cleaned MAS and IAC, now what??? Opinions please!

[duketter]

Ok, my 99 4.0ohv explorer is still humming like crazy. Oh yeah, it also pings a lot and don't get me started on the other things with this thing! Only 33,000 miles on it too right now.

I cleaned both the MAS and IAC and it still hums really loud. Any ideas? Maybe clean them again? It is also really pinging.....

I took it to our Ford dealership here and they charged me $50 to tell me a possible solution to the pinging would be to run that motorcraft carbon cleaner through it for me. I can't remember the TSB on it but I have seen it in previous threads. They are going to charge me $175 for this. $175!!!!!!! That is crazy and he said this might not even fix it! What a joke.

I have seen threads on how to do it yourself with Seafoam but have many done this and is it easy? I don't want to lock up the engine or anything. Is it a delicate procedure? I know there is always risks.

Any other ideas/suggestions what to do about the humming and pinging? I am just frustrated!

Thanks!

 

[duketter]

I called another repair shop in town that I trust. They say they can do a carbon cleaning for $50 and then there is a $25 rebate. This is compared to $175 that my Ford dealership is going to charge me for this:

Engine - Carbon Knock On Acceleration
Article No:
01-19-7

10/01/01

ENGINE - 4.0L OHV - CARBON KNOCK ON ACCELERATION


NOISE - CARBON KNOCK ON ACCELERATION - VEHICLES EQUIPPED WITH 4.0L OHV ENGINE ONLY

FORD:
1990-1997 AEROSTAR
1990-2000 EXPLORER, RANGER

ISSUE
Some vehicles equipped with the 4.0L OHV engine may exhibit an engine noise which may be perceived by the customer as a piston/connecting rod bearing knock. This carbon knock is heard only under load during the drive cycle. Carbon knock is a customer drive duty-cycle phenomenon that cannot be repaired with an engine exchange. This may be caused by carbon build-up within the combustion chamber.

ACTION
Verify condition. If normal diagnostics fail to correct the condition, de-carbon the combustion chamber to help quiet the carbon knock noise. Refer to the following Service Procedure for details.

SERVICE PROCEDURE

1. Use Motorcraft Carburetor Tune-up Cleaner PM-3.

2. Carbon removal:

a. Disconnect canister purge line from throttle body.

b. Attach a vacuum line to the canister purge port.

c. At hot engine idle, allow the engine to ingest 1/2 to 2/3 of a can of Motorcraft Carburetor Tune-up Cleaner. Use caution not to ingest too quickly due to potential hydro-lock issues.

d. Shut engine off and allow it to soak for one hour.

e. Start engine, allow engine to ingest the remainder of the Motorcraft Carburetor Tune-up Gleaner.

f. Remove vacuum line and re-install canister purge line.

g. Road test vehicle at 3500 RPM for 2-3 miles.

h. Repeat above procedure two times for a total of three times.

i. Change oil and filter.

3. Review the customers' driving habits. The recommended drive cycle should include daily periods of engine operation above 3,000 RPM, such as a brisk acceleration from a stop position. This will break/burn the carbon off the piston head.

4. Use regular unleaded fuel, 87 Octane. Mid-grade and Premium fuels may increase the probability of carbon buildup, leading to a knock noise.


Is this essentially the same thing do you think that they will do? I guess I might have to stop down there and see.

 

[Alec]

Often cleaning the IAC makes the humming worse. You're gonna want to replace it, $70 from Ford.

As for the pinging, please describe everything you've done to try to help it, what gas you're using, and when it pings.

Thanks and good luck.

 

[duketter]

I have done what my Ford dealership recommended and that is this to solve pinging. They first asked me to use a higher grade fuel. I currently use 87 so i tried 91 for a tank or two. Didn't do anything and this can make it worse can't it?

Then I took it in to have them put it on a computer test and they say everything checks out ok as far as computer equipment and sensors in the vehicle. Now they say to do the carbon remover thing for $175 from them.

It pings when there is a load on the vehicle. Especially at highway speeds around 55-60mph. When I am just idling or have my foot off the gas pedal it does not ping.

 

[Alec]

You should get the carbon cleaning. However, my dealer and most mechanics only charged $80 for this.