P0171 and P0174 Lean Bank 1 and 2

[klm]

OK, I've read all the posts on this, and have 2 questions.

Assuming there are no vacuum leaks,

1. Has anyone actually solved the problem with a new gas filter?
1A. Did the measured fuel line pressure actually improve?

2. Is there any reliable way to check the MAF without replacing it.

BTW, My CAT has 103k (bought it with 24k) and it's been a great car for a "very" reasonable cost. The price discount pays for a lot of problems, which really have not been too bad. Still looks and drives like new. No "GM rattle". This car gets too much bad press. If it weren't for the dealers ripping us off, this car would be as good as any for the $. Nice RWD, good traction, OK power, Caddy interior and sound. Best $15,000 I ever spent.


I'm new here, so I thought I'd just add my 2 cents.

[guardian]

Originally Posted by klm

OK, I've read all the posts on this, and have 2 questions.

Assuming there are no vacuum leaks,

1. Has anyone actually solved the problem with a new gas filter?
1A. Did the measured fuel line pressure actually improve?

2. Is there any reliable way to check the MAF without replacing it.

BTW, My CAT has 103k (bought it with 24k) and it's been a great car for a "very" reasonable cost. The price discount pays for a lot of problems, which really have not been too bad. Still looks and drives like new. No "GM rattle". This car gets too much bad press. If it weren't for the dealers ripping us off, this car would be as good as any for the $. Nice RWD, good traction, OK power, Caddy interior and sound. Best $15,000 I ever spent.


I'm new here, so I thought I'd just add my 2 cents.

On your first item I have no clue. Someone else here will know.

Re your second item:

Given the miles on your 2000 Cat, and if the MAF sensor has never been serviced, this backgrounder might be of interest to you:

http://www.fordscorpio.co.uk/cleanmaf.htm

And this one might also be worth your time:

http://www.spydermagazine.com/2002/M.../maf_clean.htm

Yes, I know these are not re the Cat MAF sensor. But they might be of interest to you anyway.

Did you ever obtain the shop manual you were searching for a while back? I agree with the answer you obtained back then, that the 2001 manual likely would serve you well. If I owned a 2000, I would want the 2001 manual to be certain I had the most recent, the most updated, data. Except for the ventilated rear disks on the 2001 Cats, there are scant few deltas between your car and the 2001s.

What I do not know is whether the 2001 shop manual contains instructions for proper cleaning of the CATERA MAF sensor, if indeed it can be cleaned. Perhaps someone with a 2001 or 2000 manual will let us know.

It's great you like your Cat and told us about your good experience. There were fewer Cateras made, of course, in 2000 and in 2001 than in earlier years. And the later cars do have some changes and improvements.

Hope you find a way to put your MAF sensor right.

[klm]

Thanks for the welcome Guardian.
Yes, I found a 2000 manual. Planning on doing the timing belt in a couple of weeks. I found the timing tool kit at a UK shop for about 70 pounds ($120).
I'll try cleaning the MAF sensor this weekend.
Still curious about the fuel filter and/or pressure. Anyone?

[guardian]

Originally Posted by klm

2. Is there any reliable way to check the MAF without replacing it.

Pursuant to my earlier response, and on the precise point of your question, the answer is:

Yes

Regret to say, though, I do not know how to perform this test.

A dealer can run the test for you but obviously that sucks and is of little help.

I think you might have a chance to clean the MAF sensor yourself, if you can locate a proper set of instructions.

If you already have cleaned the sensor without a positive outcome, the wire may be corroded. Hope you are not in this "toasted sensor" situation. Those things are pricey.

[AllenPacla]

I have had the experience to replace my MAF sensor and before replacing it, i had it scanned by a friend of mine with a Tech II tool and it came out working well, but the usual symptoms still persists. I then realize, that the MAF sensor could be showing that it's working well but could be out of calibration causing imbalance in the fuel-air mixture. My conclusion is that if the sensor is bad then there is nothing you can do about it but to replace it. You can try cleaning the sensor and it might work. I tried it as well but didn't help. I don't know exactly how the sensor functions, does it read using resistance, I don't know. But just like is said, if it's bad, then it just have to be replaced. One thing you can do though is go and look for air leaks along the pathway of air. Try tightening the hose clamps and see if it helps.

[guardian]

Originally Posted by AllenPacla

I have had the experience to replace my MAF sensor and before replacing it, i had it scanned by a friend of mine with a Tech II tool and it came out working well, but the usual symptoms still persists. I then realize, that the MAF sensor could be showing that it's working well but could be out of calibration causing imbalance in the fuel-air mixture. My conclusion is that if the sensor is bad then there is nothing you can do about it but to replace it. You can try cleaning the sensor and it might work. I tried it as well but didn't help. I don't know exactly how the sensor functions, does it read using resistance, I don't know. But just like is said, if it's bad, then it just have to be replaced. One thing you can do though is go and look for air leaks along the pathway of air. Try tightening the hose clamps and see if it helps.

Excellent stuff. Thanks.

My best understanding is the MAF sensor measures the ability of passing air to cool a heated "wire". The wire, apparently, is of platinum. And you wonder why these things are so pricey.

Anyway, the whole design is counterintuitive for me. And I am wrong - the entire industry is using these things so I MUST be wrong.

[guardian rattles on . . . . ]

What bothers me is the thermal inertia of the wire. Make the wire stout enough to endure over time and you increase its thermal inertia. Make the wire thin enough to minimize the impact of thermal inertia, and you have a less hearty sensor, less able to endure pollution; not to mention cleaning efforts.

Add to that the profit to be made from sales of replacement sensors. It just seems to me to be an instrument rife with scam potential.

On the other side, the OP has over 100,000 happy miles on (what I presume is) his original MAF sensor. And he has at least a chance successfully to clean it and restore its function for many more miles. Also I have seen these things for the Cat selling for south of $150 on eBay. So maybe that is acceptable and I am full of prunes.

[guardian, still thinking, wondering, and ruminating "out loud" re MAF sensors . . . . ]

I wonder if the answer to longevity of the MAF sensor is regular, periodic cleaning . . . . as opposed to waiting until failure symptoms appear.

Platinum is obviously chosen for this application because of its manifest durability, and its "non-reactivity" with the impurities (from intake air) which inevitably contact, and impact, its heated surface. So would it be better to "scour" the wire early, to impede (one would hope) the ability of the impurities to detroy it, and to minimize their buildup?

Rumination is not a solemn thing. Cows do it and I have a lot of respect for cows. But it should not be taken too seriously, or paid much heed.

[klm]

I checked the MAF. No signs of dirt or buildup. It looks new inside. I'm giving in and just bought a new one ($146) and will install it tonight plus a new gas filter. I'll let you know the outcome after a few drive cycles.

[klm]

Codes gone. I don't know which did the trick, fuel filter or MAF. But I'm good to go. Thanks for all the input.

[AllenPacla]

It has got to be the MAF sensor.