1993 Aerostar 3.0L

The plastic tube coming from the air filter closets to the engine. Help me out if this is wrong the Air intake. Stalls the van when I remove the tube while the engine is running. If the van is about to stall and I put the tube back on it prevents the van from stalling. I'm not 100% sure this is normal, because I swear I had taken this off before without the van stalling. The main reason I even took it off was because the engine was shaking like crazy and I had a bright Idea to spray some cleaner in there. Here are some changes I have made leading up to this discover. Changed the radiator, water pump, power steering pump, spark plugs, spark plug wires, distributor cap and button. I took the van for a spin after this and it stalled making a sharp right turn going slow. Am I worried over nothing?

 

First, greetings and welcome to the FTE Aerostar forum.

The Mass AirFlow Sensor (MAF) is located within that '"tube" at the point where you see the wiring connector. It senses the volume of air being drawn into the engine and allows the engine controller (e.g. the computer brain) to send the correct amount fuel through the injectors. When you pull this tube off when the engine is running you upset the fuel/air balance thus the engine begins to run poorly.

My initial thought concerning the stalling is either the MAF sensor is still disconnected or you mis-routed two plug wires causing the engine to stall a low speeds. Mis-routed leads seem to be a commonly reported error even though everyone swears they were careful when replacing them. I would recheck these first.

 

I agree with Aerocolorado, check the routing of your plug wires. Also check that they are not crossing over each other.

Since the stalling you are experiencing was happening before you changed the plugs and plug wires, another thing to check if your engine is stalling on idle is the idle air bypass valve. It is known to cause problems when it becomes dirty. Some forum users have successfully cleaned it, but it's hard to do and it seems to me that the best bet is to simply replace it. The air bypass valve is located on the intake body just to the right of the air intake tube you are talking about. Just to the left of it is the throttle position sensor.

Just a thought.

Ron

 

Last year I bought a new Mass Air Flow Sensor. I wonder if this is the problem. Instead of taking it back to find a the correct one I just used it because the pins matched up. The only difference was the connector clip was on the opposite side and the guide pin was on the front instead of the side. At the time on the website it only had one picture to view and I didn't
provide any part number. The old sensor was still in the van so I didn't have it out with me to compare. So I've been using sensor 1 instead of 2 for a year.

1.
Mass Air Flow Sensor - Reman.; ID #F27F-AA
http://www.partsamerica.com/ProductD...pe=473&ptset=A

2.
Mass Air Flow Sensor - Reman.; ID #F37F 12B579-DA
http://www.partsamerica.com/ProductD...pe=473&ptset=A

Last night I didn't get to play with it much. I took it for the emissions test and it failed. Here are the readings

MODE: IDLE
CO%
Limit 1.00 : Reading 0.05 : Result Pass
HC ppm
Limit 130 : Reading 146 : Result FAIL
RPM
Reading 710 Valid
DILUTION
Reading 14.2 Result Valid

MODE: 2500 RPM
CO%
Limit 1.00 : Reading 1.16 : Result FAIL
HC ppm
Limit 130 : Reading 50 : Result PASS
RPM
Reading 2512 Valid
DILUTION
Reading 15.2 Result Valid

Overall Test Results: FAILED

Emissions Control Systems Visual/Functinal Inspection: Pass
Tailpipe Emissions Inspection: FAIL

I'm thinking about changing the Oxygen Sensor. This is the only major emissions device I haven't changed in 2 years. My check engine light is coming on while driving also. It comes on and off while driving and is driving me crazy. So instead of wasting money again paying someone to read the codes. I'm going to put the money into a code reader.

 

You really need to carefully recheck those wires.. Before you replace the sensor

HC at idle is high indicating a possible misfire...
(Can also indicate worn engine but would usually read much higher)

Does it run rough at idle?

Let us know the codes...

 

Ya, It runs rough at idle. I am going now to pick up a code reader and after that I'm going to recheck the wires.

 

The system code I got was 172

Scanner tool book describes it as:
(Heated Exhaust Gas Oxygen (HEGO) sensor voltage signal indicates "lean" (Bank #1))

Haynes Manual describes it as:
Heated oxygen sensor indicates lean condition, right side

Chilten Manual describes it as:
No HEGO switching detected, indicates lean (right)

Here is the beep code sequence I got 111,111,1,172,172

Does this mean the oxygen sensor needs replaced or is there something else wrong?

 

Yes I think that meant your O2 sensor needs to be replaced. When mine failed, it also indicated a "lean condition" so the computer kept on pouring more gas into it, making the mixture way too rich.

 

UPDATE on emissions test. Changed Oxygen sensor saturday based on the code I got from the code reader. My check engine light never came on again after that the whole day. Took the van down to the shop on sunday for a retest and it passed with flying colors.