Ford Factory OEM wires F5PZ12259A FTE $33.70 97 Aerostar 3.0L

Ed

 

I found the factory Motorcraft wires at Summit for $40 plus $10 shipping. They didn't help much. The miss is still there. I am glad that I put them on though. I'm sure it will eliminate a potential variable. The wires to the left bank are kinda tight going around the intake per the manual. Should the wires go between the intake runners?

I still don't know why the problem seemed to disappear for a few days after the last time I changed the wires. This makes me think something like a vacuum line is cracked and I moved it or something.

I still have not done a compression test. That's next.

 

Just out of curiosity have you recently replaced the battery? I had a 00 Taurus that I replaced the battery in it and started having egr and cyl. 5 misfire codes. I went thru and cleaned ALL of the grounds (meaning the batt. terminal, to the body, at the bell housing, and even added one from the bell at the starter to the body) and the codes went away and have not come back. At work we have noticed that many times people have recently changed the batt. or alt. and start having problems.

 

USE ONLY MOTORCRAFT PLUG WIRES this has solved my recent dtc issues.........

 

aerostar1,
i reread your posts and symtoms...
1 additional point to check is the #5 injector wiring and plug
from Ford Service DVD
http://www.fordcds.com/
bottom of page


HD1 CHECK POSSIBLE CAUSES TO MISFIRE
Misfire Continuous Memory Diagnostic Trouble Codes (DTCs):

P0301 - Cyl #1, Inj Test Pin 75
P0302 - Cyl #2, Inj Test Pin 101
P0303 - Cyl #3, Inj Test Pin 74
P0304 - Cyl #4, Inj Test Pin 100
P0305 - Cyl #5, Inj Test Pin 73
P0306 - Cyl #6, Inj Test Pin 99
P0307 - Cyl #7, Inj Test Pin 72
P0308 - Cyl #8, Inj Test Pin 98
P0300 - multiple cylinders misfiring, or cannot identify cylinder due to Camshaft Position sensor failure.
Possible causes:

Ignition System.
Fuel Injectors.
Fuel Pressure.
Evaporative System.
Canister Purge.
Base Engine.
Running out of fuel.
Note: Running out of fuel may turn on the MIL and possibly store a Continuous Misfire DTC.

Has the vehicle recently run out of fuel?
Yes No
OBD II system OK. COMPLETE PCM RESET to clear DTCs (REFER to Section 2A, Powertrain Control Module (PCM) Reset ). RETURN vehicle to customer. GO to HD2 .

HD8 CHECK RESISTANCE OF INJECTOR(S) AND HARNESS
Key off.
Disconnect PCM. Inspect for damaged or pushed out pins, corrosion, loose wires etc. Service as necessary.
Note: This erases Continuous Memory DTCs.

Install breakout box, leave PCM disconnected.
Measure resistance between suspect injector test pin and Test Pin 71 or 97 at the breakout box. Refer to the list in HD1 .
Is the resistance between 11.0-18.0 ohms?
Yes No
Injector and harness resistance is OK, GO to HD9 . GO to Pinpoint Test Step H48 to evaluate fuel injectors.

HD9 CHECK INJECTOR DRIVER SIGNAL
Note: Requires a standard 12 volt test lamp.

Key off.
Breakout box installed.
Connect PCM to breakout box.
Connect Test Lamp between Test Pin 71 or 97 and suspect injector test pin.
Start engine.
Does test lamp have a dim glow while running engine?
Note: Properly operating system will show a dim glow on the Test Lamp.

Yes No
GO to HD10 . No light or bright light. REPLACE PCM. REMOVE breakout box. RERUN Quick Test.


HD25 CHECK FOR BASE ENGINE CONCERNS
The purpose of this pinpoint test step is to determine if there are any base engine concerns that may have caused the Misfire DTC or drive concern.

Perform the following tests in order to evaluate base engine integrity.

Perform an Engine Compression test.
Perform Dynamic Valve Train analysis.
Check Positive Crankcase Ventilation System.
Check possible leakage points.
Refer to the Diagnosis and Testing pages in the Engine Group Service Manual for all of the above repair procedures.
Is any service required?
Yes No
GO to Engine Group Service Manual, Diagnosis and Testing, to make repairs. RERUN Quick Test . The cause of the Misfire DTC is intermittent and diagnosis will be in the Ignition System. GO to the Intermittent Ignition procedure in Pinpoint Test Step Z50 . FOLLOW instructions for using the Ignition Intermittent Analyzer, also known as the DIST tool.

*****
you can perform another intermittent wiring test by wiggling and moving injector harness while monitoring your scanner for codes or changes in engine parameters...rpm and short term fuel trim are 2 to watch for changes....PCM will try to adapt to cylinder drop from intermittent injector....

 

This is a long post that basically leads to a dead end. I'll bring you up to date on this, but I still have not solved the problem.

I checked the compression. Two cylinders were at 165 psi. Three were at 135 psi and cylinder #5 (the suspect cylinder) was at 125 psi. The Ford service manual says these numbers are ok.

I finally got the old EGR valve off and put the new one on. No improvement.

I checked all the injector resistances at the PCM connector. All checked right at 15 ohms which is within specification and this also means all the wires are good. I also checked the injector drivers by putting a 12 volt test lamp on each injector wire while the van was running. They all produced a dim flash pulse as the manual said they should.

I put a vacuum gage on it and the vacuum is normal. Right at 19 - 20 inches. It does have a very slight flicker when the engine misses though.

I also noticed that the left cylinder head looks like it has been replaced. It is a different color (black) and the freeze plug has no paint on it.

I'm not sure where I'll go next. It is interesting that the low compression cylinder is the one that is throwing the code. Maybe the valves are bad. I think it could be all carboned up too. Or an injecton could be bad machanically. The saga continues...

 

switch #4 and #5 injectors...see if problem follows injector
i don't like to see more than 10% compression difference between high and low pressure cylinders...was a screw in compression gauge used or rubber tip hold in?

a compression leak down test will tell far more about valve condition but requires special test equipment and attention to detail..will find bent valve stems, cracked valve tulips, broken seats, damaged cylinder walls, cracked pistons, damaged rings
air bubbles out the radiator or air hissing in exhaust/intake manifolds is not a good thing

http://www.xs11.com/tips/misc/misc3.shtml

some rental shops and auto parts store rent out leakdown testers and a small compressor

 

Ok, I did the leak down test. Cylinder #5 once again comes up to be the bad guy, but some others are not that great either. Here are the numbers: #1 - 48%, #2 - 40%, #3 - 38%, #4 - 53%, #5 - 84%!!!!, #6 - 26%. The service manual says anything greater than 20% is bad. I listened for hissing on #5: Intake - none, Tail pipe - yes (faint), Dipstick - loud and clear. No bubbles in the radiator during any cylinder test. Hissing from the dip stick tube on all the cylinders.

The compression on #5 was 120 psi. Rings or valves? I put some oil in the cylinder and the compression went to 160 psi. This means rings right? But I have no blow by coming from the crank case and the van doesn't use oil, so I'm not sure it would be rings.

I'm just wondering if some of the valves are burned. I'm wondering if when the van started running great after the new plug wires were installed, maybe I burned the valves because of a bad fuel pump. I had been babying it for a long time, but when it started running good I put it to the floor a lot. If the fuel pump is working, but not producing enough flow at full throttle, I could have burned the valves. Does this sound possible? I guess I should check the fuel pressure next.

Regardless, it sounds like I'll need to rebuild the heads or the entire engine. I may just find a good used one in a bone yard.

 

was it driven several thousands miles with the old failed plug wires and plugs, rough running? with check engine light on?

either condition will cause extra rich operation, which dumps extra fuel into cylinders, washed down the lube oil, rings wear out and cylinder walls scuff=cylinder leak and low compression....you probably even have broken rings, common for failed lube from fuel

all the work that is involved in changing engines, I would not bother with an unknown used engine....almost impossible to tell condition of used engine unless it is running for exam....

i would rebuild the engine that is in the van or buy a rebuilt long block with rebuilt or new heads

 

If the rings are bad, wouldn't it burn oil? Wouldn't I have lots of blow-by? Yes, I've driven it a lot with the check engine light on and the mileage went from 20 mpg to 16 mpg (rich).

 

oil burning/blow by is not necessary a symtom in all cases of worn-broken rings and worn cyl. walls
no quick in the box fixes for this tired engine

you have probably lost 40% of its power but the loss is slow so not noticed....reason your fuel mileage has dropped

 

Ok, before we start tearing the engine apart, there is another thing you guys need to look at.........

If he has been running the engine in an overly rich condition more than likely there is a huge build up of carbon on the valves. Carbon build up can cause the valves not to close tight which will give a low compression read.

When he poured oil in it was the same as when spraying WD on Vacuum lines to find/seal the leak. It sealed the gap around the valve for a higher compression.

So you might have to pull the Heads and do a valve job if you can't find a good additive that will burn the carbon off and clean the valves.

JaY

 

all his air leakage he hears on the leakdown tests is into the crankcase....NOT thru the valves

top para. of post #23, dipstick air leak only

no air leak sounds in intake
very little air leak sounds in exhaust

 

I'm in the process of pulling the motor. I just wanted to make sure it wasn't something simple before going to all the trouble. If it is only the heads, I think it will be much easier to work on them with the engine pulled from the van any way.

One thing about the leak test. The instructions said you would always hear hissing in the crank case. I guess you're supposed to listen for ones that are abnormally loud. Another bit of info is that the plugs are always very clean. If it was running rich, wouldn't they be slightly black with carbon?

I’ve checked around for rebuilt heads. Ebay has some and a lot of places show up if you Google them. I could rebuild the ones I got too. I have a very good machine shop here in town. I have read that some of these heads can crack. Mine are 1997. Should I trust them, or just get complete new finished castings?

 

have them solvent tank dipped and magnafluxed at your engine machinist shop...'97s have the new lean burn heads, few cracking or leak problems
have them test the valve guides for wear...heads need to be checked for warping....then 3 angle grind the valve seats and lap in the valves....new valve guide seals from your new engine gasket kit...also have them inspect the pushrods and rocker arm sockets for excessive wear, Ford poor oiling design fault
good shop will charge $100 to $200 per head for work depending on location and any extras

heads can be done with engine in veh.....far easier and less chance for error out of veh. and on engine stand...torquing sequence of new head bolts is critical to no leaks and no warpage-cracking...difficult to do well in the rig...4.0L is far more critical and 3.0L

have new soft plugs replaced in heads and block...should be included in engine rebuild gasket kit or buy extra

new head bolts required on 4.0L...torque to yield bolts....one time use only or risk leaks and ugly redo