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Problem after cleaning throttle body

46844 Views 150 Replies 18 Participants Last post by  Bjay
So last night I removed my throttle body to clean it and had to gently use a copper wire brush to get some of the gunk off, also is it bad to spray the tb cleaner down the copper pipe that connects to the fuel line? It ran fine last night but this morning when I started it, it was sputtering and the cel was flashing then stayed solid. Seems to run fine aside from the start up issue. About to get the code read
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What's the code?

Very likely by spraying down the breather tube (no gas line on the throttle body) you dislodged some gunk inside the tube and it could be clogging the breather port.

You didn't spray the electrical connector or throttle motor did you?

As for the copper brush, next time use an old toothbrush. It should be fine but depending on the alloys, the brush could be harder than the aluminum of the TB.
Codes that came back:
Freeze Frame -> P0507 idle control system rpm higher than expected
Pending -> P0171 system too lean (bank 1)

Electrical connector I did not spray that
I'm not sure I know what the throttle motor is.. The part that the electrical connector goes to? If so, I don't believe I did unless a little overspray got to it.

Both of those codes I've gotten before but they seem to come and go. They came after I put on a Volant cai and mbrp exhaust

All the hoses seem connected just right but I did notice that the grey clip which holds the fuel line to the throttle body is loose and I actually had to push the fuel line back on
As long as the butterfly is closing as far as it is meant to for idle it shouldn't cause a lean condition. It will not fully close of course. If it's got a lean condition the system is registering an intake leak someplace, or the butterfly can't close far enough and it's sucking in more air into the intake.

Did you scratch the throat of the throttle body with the brush?
Try erasing the codes, disconnecting the battery for a bit and see if the codes come back.
I didn't notice any scratches when I inspected it before putting it back on last night. I also didn't put force on the brush, I just moved it back and forth enough to remove the gunk. There's a miniature gap between the butterfly and throat but I assumed that was normal.

I turned the ignition on and off about 4 times consecutively and the cel turned off but the P0507 code was still stored and a pending code that didn't show.

I also cleaned the MAF sensor when I did the tb. I forgot to mention that I only removed the positive cable from the battery instead of removing both cables
I'm 99.9% certain that lean bank code is coming from a hose that's either not put back on or leaking. Double check that the hose is plugged back in and if so put a tye wrap around it.
I noticed that the hose behind the resonator box looks dry rotted and flimsy so I'm hoping that's the culprit
So another code popped up when I got to Oreilly's.. P0300
That leaky hose can cause all kind of wild stuff. Get it fixed then reset everything
Ok so I couldn't find an exact replacement hose so the guy at Oreilly cut me a 3" inch piece of 1/2" diameter hose and some clamps for $3. Decided to clean the MAF Sensor again, take apart and re-install the volant intake to make sure everything is on good and tighten all hoses and clamps. I got the hose put on and started up the truck after having the battery disconnected for a few hours, seemed fine and no cel so I'm praying that fixed it
Here's what my throttle body looks like when it's closed and a picture of the hose that connects to the resonator


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That hose was pretty cracked-up...hoping you fix'd all the intake gremlins. Keep us posted...
I replaced the hose last night and let it sit overnight, started it up this morning and it's still a rough idle. It jumps up to around 1100 rpm and slowly drops to around 800 and that's when the rough idle/shaking/stuttering starts.

Under normal driving conditions the rpms are at about 650 at a stop light and going 35-40 mph it's between 1500-2000 rpm. I don't notice any lagging/hesitation or loss of power. The temperature stays right around the half mark (been that way since I got the truck last year)
Also the check engine light has not come back on yet. I'm just trying to figure out why it started doing all this after I cleaned the throttle body on Thursday
It might have something to do with the battery disconnect. Common safety practice is to remove the negative battery cable first. That prevents shorting the battery if the wrench touches something metal while loosening the connection. Not sure why disconnecting only the positive cable would have any affect, but most guys don't get a P0507 after cleaning the throttle body.

Interesting; a guy over at C'Fans got the P0507 TC after he cleaned his throttle body without disconnecting the battery. Maybe coincidence. Cleaned TB, P0507, weird idle. - Chevy Colorado & GMC Canyon
Well both times that I've disconnected the battery I took the positive off first, my battery has died on me before so I'll go get it tested.

Read the link and it doesn't give the same issues as me. All my rpms seem normal while driving, it's just the initial start up that has the idling/rpm issue and that's why I'm stumped
Also noticed that while it's going thorough the rough idle it sounds like a big v8 does when it's idling, could that have something to do with back pressure of the exhaust? I remember when I got my inspection back in September that the catalytic converter wouldn't switch to a ready status
Did you try disconnecting the battery (both cables) to see if anything changed? Cleaning the throttle body may have changed the idle speed. The PCM "watches RPM and adjusts the throttle plate to adjust idle. If the PCM is "stuck on" the old setting and the idle if off by 150 rpm the DTC will set.

I am assuming that we aren't discussing the P0171, as you said that it was there prior to the throttle body cleaning, and could very well be caused by your aftermarket intake installation.
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