jjj

I have the following codes and my car is hesitating bad when engine rpm goes over 2000. drives like there is a governor on engine above 2000rpm.
any help would be appreciated:

P0102 (twice) MAF OR VAF CIRCUIT LOW INPUT
P0159 O2 SENSOR CHECK SLOW RESPONCE
P1167
P0732 GEAR 2 RATIO
P0731 GEAR 1 RATIO

slidewayzm5

I'm not sure...
I had a mechanic connect the OBD scanner while the engine was running - we watched the 4 O2 sensors... is it possible that 3 of them are bad all at once?
3 of them were switching VERY slowly - one of them actually not at all..


I've had the car stalling sometimes at startup when left idling... also loss of power @ higher rpm, or WOT above 3500.. also hiccups... hesitates for 3seconds and then power comes back.

I cleaned the MAF sensor with the CRC sensor kleen, and it seemed to help, but now symptoms are back... is this all attributed to the supposedly bad O2 sensors?

Scottwax

iTrader: (8)

If the car won't rev over 2000-2500 rpms, most likely the problem is the MAF sensor.

slidewayzm5

I tried to search all over for the answer...
And it also says I can't post a new thread... newbie something.. ???

Anyways - I have 3 sensors that are bad... Do I HAVE to go Oem O2 sensors.. what is the +/- if I were to use a cheaper or generic 4 wire O2 sensor?

I need Bank 1, S1 .........also Bank 2, S1 AND S2.
Any deals to be had?

Ghost_54

iTrader: (13)

I am with Scottwax on this one, I would start by replacing the MAF sensor you may find the other codes once cleared don't return ... an MAF sensor can play some real games with the other sensors. The lack of any ref/power over 3500rpm really is pointing to a problem at the MAF

slidewayzm5

It loses power up there.. not complete loss. When I unplugged the MAF - it would not accelerate past 2000rpm. It was like rev limited there. I cleaned the MAF and it drives better.. tops out around 200km/h.
Also why I believe it IS the O2 sensors - with the car running and the OBD scan tool connected - we were able to watch the signal on the O2 sensors.. revving up the car, and at idle. One was not switching at all (it actually threw a code/CEL while we scanned it - which was the O2 sensor as predicted).. and the other 2 were very slow.

So back to the question - with the O2 sensors.. Do I need the good ones.. what is the difference etc?
I'd rather not spend $300+ on O2 sensors if I can get the same result for less... reliably. So I'm asking for the experts... any opinions?

ridinwitha35

iTrader: (1)

Unplugging the MAF, it's expected to be rev-limited. What people usually do is unplug the MAF if they have idling problems or the car dies. If the bad idle/dying stops once the MAF is unplugged, they've found the culprit.

You mention km/h so I assume you're in Canada which then makes me assume cold weather. How soon after a cold start was the monitoring done? The sensors need to warm up before they start switching, and I know the post precat sensors take a lot longer than the the pre precat sensors to start switching. Unless your scan tool indicated the fuel system was in closed loop, the O2 sensors signals don't matter.

Not an expert by any means but I have a bad postcat sensor; I went with a Denso Universal sensor. I know there's a debate over OE vs. Universal but being an electrical engineer, I see no reason to spend an extra $50 or more for a plastic connector when 2 minutes of soldering is all it takes.

sontakke

The rear sensors are *SUPPOSED* to switch very slowly; replace your mechanic if he does not know that! The front two needs to switch fast and if they are not, then replace the appropriate one. You said one of the sensor is throwing the code. What is the specific code?

O2S1B1 should fast switch
O2S1B2 should fast switch
O2S2B1 should SLOW switch {if switches fast, you get P0420}
O2S2B2 should SLOW switch {if switches fast, you get P0430}

S1 front sensor (on exhaust manifold), S2 rear sensor (precat)
B1 bank 1 (near firewall), B2 bank 2 (near radiator)

Front sensors controls the mixture and when they fail car drives poorly. Rear sensor *rarely* fails but
what fails are the pre-cats which leads to P0420/P0430 code.

Please don't get me started on this subject ... :-)

- Vikas

slidewayzm5

I ended up replacing all 4 - O2 sensors.. still had an issue.. even more pronounced actually.
Then I took the car in for diagnostics.. some bulletin regarding the air flow meter...
they replaced the whole AFM, and did an ECU reprogram, and now it runs like a champ.

I didn't know the last 2 were supposed to switch slowly.. thanks.