I have a 93 Aerostar with 130,000 miles. It has performed perfectly since I purchased it new. I have not had to do anything to it except routine maintenance and breaks. About a month ago I noticed a little ping on acceleration and some times the check engine light would come on but after a while it would go out. Last week while I was driving to work it started to act like the ignition was cutting out at it would jerk around until I let of the accelerator. Then it would drive fine for a while. I also noticed if I tried to do a hard acceleration there was no power as if the engine was not getting enough gas.

I checked the OBD codes and here is what I got: 172, 181, 185, 186 and 187.

I checked the Chilton’s manual but the information it gives me for the codes is of very little help. They use abbreviations which are not referenced and I don't not know what they mean. An example is a reference to a “HEGO sensor”, what is that?<O:p</O:p
Any help diagnosing my problem would be appreciated.<O:p</O:p

Thanks<O:p></O:p>

Aero93<O:p></O:p>

 

The HEGO sensor it is referring to is the HEated Gas Oxygen sensor. Its referring to the O2 sensor. That would be a good place to start in solving your problems....if you could post descriptions of the other codes its giving then I could prolly help you with those too. And with 130,000 on it you need to replace the plugs, wires, and distributor cap & rotor (if so equipped). That will most likely cure your problems.

-John

 

The Chenck Engine Light is there to tell you that there is a problem, just because it went out, does not mean that the problem went away. Lecture done.

So here are your codes.

172 - Oxygen sensor not switching - system is or was lean - Single Right or Rear HO2S

181 - Fuel system was lean at part throttle Single Right or Rear HO2S

185 - Mass Air (MAF) output lower than expected

186 - Injector pulse width longer than expected or Mass Air Flow (MAF) lower than expected

187 - Injector pulse width shorter than expected or Mass Air Flow (MAF) higher than expected


With that millage I would say that your O2 is way past its prime. (and the reason for code 172 & 181)

Also it looks like your MAF sensor (that metal thing with a fishing line in it right next to the air box) is dirty/toast (I think it might be toast with all the codes.) I would first try cleaning it with electrical contact cleaner, if that does not work you are going to have to replace.

Do both as soon as possible, otherwise you are going to have to replace the cats too.

 

Actually TB cleaner works well too, sometimes even better than elec parts cleaner. The reason for this, is it is better at removing the type of gunk that you will find in an intake.

 

Yeah I had the same codes on a 1995 AWD with 231000 miles. Changed the 02 sensor, same codes. Cleaned the maf sensor and all codes gone and mileage went up a hair .

 

Why couldn't they just refer to ti as the O2 sensor. I must have looked through three of four books trying to get an explanation for this abreviation.

Thanks for you help.

 

I am an old time shade tree mechanic that used to work on cars before the addition of all the polution controls and the addition of the computer. I was a little affraid to try to work on my car because I did not recognize much of what I was looking at. This was my first attempt and was very successful. You analysis was righ on. I replaced the O2 senser and reset the memory first to see what would happen. The 172 code cleared and has not returned. I repeated this same procedure with the mass air flow sensor and all codes cleared and the old Aerostar is running like new.

By the way I new the engine warning light was telling me that something was going wrong but I just didn't know where to begin.

Thanks for your expert help.

Aero93

 

I decided to replace the mass air flow sensor since I have over 130,000 mile on the Aerostar. In the future if I want to clean the MAF with TB if you can tell me what that is. Is there any evidence that cleaning the MAF extends the life or improves it's performance.

Thanks
Aero93

 

TB= Throttle Body Cleaner, bassically an updated version of Carb Cleaner, but safe for O2s (which some Carb Cleaner is not.) I recomend Electrical Contact Cleaner (CNC version) because it does not leave a residue and there is no chance of damaging your MAF by using it.

Cleaning the MAF does extend it's life and your performance/fuel millage because that is what the computer uses to determine how much oxygen is comming in the system. They do get dirty because of the PCV valve going to the air box and Fords are notorious for hating K&N Filters because people over oil them and that oil is sucked onto that string (which reads the amount of O2 comming in.)

Todays modern computer controled cars do look daunting, but IMO are easier to work on because the computer does tell you what is wrong, instead of guessing. (I started wrenching on 60s/70s cars and sometimes it took forever to hunt down some issues.) And thanks to the computer age, we now have the internet where like minded people can congrigate and learn from each other.

Thats ok, now you know where to come if you have any more issues (or just want to chat.)

 

MAF air sensor does not detect amount of oxygen, but rather total amount of air. It can collect data about total air volume and density, velocity, and also humidity, though the computer does not neccesarily use all the features. When combined with the readings from the O2 sensor, it allows for very accuracte fuel mixtures. If the MAF fails, the computer will still operate within reasonable parameters, but performance will greatly suffer. This is not as bad as the limp mode however. If the O2 goes out, then the computer switches into limp mode and performance and fuel economy will really plummet. If both go out, then the 2 most important sensors for controlling fuel economy are gone. The computer must not rely almost entirely upon preset values and the TPS (Throttle Position Sensor) to control the fuel mixture. Depending on a lot of factors, your performance may vary from mild unresponsiveness, to not running at all.