How To Clean Throttle body and intake plenum

[widlin1]

How do you clean the intake plenum and throttle body? I bought a 97 Taurus wagon that was missing on cylinder 2 and lean in bank one. I built a an injector cleaner and ran the car on a 50% mixture of gas and Sea Foam at 47 psi, which help but not as much as I had hoped. The previous owner told me he changed the plugs and wires but there were two un-used plugs in the back storage container so I pulled the upper plenum off to check all the plugs the number 1 and 2 are different from the rest. But I noticed it says on the throttle body not to clean it because of a special coating. However the backside is covered in brown and black residues and so is the intake plenum and I guess what I am going to call the secondary throttles next to the main intake for each valve. I also looked at the valves and all the valves except number 3 intake are clean so I guess the injector cleaner did work. Back to my original question. How do you clean the intake and throttle body without damaging the special coating? Also I noticed that the vacuum line from the intake plenum to the fuel pressure regulator was off, could that affect the idle or only the high speed?

Thanks

Jeff

[sfontain]

Originally Posted by widlin1

How do you clean the intake plenum and throttle body? I bought a 97 Taurus wagon that was missing on cylinder 2 and lean in bank one. I built a an injector cleaner and ran the car on a 50% mixture of gas and Sea Foam at 47 psi, which help but not as much as I had hoped. The previous owner told me he changed the plugs and wires but there were two un-used plugs in the back storage container so I pulled the upper plenum off to check all the plugs the number 1 and 2 are different from the rest. But I noticed it says on the throttle body not to clean it because of a special coating. However the backside is covered in brown and black residues and so is the intake plenum and I guess what I am going to call the secondary throttles next to the main intake for each valve. I also looked at the valves and all the valves except number 3 intake are clean so I guess the injector cleaner did work. Back to my original question. How do you clean the intake and throttle body without damaging the special coating? Also I noticed that the vacuum line from the intake plenum to the fuel pressure regulator was off, could that affect the idle or only the high speed?

Thanks

Jeff

I will say it's "generally believed" that the "special coating" does nothing, but I guess I would avoid brushing the TB/intake with anything; still, I doubt you'll do much harm if you do. If you want to take everything apart, you can soak the TB and intake manifold in a cleaner; if not, you can run the engine and open the throttle manually and slowly squirt about an entire can of carb or throttle body cleaner in there (try not to stall the vehicle)--it won't be as good as the soaking, but it's better than your current situation.

You definitely need to change those plugs. It's BS that the guy changes four plugs and tells you he changed the plugs. I would at least replace those two that you found in the trunk, making sure that the others match, but, while you're at it, if the four he did change are showing much wear at all, I would just replace them all--$15 for a set of Autolite Platinums.

If the plugs don't solve your misfire, you may need new wires or a new injector.

Another thing I would do is clean your MAF sensor, which is easiest done by squirting the wires inside with electrical cleaner (safest) or carb cleaner (okay too but not the "proper" way). You can get generic carb cleaner for $1 at Wal*Mart.

The more gas you need (e.g., the faster you are going, give or take), the more the vacuum line off the fuel pressure regularly will hurt you. As you open the throttle, the vacuum in the intake lessens, causing the pressure regulator to allow more fuel per time into the rail. So I'm thinking with no vacuum you have more fuel pressure than is necessary, but your computer may be compensating by shortening the injector pulses. Definitely reattach; make sure you feel a vacuum at idle at the end of the hose.

Sounds like you had the codes read, but is the car running poorly too? Let us know about your progress.

[way2old]

Various companies now make a throttle body cleaner that is safe for the bore coating. Just do not brush heavily.
The line off the regulator will cause the vehicle to run rich. Eventually causing emission problems and poor performance due to fouling of the plugs.

[widlin1]

Thanks for the advice. This weekend melted away and I got nothing done on the car except for sprying some carb cleaner on the throttle plates in bottom half of the intake plenum. It has help clean them. I plan on getting some plugs and throttle body cleaner at lunch tommorrow and then continuing if boy scouts dosent take the last remain in day light.

Thanks

Jeff

[bbrd177]

Originally Posted by widlin1

How do you clean the intake plenum and throttle body? I bought a 97 Taurus wagon that was missing on cylinder 2 and lean in bank one.
Jeff

Hey Jeff,
I had a 91 with idle problems. Pulled the injectors and took them to a local community college auto-tech class. The instructor had his students run my injectors on a cleaning machine circulating a solvent. The cleaning improved the spray cone and stopped leakage that was screwing up the idle speed. I plugged them back in and got 34 miles to the gallon on a long trip. I could not believe the calcuator when I ran the MPG. You might check into a local tech school to do the same.

Good luck

[maspoon]

be careful not to over heat the cat converters when using cleaners that you spray directly into the intake with the car running, also you can take the mas air sensor apart and clean it just be careful not to damage the wires when cleaning them.

also you might as well change the fuel filter while youre at it