My 91 3.0l Aerostar just started surging, not idle'ing properly a week ago, just after i feuled up, thot it was gas related, but i've eliminated water in gas as culprit, changed fuel filter, now i'm thinking some sort of censor HELP!!!!!!!!!!

 

Hi Snooopy:

Read the code, but I suspect it's the Idle Air Control Valve.

Anyway, welcome to our FTE forum

 

Pull the connector off the mass airflow sensor. If things settle down, the sensor could be dirty. I have had quite a bit of trouble with these maf sensors. on mine, the pcv connection to the duct used to oil the sensor and louse up the idle. Mine got so oiled up once, the engine would not run. I pulled off the connector and the truck ran fine until I could clean the sensor wire.

Ken

 

You know in the FWIW category, I was having a similar problem, and one bottle of fuel injector cleaner later, everything was much better.

Dan

 

this unit doesnt have a MAF , or so the PartSource says 91' 3 litre v6, if i can't find out whats causing the bucking bronco effect, i'll buy some dynamite, i sware these Aerostars were put together by 3 monkeys, 2 parrots & an Ardvark

 

Thats one opinion, but those of us with experience have found them to be the best minivan ever built. They do have some quality problems with the interiors, but the strength of the fram and the overall durability of the vehicle far surpasses any other minivan ever built, including the Astro. They outlast a Caravan by about 100,000 miles on average, and the Astro by 150,000 miles on average. Thats a really big difference. That engine may be crammed under the hood, but what is in there is quality stuff. But, youwill find consistent components failing. The IAC valve (Idle Air Control) is one such part. They gum up because every time the engine is shut off, fumes from the oil go backwards up the breather tube and condense on everything in the intake system. This is not unique to Aerostars or even Fords, I had a legacy Mazda that does the same thing (By legacy, I mean from before they were purchased by Ford and shared parts with the Ranger). Their design is among the best for a minivan. By putting the engine in the way God intendened instead of transverse, you gain the benefit of RWD. This gives you some things other minivans cannot do, like towing capability. (Sure other minivans can tow lightweight trailers, but the Aerostar is rated to tow as much as 4800 lbs, which for a minivan is a lot. You could load a ton of cargo into the back, and another ton in a trailer and pull it. (you would really want the 4.0L for this, plus the rear springs should be enhanced with air rides to enhance the stiffness and prevent sagging. Also the trailer should have trailer brakes in the even ou were actually towing that much. I tow 3,000 lbs in my '94 4.0L Extended all the time, typically about every month. I don't just pull it across long flat roads either, I live in Utah and as such, there are lots of mountains.

My best guess to solve this surging problem is to determine whether or not the IAC valve is contributing. If you, it must be either cleaned or replaced. Other probelms that could factor in, include vacuum leaks, Faulty or dirty MAF sensor (mentioned above), dirty injectors, clogged fuel filter, bad fuel pressure regulator, or a faulty fuel pump. Start with the simple stuff like filters and cleaning things.

 

Check IAC valve coil resistance first if it is ok, your IAC may be so dirty!

 

Any CEL or codes ? Can you hear the fuel pump buzz when starting the engine?

Surging could be caused by rich mixture (also known as "hunting") so, anything which restricts Idle air flow or increased injector duration to the engine could cause this.


Whats the engine like on a cold start? & is fuel consumption yet affected?
Also see the thread " running rough " also has an idle problem a few threads back.
Aeroman.

 

I replaced the IAC & TPS , the o2 sensor before the caddeletic needs a torch to losen it-i'll wait to replace tell my bro brings a code scanner this comming weekend, signed; "impatient" LOL

 

Snooopy, I replaced my O2 sensor just last weekend. I soaked the connection with Liquid Wrench 5 times over a 5 hour period, giving it a really good bath before bedtime on Friday night. Early Saturday morning, I whacked the base of the sensor a couple times with a hammer before connecting an old fashioned pipe wrench to it. I muscled up and threw my entire 200 pound body into pushing the pipe wrench only to find out it was ready to come out. When my motion stopped, I had already torn the meat off every knuckly on my left hand. I had gone two days working on my Aero and was due a blood letting...LOL.

Take it easy and she'll slide right out for you. Make sure you use some "non-seize" gunk on the new one. My new O2 sensor came with some already applied to the threads.

Michael
'93 Aero 3.0L 2WD Ext
'94 Aero 4.0L 2WD Ext

 

Snooopy:

If you plan to work on your car from time to time, get an OBD-II scanner. They are rather inexpensive these days. I have seen them sold for about $30.

 

Copper, should'nt he buy an OBD I if he's driving a '91 Aero? I just bought one online for $30 and it's GREAT.

Michael
'93 Aero 3.0L

 

Hi Michael & Snooopy:

Yes, I screwed up. I thought Snoopy had a '96. Forgive my old age

For OBD-I (EEC-IV) systems, you don't need a code reader.

https://www.ford-trucks.com/forums/s...17&postcount=5

 

There definitely is an aardvark involved with some areas of Aero design. maybe only one parrot but the concept of a rear wheel drive smaller van is a good one.

ken

 

Is there an ECG valve on my 91 3.0 liter v6 & if so ? Where is it located ???