Blinking check engine light

[stew47]

So the light started blinking and stayed on under hard acceleration. It's a 2008 f350 with 6.8. Truck didn't seem to be lagging in performance. Tomorrow I'll go to autozone and see what code it threw but first anyone have any experiences of what they did?

[stew47]

Gde trailer thanks for all your help. Just an update then I'm going to that ford enthusiast page. I got truck in to shop and they scanned, only saw the po300, checked plugs and found to be in good shape. Found nearly plugged fuel filter so replaced. Lol accelerates again. All was well for couple weeks and when passing a car today the light blinked a few times and didn't stay on. I'm gonna check for code with my neat new blue tooth scanner. Thanks again all.

[Gdetrailer]

Bobbo wrote:

Gdetrailer wrote:

Bobbo wrote:
A solid check engine light means check the codes whenever it is convenient.

A blinking check engine light means pull over, stop and call a tow truck.

No, not even close.

2008 Chrysler Town & Country Manual wrote:
19. Malfunction Indicator Light
This light is part of an onboard diagnostic system
called OBD that monitors engine and automatic
transmission control systems. The light will illuminate
when the key is in the ON position before engine
start. If the bulb does not come on when turning the key
from OFF to ON, have the condition checked promptly.
Certain conditions such as a loose or missing gas cap,
poor fuel quality, etc. may illuminate the light after
engine start. The vehicle should be serviced if the light
stays on through several of your typical driving cycles. In
most situations the vehicle will drive normally and will
not require towing.
If the Malfunction Indicator Light flashes when the
engine is running, serious conditions may exist that
could lead to immediate loss of power or severe catalytic
converter damage. The vehicle should be serviced as
soon as possible if this occurs.

emphasis added

LISTEN UP FOLKS.

THE OP'S VEHICLE IS NOT A CHRYSLER.

Chryslers and Fords CEL lights OPERATIONS MEAN DIFFERENT THINGS, PERIOD.

Ford calls it SERVICE ENGINE SOON LIGHT.

DIRECTLY FROM FORDS OWNERS MANUAL HERE one page 13 of the Ford owners manual it says..

"Service engine soon:

The Service engine soon indicator light illuminates when the ignition is first turned to the RUN position to check the bulb.

Solid illumination after the engine is started indicates the On Board Diagnostics System (OBD-II) has detected a malfunction.

Refer to On board diagnostics (OBD-II)in the Maintenance and Specifications chapter.

If the light is blinking, engine misfire is occurring which could damage your catalytic converter.

Drive in a moderate fashion (avoid heavy acceleration and deceleration) and have your vehicle serviced immediately"

The indicator light in question looks like THIS..



It is only ONE COLOR and only has TWO "modes".. Solid ON and BLINKING.

Folks, please quit "comparing" other manufacturers CEL light functions to how Fords CEL light functions..

INSTEAD QUIT "ASSUMING" AND READ FORDS MANUAL BEFORE SPEWING A BUNCH OF WRONG INFORMATION....



The OPs vehicle is not going to self destruct with a CEL light blinking or on.

On edit..

stew47.. I would highly recommend you go to FORD TRUCKS ENTHUSIASTS FORUM

You will find nothing but FORD OWNERS WHO ARE MORE THAN HAPPY TO HELP OTHER FORD OWNERS instead of someone who "knows a owner of a Detroit Diesel" or a Chysler owner or a GM owner or a Toyota owner just making guesses at what a simple indicator light means for YOUR vehicle..

I AM a Ford owner of not one but THREE trucks with 5.4s, a 2003, 2006 and a 2013.. I can honestly tell you that this entire thread is filled with a lot of misinformation and it didn't come from me..

[Campinfan]

My F20 (2008 with the v-10) did the same thing. Turned out my catalytic converter went bad. Good news: covered by warranty. The Ford dealer asked me the color of the light, orange is not a "stop or you will destroy the vehicle", whereas a red light would be worse.

[Adam_H]

WOW, so many interpretations.... Fix your missfire (common on a V10) before you have to replace the cat... Not a lot to it

[westend]

My WAG, at that mileage--COP. Be careful if you replace the plugs, make sure you understand the TSB's and follow the procedure.

[Bobbo]

Gdetrailer wrote:

Bobbo wrote:
A solid check engine light means check the codes whenever it is convenient.

A blinking check engine light means pull over, stop and call a tow truck.

No, not even close.

2008 Chrysler Town & Country Manual wrote:
19. Malfunction Indicator Light
This light is part of an onboard diagnostic system
called OBD that monitors engine and automatic
transmission control systems. The light will illuminate
when the key is in the ON position before engine
start. If the bulb does not come on when turning the key
from OFF to ON, have the condition checked promptly.
Certain conditions such as a loose or missing gas cap,
poor fuel quality, etc. may illuminate the light after
engine start. The vehicle should be serviced if the light
stays on through several of your typical driving cycles. In
most situations the vehicle will drive normally and will
not require towing.
If the Malfunction Indicator Light flashes when the
engine is running, serious conditions may exist that
could lead to immediate loss of power or severe catalytic
converter damage. The vehicle should be serviced as
soon as possible if this occurs.

emphasis added

[stew47]

Kayteg1 wrote:
When CEL on most vehicle is mostly emission stuff, it is the unknown that can kill our mind.
Would you drive your coach without fuel gauge?
So why you hesitate to spend $20 for Bluetooth reader, or $30 for independent scanner?

Lol since you put like that..... I ordered one for 16$ on Amazon. Friend at work showed me his blue tooth reader and while simple it gives a code and that's good enough.

[72cougarxr7]

Since OBDII came out in 96, a flashing "check engine" light is a more serious problem ,usually a misfire, and catalytic converter damage can occur if the vehicle keeps being driven. Usually an ignition system problem, or a faulty injector.
A solid check engine light is a more minor emissions system problem, but damage won't be done to the vehicle from driving it.

[Kayteg1]

When CEL on most vehicle is mostly emission stuff, it is the unknown that can kill our mind.
Would you drive your coach without fuel gauge?
So why you hesitate to spend $20 for Bluetooth reader, or $30 for independent scanner?

[grizzzman]

stew47 wrote:
So the light started blinking and stayed on under hard acceleration. It's a 2008 f350 with 6.8. Truck didn't seem to be lagging in performance. Tomorrow I'll go to autozone and see what code it threw but first anyone have any experiences of what they did?

The simple truth is the "Check Money" light serves the catalytic converter. A blinking "check engine" means a catalytic damaging event is is happening. The EPA has the average person by the......well you know;)

[Gdetrailer]

stew47 wrote:
Well I notice eBay has complete tune up kit with cops, plugs, fuel filter, air filter, pcv valve for 300$. Maybe it's just easier to do at home i dont know. Is there a good place to get the plug socket that's magnetic and long enough extension?

Only use Motorcraft brand COPs, they are expensive BUT they are much better quality and will last much longer than the cheap generic brands..

Been there, done that. Bought a kit of 8 generic COPs from Amazon for a mere $50.. Less than one year of driving ONE of the generic COPs died.

Typically you buy one brand new Motorcraft COP, and substitute it for one of the existing ones you have. Keep track of where the new one is and continue to swap coils until you eliminate the problem.

Typically only ONE COP will go bad, not very often will more than one go bad so buying ten new coils is not needed.

You can get real deal Motorcraft COPs from Amazon for around $54 each..

Air filter, fuel filter can be had at your local Walmart shouldn't cost more than $30 for both.

Plugs, get Motorcraft brand, those are the best for this job.

For the plug socket, use standard plug socket (which should have a rubber insert to hold the plug) with a 6" extension..

Use black plastic tape to hold the socket to the 6" extension..

You will need a variety of other extensions and perhaps a universal joint for some of the positions to get around wiring and such.

Some engines may have the airfilter box on top of the engine above the Throttle body, you may need to remove the air filter box to get to the rear plugs.. Be careful, there are some vacuum lines on the box.

You may need to disconnect the MAF (Mas Airflow Sensor) if located on the air filer box. The plugin is stubborn and can be difficult to get the connector off.

For some plugs, you may need to disconnect the injector wire harness, just remember to plug injector harness back on when done with that plug..

Before removing the plug, shoot a blast of air into the plug well, this will remove any dirt which may have fallen into the well when you removed the COP and boot.

Some Boots MAY get stuck in the well, you might wish to consider buying a couple of new boots (can get at places like Autozone).

[stew47]

Well I notice eBay has complete tune up kit with cops, plugs, fuel filter, air filter, pcv valve for 300$. Maybe it's just easier to do at home i dont know. Is there a good place to get the plug socket that's magnetic and long enough extension?

[Gdetrailer]

stew47 wrote:
Lol helps greatly. Sensory overload! Makes me think I might drop off to mechanic so I don't start the costly process of changing parts. I bought with 169000 and I have 174000 on the odometer now. No idea when plugs were replaced or if any cops have been changed out. Since its at full throttle what do you think about fuel filter as a first step? I guess I could pull a plug out and look at the general condition. I've watched the videos about using carb cleaner to dissolve carbon on plugs first but still scares me

Thinking further about when lights went off the truck didn't seem to have quite the power as normal which I guess could be starving for fuel or a cylinder dropping out.

Fuel filter is a cheap part, good idea to change as preventative maintenance since you do not know the history of said vehicle.

Since you bought it used, there are a few things that may need to be addressed.

Plugs, might want to change them, not sure if 2008 used the infamous two piece plugs (2006 5.4 did), this plug style has a bad habit of getting stuck and breaking off.. There is a special removal tool that is needed if this happens.

IF for any reason the previous owner had a plug eject they may have used a "timesert" or "Helicoil" to fix the damaged threads.. Sometimes that fix may cause intermittent issues with the strength of the spark.. That may need attention if that is the case.

If for any reason the previous owner changed the plugs and did not use a torque wrench to set the plugs, you could have LOOSE PLUGS which can cause random miss fires.

The torque specs have changed over the years so you will need to get that info most likely from a Ford mechanic.. I can tell you this, for our 2006 5.4 the factory torque was 33 ft lbs and the replacement plugs are supposed to be set to 27 ft lbs.

Additionally, Oxy sensors are a "wear item", if those are the originals they HAVE done well and are most likely end of life. As the sensors age they tend to react slower and they often do not respond fast enough under hard acceleration.. A code reader with live data function can easily see the speed of change on the oxy sensors.

The upstream oxy sensors handle the fuel mixture settings (these are before the Cats) and the downstream sensors are mainly for emission performance checks..

With the miles you have, I would highly recommend a good cleaning of the Throttle body. Most likely this has never been cleaned.

You should have electronic drive by wire throttle body, unlike the older throttle bodys that had a direct connection to the foot feed you can not feel the throttle plate sticking.

Ford has the PVC valve vented directly under the throttle body, this allows oil vapors to collect on the throttle body and the throttle plate.

Over time this builds up until the throttle plate starts sticking..

This can cause stalling, extremely slow idle and when it gets bad enough you will lose complete throttle control (nothing happens when you step on the go pedal).. This condition will be indicated with a little "wrench" Icon on your dash.

I would try filter, but plugs would also be good to get done but at the same time check all the vacuum lines for breaks or cracks. When changing the plugs, inspect the COP boots for damage, cracks, dirt.. Replace them if they do not look good.

If you find antifreeze in one of the plug holes or on the COP boot, you may have a cracked intake manifold. This is a common problem and can cause random misfires.

Otherwise, might want to see if your mechanic is familiar with Ford modular engines.. Much easier and cheaper if you have a good mechanic.. I wasted a lot of money at my local Ford dealer, they caused a lot of problems, changed a lot of parts and wasted a lot of my time by just guessing and randomly changing parts..

Took me a few searches on the Internet with the symptoms I was having and I solved all the problems that my dealer caused plus figured out the original problem..

[Gdetrailer]

wa8yxm wrote:

Bobbo wrote:
A solid check engine light means check the codes whenever it is convenient.

A blinking check engine light means pull over, stop and call a tow truck.

Happened to my brother once as he was pulling off the freeway in his Detroit Diesel Powered Semi. His made it to the end of the ramp and coasted onto the shoulder.. Buddy said "Wooee, Looks like the clown car at the circus with flames shooting out from under the hood"

He left the terminal with a Detroit Diesel under the hood. By the time he stopped (near instant after the light came on) He had two halves of a Detroit Diesel under the hood.. Not so little brother (6'6.5" tall to my 6'3" but younger) is a certified Diesel Mechanic (Also Auto) Inspected it, Hitched a ride to the truck stop a short distance away..Called Detroit D His buddy dropped his trailer and they went back intending to pull his tractor out from under his trailer, then pick up his trailer and tow it to the truck stop.. Tow truck was already hooking up to tractor (Detroit D sent the Tow) so they took the trailer back.. Detroit had a new engine, AND an installer, on a plane the next day putting it in and he was on the road again.

Blinking Check Engine is serious.

Blinking engine light on a DIESEL is a DIFFERENT BEAST..

Each manufacturer has their own "system" to what functions a particular light means.. So no way to compare the actions of a Detroit Diesel to a Ford 5.4/6.8 engine light.

NOT THE SAME AS A FORD 5.4/6.8 gas engine, PERIOD.

I have personally been down this road with a 2006 5.4 and am very well versed on this..

Fords CEL (which in this case looks like a little engine Icon) ONLY MEANS a malfunction has been detected which can affect engine performance power wise or emission wise..

IT DOES NOT MEAN THAT ENGINE DAMAGE IS OCCURRING!

I can assure you and anyone else on Fords of this vintage and most since the 1990s there is not going to be flames, broken engine parts or severe damage done with a blinking or steady CEL.

[wa8yxm]

Bobbo wrote:
A solid check engine light means check the codes whenever it is convenient.

A blinking check engine light means pull over, stop and call a tow truck.

Happened to my brother once as he was pulling off the freeway in his Detroit Diesel Powered Semi. His made it to the end of the ramp and coasted onto the shoulder.. Buddy said "Wooee, Looks like the clown car at the circus with flames shooting out from under the hood"

He left the terminal with a Detroit Diesel under the hood. By the time he stopped (near instant after the light came on) He had two halves of a Detroit Diesel under the hood.. Not so little brother (6'6.5" tall to my 6'3" but younger) is a certified Diesel Mechanic (Also Auto) Inspected it, Hitched a ride to the truck stop a short distance away..Called Detroit D His buddy dropped his trailer and they went back intending to pull his tractor out from under his trailer, then pick up his trailer and tow it to the truck stop.. Tow truck was already hooking up to tractor (Detroit D sent the Tow) so they took the trailer back.. Detroit had a new engine, AND an installer, on a plane the next day putting it in and he was on the road again.

Blinking Check Engine is serious.