The truck also shows 392 deg F as the head temp no matter how hot the truck is. I am going to order a new sensor for that.
I also still have the misfire on Cyl 5, 6, & 8

The misfires are straight across from the lowest 3 compression cylinders as well.

Cyl #1 (~95 psi) ---> Cyl #5 misfires lots (mostly at idle or low rpm)

Cy # 2 (132 psi) ---> Cyl #6 misfires at idle

Cyl #3 (140 psi) ---> Cyl #7 has never misfired

Cyl #4 (120 psi) ---> Cyl #8 misfires at idle

Cyl 5-8 has high compression 150psi - 174 psi

 

have you checked the coil for cracks? i had a low rpm miss like that and chased it for a month and it turned out to be the coil

 

I swapped the coil pack for bank one with a friends truck an the behavior did not change.

 

hi I am new to this, anyone ever solve this????

Judd wondering how you are making out with your truck. I am having the same problem here, and the heads have not been shaved. My misfires are on bank 1, 301,303,304. Bank 2 manifold has a cracked bolt, but the truck is quiet. I was going to repair, but if you are haveing a problem it must be more. You don't by chance have a cracked manifold or bolt on Bank 1 Passenger side?

I have changed gaskets on intake, plugs, coils, temp sensor, then swapped with used DPFE, Cam sensor(made most diff, but still not there), Crank sensor, and all other components with no success. Fuel pressure is 38 lbs, raises when vacuum unplug, I even did the fuel pressure drive test. Changed EVR with a cleaned out used one, apply vacuum truck stalls, I have no vacuum leaks, checked and changed all hoses including 90 off intake to PCV, with new PCV.

I think I am going to change the DPFE, wonder if anyone could say if the DPFE can cause misfire of extreme. If I unplug the DPFE the ping is less, but power is none.

My fuel trim has been everywhere; neg5 to now both banks are around 15
My advance timing at idle is 14.5 to 17, when accelerating my timing is dropping to 0 to 4 and the miss can be felt withmore than 1/2" gas peddle depressed.

Have you changed your front O2, and are they white as snow on both sides?

My truck idles good, and misfires on acceleration, or when the peddle is pressed beyond 1/2" or so. Sometimes seems to clear at high rev.

Overall it does run better cold.

If I induce a small, battery area vacuum leak it seems to run better pobably more oxygen. The air filter and maf have been changed also.

 

I apologize for the delay as I do not drive my truck much during the summer so the pinging has not been on my mind for some time. The truck still pings when loaded but I have not had a check engine light for the last 3k miles. I have no power at high RPM when trying to accelerate. I have not looked into a cracked intake manifold but both the exhaust manifolds have been replaced.

I was actually thinking about tearing it down and checking the timing to see if it was assembled "off" from one back to the other.
I have not changed the O2 sensors or even removed them.

 

I think I solved mine(bank 2 drivers lean) although I sold the truck without replacing the catalytic converter. The pressure on bank1 O2 sensor passengers side closest to the exhaust manifold(upstream) was over 7lbs(google it I think it is suppose to be less than 4psi. Due to this the computer was cutting down on fuel, hence running lean, causing ping and power issues. The drivers side bank 2 converter was new, and the pressure was under 3 lbs yet it was this side running lean. Anyway this could be crap, but after testing and trying a whole lot of different things, intake gasket, sensors, plugs, coils, etc. this was my conclusion.

 

so did the next owner do this fix or do you 'think' this would have fixed it?

can a shop test pressure where the O2 sensor is?

 

Hey Judd

I do believe it was the catalytic converter to 95 percent. You can easily test it yourself, I believe the thread for the 02 sensor was M18x1.5 any hose and fitting shop will be able to measure your 02 threads and supply an adapter to NPT(National Pipe Thread) or to JIC, then build a hose, throw on a cheap gauge(0-15PSI) . The hose should handle at least 150 psi as temperature causes a problem, but you will only need to do the test for a few seconds. In your case I would test the drivers 02 sensor first, also it is the easiest to get at(very easy). Another quick test you could do is using an infrared thermometer after a drive. I didn't do this one, but the temp should be only around 600F MAX I think. The pressure test would be more accurate. Be careful with the temperature during testing, and if an end was to blow no one gets hurt.Tape or twist tie the gauge to something solid.
You may have an adapter in your cylinder pressure kit you can make work also.

 

joat,

I took the truck to the shop and they tried to remove the 02 sensors. They would not budge so they removed the exhaust pipe between the down pipe and the cat. I drove the truck and so did they, it still made the pinging.

 

Lets review a little about what ping is from two reasons.
1. It is the ignition firing the cylinder mix to early in the stroke cycle.
This causes cylinder pressure to "peak" to early where the piston is located and can't respond to it.
This causes the piston to rattle/ring/knock. This is what you hear as ping.
*
2. The second source of ping is the mixture is to "lean".
This speeds up the flame front and results in the same end result of pressure peaking to early.
Since the computer never gets into condition 1 of too much advanced timing, it can get there from the second discription.
What is the source?
The source is the EGR SYSTEM.
Once the OX sensors detect the lean mixture from exhaust contamination through the LEAKING EGR, the computer does advance the timing, closes down the fuel to make matters worse.
Service the EGR system and make sure there are no leaks.
Leave the OX sensors and exhaust alone. They are not the cause.
Good luck.

 

Your explanation looks like you have spent a lot of time thinking this through, however, your conclusions are completely the opposite of the effect that an EGR leak would have.

The EGR system, stands for Exhaust Gas Recirculation. It is a device introduced to control NOX emissions. NOX emissions are created from high combustion temperatures, which causes atmospheric oxygen to bond with free oxygen. The formation of NOX also ties up oxygen that could also be used to more fully burn the fuel. So NOX formation is bad for both emissions and performance.

Exhaust is depleted of oxygen, most of the oxygen it once contained was used in the combustion process. So if you recirculate exhaust gas back into the engine, it is basically an inert gas. The purpose is to introduce an inert gas to dilute the mixture in the cylinders without having much of an effect on the fuel to oxygen ratio (notice I used the word oxygen and not air). It is important not to disturb the fuel to oxygen ratio as the goal is to still burn as much fuel as possible. The exhaust being reintroduced simply slows the combustion down and lowers the peak temperature. This in turn reduces the amount of NOX that is formed in the engine.

So, if you have an EGR system leak, it will prevent pinging to a fault. Severe cases will cause the engine to stumble and hesitate and even stall. But it will not ping.

Now if the DPFE sensor detects more EGR flow than actual flow, then the potential for pinging can occur. The computer does advance timing when the EGR is open because if the mixture burns more slowly you need more advance to get the same performance. If the computer is detecting EGR flow when no EGR flow is present, then the excessive advance may cause pinging.

Now a vacuum leak will often cause pinging, because it allows unmetered air which contains oxygen to enter the engine, where it alters the fuel to oxygen ratio. A vacuum leak is highly likely.

The purpose of an automotive forum is to as much as possible help others solve their automotive problems, and that means that you have to have a pretty good grasp on how the systems work before you can state that a certain thing is causing the problem.

So do I think the EGR is causing the pinging? Very very very unlikely unless there is a leak in a vacuum hose associated with the EGR system. More than likely you have a lean condition caused by a vacuum leak, a dirty or faulty MAF sensor, low fuel pressure due to weak pump or plugged filter, wrong spark plug gap, wrong spark plug, carbon deposit build up, plugged injector(s), etc. A faulty in the EGR system would belong near the bottom of even theoretically possible culprits, it certainly wouldn't be among even the uncommon problems.

Your explanation for what ping is is not accurate either.

Under normal operation, the spark plug fires, igniting the mixture. This causes a flame to expand out (not an explosion, a flame). It takes a little time for this flame to propagate, so the spark is fired at a predetermined time prior to the piston reaching the top of the compression stroke. This expanding flame causes the piston to move downwards in the power stroke.

When pinging occurs, the spark is either early, or a hot spot in the combustion chamber causes the ignition to occur to early, or the flame is too hot and fast. The causes can vary, but here is a breakdown on the mechanics of what is happening. Basically, the flame starts as the spark (or secondary ignition source) which then causes the pressure to build, which causes the temperature to rise. This rise in temperature causes the mixture to become really volatile. This will cause the mixture to spontaneously ignite from a second source. This second flame front will expand and when the two flame fronts meet, it creates a shockwave, which then resonates through the entire engine. It is this shockwave you hear as pinging (rattling, marbles, etc.) The combination of temperature and pressure can cause serious damage to the engine, and the shockwave can amplify the damage by stripping away the protective boundary layers of cooler air that surround the metal parts.

 

This is the second time your trying to jump me on an explaination.
I need no schooling on EGR operation nor effects of lean combustion, flame front speeds, chamber carbon, effects of high compression on fuel octanes or any other items you are trying to offer.
If you think a lean condition is the cause then you ask him where the lean codes are, to allow the motor to go into ping!
*
Not related to this thread, but the LED tail light deal of reccomending a 5 watt resistor without a value to someone who has a no idea, tells me your not very well versed in DC circuit theroy, and you still said something trying to dig me again for which I chose to let it go.
But not this time.
Since you are going to do this, I will do it back to you until you see it's not the way to answer by digging me.
I suspect you have a lot of back ground but you know nothing of my background either.
Get a little respect and lets go forward without the attacks and one upsmanship playing.
There is no need for it here.

 

Ok, I'm sorry, did not mean disrespect. However, I have a background in emission control devices and advanced diagnostics. I am just letting you and everyone know the mechanics of how everything works, and how your conclusion is not consistent with a leaking EGR valve. If I came across as too harsh, I apologize.

As for the counter attack on the LED issue, I think a little background as to why I would insist so strongly on that issue is because of personal experience. I do not wish anyone to go through the expenses that I had to go through, simply because LED lights look cool.

The circuit seems simple just looking at the schematics, looks like nothing could go wrong. The problem is in what is not seen in the schematics, an issue that would rarely be encountered outside LED bulbs.

I had a 1994 Ford Aerostar 4.0L AWD. It had an overbuilt A4LD transmission that was upgraded to handle the heavy towing I do. I wanted my vehicle to be unique, so I had clear tail lights with LED bulbs. I ran a heavy duty flasher on the turn signals to address the rapid flashing, and nothing special on the brake circuit.

I had this setup maybe a year without any issues. Then one day while I was out of town coming back from a 350 mile trip (one way), the trans began to feel a little off, but it was difficult to place my finger on as I was traveling and highway speeds. When I got to surface streets back home, it was apparent the the shifts were delayed, and that the trans was sometimes starting out in second gear.

So off the the trans shop. Diagnosis, the transmission had been badly overheated, the seals were toast, the torque converter was toast, some of the bands had begun slipping because the valve body had been cooked enough that the pressure was being lost through basically melted rubber seals.

So $2800 later, trans gets rebuilt back to the same specs it previously had. They take it on a road test, TCC lockup isn't happening. Determined that overheat was due to the TCC lockup not working. So they test the solenoid and its circuits, they are fine, but are not being commanded on by the computer. Closer investigation reveals the computer is seeing the brakes as constantly on. So the brake switch is tested. Switch is working correctly. Test reveals that they is a constant 2v signal on the brake circuit when the brakes are not on (this is on the non-powered side of the switch). Turns out the brake signal is a biased circuit. The biased voltage is a low amperage voltage that is applied inside the computer. It may have been part of a brake bulb failure that was never implemented, or it could be normal diode leakage, anyway, many Ford models have the same design.

When an incandescent bulb is used, this biased voltage is not detected, the incandescent bulbs draw enough power to discharge this voltage, causing a 0v reading on the brake circuit. Disconnect all the brake bulbs, the 2v signal returns. The computer sees this low voltage signal as the brakes being applied. The LEDs draw low enough power that they do not discharge this circuit. My van worked flawlessly for almost a year because my third brake light was incandescent. But on that trip, the third brake light burned out.

The trans shop disconnecting the LEDs, and make it go away by using regular bulbs. By looking at the schematics, you would never know this is the case. So if I seemed harsh on that issue as well, its because I had a very costly experience. Who is to say if all other Fords are affected the same way? I doubt all are. But resistors are cheap, and can be bought from the same companies that sell the LED bulbs in many cases. Transmission controllers, traction control, AWD modules, ABS, all make decisions based upon the state of the brakes. Any of those systems could malfunction, possibly in unexpected and expensive ways. Hindsight is 20/20. Cheap resistor or $2800 transmission rebuild.

As far as what resistor to use, you don't use just any Radio Shack resistor. Many sites that sell LED automotive lighting actually sell special made resistors that approximate the load of a 5w incandescent bulb. I don't know off the top of my head what resistance. I'll just attach a link. http://www.v-leds.com/BlinkerWarning...85827-1-3.html

So if I seem a little harsh on issues, I don't mean to offend anyone. The thing about written word instead of verbal communication is that vocal tones and language are often not read as intended. You only get the words. I tend to get a little pointed, and tend to correct things that I think are wrong, partly because I don't want people to make the same mistakes I made, and I don't want people to spend excessive time and money chasing ghosts. I also don't want to see a sudden matter of factly, "this is your problem", when there is still incomplete diagnostics info, and no supporting scanner data. I see no scanner data to support a leaking EGR valve, or even enough data to conclusively diagnose this issue as any particular cause.

So could an EGR valve leaking cause pinging, I guess it could be possible, however I have never seen a case of such an event, and from a theory and operations standpoint it doesn't make sense. But I guess some of that could depend on whether you define an EGR valve leaking as leaking exhaust gas into the cylinders, or as a vacuum leak in the EGR diaphram, which would technically be a vacuum leak.

Excessive carbon deposits would likely cause no codes, and could cause severe pinging because it could artificially raise the compression. At one point in time my '94 Aerostar was pinging due to a faulty MAF sensor. However it was not setting MAF codes, the diagnosis on that was confirmed by other means. A vacuum leak on an intake runner may not set lean codes, depends on the severity of the leak. A partially plugged injector could also may be cause issues, though it would be unussual to have a partially plugged injector without a misfire. The thing is they could be a lot of grey ares, where the computer cannot trigger a specific code because the sensors and readings are still within spec, but that doesn't mean they are correct.

On my Aerostar, it would ping on acceleration, but did not hesitate or stumble. Fuel pressure was tested, it was within specs, ignition was tested, and checked, it was within spec. It then had a CEL that would briefly illuminate infrequently, often on downhill light throttle deceleration. But the code would clear rapidly and wouldn't store. So I hooked up a scanner and left in connected, with live date, the mixture seemed slightly lean, but within specs, and then because the scanner was connected, I drove it and replicated the most common condition that briefly turned on the light, MAf codes were present, but would clear almost immediately. Replaced with OEM MAF sensor instead of the aftermarket one that was on it, pinging went away, throttle response seemed improved, fuel economy improved.

There are many possible culprits. It takes a good diagnostician to find the issue sometimes, and when the sensors are operating in the grey area, sometimes it takes a little luck. Either that or you can play the expensive and frustrating game of change the part. If you (the OP) can gain access to a scan tool that can read live PID data, I would love to see your LTFT% and STFT% on both banks at various RPM ranges, if possible under various loads. especially when the pinging occurs. I would also like to see other data as well, but diagnosing over the internet can be difficult. The more data the better.

 

Very good.
Thanks for the heads up on experiemce.
On these boards as you can see the typical owner has no background and needs the most basic explaination if it is going to be of any value. Even then, some roll their eyes over an explaination.
Doing diagnostic on a forum is a very difficult thing to do because accurate info is not always forthcoming until it is uncovered or comes to light later in the thread.
Agreed, these systems at the point in time of developement, have some grey areas that leave room for some actions without a clear cause and effect.
For example, the missfire in OD and under light throttle loads without CEL or code set.
The cylinder causing the issue often can be seen in a Phase 6 look but the owner has little knowledge of acess to it.
Easy way is to trap the fault while driving but even then, a scanner with the capability has to be used and interpeted.
When I first came on the boards, the complaint was often seen with no positive answer other than maybe the coils were changed and the issue cleared by luck. No one knew the 'mechanics' of the failure, at least not on the boards.
Many shops to this day still do not know what causes it.
.
Your transmission experience is unique.
I do know that a brake application will trigger the transmission to unlock the converter as a normal response. The reason is to give the driver the best chance of min braking distance in cases of panic braking so the drive train does not continue to add forward momentium to the vehichle. It's also a cause of greater brake pad wear on modern trucks with higher weight as opposed to the old truck of years back.
This also involves the Cruise control knock-off.
With a dash tach, this action can be seen by touching the brakes while in OD cruise then reapply some throttle. The Tach will often raise in RPM the amount of the converter slip then go back into relock, as a time delayed action. This function has been in effect since about 1984 or with any electric lockup control transmission in Fords. The old Bronco/Rangers of the mid 80s even have the function in the old EEC control systems.
As well, running an auto in an unlocked converter condition will run them hot just from converter slip and under towing conditions it's worse yet. The only protection is extra aux cooling unlike the old C4 and C6 that never had OD or lockup and always ran in a slip condition with a different converter design.
You had a good shop to detect the problem.
I often wonder about people here trying to tow at very high gross weights if they really understand the issues and limits they are playing with, using stock setup without extra cooling and frequent fluid changes to keep the clutch and band debree from accumulating in the fluid and promoting an accelerated loss of grip coesfficient as they engage.
As to the LED changes affecting the trans; I would say it's nearly unknown to the average owner about this, let alone the way the PCM handles the lock/unlock feature.
Sorry, about the 5 watt resistor. As part of Ohms law, one can't 'technically' refer to a 5 watt resistor without specifying a value in resistamce.
In Ohms law, two values must be known to work with a circuit.
They are power, resistance and current. Taken in conversation as a given to a speciality use, I could see your point that a store might have the correct value if for no other reason there is only one value and power rating used. That did not come accross to me.
Thank you for returning the conversation. It was good and enlighening.
I don't do the LED thing but can very well see the effect on the transmission and why it can be a serious issue in the long term that could even repeat a second time still without ever knowing why..
I to had to resort to a special high performance build for towing high gross loads.
The converter balloned so was not prudent to rebuild as stock again.
It's cost was ,well don't ask, was way more than 2800! The trans has been perfect to this day after te special build by Level 10.
Thanks again.
Good luck.

 

Yeah, my application is uncommon and unusual. I am also one of the few people that actually does heavy hauling with an Aerostar. Same trans as the Ranger and V6 Explorer up through '94. Trans was know to be weak. They can be upgraded to handle a lot more than stock, mine was a serious build. How much it costs often depends on hard part damage. I do a lot of business with the shop, so they always give me a price break. Lets just say, I have enough vehicles that I own either with my business or persona vehicles, that I have had a few rebuilds.

I still have that trans they built, it never skipped a beat after that affair, the van was rear ended and totaled. I just scrapped the van, but I kept the engine trans, and both axles and the whole front sub assembly. The trans is just too tough to let go. The engine is a parts source for now, I have more vans that I can use parts on. The trans is going into a special project that will need its heavy duty toughness. I don't wish to reveal too much on that build, just that its going into an unlikely and unusual sleeper.

Glad to see there are no hard feelings. I know that you are an experienced and knowledgeable member of this forum. Of course I don't always agree with your opinions, and you mine. Doesn't matter, you have your experiences, I have mine, I have learned many things over the years, I have said dumb or false things too, and had to be put in my place or learn from those who knew more about it.

I do understand that I tend to be a very technical minded person. I am big on details, I don't usually see things as black and white. I know that people who are used to everything in laymans' terms very often find me overwhelming, both on this forum and in face to face real life. I will frequently speak out in complex terms, and use words that some people don't understand, had one guy ask me if I just made up "endothermic" as a word, which means a chemical reaction that absorbs or cools its surroundings. He had never heard the word, and I had to explain it in more understandable terms, and he still didn't grasp the concept.

Was dealing with an emissions issue in which a catalytic converter could cool the exhaust if there was too much NOX in the exhaust and the front converter was damaged and readily converted NOX back into its basic components, but in the process cooled the exhaust so much that the second cat could not break down the HC and CO. Vehicle was loosing 120 degrees in temperature through the front cat, instead of getting hotter like it was supposed to. Turns out the vehicle had had a blown head gasket, and the head was warped, and was shaved enough that it altered the compression ration, which in turn caused more NOX formation than normal. No pinging, fortunately. Like you said, up front, the details were not fully known. In this vehicles case, the customer was also running 85 octane in an engine that was designed for 87 prior to the head work. We replaced the damaged cats, then refilled with 89 octane, the problem was solved.

Told this story just to illustrate a bit more of what I often do, and how I tend to be quite technical. In this case too, the shop lacked the diagnostics knowledge and experience to resolve the issue, so in the end, while the shop still did much of the work, I was allowed to step in with my diagnostic tools and knowing what I was looking for and doing a few tests, was able to isolate the cause and correct this issue. The customer never had another problem to my knowledge.

I have done a few special seminars on emissions diagnostics, which have had limited success, most mechanics are not that technical, where as I do have some background in mechanical engineering as well. My father was also a mechanical engineer, he was involved in the space program for over 35 years.