My Check Engine light has been on for about a year now. Every time I went to the mechanic for something else, I would ask him about it. He would scan it (not when I was around) and tell me that it was 'nothing'. Sometimes he told me it was just due to 'bad gas'. He would then reset it.

Sometime thereafter (originally a day or two later, more recently an hour later) it would come back on. The van itself has been driving more or less fine. Yes, it has some quirky habits that I would like fixed, but my mechanic was not enough of a genius to figure it out. He used to have a good diagnostician on staff, but I just found out that he left, and therefore I will no longer use that mechanic.

Last week my vacuum lines cracked again, this time no longer repairable with electrical tape anymore. The A/C vent became stuck on defrost. So I had to get it fixed. I am about to go on a 3000 trip with my family to Minnesota and back to NY City, so I got the belt changed as well. I used a different mechanic. He scanned the codes (and of course reset it) and told me it was an 'EVP' code.

What is that??

Could it be just due to the leaky vacuum lines? Maybe it won't come back on this time (I am not so hopeful.)

On an unrelated or related note, the quirky things that are bothering me are:

1 - On startup, for the first few seconds (in the Summer) or the first few minutes (in the Winter) the idle is extremely high. Once it warms up, it drops suddenly and drastically. What controls this?

2 - The cruise has stopped working. This is probably a long diagnostic process, so I am just mentioning it but not really hopeful. Maybe the vacuum leaked caused it? Do I have to be at highway speeds for it to turn on? If so, I haven't tried that since the repair.

3 - it might be my imagination, or it might have just been due to the vacuum leak, but I think that sometimes the Transmission is a little slow to shift, as if when I am in gear 2 instead of D. I keep checking the OD-Off light, because that could also cause that feeling, but it is not on. It just feels wrong. The Transmission is only about 20,000 or 30,000 miles old, so hopefully is still fine.

 

most auto parts stores will read codes for free in most states. call ahead.

1. IAC, best to replace. on driver side of intake plenum toward front. they get sticky from dirt/carbon buildup.
Ford Fuel Injection » Idle Air Bypass (IAB)

2. many codes will disable the OD to protect the engine/tranny. the OD system is vacuum controlled on the Aero. vacuum leaks will cause problems

3. vacuum leaks will cause the PCM to not shift properly.

look at the tubing and valves on the gas fume extraction system. remove air filter box/ underneath it. vacuum line that feeds extracted capture gas fumes to throttle body runs from carbon canister valve to throttle body. major leaker breaks down from the gas fumes passing thru it.

check the vacuum distribution tree on the back of the valve cover.

if you have more than 100k miles on fan belt tensioner, change it also. they loose tension and bearing wears out. major cause of belt slip. don't want that long serpentine slipping with all the a/c use it's going to get.

 

Thanks, I will check these as best as I could. I am not sure about all the locations, but I could look them up.

I already changed the IAC twice in 2 years, hoping not to have to do that again. Before changing, it was whining like an airplane on takeoff. Changing it helped.

The Check Engine light came back on today already, so it is definitely not fixed yet.

 

I think the EVP code might be the evap purge valve. I never had all the problems you have but I have experienced a few of the symptoms. When I brought my Aerostar it had 9 codes. EVP was one of them.

I was in a hurry to get all the codes gone so I replaced the Canister Purge Valve, Canister Purge Valve Solenoid, EGR Vacuum Solenoid, EGR Valve, EGR Valve Gasket, and EGR Valve Pressure Sensor from Autozone.

I shotgunned the problem like this because I figured that if I had only replaced one at that time another EGR part would fail later on. This way it will most likely be a good while before I see any EVP or EGR codes. Besides I hate hate hate messing with the belt tensioner. At times I would loose my grip and get my hands painfully smashed

The van ran allot better after all that EGR stuff was replaced.

Good Luck

 

Alas, the EGR valve...

A while ago I wondered if the EGR valve could be part of the trouble, so I bought one. It was not easy to find. No one stocks it anymore. I ended up getting it special ordered from AutoZone for about $52. It came with a gasket.

Then I couldn't get my old one out - too rusty and hard to reach. I asked the mechanic (the old not so good one) to change it, but he hooked up the scanner, and told me not to bother - the old one is running perfectly.

So I sold it on eBay for less than I paid, but better than having it sit around and rot.

The other parts are not too cheap either, even if they are available. I will look on Rockauto to see if it is any cheaper. Is there a way to test and see what needs to be changed and what doesn't?

Also a shame about the tensioner, because I already had the belt changed. I didn't know that I should change the tensioner. At this point, I am going to have to take my chances with the old one.

The Canister Purge valve is also expensive, and not sure that I need one. The only possible candidate might be the Canister Purge Valve Solenoid, which is only $20 on AutoZone, though it is also a special order.

Oh well, I hope I make it there and back okay. Some things will just have to wait.

 

The fuel evaporation canister is connected to the intake manifold with a long hose that gets stiff over time, and can crack if carelessly handled. That would be a source of vacuum leak. I think your engine may have a purge flow sensor, so it can actually detect when the canister is supposed to be purged.

You can test the solenoid by activating it with 12VDC and see if it opens and closes correctly. You can disconnect hoses on each end and try blowing into them.

The cruise control works off vacuum as well, but if you have such a big leak that it causes that to stop working, you engine would be running pretty badly as well. It's more likely to be bad contacts in the steering wheel or buttons, or maybe a brake light bulb is out.

 

If I may suggest something.

Stop buying parts to fix problems that might not be broken!

By taking the time to learn a bit about testing with simple meters, a small vacuum pump and how to read a electrical or vacuum schematic you will save big bucks on unnecessary parts.

Also when you make trips to the junk yard, you can find many parts like sensors, fuel injectors, and relays that might go on the fritz in the future. If your van is running correctly, you can test the junk yard sensors and know if they are good or not, so you can keep them on the shelf of they are good.

The "toss parts at it until the code goes away" phenomenon is common enough to find plenty of cars in the grave yard that have nearly new components.

For a $7 investment you will save yourself the aggravation of having to pay $50 only to find out that the original part was not the problem.

There is a reason that auto parts stores refuse to accept returns on electrical parts.

 

Than you for the encouragement. I don't disagree at all, in fact I had written: "Is there a way to test and see what needs to be changed and what doesn't?"

However, bear in mind that I live in New York City, which is very different than other places in the USA. Here in the city (and the outskirts too) real estate is much higher than elsewhere. Plus the value of steel and other metals are very high now. So the junkyard here do not stock anything as old as 1997. Not single part whatsoever. I called a while bunch of them recently when I needed a ball stud for my rear hatch.

The closest places that have You-Pull yards where I might find good deals on Aerostar parts are 3 hours away. Add to that the time spent searching and pulling, and it adds up to a full day including 6 hours of driving, and even then I might not have any luck.

It changes things significantly, and makes eBay my best friend.

 

Evap codes are very often caused by either that solenoid being faulty, or by leaks on the line. Leaks are relatively easy to find and repair, and not to costly to just replace the lines. There is a formed plastic line that goes to the purge canister and solenoid. One the ends of this line are rubber hoses that can harden and crack. There should be one rubber elbow that comes in at the bottom of the throttle body, the others are underneath the airbox where the purge canister and solenoid are located. If these hoses are cracked or don't feel right, just replace them.

The other thing you can do is find a good mechanic with a smoke machine. They can smoke your intake and look for leaks. The smoke will come out anywhere a leak is present.

 

yitzy has a 1997 Aerostar.
The 1997 Aero is a strange creature in many ways. One of which is that it's the only year that doesn't use the venerable vacuum servo cruise control system. It's an electric servo & amplifier, all-in-one unit. From the Factory Service Manual, Section 10-03:




(click on any image for larger)


'86-96 use the vacuum servo, with separate CC amplifier under the dash (above driver's right knee through '91, next to glovebox left side '92-96) and a vacuum hose to the brake pedal.



The '97 doesn't have any of that.
The CC will not engage below 30 MPH (according to the Service Manual). I think I've been able to get it to work at 25 MPH.

 

So the Check Engine light is still on, and my inspection expires at the end of the month. I ordered a new Purge Solenoid, and tomorrow I will find out if it helps or not.

I still have a vacuum link too, but hopefully that was not related. The CC was a bit buggy, only engaging at about 50mph, and a few times it locked my accelerator pedal so that I could not speed up until I turned it off.