Hi,

We have a 1993 Ford Aerostar 4wd Eddie Bauer edition. This van has 150,000 miles on it. In the past 2 years we've had a number of problems related to the van idling hard and having a lack of power.

First, the van revved high and low and was unable to maintain a steady idle....I replaced the throttle positioning sensor and this fixed the problem. Next, the van was running sluggish and was very slow to respond when you pushed the accelerator....I replaced the oxygen sensor and it fixed the problem.

Currently, (a few months after changing the oxygen sensor and the problem being temporarily fixed) the van is having the same issue as before I replaced the O2 sensor (running sluggish and slow to respond to the accelerator). If you press the accelerator down (even to the floor) it barely responds, you can get it driving at highways speeds but it takes a long time to baby it up to those speeds. When you let off the accelerator after pressing the petal down it actually sometimes gets a second of power. It also is not maintaining a stable idle (fluxtuating between high and nearly dying). I bought a new 02 sensor and installed it but it didn't fix the problem this time. The exhaust smells rich in gas if that helps.

Can anyone think of what else might make the van run like this? Possible solutions for where to look next?

Thanks!

 

Did you check the simple things, like the spark plugs, fuel pressure, or run the EEC self-test? Besides that, when was the last time the fuel filter was changed?

The less simple thing I would suspect would be the ignition system. Your Aerostar uses EDIS, which includes the control module mounted on the right inner fender, and the coil pack mounted to the right of the right valve cover. Those have been known to go bad, causing weak performance like you describe. If your spark plugs are wet, this could be the problem.

Run the EEC self-test first if you haven't yet; that should point you toward the problem.

 

Hi xlt4wd90,

Thanks for your reply, I actually have not checked the spark plugs or fuel pressure...nor have I run the EEC self-test...I wasn't even aware of the EEC self test. I've taken it to mechanics in the past and they have run the scanner on it and it has come back with a persistent vacuum leak error code since we've had it. I was told the vacuum leak was not ideal but not a must fix type of thing.

I'll run the EEC self test tonight and let you know what codes I get. Thanks again!

 

If your mechanic has already run their scanners, that's usually using the EEC self test, so you have already seen the error codes. A vacuum leak will definitely cause poor running. You should try to find and fix it before trying anything else.

 

Maybe clogged exhaust...or fuel supply issues...if its not skipping/running on all six.

 

Hi,

Sorry it's been a few days.

XLT4WD90...to be clear, when I took the van to the mechanic with the scanner it was before this problem was occurring. Unfortunately, I live in a very rural place and I currently don't have access to a scanner. I tried running the self test, the van went through the checks, but the code was very difficult to decipher...there were a lot of half-flashes and there was no decipherable code it was repeating. Is there some special technique to this that I'm missing? I used a paper clip to link the second from right port to the white port that's separate in the EEC plugs.

99f350sd, how would you go about checking if it's a clogged exhaust issue? It very well could be the fuel filter, I replaced one on a Jeep once and I remember that being a hassle though since you had to drop the gas tank...so I'd like to have some inkling that's what it is before I go down that route.

Thanks

 

It sounds like you're doing the proper thing to run the self-test, but having a hard time reading the results. Here's a through guide:

https://www.ford-trucks.com/forums/1...an-eec-iv.html

and some illustrations:

EEC IV Self Test hookup

You can usually watch the check engine light to blink out the codes. But if that's too hard to read, you can buy a cheap code reader like this one:

https://www.amazon.com/INNOVA-3145-F.../dp/B000EW0KHW

The fuel filter on an Aerostar is located on the frame rail in front of the tank. It's pretty easy to replace; just don't have your face under it when you pull the lines off.

 

xlt4wd900, I purchased the code reader you suggested from Amazon, and it should arrive in a few days. I'll let you know what codes it throws out and hopefully that will lead to a fix!
Thanks!

 

Also, thanks for the info on the fuel filter...didn't realize it was that easy to get to. I ordered one on Amazon and I'm going to replace regardless.

 

Hi All,
As an update, I bought a Ford OBDI code reader. Plugged it in and it works great. The code it gave me, however, is 172 (HEGO(HO2S) sensor fault/lean)....which as I understand is related to the O2 sensor reading lean. As I mentioned, I've already replaced the O2 sensor and this didn't fix the problem. Any further ideas?
Thanks!

 

This could be that vacuum leak causing the constant lean condition.

I've had some experiences with vacuum leaks; the engine idling and running poorly, but I never got to the point of driving it so I can't tell about power loss. It usually turned on the check engine light. In all my cases, the leak was caused by a bad start; I didn't keep the starter going long enough to get the engine to actually start, and it backfired, causing one of the caps on the vacuum tree to pop off. The tree is on the rear of the intake manifold on the driver's side, so it was kind of hard to find the leak. You have to pull off the dog house cover to find the tree and look with a flashlight, or feel with your fingers. After the first event, which shot the cap off to oblivion, I got a short length of vacuum hose and looped it between two of the nipples, a big one and a small one. I use a larger hose that fits tightly over the bigger nipple, and loosely over the smaller one. When the engine backfires again, it will blow the hose off of the smaller nipple, but it should stay on the bigger one. I just get in there and put it back on, and the engine runs OK again.

 

Also check the hoses and apparatus on the fuel vapors extraction system under the air cleaner box. Especially the hose running to the throttle body which cracks in the bends. Replace hoses at the sign of any surface cracks especially on the ends.

 

Have you checked fuel pressure? If it's high, the engine will run rich as you mentioned above.

Also, the fuel pressure regulator diaphragm could be ruptured, letting gas flow into the intake via the vacuum line attached to the regulator. Remove the vacuum line from the fuel pressure regulator and look for gas present.

Lastly, the vacuum line to the regulator could be disconnected or broken somewhere between the regulator and where it connects to the intake. On my Aerostar, the rubber elbow at the regulator connection was rubbing against something and wore a hole through the elbow. As the fuel pressure regulator is suposed to be referenced to the intake manifold pressue, fuel pressure will go up if the vacuum line is missing from the regulator or has a big enough hole in it.

And while you're looking for vacuum leaks, don't forget to check the brake booster and associated vacuum lines.

A bad or dirty MAF could also fool the computer and cause the symptoms you have. You could try cleaning it. There are plenty of youtube videos that show how to do this. Be careful not to damage the sensor elements.

 

Ok just got done rebuilding my 93 3.0
When I got done it didn't want to Idle & acted like it was Missing.
Well after 2-3 weeks of checking Hoses & Grounds & the New spark Plugs, Wires, Cap & Rotor I found the problem..........
Since they were running fine before I just put The fuel ejectors that was on it back it.
Checked them 3 were fine, 1 was barely letting gas thru, & 2 wasn't letting any thru.
Ordered some, put them in & the thing is Purring like a Kitten.

Here is the ones I got. He has more sets.

http://www.ebay.com/itm/191888180787?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

I've seen stuck injectors as well. In that case, they were in a car that had sat for over a year without being run. I'm guessing the pintles got stuck from sitting for so long with gas that dried up around it. I was able to resurrect 7 of them by soaking them in Seafoam Deep Creep and actuating them with a 12V battery. The last one just would not open up again.