Last post on Apr 15, 2013 at 8:56 AM
You are in the Mazda 626
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Mazda 626, Sedan
#1128 of 2544 Idling problem on '93 626
Jun 10, 2002 (6:58 pm)
I've had this car for about 8 months, it's my first car. 1993 626 LX 4cyl automatic (yes it's slow ). It currently has 131k miles. First off, the tranmission shifts quite rough and sometimes hesitates to downshift, like if I was to come to a rolling stop and then hit the gas it pauses for a while as it downshifts to accelerate. It's not really that bad, but I did notice it especially yesterday when I was making a left turn and I had to kinda hurry so I wouldn't cut someone off and when it hesitated like that I was stuck in the intersection a tiny bit longer... but I guess it doesn't really matter. I'm surprised it's gone this far, but from all these other threads it looks like the 93 trannys are decent and it's not till the 94 when it had MAJOR problems.
Now on to the idling... It shakes quite a bit when idling at a stoplight or whatever. Before in the winter when I got the car, it took like 5 minutes of driving before it'd start to do that but now since it's warmer it's pretty much like that always. And the rpms are REAL low. They're only about 400-500, but steady, not jumping around. And it just kinda feels like the car is going to stall cause it's so quiet and almost like it's skipping. But it never has stalled.
But it idles very quietly. Like today when I was unloading some stuff and it was running, it was very quiet, much quieter than you'd expect from a 93 with lotsa miles and the exhaust still isn't like it should be (stupid ppl, they really FIXED it). But then after I finished and was about to move the car, some type of fan (in the engine area) started up. It was quite a bit louder, especially over the very quiet engine. That was the first time I've heard it then. But maybe a fan is on when I start the car cause it is louder for like a minute when I first start it.
Otherwise the car runs great. Again it doesn't shift very good, but it revs very nicely and is very smooth while driving.
Any ideas? I heard several possibilties from reading a ton of threads here and other places: radiator mounts (?), engine mounts, idle gasket cover, idle throttle adjustment.
Also, any ideas on a cost? Do you think the mazda dealer would look at it and tell me what it is and how much it'd cost for FREE then I could decide? And is there really any reason to fix it? I mean there's probably other things that might need fixing considering I have all the service reciepts from original owner and it's pretty much brake work every couple years, exhaust work every couple years, and new alternator. But damn reliable I'd say. But I would hate to spend a lot of money fixing it only to possibly have the tranny go on it which would definitely f*ck me over since it'd cost like $2000 to fix from what I hear and hell I got the car for $2500...
Jun 11, 2002 (4:23 pm)
Proper idle on this car is 700 rpm. I suspect that if the correct idle can be restored, the shaking will be reduced. (Mounts are a potential issue, yes, but try the easier stuff first.)
As for that fan, it comes on as needed when the temperature is high enough - such as during a period of extended idling.
#1130 of 2544 Getting ATF through the dipstick...
Jun 11, 2002 (6:08 pm)
A little update. As I mentioned in previous posts, I was considering draining/changing the ATF through the dipstick several times to improve the condition of my fluid. I finally got my little oil extractor (a PELA oil extractor used for boats), and was able to get 2.5 quarts out through the dipstick. The whole process was clean and quick (done in 15 minutes)...
I know, I know, I will have to do this 5 times to get 80% new fluid in, or 7 to get 90% clean fluid (and something like 12 to get more than 95% of the suff clean). In any case, I think that this gradual change may be better on the internals of the tranny than a single complete flush.
I plan to do this 4 more times (every night after my wife gets home from work), and after driving the car with 80% clean fluid for a week or so, do the real complete flush using the two-bucket method. I did drive the car after the partial change, and it shifts just like it did before. Oh, well, at least I did not screw anything up in the process...
I'll keep you guys posted. Please let me know if you think what I'm doing is extremely idiotic...
#1131 of 2544 O2 sensor on '89 Mazda 626
Jun 12, 2002 (10:26 am)
I have a '89 5-sp Mazda 626 with 198K miles, and it still runs like a charm. I've taken very good care of it over the years (regular oil change, belts, etc).
Last week I failed emissions inspection for the first time: the HC measurement is too high, by about 30%. I have tuned the car up since (should have done it before having the state inspection, stupid me) and put in new plugs, a new air filter, and a new PCV valve.
I've never replaced the O2 sensor in the car's life and wonder if it's still good. The shop manual calls for checking voltage at the O2 sensor, but how do you get the O2 "boot" off? It looks like a regular spark plug boot, except that it is much smaller, and it's made out of metal instead of rubber. I have tried to pull on it, but it won't come out. It has no flat side, so I don't think it's threaded. Can somebody offer a hint? Do you just pull on the boot like a gorilla, or is there a more subtle way to get it out? Thanks in advance.
#1132 of 2544 O2 sensor and idle speed
Jun 12, 2002 (10:48 am)
kbui, maybe you can check the voltage at the other
side of the wire, where it plugs into the connector towards the engine computer?
This will allow you to check for problems in the wires also, although wiring problem is unlikely to hallen.
BTW, anyone know how to adjust the idle speed of a 93 V6?
#1133 of 2544 O2 sensor voltages for kbui...
Jun 12, 2002 (11:15 am)
One way of doing it is to take the sensor out, find out which cables are the 'signal' (I think they are the white and gray cables), attach that to a voltmeter, and cook the tip of the sensor in your gas range (the exhaust temperature is ~ 700 F...). The voltage should go up, because there would not be O2 in there (I think the value is more than 1.2 volts). I haven't done this myself, but read about it on the web, so take it for what it's worth. Actually, if you do a google search by "O2 sensor testing" you'll get zillions of hits that will describe different ways of doing this.
I agree with jskho about 'back-probing' it while on the exhaust pipe. You will have to find a way of getting two wire leads into the connector. You may do this by disconecting the wire, which is a real pain, and putting two leads in there being careful that they don't touch each other, and then running the car and testing with a voltmeter at the leads that come out of the wire harness. Watch out for the fans!!! They will turn on when you least expect it, and will scare the crap out you when they do (personal experience)... Usually the O2 sensors get lazy and don't change their voltage as fast as they are suposed to.
Hope this help,
Jun 12, 2002 (4:18 pm)
Irish. Why would you want to do any more than an 80% exchange given the cost benefit ratio. I think that would be enough especially if you went to NAPA and purchased the right amount of Lubegard to add on the last exchange. My son's transmission was going bad and adding Lubegard immediately smoothed out the rough shift between first and second. Found about this stuff through my Mazda mechanic. Sorry if I'm being repetitive.
kbui Ohmygosh, you got 198K on a sensor that is supposed to be routinely changed at 60K. That's real good. I changed mine at 120K and noticed the difference. Don't think I got much of a gas mileage improvement, but the engine does run smoother and is more responsive. I got a Bosh for about $80. I got the OEM so it was a simple matter of unscrewing and unplugging the old one then putting on the new one.
#1135 of 2544 thanks for the O2 sensor tips
Jun 12, 2002 (6:56 pm)
jskho, irishalchemist & mrdetailer, thank you for the O2 sensor tips. I will try the "backprobing" method - that's a real good way of checking the sensor and the wiring.
I've monitored my mileage ever since I bought the car (I bought it new), and it has always hovered around 33-35 mpg. That's why I thought the O2 sensor was "doing its job."
#1136 of 2544 transmission
Jun 13, 2002 (2:01 am)
I have a '98 626 4 cyl. automatic with about 85k miles. I asked the dealer regarding a change in the automatic transmission fluid. The dealer said new tranny fluid at this point would strip the gears. Just wanted another opinion on this and if there is anything to be done to try and ensure the transmission doesn't break. Otherwise the car has been running just fine w/o any major problems and I'd hate to have to replace it.
Jun 13, 2002 (6:16 am)
freds5, unless you use Aqua Regia (a mixture of hydrochloric and nitric acid - sorry, I'm a chemist), you won't "strip the gears". Only problem may be that the new fluid could dislodge crud that is sticking here and there harmlessly and get it somewhere it's not suposed to get to (i.e., a valve). FYI, if you read a couple of posts above these ones, you'll see that I've been 'diluting' the old fluid with new fluid. So far I've done it three times (I can get 2.5 - 2.8 quarts each time through the dipstick). By the third time I have > 1/2 new fluid, and have not stripped the gears yet
I plan to do this 2 or 3 more times, and then add LubeGard as suggested by MrDetailer. Although my wife says the car behaves the same as it always did, I think it is starting to shift smoother and it's not 'clunking' as bad when going into 'D' in the morning...
Hope this helps. G.