Two O2 Sensor Questions...

no.

Is getting your spark plugs from a go-fetch a good idea?

Is it THAT stupid of an idea???

well I didn't use the word stupid. I mean to say I don't think it is a GOOD idea.

I didn't mean to imply stupidity, what I am saying is buy the stuff new in the box, otherwise you don't know what you're getting.

Lg

OK, but I can pull one from a go-fetch boneyard for a fin or spend $200 at the dealership... that is a big difference!

So, if I understand your caveat, it may not be such a bad idea, no?

Steve snipped-for-privacy@hotmail.com Remove the spam-spoofing triple x's to email me directly.

Yes. Used O2 sensors are in the same category as used brake pads, spark plugs, windshield wipers, mufflers, ball joints, water pumps etc. Would you buy these things used and put them on your car? You will replace the O2 sensor(s) on your car, maybe, once in 10 years. At$100 for a pair spread over 10 years, that's pretty cheap. O2 sensors actually rarely fail. Do you think yours are bad?

Yes, a local (and trusted) mechanic did a once-over on my 93 GT because of:

(i) a miss -- usually accompanied by, but not always, a backfire -- at all RPMs or speeds, and

(ii) the engine when "cold" -- December or July -- stalls out after about 5 seconds on the first start-up, I mean 5 seconds after each and every first cold-engine start-up, but on the second try, attempted immediately after the stall, the engine always starts "normally" and idles "normally" which it must do -- December and July -- for 5 minutes before I attempt to drive it. If I tried to promptly drive off after the second start, the car would sputter and backfire for miles.

His once-over resulted in: o Good compression across all 8 cylinders, o Normal oil pressure at warm idle, but borderline-low oil pressure at 2,000 RPM, o MAF sensor code, and o O2 sensor code.

Steve snipped-for-privacy@hotmail.com Remove the spam-spoofing triple x's to email me directly.

=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+ =+= Sarcastic remarks are always welcome! =+= They might as well be welcome since... =+= I am going to get them anyway. =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+

sounds like it needs a maf cleaning, throttle bore cleaning, IAC cleaning, and a new O2 according to the code.

As far as prices on O2s, check Autozone, pep boys, ect. The price will most likely be much lower. O2 sensors wear out, getting one from a junk yard is like getting an oil filter from the junk yard. Not a good idea.

For the cold start.... your PCM isn't even paying any attention to the O2 signal (simply because it is still too cold to generate a signal). If you are recieving an O2 HEATER code, then the problem could well be an O2 sensor.... if you are getting a code like "O2 always lean", you more than likely have some other problem making the O2 sensor experience a mixture that is always lean. Changing the O2 sensor over and over and over wont fix that.

Let's take a look at your misfire - sometimes with a backfire and that makes me want to say ignition... Somewhere, somehow a mixture is being lit at the wrong time or unburned fuel is getting into the exhaust and lighting off. One thing that an ignition misfire will deliver on an OBD1 car, is a lean mixture (important to remember that the O2 sensor can only measure oxygen content - as far as mixture goes, it dont know shit from shinola... all it knows is high O2 content and low O2 content).

So... we have a misifre dumping a lot of (unspent) O2 down the pipe and a lean code????

Let's take a look at your MAF code... this car is over 10 years old and most likely has it's original MAF sensor..... complete with it's lovely, warm little fur coat. This collection of debris that gets past the air filter element has an insulating effect on the sensing element in the MAF sensor... the PCM thinks less air is getting into the motor than really is..... Less air, did I say??? The PCM sees "less air" and reduces injector on time..... leaning out the mixture....

So.... we have a misfire and an inaccurate MAF indication dumping a lot of O2 down the pipe????

One last comment on the oil pressure.... if the pressure is "good" at idle but approaching low at rpm, I would be concerned about oil pump starvation... crap on the pick up screen as a likely cause.

Time to go back and have a chat with your mechanic....

Jim,

(1) Let's ignore the cold start for now.

(2) Let's take a look at the misfire and assume the ignition is the culprit.

Here is what I have done related to the ignition recently either to address potential ignition-related causes or because I thought it might just be a good idea without any knowledgeable rationale: o Timing: Adjusted to OEM Specifications o Ignition Coil: Replaced (Aftermarket) o Distributor Cap and Rotor: Replaced (Aftermarket) o Distributor Stator: I have been thinking about replacing it, but have not done so yet o Sparks Plugs: Replaced (OEM) o Wires: Replaced (Aftermarket) o Alternator: Replaced (Remanufactured)

Are there other "places" where ignition-related problems can originate?

Can poor harness connections cause ignition problems that then cause misfiring?

(3) Let's take a look at the MAF code.

Since the car is over 10 years old and does still have its original MAF sensor, why don't I just clean the sensing element?

(4) Finally, let's look at the oil pressure.

If there is no downside in attempting the following, why don't I just clean whatever crap is on the pick-up screen?

(5) I am my mechanic. the "local and trusted mechanic" is a good friend, whose profession is repairing automobiles, and has all of the sophisticated stuff necessary to do so professionally.

I eagerly await your comments, corrections and suggestions!

Steve snipped-for-privacy@hotmail.com Remove the spam-spoofing triple x's to email me directly.

[SNIP]

1) Let's not ignore the cold start for now until we can rule out any possibility that it is part and parcel of being part of the other concern(s). We are testing a machine... assumptions can be dangerous if we are using that assumption to bypass an appropriate testing step.

2) was the timing adjusted correctly... spout connector removed and car started with the key rather than a remote switch? For the new parts, new simply means "unused" in this day and age. Is the module supplying enough dwell time to saturate the coil? Are the plugs the correct heat range and gapped properly (please don't tell me they come gapped - many's the slip twixt the cup and the lip). Is there a moisture concern inside the distributor? Are the plug wires routed properly? The backfire still throws me but we can also look outside the cylinder.... is there an injector or vacuum leak concern? Is this a regular, predictable miss? Lean mixtures can result in a slow burning charge. Are the plug wires routed properly? Is the insulation on the wires up to the task?

3) There's nothing that says you can't clean the MAF... this has worked many times in the past for me BUT there are times that I have cleaned a MAF that was bad, anyway. Needless to say, I had to replace the MAF in the end.

4) I don't like "cleaned" pick up screens..... it's your money but I have a reputation to uphold and customers to please.... These customers deserve the best I can offer and the best I can offer is to replace the pick up screen ass'y.

5) Your mechanic would NEVER ask if used emissions parts are a consideration. Your particular idea of auto repair may differ from mine.... For me, repeat repairs are unforgiven and label me as a charlatan. If you want a dependable repair, carried out properly, a repair that leaves your car looking like I was never in there and a troublefree experience after the repair, I will do it my way. If you are after pinching pennies, you will at one time or another, experience repeat failures, inconvenience and embarassment. Back when I wa young and foolish, I used to carry tools with me.... Now, I don't. My loving bride often travels far from home alone.... I leave nothing to chance. I have no idea what "all the sophisticated stuff" is... How about a $20,000 scan tool with an update subscrition that would rattle your bones? Would that be sophisticated enough?

Repairs to the modern automobile are not as simple nor as cut and dried as many think. We need to differentiate between "causal" codes and "symptomatic" codes... Above all else, we need to avoid deception.... once we show ourselves in a lie, it is hard to retrieve our integrity and anything we say can be considered "suspect".

I certainly can not disagree with you.

Yes, twice, by me.

OK, but I am not sure of the context in which you intend this statement to apply.

I do not know, but I will put forth the effort to determine the answer.

The plugs are Motorcraft Part Number identical to the original Ford specifications (as revised) and each one was personally gapped by yours truly.

1. This is probably an insufficient answer, but its the tooth as I no it: No visible moisture, condensation, etc. 2. If this is an insufficient answer, please direct me more specifically as to the whats and hows. Thanks!

1. If you mean: Is each individual wire connecting a spark plug to its proper distributor cap terminal, yes it is. 2. If you mean: Does each individual wire lie in the exact same path, crossing over its peers in the exact same manner as when the car rolled off the showroom floor, hell no.

Sounds like a plan to me.

1. I do not know, but I can use an unlit propane torch to check for any vrooms. 2. Will doing so address both the injector and vacuum portions of your question?

No, insofar as I have not observed any pattern... and I have been known to spot patterns that don't even exist, except in my own head, I guess.

1. If you mean: Is each individual wire connecting a spark plug to its proper distributor cap terminal, yes it is. 2. If you mean: Does each individual wire lie in the exact same path, crossing over its peers in the exact same manner as when the car rolled off the showroom floor, hell no.

1. They are in fine shape, if that is what you are asking. 2. If you are asking about the quality of the wires purchased, I typically buy the better (or middle) grade when offered Good, Better and Best at Advanced Auto Parts or AutoZone.

Nothing to lose but a little time and effort... It is my understanding that a new MAF is $450 DIY.

Sure... Any idea what a pickup screen might cost at NAPA or AutoZone?

I am sorry if I suggested or implied that my mechanic made such suggestions... He simply informed me that the cost for a new O2 sensor was $150 and a new MAF was $450 excluding labor. I agree with everything else you are saying. An unbroken plastic brakelight cover from a wreck in the boneyard is no worse than my plastic parking brakelight cover moments before I backed into that jerk on a bicycle, and I would never think of obtaining my next set of plugs from that same wreck. My inquiry was to determine where these components fell in the continuum.

I certainly appreciate what you are saying!

Jim,

Significant progress made when I cleaned the MAF sensor...

How can I be sure I have cleaned the sensor the best it can be cleaned?

Steve