Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!





Got a Quick, Technical Question?

16667697172280

Comments

  • alcanalcan Posts: 2,550
    Peter, let's go back to basics. When the engine's first started, it runs in open loop with the ECU controlling fuel injector pulse width (and air/fuel ratio) based on inputs from the following sensors: throttle position, engine coolant temp, mass airflow, manifold absolute pressure (if equipped), and r.p.m. The ECU goes into closed loop control when the O2 sensor warms up, about 700*F, and starts generating a voltage signal feedback to the ECU based on the oxygen left over in the exhaust stream. The ECU can now more precisely control fuel delivery. Usually if an O2 sensor signal is lost the engine stays in open loop, resulting in a bit richer air/fuel mixture and decreased fuel economy but not the symptoms you describe.

    Considering that the symptoms changed after you accessed the MAF sensor, I'd be inclined to think there's a problem with the sensor itself. If it's giving the ECU a false signal re the amount of air the engine's ingesting, the air/fuel ratio would be skewed resulting in the driveability problems, CEL, and O2 sensor code. Which brings me to another issue, Mazda has been famous for developing cracks in the air inlet ducting between the MAF sensor and the throttle body, allowing unmetered air to enter the engine and resulting in a lean mixture causing the same symptoms. More than one has been temporarily fixed using duct tape, which is probably the only time it's been used to actually seal a duct. Any chance you could drop a dime (or 2 or 20) on a call to Greece and have somebody remove and inspect the ducting?

    Btw, how did you retrieve the stored trouble codes? My info differs from yours:

    http://www.troublecodes.net/mazda/
  • mazda626atxmazda626atx Posts: 227
    My Car has the EEC IV version FORD diagnostic OBDI connector PLUS the Mazda DLC. The mazda DLC only has 6 pins in it : +B, GND, FBS , FSC,TBS,TSC which according to the haynes manual are either cruise control , or abs . The Ford EEC IV connector has a sti and sto but not grd in it. I jumped the STI to the battery and read the codes off the check engine light directly as per the Haynes manual. According to the manual the car should have either or, but I have incomplete versions of both. I guess Mazda was in a transition year then (1994). I have inspected the ducting visually without removing it and found nothing. Maybe removing it and checking it better is in order.
    I think what you suggest barring the ducting being cracked would be to replace the MAF first. I have found only Bosch parts for this car I hope they will not be a problem as the original parts Number is a Ford.Does the inability to hold 2000 rpm indicate anything more than sensors struggling with mixture ??
    My codes are 3 digits as per the book
    THx a lot ALCAN
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,648
    Alcan also brings up a good point worth mentioning here but that he did not emphasize.

    The O2 sensor is really for fine-tuning mixture--a defective 02 is not likely to cause really severe driveability issues, but people keep replacing them with, of course, no solution to their problem.

    A defective 02 code also is not a slam-dunk indication of a faulty 02 sensor, only that something is probably tickling it in a way it doesn't like.
  • mazda626atxmazda626atx Posts: 227
    Could the MAF be tickling it? Could it be a 10 year old car in a HOT dry country where the wiring is half cooked and I should just disregard it if I see no serious problem ? Questions Questions Questions.
    The real concern is that the last time this car had sensor problems they progressed to the HOLD light, tranny clunking etc, and eventual tranny rebuild that was 95% unnecessary even according to tranny rebuilder. So I am a little gun shy when the CEL comes on.
    Thats what half baked mechanics like me try to answer. If I get the right answer I will feel a great sense of accomplishment with the help of guys like you my PAL :)
    Thx PGP
  • mazda626atxmazda626atx Posts: 227
    Alcan the symptoms actually changed after I installed the externall tranny cooler. At least the incidence of symptoms. But I can not remember if I got the MAF sensor code before installing the cooler or not.I know for certain that I got it after . So much stuff I did and my memory is shot
    Peter
  • alcanalcan Posts: 2,550
    Might be coincidental or you might have jostled the air intake ducting. I think what I'd do in your position is buy the MAF sensor (Bosch is fine), but ask if it can be returned IF NOT OPENED OR INSTALLED. Most part houses don't like electrical returns because the end user can fry them with improper installation, but if it's not been installed they might. The worst that can happen that way is you'll have to pay the postage to send it back.
  • mazda626atxmazda626atx Posts: 227
    Wonderful ! You just jostled my memory . When the guy was installing the external tranny cooler he had to unbolt the radiator and push it away from fascia to make room to get his hand in for the fasteners. Thats about all I think he may have jostled. Prolly not significant. If you think it could be let me know.
    Does the inability to hold 2000 (surge to
    2500 and then fall back to 1500 ) mean anything to you? I have never experienced anything like it before in any car.
    I am going to ask wife to have a mechanic take a look at the ducting. Otherwise I will buy the Bosch and take a chance that the MAF is the culprit. It will prolly cost more to send back to US than it costs LOL
    I may be stuck stateside for a while but I will most certainly let you know how I made out.
    Again Many Thanks
    Peter :)
  • rbillieuxrbillieux Posts: 36
    Stupid engine light went off by itself trans shifting normalily rpm normal not racing in park code still on meter--map sensor and codes pending and up and down indicated did not erase this time--last time light came back on- :confuse: convinced muffler very little slowing down when put into low at 40 mph Bob
  • rbillieuxrbillieux Posts: 36
    Well got rid of one code--got another---one that says heat sensor in thansmission not working properly 17011 --not slowing down--shifting funny-not going into high gear till 40 MPH-engine surging--almost stall then up to 3000 releasing in park only wnen gas is floored R Billieux--@&&^%%$^&* :mad:
  • smearpsmearp Posts: 1
    Hello All-

    I'm not sure what details will help, so I'll post what I know, and I will be glad to clarify anything that may help.

    I have a '94 Chrysler LeBaron with a tad over 200,000 miles. It has been running like a champ; until recently, when 2 problems cropped up at the same time. 1) My car was took longer and longer to start, and 2) It started hesitating quite noticeably when accelerating. That is to say, you step on the gas and nothing happens for 1-3 seconds, and then it accelerates with not problems. I took it into a mechanic after it stopped starting at all, and he replaced the starter (which he said was soaked in oil from some bad gaskets that should also be replaced).

    It now starts up fine, but the hesitation has only gotten worse. I tried some Fuel Injector cleaner, and for one day the car ran fine, but I have now gone through two tanks of gas with two treatments of fuel injector cleaner, and the problem is only getting worse. I am having to anticipate any acceleration I may need to do, and step on the gas a few seconds before doing so. Sometimes, if I start the car up and put it in reverse, it starts shaking as if it is going to die, and I get the impression that it is not getting gas or air... Other than this particular (although admittedly severe) problem, the car has been a trooper and I would really hate to get rid of it.

    Is there anything I can do myself or things I should look out for? Spark Plugs, Fuel Injectors? Fuel Pump? It is not a problem that built up over time, it happened rather suddenly (in the space of around a week). Any ideas would be greatly appreciated. Thanks,

    -Sean
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,648
    Ever replaced your catalytic converter? You can install a temporary by-pass tube to test it. If your problems go away, there's your answer. Otherwise, you might want to have the tail-pipe sniffed, and also read the trouble codes.
  • fblackfblack Posts: 26
    I've found a 98 Grand Marquis with 28,000 miles at a local dealer for 8150. Seems like a good deal, only I've heard some bad things about the plastic intake manifolds. I guess some Crown Vics got a recall but not the Marquis, even though people have reported it cracking. Is this a common or inevitable problem? I really like the car but will have to get them to knock down the price before I would buy it without getting the intake manifold replaced. I'd just like to know how much of a problem I should consider this before making a decision.
  • crankshaftcrankshaft Posts: 105
    last year my brother bought a 97.everything seemed ok until the third day.he was getting on the freeway when he noticed steam coming from under the hood.you guessed it,a cracked intake manifold.he had the dealer replace it withthe latest revision.the new ones are built better in the area where they always crack behind the alternator.if yours is original,it will go sooner or later.it is just a weak part and there is a alternator support even attached to it.other than that they are great cars for the money.
  • prlady1prlady1 Posts: 573
    Care to read about a problem we had with our 2000 S40 yesterday? The car appeared to be accelerating when it was coasting and no pedal was pushed. My husband pulled into a parking lot; the car began revving its engine up at 4500 RPMs when it was in park. He shut it off and had trouble restarting it. Then, he got the car started and driving again but then smoke started billowing out from under the hood and coolant was obviously leaking. He had the car towed the rest of the way to the dealership; the service advisor said the temp sensor went bad and caused the engine to rev because it perceived the engine was not hot enough. He says we need to change the temp sensor, thermostat, lower radiator hose and replace all the antifreeze and reset the OBDII to account for the new components. He also said it was time to do a transmission flush and I knew that was something we'd do at the next service interval so I gave him the ok. He estimated the total bill at $650-675 and that includes $110 for the transmission flush. Any thoughts?
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,648
    Well those are "dealer prices" but if all this makes the car like new again, there's no complaint. Not sure about the sensor being "bad" though....if there's no water in the system, the sensor won't read right anyway, and I don't think the bad sensor explains a 4,500 rpm level (at least not to me, the way you describe it).

    But again, if the car gets fixed then whatever they did is worth it. You could have lost that engine in a red hot minute.
  • burdawgburdawg Posts: 1,524
    I can see a failed temp sensor causing a PCM to think the engine was cold and run at a somewhat higher idle than normal, but not 4500 rpm. It sounds to me more like something in the cooling system failed, hence the "smoke" (probably actually steam) from under the hood, the need for a new radiator hose and coolant. I don't know about that causing the engine to rev....could coolant have been blown into an electrical module and caused that?
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,648
    That's the part that doesn't make sense dawg, and I'm not buyin' that part....and I'm not sure he should be "buying that part" either.....but if the sensor is not too expensive, what the hell....
  • fritz6fritz6 Posts: 1
    My 1986 nissan pickup wont start. It run for awhile then died and would not start for a day or two then it would start every time for two or three weeks then would act up again and do it all over again. I have a new starter in it, good battery, 40 pounds of fuel pressure, I even tried starting fluid but still wouldnt run. Truck will turn over but wont start. Thanks Brad :cry:
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,648
    Well if it won't start with starter fluid then you have an ignition problem, so you know that much.
  • rtlattimerrtlattimer Posts: 1
    I need to know what position the cmp sensor reluctor wheel on exaust cam goes.
    it has 5 lobes 4 equaly spaced and 1 in the midle of 2 of the 4.
    do the 4 equaly spaced lobes corespond to the cam lobes, and the 5th to just before tdc. on number 1 cylinder? :confuse:
Sign In or Register to comment.