Stephenrod

i have a problem with acceleration, it bogs when i give it a little gas and pops. i have change the plug wires. i am getting a code P0141, but i haven't changed the O2 sensor yet yet would that be causing the car to bog?
any info would be helpful. thanks

nus_dogg

That maybe why. Even though the CEL is on, it doesn't mean that its the 02 sensor itself. There's a problem in that circuit which you'll have to get it diagnose.

TheMuffinMan

iTrader: (1)

Changes the wires but not the plugs? Seems not worth the time. Change out the plugs.

Clean out the injectors

Fix the O2 sensor

joe_accord23

doesnt always mean its the sensor, chk the wires, fuel pump filter,thecode is juust an idea of wut the problem could be and friend.................its V-TEC not Vortec!

sgraham01

p0141 is for the after cat o2 heater circuit. this usually means the heating element in the sensor is bad, but not necessarily. you need to check the resistance through the heater using the leads coming off the sensor. I think it's the two black wires. if you have no continuity, then the heater is bad and the sensor would have to be replaced. however, this problem should not affect driveability.

f22a1 ftw

its vtec not vortec...vortec is for fords

MAD_MIKE

Vortec is what GM calls its line of gasoline truck engines.

f22a1 ftw

oh w/e im not a huge usdm fan all i know is my uncle had a badass 357 votec in his s10 and it hauled ohwell..

Stephenrod

ok my bad v-tec i'm helping out a friend here. i'm a chevy guy got chevy in the brain.
but any way the CEL is not on. changed plug wires and checked O2 and is bad. did a brake test and it will not go over a 1k RPM. checked fuel pressure key on 35 running 40-45.

Stephenrod

just got through cleaning the EGR ports and checked the mechanical timing everything is good. i am still getting the stumbling and backfire through the intake while in park. what else could it be please help iam stuck. thank you afor any info.

sgraham01

test the heater circuit in the o2 sensor before you do anything else. unplug the rear (after-cat) o2 sensor and check the resistance of the heating element with an ohmeter. should be the 2 terminals at the bottom of the connector (opposite the retaining clip). if there is no continuity or the resistance is out side the range of 10-40 ohms, the sensor will have to be replaced unless you want to bypass the heater with a resistor. if you find that the heater is bad, you can cut the two wires of the o2 sensor harness (NOT the main wiring harness, but the wires attached to the sensor) and connect one wire to each end of a 15-35 ohm resistor. doesn't matter what value, just stay in that range. I would suggest 30-35 ohm to reduce power comsumption. at 35 ohm, you would need a 5W capable resistor. you may be able to get one at radio shack. I bought some there the other day.

this will simulate a functioning o2 heater and should get rid of the code. Either replace the sensor, or bypass the heater and go from there on diagnosis. My feeling is that it won't solve the problem, but you never know.

also, you should probably be getting other codes as well if you are having a backfire issue.

Are you sure that's the only code?

Stephenrod

i have replaced the down stream o2 sensor cause i was getting a lean code 0141. iwas told i had to drive it 25 milesto see if i was going to get a lean code again. but only made it to 15. it would accelerate slowly and backfire through the intake. i could barely make it through the intersection. had a hard time getting it past 60.
yes i ha d only one code that is all my scanner could pick up

sgraham01

check for a clogged cat. that sounds like a good thing to check since you have no pre cat codes. a clogged cat could create a lean reading on the rear 02 and high exhaust restriction.

Stephenrod

how could i check it properly. do i have to disconnect it disconnect it?

sgraham01

as far as i know the only way to check it properly is to unbolt it and look into the front of it. It's not that difficult to unlbolt. you will likely need to unbolt the hanger behind the cat so that you can drop the whole pipe down to look inside. if your cat is bolted in at each end, you can unbolt just the cat. If you see that the screen inside is clogged or broken up, replace it before driving it again (unless you have to drive it to the exhaust shop of course). just take it easy and keep the RPM low. keep me posted, i'm curious to see what it looks like.

Stephenrod

i disconnected the down pipe from the manifold and turned it on to see if the restriction was causing it, but it not that it is still doing the same i will take it apart further and check the internal of the Cat. do you think it might be the distributor?

sgraham01

I would get a timing light and check the timing.
on an OBD2 vehicle, you should be getting other codes for misfires as well.

I would still check the cat. If you run the car with the downpipe disconnected, you will definitely get a rear o2 code since it isn't seeing any exhaust flow. however if it's still backfiring with the downpipe off, it's probably not the cat. I'd still look at it though to aid in the o2 sensor diagnosis.

Stephenrod

i finished checking the cat and all i see is the screen and it looks good just arust color no other particle going to put it back together and check the timing

Stephenrod

i haven't changed my plugs i just cleaned them, you think they could still be fouled out and be causing it to act this way?

sgraham01

you should only get a misfire with a fouled plug. if you are having a backfire problem, I don't know what to tell you to be honest. if you are really having combustion take place in the intake manifold, maybe you have a broken intake valve spring or something. I would run a compression check on each cylinder to rule out bad valves.

Stephenrod

so how do i get a bad valve? i will check compression next. could the distributor cause it?

sgraham01

it's not likely, but sometimes valve springs just break. It's only an idea, but that would let the air/fuel mixture get forced back into the intake manifold and it will be forced out at high pressure which is when the mixture gets ignited. Basically, the mixture would start leaking into the intake at around the time the plug fires and burn inside the intake. I'm just throwing that out there. just check the compression and may will rule that out.

Stephenrod

just did a compression check had to go buy a gauge. every cylinder is at 100. could it be the distributor?

sgraham01

i can't say if it's the dist. once you check the timing, you'll be able to know if the dist. if firing it correctly. maybe the ignition control module is going bad, but I still think you should be having more codes, edpecially with OBD2. I'm not sure why you aren't. sometimes if a car is running that poorly with no codes, the ECM can be at fault since it doesn't see the problem.

Stephenrod

ok i think i have located the problem sgraham01. the injector voltage is .03 at idle at lil acceleration the vot\ltage jumps to .12, so some thing is causing the injectors to dump alot of fuel at one time. the TPS would be the cause but by the reading on the scanner it is operating properly. though the CEL is not coming on when codes are present and the low fuel light not working i am assuming the ECM is the problem. iw ill be changing today. iwill let you know the results. thank again for your help.