The check engine light is blinking on my 98 Mazda Protege. I’d like to purchase one of those little hand held computers so that I can diagnose the problem myself. Is this a bad idea? Should I leave it up to the professionals? If it’s not a bad idea, which device do you guys recommend?
I don’t own one, but it isn’t a bad idea. Auto parts stores like Advance Auto Parts read the codes for free (in most states), and I generally do that.
That said, a flashing check engine light is serious. This is a misfire or some other serious issue, and you may need to have the vehicle towed for repair, or repair on the spot, depending on your level of expertise. I would not drive it very far in its current condition.
If you own a laptop computer, check eBay for a “USB to OBD2 cable” Look for one that comes with software…A free-standing code reader can be had for $30-$70…
Or have a parts store read the codes for free…The blinking light means the computer REALLY wants you to do something NOW…Usually a misfire that can burn up your CAT if not repaired quickly…
I just got back from having the codes read by Advance Auto Parts. It seems to be the same thing (# 3 cylinder misfire) that it’s been the last 8 years with the engine light on - only now it’s blinking. The cylinder is causing a misfire because of low compression due to a worn piston ring. (determined via compression test) Is it likely that the ring is more worn down now and has made the misfire worse and that’s why the engine light started flashing?
Is it likely that the ring is more worn down now and has made the misfire worse and that’s why the engine light started flashing?
Yes. The engine is toast. What were the compression readings, and is whomever did them sure it was a piston ring issue rather than a valve issue?
#1:170
#2:150
#3: 85
#4:180
After the compression test they put oil into #3 and the compression came up.
Pretty amazing it’s been running perfectly fine for all these years. I would have never known anything was wrong if it wasn’t for the engine light. It does smoke for a few seconds when I first start it up in the morning after it’s been cold outside…but that might not have anything to do with the weak cylinder.Who knows.
Also, what’s a CAT?
The CAT is your catalytic converter. Since this car probably isn’t worth the engine repair I doubt its high on the list of things to worry about.
BUT - if you do plan to save it, then you should worry. You can probably get a used engine for that car at a reasonable price.
ABSOLUTELY…go and get yourself one…they are obscenely CHEAP nowadays. YOu can even get one at Walmart from 50-100 bucks for the fancier ones. On the internet you will save even more… I think everyone should have one of these…it will give you the ability to read your own codes…erase your own codes…AND compare notes to any shop or garage that tells you X Y and Z about your vehicle… See if they are telling you the truth…
Blackbird
Is replacing the piston ring out of the question?
Regarding the handheld code reader, I think it’s a great idea. Stop by the parts stores and look at the choices. I’m with Honda BB on this one.
Re: the catalytic converter…if your question stems from the cat having been mentioned by the shop, than you should know that burning oil can render a cat converter ineffective. And you know you’re burning oil. As a minimum, that puff of smoke in the morning is due to oil from the valvetrain passing worn valvestem guides overnioght and settling on the backs of the valves (and in the cylinders if the valves are open). It then gets burned when you start the engine.
The method by which the burning oil renders the cat converter inoperative is thus: the comverter is a ceramic honeycomb coated with a precious metal that when heated causes oxides of nitrogen (NOx) that come in contact with it to seperate into nitrogen and oxygen. However, when the catalyst gets coated, in this case with oil residue, the NOx cannot come in contact with the precious metal and the converter no longer seperate the NOx molecules.
Note that a cat rendered inoperative in this manner will not affect the engine’s ability to run well. Should the upstream oxygen sensor also get coated, that can cause poor operation, but the converter itself will not.
Replacing a piston ring isn’t that simple. It requires (at a bare minimum) the head, oil pan, several parts on the front of the motor and some one the sides be removed, the piston removed, new rings installed, and the motor put back together.
It’s a lot of work, and at that bare minimum level won’t last very long at all.
Any decent mechanic will want to remove the engine, have it properly rebuilt, then reinstalled. Broken in, oil change, and monitor for a thousand miles or so to make sure it’s running right.
I wouldn’t think it would really be worth it for this almost 14 year old vehicle. Make a few phone calls around, and see what prices they quote you. You can ask for a rebuilt, see what the cost is. Some places (like AutoZone and the like) will sell partial motors (block and head, you have to use all your other parts). They’re not cheap. Phones calls are, though. Arm yourself, and see what your options are. You can try a junkyard (err, “automotive recycler”)for a used engine.
85 is very low, and 150 is low, too. 1, really, is a tad on the low side, but those 2 are pretty much done.
There are tons of low mileage engines from the JDM market for your Protege if you were so inclined to go that route. You must REALLY love this Mazda … No? Your most cost effective route would be to swap in a JDM used engine into this vehicle…engines should be around 600-1200 used w low miles… The rebuild will be closer to 2000…then with labor… It really isnt worth it, in my book. If I had the car and really loved it or needed to have it in working order I would swap in a JDM engine myself…That is the only real way it would be worth it…by doing it yourself and not involving a shop…that is where you lose a lot of money and make the project not worth it.
I just realized that I never answered your question!
Yes, it is highly likely that the problems you describe are causing the misfire. You can verify this by looking at the sparkplugs.
As to the engine being “toast”, heck…if it’lll keep running, keep driving it. You have nothing to lose. When it finally “gives up he ghost”, then you can make a decision.
You don’t want a JDM engine. JDM stands for Japanese Domestic Market. They are low mileage, but they have a LOT of hours. Normal traffic in Japan resembles the worse traffic jam you have ever encountered stateside. JDM manual transmissions are a bargain though.
Ive had great luck with JDM engines…and every one of them had beautiful looking valvetrains…a clue to oil changes and cleanliness of the engine internals… But to each his own… I never thought about the traffic in Japan actually…thats something to consider for sure… Hmmm… For me, so far, its been very very good
I do like this car a lot and have grown quite attached to it. Was hoping to be like Million Mile Joe. : )
Let’s say I do the valve stem guides myself so there’s no threat to the oxygen sensor becoming damaged and to do away with the embarrassment of smoke pouring out when I first start it up and to do away with the wasted/burnt oil: What kind of CAT damage can be done from the #3 cylinder misfire? Would it just cause the CAT to not operate properly or would it make the car run poorly? I don’t have e-check where I live so as long as it wouldn’t affect the way the engine runs I wouldn’t mind.
mystic — "What kind of CAT damage can be done from the #3 cylinder misfire? Would it just cause the CAT to not operate properly or would it make the car run poorly?"See Catalytic Converter Failure
the same mountainbike – “that puff of smoke in the morning is due to oil from the valvetrain passing worn valvestem guides overnioght and settling on the backs of the valves (and in the cylinders if the valves are open). It then gets burned when you start the engine.”
So to prevent this I would have to replace the valvestem guides or just the valvestem seals?
“valvestem guides or just the valvestem seals?”
Short version:
Remove the valve cover, rocker arms or cam and valve springs.
Then check the valve stems for wobble (free play).
At this point the stem seals can easily changed and if the valves feel snug in the guides the top of the engine can be reassembled.
If the valves are loose in the guides then the head is removed and taken to a machine shop for valve guides, valve seat grinding etc.
With the low compression low on #2 and #3 the head needs to come off anyway.
If you start messing with the head you might as well be prepared to just do the entire job - as in rebuilding the block as well. Given the results of the wet compression test, whatever you do to the head won’t fix that 3rd cylinder issue. But that just puts you back at the fact that a used engine would probably be your best bet.