugs for it (left the 02 sensors in the headers and just dropped them down). could this coolant just have dirtied the connectors? what could i use to clean them? could this problem cause all the symptons above?

FinalTA

iTrader: (1)

Well, it for sure sounds like your driver's side front O2 sensor is toast. Replace the sensor and see what happens?

gomer

iTrader: (13)

Also check the connection of the two vaccume hoses on the drivers side of the intake.. one goes to the AIR system and one goes to the intake, if you swith those two lines it will cause stumbling and SES lights.. I learned that on my first head swap! Also, check the ground connections on the back of the drivers head to make sure you didn't leave one of them off.. there are three on the drivers side head I belive.

Tally TransAm

iTrader: (17)

ground connections are good, i double checked that on install.

what lines are you talking about on the drivers side of the intake?

Darkhalf

iTrader: (1)

I would check for leaks around the intake area like previously mentioned.
It also sounds like you need to replace that O2. I have read that anything like antisieze or coolant getting on the O2 will destroy them.

Did you get any autotap readings from that O2? ie in mV?

blk~2000~Z28

I would have to agree that your only problem will most likely be that O2 sensor. I had a few missfires due to a faulty plug wire and I got that same front O2 code after running the car like that. My car ran like crap because it basically was going into gimp mode due to the lack of info from the sensor. Fix that 02 and reset your PCM and you should be fine.

Visceral

iTrader: (1)

Ive toasted at least one 02 sensor every time I did a head swap to my car. (shrug)

MTI was having problems after they did another head swap for me and they found the 02 sensors screwy too.

If you have any of the previously removed rear 02s around you can swap them in without a problem.

chris

Tally TransAm

iTrader: (17)

well i just swapped my "bad" front o2 with a buddies old rear o2 sensor.

hope it worked

oldschool68

sounds like you have a vacuum leak by your fuel trims. i am a ford driveability tech. i've never seen antifreeze ruin an 02 sensor from the OUTSIDE but if any gets on the actual sensor portion then that will kill them. i'd check into that vacuum line thing the other guy said if the O2 doesn't fix it.

Tally TransAm

iTrader: (17)

i swapped out the front o2 sensor and reset the codes and the car runs great. so as of now im pretty convinved that was the problem because i just put like 12 miles on the car and i ran beautifully

(nice power increase to )

Tally TransAm

iTrader: (17)

well the car is stumbling all over the place again this morning so i dont think it was the o2 sensor

i already have the intake off and everyhthing looks fine, i cant see any reason why it wouldnt seal. but im just gonna torque it back down and see what happens

any other ideas

this is getting really annoying

Visceral

iTrader: (1)

Intake vacuum or similar leak?

a vacuum leak on eone side, if bad enough could really mess things up... but I would expect the idle to be high, not the stubling 500 rpm.

I think it might be telling that you have a fine car when you reset the computer. I suspect one of your sensors is towing the tune way off. Perhaps a bad ground, or similar sensor issue.

Sorry to say this, but Im pretty sure you are going to have to find someone around with Autotap or similar.

chris

jmX

Crossed O2 wires will do this (if you have left plugged into right, and right into left), but that is more of a common thing on corvettes since the o2's are close together. If you go WOT, does the car run fine every time?

Tally TransAm

iTrader: (17)

i just put the intake back on and drove around for about 10 miles. the pcm was reset because i had the battery unplugged when i took off the intake. the car ran fine for those 10 miles and ran fine at WOT too

but this is also the same thing that happened last night. ran fine for 10-12 mile and this morning ran like crap

i can atap the car tomorrow and see what is going on, ill post the results here so you guys can take a look at them since i wouldnt even know what im looking at.

in about ten minutes im also going to check my header to block and header to ypipe connections to make sure i dont have any leaks there as well.

quick question, what are the lterm's supposed to be at idle?

any other ideas of things i should check or try and do. this is getting really annoying and i would really like to get this taken care of

jmX

So does it run fine if you got WOT right now? That could be a hint.

Louis

iTrader: (7)

Unplug a FRONT O2.

This will put the car into open loop. If the car runs fine, you have a problem with something when it goes into closed loop ( Would explain why it runs fine when cold)

Check for frayed 02 wires, leaks, ect.

what longtubes do you have?

EDIT: Front 02

Tally TransAm

iTrader: (17)

i have macs

heres an update:

i got the manifold torqued back down to spec, i also dropped the drivers side header down and bolted it back up to make sure there were no leaks. and i unbolted the drivers side collector from the ypipe and bolted it back up to make sure there was no leaks there either. did the drivers side since atap showed problems on bank1. there are no exhuast leaks period, and i really dont think the intake is leaking either

i got in to test drive it and for the first 1-2 minutes it was surging and didnt want to get up and go. after that for the next 15 miles until i got home it drove perfect. fine at cruising, fine at WOT. no problems at all

you think i should unplug front 02, one or both? if it drives fine then, where should i look after that to find/solve the problem, what if it surges with the o2's unplugged, where should i look then??

thanks

Tally TransAm

iTrader: (17)

its been just over 40 miles since i redid the intake and exhuast this morning and no SES light (yet, knock on wood)

the thing is it still stumbles really bad but it ONLY does it when the car is COLD. as soon as it hits normal operating temp it runs fine. what could be causing this, does this sound like a problem only in open loop mode

im sure the atap files will help a ton and ill have them tomorrow and ill post them here, im just getting really annoyed and frustrated that i cant get this fixed

any help would be appreciated big time and i really appreciate all the tips so far, but i just cant seem to get this solved

Louis

iTrader: (7)

Are you saying it ran fine when it was cold, now it doesnt run fine when its cold, but runs fine when its warm?


Please clarify for me