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Check engine light blinking, backfire

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58K views 10 replies 8 participants last post by  good dog  
#1 ·
Ok this isnt my car, my sisters car. Just trying to fix it for her as soon as possible. The car is a 5 speed and if the motor is ever lugged it will misfire and even backfire. If you start out in first, lug it then floor it. It will misfire, backfire a few times then the check engine light will blink for about 20 seconds. I have a code reader from my wrx and i tried to check the code but nothing would come up. The check engine light would then turn off after about 20 seconds. The car idles fine just has a problem once you accelerate.... anyone ever had a problem like this?
 
#2 ·
Welcome to the forum. :biggrin:

More vehicle information would be helpful. :wink: If the CEL is on solid you should be able to pull the stored code & that should point to the fault. :confused:

I've had flashing CEL with poor engine performance & when the CEL finally went solid & I could pull the stored code, it was misfies on several cylinders. Keep in mind, I'm not saying that's your problem. :smile:

Bobby...
 
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#5 ·
the blinking light is set for a misfire which can damage catalytic convertor.(stated in owners manual).this misfire isnt happening long enough to set a code.
i will walk you thru the 99.9% cause of this.
get a spray bottle and fill with water.
run the engine in park and mist the coil with water.
cover the coil and plug wires.
you will then see the arcing.

if not you will need someone to brake torque the car will observing.
make sure they brake torque it while in reverse so as not to accidently run you over.
also pull the plug wire out of each spark plug tube.
if the is oil on the boot of plug wire,you will have to remove the valve covers and replace the tube seals,cover gaskets,ignition coil,plug wires,plugs.
 
#6 ·
There are two kinds of flashy-flashy.

Fast = knock
Slow = misfire

The first is bad and is rarely a problem on the N/A cars. The second is usually caused by plugs.

When was the last time plugs were replaced? It could be a bad coil or bad wires, or bad plugs.

If it's been a while since the plugs were done, it wouldn't be a bad idea to replace them with a fresh set of Platinums and fresh wires to go with them. If you don't mind changing plugs frequently, use NGK Coppers (replace them every ~15,000 miles).
 
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#9 ·
Help! I have an 01 Forester S and this morning on my way to work it started making an odd sound under the body while driving off the interstate. Each time I would accelerate it would make an odd small pebbles in a tin can sound under the body. I then had the check engine light blink and the car start vibrating at the stop light and when I parked it at work. I checked my oil and have no water or milky oil. I had the radiator replaced last month because I did have a leak. May it be the catalytic converter? I'm stuck here at work and I really don't want to drive it any further. I have had extensive work put in to this. at 125,000 miles had bent valves from the timing belt. I had all that replaced including the head gaskets. All in all I have put over $3,000 in to her in the past year and a half... I really don't want to get rid of my Forester...
 
#11 ·
Go to your local AutoZone, O'Reillys etc. and have the code read from the CEL. That will probably point you in the right direction. The vibrations while stopped point to a rough running engine. The pebbly sound while accelerating can also be related to the knock sensor but the vibration at idle tends to be ignition related. A bad misfire as you accelerate can also produce the sound you are describing.
How long ago was the major work done in relation to when the problem began?

I'm going to go with ignition related. Coils are a common issue at around this age to begin failing, definitely wires too, even spark plugs. The coils you can mist yourself with a fine spray at night with the car running to determine if they are part of the problem. If you see arcing, it's time to change them up. It's also a good time to change the wires and possibly the plugs if they were not changed when the head gasket was done.

Check your bill! If these items were not replaced, replace them!
The replacement coils and wire sets should be able to be sourced at your local auto supplier. Wire sets are usually NGK and if I recall another thread the coils were from the OEM supplier as well easy to swap yourself. The plugs if needed are a little harder but can be done by yourself. http://www.subaruforester.org/vbulletin/f66/n-spark-plug-replacement-anal-55431/

First get that code read!!!
 
#10 ·
Welcome aboard!

It might be time for plugs and wires, if they weren't already done. Since the original poster never came back after that recommendation, I'm guessing that could've solved that problem. That, or the spark plug tube seals/valve cover gaskets.

As for the pebbles-in-a-tin-can sound, it's most likely a heat shield that's starting to work loose. It's nothing serious, but annoying. It can usually be remedied with a large hose clamp or a metal coat hanger.

As for the timing failure, I'm going to guess it was a pulley that gave up, causing it to happen. That's the main reason why the complete timing job (not just the belt) should be done by 105 months or 105,000 miles.

You mention vibrations while stopped. Have the front axles been replaced? If so, are they genuine Subaru? Most aftermarket axles are known to have that symptom after a little use. It's best to re-boot the original axles when they start leaking grease. You can identify original axles by looking at the "cup" right were the axles meet the transmission. The "cup-looking" part should be green. Any other color indicates aftermarket.

Picture showing where to look.
 

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