Follow up
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Mountain Pass
Joined: Oct 2002
Posts: 205
Likes: 0
From: Jaqcksonville
Follow up
Update. After 2x700mile roundtrips I can attest to the abuse the 4.0 Aerostar with 260k engine can take. My onging issue of a stubborn miss with the following codes in order P0401,P0301,P0304,P0171 has me some what confused. I have replaced the coil pack, new spark wires autolite and new autolite dbl plat plugs. I have also pressure cleaned the injectors and checked the Pcv, fuel pressure ok,fuel press regulator ok. If the engine is left to idle after 2-3 minutes the exhaust starts to smoke a blue off white smoke which gets worse leaving an oily residue on the tail pipe. After a drive on the highway it burns it all off and is smoke free again for a while. While on the highway the CEL light flashes on inclines then stays on continously as I crest the hill. I replaced the drivers side head 5k ago due to a crack between the valve seats. I will do a compression test and update the results when it cools down.
Post Fiend
Joined: Apr 2005
Posts: 5,720
Likes: 5
From: Washington state
any blue smoke if you take it up to 30 mph in 1st gear and let off gas and coast down on compression?
any black oily residue on the plugs?
how did the valve seals and stems look on the replaced head?
any oil consumption?
what's the fuel mileage?
my guess
broken or worn rings. will show on compression/leakdown tests
or
worn intake valve stems/guides and/or worn broken valve stem seals. common on the 4L with the poor low flow upper rocker arm valve oiling system
A code P0401 most likely means one or more of the following has happened:
* The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced
* There is a blockage in the EGR (tube), most likely carbon buildup
* The EGR valve is faulty
* The EGR valve may not be opening due to a lack of vaccuum
p0401 and p0171 probably caused by oil carbon buildup in EGR system and on O2 sensor
any black oily residue on the plugs?
how did the valve seals and stems look on the replaced head?
any oil consumption?
what's the fuel mileage?
my guess
broken or worn rings. will show on compression/leakdown tests
or
worn intake valve stems/guides and/or worn broken valve stem seals. common on the 4L with the poor low flow upper rocker arm valve oiling system
A code P0401 most likely means one or more of the following has happened:
* The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced
* There is a blockage in the EGR (tube), most likely carbon buildup
* The EGR valve is faulty
* The EGR valve may not be opening due to a lack of vaccuum
p0401 and p0171 probably caused by oil carbon buildup in EGR system and on O2 sensor
Thread Starter
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Mountain Pass
Joined: Oct 2002
Posts: 205
Likes: 0
From: Jaqcksonville
Did a compression check 30psi on cyl 1. Pulled intake and valve cover.....No pushrod. Bent pushrod sitting in valley area. Noticed the plastic lifter guide missing as in cant find it anywhere so I guess it must have gone down the oil drain returns. Checked valve operation with a lever and its ok. Puzzle how the pushrod bent as I never felt any knocking before it happened
Postmaster
Joined: Apr 2001
Posts: 3,818
Likes: 3
The lifter socket for the pushrod is prone to wear on the 4.0L engines. Your missing plastic pieces could have hastened the failure by plugging the oil gantry. Sufficient wear would, at some critical point, allow the pushrod to fall outside the socket and wind up as you found it.
Here is a link to an article mentioning the socket wear problem. Scroll down through the article about 3/4 way. ((Courtesy of 96_4wdr: (my reference files were lost in a disk crash): Rebuilding The Ford 4.0L Pushrod V6, Doug Anderson, Automotive Rebuilder, April 2001
Here is a link to an article mentioning the socket wear problem. Scroll down through the article about 3/4 way. ((Courtesy of 96_4wdr: (my reference files were lost in a disk crash): Rebuilding The Ford 4.0L Pushrod V6, Doug Anderson, Automotive Rebuilder, April 2001
Thread Starter
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Mountain Pass
Joined: Oct 2002
Posts: 205
Likes: 0
From: Jaqcksonville
Thanks for that link to that article on the 4.0. I purchased a new lifter to get the plastic guide piece and the lifter insert that was pushed out by the oil pressure Hopefully it is in the oil pan. I inspected the other pushrods and didnt notice any undue wear but changed them anyway $4 a piece at Autozone. I cranked the engine over with the intake off and valves operated normally. As the engine has been regularly maintained since 30k when i bought it and has served me well it may be time for an engine change before it starts to need more mechanical repairs .
Lead Driver
Joined: Sep 2003
Posts: 7,015
Likes: 208
From: SoCal
I had a 2.8 liter version of this v6 that broke one of the springs that kept the rocker arms in place on the shaft. When that happened, the engine obviously got very weak, as rocker arms from two adjacent cylinders slipped out of place, and their pushrods just bounced around. I replaced the broken spring, and it ran for a while before it broke again. We got rid of the car shortly afterward, but I never did figure out what caused the problem. It had all sorts of other problems too, so I was glad to be rid of it.
Posting Guru
Joined: Aug 2007
Posts: 1,036
Likes: 2
From: Portland, Oregon
dang so once cylinder wasn't even getting air into it? i wonder how long your engine's been running like that?
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Elder User
Joined: Apr 2005
Posts: 882
Likes: 0
From: Wichita
On old rebuilder's tip - roll the pushrods on a piece of glass or other know flat surface to check for straightness. They should roll smoothly.
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Mountain Pass
Joined: Oct 2002
Posts: 205
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From: Jaqcksonville
Yes cylinder 1 was getting fuel as normal, spark but incomplete combustion. I probably put 3k miles on the van as it was. At 70mph the miss became less noticeable however to get to that speed o/d had to be locked out because the locked up torque converter made the miss more prevalent. I guess the smoke after a while of idling was due to the cat loading up . Even with the miss trying to isolate the bad cylinder before getting a compression tester was difficult as the engine shakes with which ever injector plug was pulled and separatly with each of the spark plug wires.
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Mountain Pass
Joined: Oct 2002
Posts: 205
Likes: 0
From: Jaqcksonville
I figure that with the intake pushrod in the lifter valley the intake never opened. The exhaust did as normal as did the injector and the sparkplug however no air for combustion. This probably resulted in the smoke from the exhaust after idiling for a few minutes. I have driven approx 50 miles since the repair and it feels strong and peppy. The only crib I have that if you buy the Felpro intake gasket on its own it is a one piece combined left and right compared to the felpro head gasket kit which have two separate intake gaskets. Much better i think.