How do I clean out my fuel system?

[TheV6Bird]

I have a 95 3.4 A4 w/ 99,700 on the odo.

Recently, my car has been idleing VERY rough when I cold start it. It is fine when the car warms up. (The car sounds awesome when it is cold in this rough condition, though [img]smile.gif[/img] )

I have a feeling my fuel system is dirty. I want to clean out the throttle body. How do I go about doing this? Take off the rubber inlet and spray some cleaner? What kind of cleaner? Carb cleaner?

I also want to pour in some Chevron fuel system treatment as well.

When I get the time (and the balls), I may change the fuel filter as well.

[RamAir95TA]

Never use carb cleaner on a fuel injected engine. Most throttle body blades and components have an anti-carbon coating on them, and the caustic ingredients in carb cleaner will corrode the coating, inviting the opportunity for buildup.

Using a bottle of fuel system cleaner and changing your fuel filter is about all you can do. Cleaning your injectors would be another step. If you want to get drastic, you can drop the tank, flush out all the dirt at the bottom and replace the filter sock on the fuel bucket.

You'd be amazed at how much dirt is in your gas tank. [img]smile.gif[/img]

[Dmitriy]

In addition to what RamAir95TA suggested, you can buy some Throttle Body and Intake Cleaner - it is sprayed into the throttle body while your car is running.

[ssbauer]

I use Sea Foam ;)

It works.

[Christian]

<blockquote>quote:</font><hr>Originally posted by Dmitriy:
In addition to what RamAir95TA suggested, you can buy some Throttle Body and Intake Cleaner - it is sprayed into the throttle body while your car is running.<hr></blockquote>

Are there any do's and dont's about doing this, I hate messing with parts when it requires a liquid, just me I guess. Any tips???

[RamAir95TA]

Use throttle body or fuel injection cleaner. Those are made to prevent damage to sensors (IAC, etc.).

Sea Foam does not clean the fuel system, but rather cleans carbon buildup on piston tops, valve stems, cylinder walls, exhaust ports, intake ports, etc., any place where carbon can build up.

[Dmitriy]

<blockquote>quote:</font><hr>Originally posted by Christian:


Are there any do's and dont's about doing this, I hate messing with parts when it requires a liquid, just me I guess. Any tips???<hr></blockquote>


Just follow the instructions on the bottle. I used this product three times while performing tune-ups on my car. Usually my car misfired for about 5 minutes after this cleaning and then ran fine. Last time, however, the engine did not stop misfiring and even died a few times. I resetted the pcm and it fixed the problem.

[RamAir95TA]

The reason it fixed itself after you reset the PCM is because when the PCM is reset, the IAC stepper motor reset itself after the gunk was cleaned off of it. [img]smile.gif[/img]

[Christian]

<blockquote>quote:</font><hr>Originally posted by RamAir95TA:
The reason it fixed itself after you reset the PCM is because when the PCM is reset, the IAC stepper motor reset itself after the gunk was cleaned off of it. [img]smile.gif[/img] <hr></blockquote>

In the event that I have a similar pblm with misfiring (GOD forbid). How is that done?

[RamAir95TA]

If you're OBDI, pull the PCM fuse for a few seconds and reinstall.

If you're OBDII, pull the fuse for a half hour or so. For some reason, OBDII requires a bit longer.

NEVER pull the fuse with the key in the 'ON' position, because you risk damaging the PCM due to voltage spikes. You can also disconnect the battery if you'd rather.

[TheV6Bird]

Thanks for all the replies, guys! Good thing you told me about the misfiring with TB cleaner; I would've crapped a brick if that happened to me and I didn't know what to do.

I've never heard of Sea Foam. Is it a pour in your tank type thing, or do you need to spray it in (a la TB cleaner)?

[RamAir95TA]

Sea Foam is introduced into the engine by vacuum, picking a vacuum line of your choice (usually brake booster), and then flows through the engine, removing contaminents and carbon deposits. This site has a lot of good information (LT1-specific, but the jist of it is there). [img]smile.gif[/img]

http://w3.one.net/~roz/cars/z28/seafoam.html

[ssbauer]

Using a can of Sea Foam in the gas tank will help clean the fuel system.

In addition, Sea Foam Deep Creep can be sprayed on the throttle body...

[PewterBird]

I read another post you shouldn't pull the tb plate open, you can turn the key to on, then press on the gas to open the plate, don't get fingers caught up in there. Just FYI. [img]smile.gif[/img]

[TheV6Bird]

<blockquote>quote:</font><hr>Originally posted by RamAir95TA:
Sea Foam is introduced into the engine by vacuum, picking a vacuum line of your choice (usually brake booster), and then flows through the engine, removing contaminents and carbon deposits. This site has a lot of good information (LT1-specific, but the jist of it is there). [img]smile.gif[/img]

http://w3.one.net/~roz/cars/z28/seafoam.html<hr></blockquote>Thanks for the link! Too bad you have to do it before you change your oil, as I already changed mine. Oh well, I'll do it next time.