i just bought my 4th aerostar but my first awd shorty,the problems i'm having is my engine has a miss ,like a faulty injector,i have replace the maf sensor and also the spark plug wires[wires from the ford dealer,motocraft wires]engine has a puff puff sound out of the tail pipe,thinking of replacing the plugs,the second problem is the awd light blinks twice driving and at idle,have taken out fuse till i find the problem. my aerostar is a 1994 awd auto,4.0litre engine,any help would be gratfull. thank you

 

Better plan on getting out the compression tester as it sounds as if you may have a burnt exhaust valve. That 'puff-puff' sound is indicative of a bad valve and a compression test will confirm the suspicion.

On the blinking AWD drive light. As a first step, replace your fuse and then locate the AWD computer module under the driver's seat and unplug the module connector. Drive it above 35 mph, stop and replace the connector. If light remains on, next step is to check the two speed sensors, one on the rear differential and the second on the transfer case. Both are small, single connector, plastic pieces mounted near the top of the case by a single bolt. Check to see if the wire is connected properly at each sensor. If the connection looks good, then unbolt the sensor and pull it out of the case. These are just magnets and as such, will pick up stray metal particles out of the lubricating fluid if either unit has been poorly maintained. If you find a sensor 'fuzzy' with metallic particles, clean it and then drain, flush and replace fluid in that case. (Note:the rear diff and transfer case use different fluids, rear=gear lube, T.case=automatic transmission fluid).

If this still does not solve the problem, you may have an open wire from the sensor(s) to the module or perhaps even a bad module (rare).
Please post back with your findings.

 

i,m going to test compresion in my engine tonite also i'll try and disconect the awd module under the driver seat ,will let you know whats happening after these trys ,thanks aero.

 

checked compression,all cylinders at 150 psi except cylinder no;2 it is at 0 psi ,going to have to take engine apart .do you know how much time to change the head aprox.will start taking apart saturday,my van has 132000 miles think i should change both heads or get a valve job done or used heads, what ever is the best method,did a valve job my self 10 years back on my f150 worked fine ,mabe i will order the valves and do it my self, a little longer but less expensif,going to check awd today and give results,thanks

 

There is always hope it may be a broken valve spring, however you should also hear a tapping noise from the lifter. Given the amount of labor to remove one head, removing/rebuilding both would make the most economic sense. With your prior experience, rebuilding the current heads would be least expensive option or you could farm it out to a local machine shop and do the balance of the grunt labor.

Mikeman, a highly knowlegeable and frequent poster here, has several previous posts regarding head removal and work for the same problem as yours. The search feature may or may not be working yet, so you may need to scroll a ways to find the information, or you could send him a private message for further information.

Bummer to have this happen to a newly acquired van, hope it doesn't sour you on marquee. Keep posting for future reference.

 

awd light is out, did what you said and it worked,cleaned sensors just to make sure, will do valve job next weekend ,thanks aero for the input.

 

 

hey aero got my van running,had to change one head ,the other head was scraped due to the valve seat,also didn't know i needed torx tools to take off head bolts,gaskets are really getting expensif,$215.00 {can} for the upper set.thanks for all the help,hoping my ride will give me a couple more years,

 

Ouch! $215! They better be gold plated for that price. Congratulations on a successful rebuild and thanks for the updates.

 

cheech, when was your Aerostar built? My '95 was built at the the end of '94 (11/94 if I'm remembering correctly). I recently went through the same thing as you but at only about 70K miles. When I took the heads off, I found that one head had been replaced already prior to my purchasing the van used. The first head was replaced before 47K miles.

 

mikeman my aerostar was built 01/94 ,didn't check casting dates, did both heads ,new seals and gaskets,running like a charm,total cost around $400.00 also replaced one exaust flange at $18.00,the left side,will be going fishing with the van on weekend pulling my trailer and with 16' allum boat,have a nice day, bye

 

forgot to let you know bought used head for $ 50.00 did valves on it to be on the sake side bye.