My CEL has been on for ages, but just recently started 'flashing'. Seems to only happen on the highway, when the RPM's get a little low. Would this indicate multilple codes?

Also, one of the codes I keep getting is mis-fire on cylinder #1. I have re-gapped the plugs and checked that the plug wires are tight - bad coil pack ?

A flashing cel usually mean something catastrophic has potential to happen. In your case probably a dead miss in cylineer one. If I were you I would be a bit more exoratory as to what is causing you miss. Check everything in ignition and fuel delivery to that cylinder. Best of luck

Flashing CEL means misfire.


- Your not-so-local, untrained, uncertified, backyard mechanic. But my @!#$ runs

OK - checked the codes again this morning - now getting 2 separate ones.

P0300 - random / multiple cylinder misfire

and

P0301 - cylinder 1 misfire

So, I replaced the coil pack with one from the wrecker. Still getting flashing CEL and both codes.

Could this be a weak alternator ? The battery is new in the past couple of months.

is this an eco, or 2200? if 2200, move the spark plug wire to cyl 4, and four to one. see if the problems moves to cyl 4. if so, get new wires. if not, its either the spark plug itself, the injector for cyl 1, or something REALLY bad in the cylinder, like burnt/broken valve. but i'd bet its either a wire or injector, with my guesses in that order. also, after the spark wire move, do a compression test of the engine. and plugs are cheap enough, if its not the wire, just change to new plugs to rule them out.

It is a 2200. I have tried replacing the #1 plug wire - no change. How do I test the injector? I will do a compression test and replace the plugs next chance I get. Thanks for the help.

YOUNG J wrote:A flashing cel usually mean something catastrophic has potential to happen. In your case probably a dead miss in cylineer one. If I were you I would be a bit more exoratory as to what is causing you miss. Check everything in ignition and fuel delivery to that cylinder. Best of luck

Where the f*ck did you come up with that?




i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick

must have pulled it out of his A$$, Jason its comment like that, that piss me off cause its untrue and not informative



JBO since July 30, 2001

it could also be the terminal on the coil pack. you could switch the 2 coil packs and see if the misfire moves with it. first check the easy stuff. there is an injector self test where the pump builds pressure, then turns off, it logs the pressure, then injector one fires 10 times(all with key on, engine off), then it records the pressure after it fires all 10 times, then it builds to the same original pressure and turns off, then injector 2 fires, and so on and so forth, all to see if they flow the same, and if one leaks/clogged. but you need a scan tool so we'll save that for later. easy stuff first. switch coil packs, see if it moves, if not, coils are good. then it seems like the wire isn't at fault(i would still just to be sure, move one and 4 wire before the coil swap to make sure it doesn't move from that), and i would still do plugs. after that, comp. test, and if all of that is good, it pretty much has to be fuel, or it could also be a leak in the intake manifold gasket by cyl 1. what is your long term fuel trim reading? i just had this issue on a 00 sl2 saturn. it had a bad mis on cyl one and the other cylinders were not too bad, but the engine ran lean, and the fuel trim was as rich as it could go. smoke tested the intake system and it was pouring out of the mani gasket. replaced the gasket and everything got fixed from it. but again, not everything has a smoke tester, so we'll stick to the basics till we rule that stuff out.

btw, flashing cel means its a very bad misfire, and the fuel that isn't being burned will clog up the cat if its not fixed. the cat soaks up fuel like a sponge and it will lose all effectiveness and eventually be a very big restriction in your exhaust system, and your car will barely rev up at all. after you fix the problem, i would take the car out and beat on it a bit to get the cat good and hot to burn up as much fuel from the cat as you can so it lasts as long as it can.

It flashing means it's trying to get your attention to tell you "HEY! HAVEN'T YOU SEEN ME BURNING BRIGHT FOR A WHILE NOW?!?!?!"





-----------------------------------------------------------------------

-----------------------------------------------------------------------
- Sold my beloved J in April 2010 -

OK - so I checked the compression tonight - 30 / 182 / 184 / 182 - so, cylinder #1 is definitly bad. Next step is to pull the head and see what is up - then off to the wrecker for a 'new' head.

Thanks for all the help guys.

Just to take a chance here, and it's probably a long shot. I would pull the valve cover and make sure that you didn't have a pushrod fly off of a rocker. I had it happen before. This could affect you pretty bad.





i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick

david monteith wrote:OK - so I checked the compression tonight - 30 / 182 / 184 / 182 - so, cylinder #1 is definitly bad. Next step is to pull the head and see what is up - then off to the wrecker for a 'new' head.

Thanks for all the help guys.

wow! that is really bad! lol that'll cause a cel to flash alright

I'd just like to correct a bit of info here. Dave said it already, but it would be a bit confusing.

A Flashing CEL means a severe engine misfire causing catalyst damage.

who says its the head thats bad? i'd be doing a leak down test before pulling anything , fined out where the problem is.

Sunfiretun3r wrote:I'd just like to correct a bit of info here. Dave said it already, but it would be a bit confusing.

A Flashing CEL means a severe engine misfire causing catalyst damage.

thanks for explaining it easier. sorry if i said anything in too confusing of a way before. if i ever say something that anyone doesn't understand, just ask. i'll do anything i can to clarify.

inspect the head for a crack inbetween the plug and valves and the litle peice inbetween the valves that is the common area for cracks on that engine. chances are if its cracked you had coolant goin in

to be honest if i were you i would go pick up a new motor THOSE ONES ARE CHEAP and just swap it you could change out the head put a bunch of new parts on and have bad rings

you should be able to find a good motor with decent milage for less then 300



JBO since July 30, 2001

Dave De Stefano wrote:
thanks for explaining it easier. sorry if i said anything in too confusing of a way before. if i ever say something that anyone doesn't understand, just ask. i'll do anything i can to clarify.

No worries man. A flashing CEL is a common mis-conception. People think their engine is going to blow up, which isn't the case necessarily.

Sorry if that was bad info guys, that is what was told to me by the Automotive instructors at the trade schol where i got my Automotive degree and beleive it is actually in my textbooks. If I am wrong I do apologize, but thatis the wayI was taught. I thought having a spark miss and still injecting fuel can cause hydrolock and having a fuel miss and still adding spark to the equation cqn cause detination to piston? This is just what I was taught by instructors so if untrue, I'm sorry.

Thats where the f*ck I got it. Not just pull outa my a$$

On the other hand a fIre caused by a gas soaked catalytic converter doesn't sound catastrophic at all

YOUNG J wrote:Sorry if that was bad info guys, that is what was told to me by the Automotive instructors at the trade schol where i got my Automotive degree and beleive it is actually in my textbooks. If I am wrong I do apologize, but thatis the wayI was taught. I thought having a spark miss and still injecting fuel can cause hydrolock and having a fuel miss and still adding spark to the equation cqn cause detination to piston? This is just what I was taught by instructors so if untrue, I'm sorry.

Thats where the f*ck I got it. Not just pull outa my a$$

well, a misfire because of no spark, but still adding fuel could potentially hydrolock the engine. its just not as likely to happen as some ppl might think. and if you have no fuel but spark, you will not have detonation. there is no fuel to ignite. detonation is defined as a second flame front that begins from a hot spot in the combustion chamber, but it must occur after the spark plug ignites the mixture. if you have a dead miss, you have no ignition whatsoever. in this case, your o2 sensor sees all that oxygen in the exhaust because it wasn't burned up, and it thinks you're running too lean. it dumps more fuel, and now you have an extremely lean cylinder(since that one has a fuel problem) and the rest all too rich.

there are different degrees to misfires, but generally, a flashing cel means a dead miss, which the computer just automatically asssumes that due to that dead miss, there will be too much fuel that wasn't burned going through the exhaust, to the cat. the cat absorbs the fuel(acts like a sponge) and once it is all saturated, and coated in fuel, the precious metals that are in the catalyst can no longer do the job of reacting to the harmful gasses(and sometimes they can even melt from the fuel trying to burn in them if theres that much fuel in em). if it gets this bad, and is ignored, generally, you need a new cat, but you should always fix your miss first. otherwise you'll just destroy your new cat.

the cel doesn't really care about the engine at all directly. its only there for emissions related devices, but the engine can effect the emissions of the car, so it monitors it. so don't think of a cel flashing because you will hydrolock, think of it as an emissions monitor(if flashing, then cat related), and this problem can also cause a bad engine problem(or be caused by one).

YOUNG J wrote:Sorry if that was bad info guys, that is what was told to me by the Automotive instructors at the trade schol where i got my Automotive degree and beleive it is actually in my textbooks. If I am wrong I do apologize, but thatis the wayI was taught. I thought having a spark miss and still injecting fuel can cause hydrolock and having a fuel miss and still adding spark to the equation cqn cause detination to piston? This is just what I was taught by instructors so if untrue, I'm sorry.

Thats where the f*ck I got it. Not just pull outa my a$$

Whatever you got from that trade school..... I'd take it and throw it away. Also, try reading your owners manual for your car, it says right in there what a flashing check engine light is for. As for hydrolocking an engine while it's running, just off of injecting fuel.... LOLOL. I mean, they did teach you at school about how gas burns right? You can throw a match on a puddle of gas, and just the fumes will burn. The liquid part won't burn. So I guess it stands to reason that you're injecting a small enough amount so that you still have something that atomizes in the cylider. You've heard of the trick of spraying water into the TB in order to clean out carbon, right? You're not going to hydrolock it under any circumstance with an engine that's still running. It'll just throw it out the exhaust side.

Well, I guess if you drive the car into a pool of gasoline and submerge the intake, that would probably do it. But, I think at that point you'll have a SLIGHTLY more important issue than that of hydrolocking the engine.

Since you're tough now that you were called out. What school did you go to to get your degree?





i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick

I'm not tough now that I was called out. Was just originally stating what I thought was useful information. Not going to argue with you, just explain myself and be on my way. I have a two year associated degree from New Castle School of Trades with a decent GPA. Its only entry level but gotta start somewhere.

During the time I was in school, my CEL started flashing while on my way in for classes. When getting to school I was told that I should have pulled over and called a tow truck to come get me because I could have caused a catastrophic problem. I told to OP the there was POTENTIAL for something catastrophic, but never said it was definite. My problem was not the same as his and was definitely not a major issue.

I also have no problem admitting when I am wrong and in this case I am. I stated above that if I gave bad info then I am sorry, which I am. I know there are a lot of people on this site that know a lot more than I do about diagnostics, my experience is limited and again I did think I was being helpful. You are also right that hydro locking a running engine doesn't sound logical and without atomized fuel to ignite, detonation is a ridiculous idea. I did also look in my mentioned textbook and it basically says the same thing that Dave De Stefano and Sunfiretun3r have already RATIONALLY stated. (Thank you for clearing up MY confusion)

I never said that I was some master tech, just that I had a degree. Hell, I'm not even ASE certified yet because I know there is still a lot I need to learn and have forgotten info that I have already learned. All I can say is that SO FAR my diagnostics at work with the car in my possession have been good. I guess I will keep my diagnostics at work and off the forum.

This is my formal apology for my lack of INFORMATIVE information. If you still feel the need to continue giving me crap, go ahead.

For the record, even tho I'm not one of them, there is a rather large percentage of people in the world the find a blown head gasket/cracked head/ bad rings to be catastrophic. Not so much a push rod off a rocker tho.

To the OP, best of luck with the repairs. Sorry I was of no help

Well - the ' good ' news is that is was just a burned valve. No other visible damage. New head installed, it fired up on the first turn of the key, and idles like it it brand new - bring on the next 400KM.

Thanks everyone for your input.