96' 850 GLT Long saga of P0140 P0133 MVSOLVED

[abscate]

Cruise control and SAS stuff lives under the battery on your year I think.

Vacuum leak problems >>>>>> ECU problems

[DARK_BLU]

What makes me mad is that it took me maybe 10 minutes tops to find this disconnected hose and I am not an ASE Certified mechanic. These guys at Peachtree Imports had this car overnight numerous times in March and April and never checked for or noticed this disconnected Vacuum hose, then go straight for "It might be the ECU and that's expensive", when I could've gotten a used ECU from Voluparts for $125, installed it myself, and it's plug and play on my 96 850 GLT/NA? I'm never going back there again. I will be replacing the plug wires, plugs, and Ignition, MYSELF.

Thanks again, guys!!

[esl_97_850_T5]

After replacing plugs, wiring, and ignition, if P0133 returns...

What are your compression test numbers? Is the compression uneven between cylinders?

[DARK_BLU]

Haven't yet replaced plugs, wires, and ignition but when I do, if the p0133 returns, I'll get a compression test and see what those numbers are and report back. TY.

[DARK_BLU]

I can verify that the car is definitely running better with the new IPD HP Plug wires. On my way home from Voluparts to pick up the Volvo Spark plugs, I got a CEL. I don't think it's Cylinder compression, as the car is running noticeably better with just plug wires. Same recurring problem with these two 02 sensor codes. I've had both of these codes (P0133 and P0140) come back again and again after having both front and rear 02 Sensors replaced, twice. Of course, "The Shop" didn't think to inspect the flex joint of the exhaust manifold. I was wondering if the cable extension to the front 02 sensor not being replaced when the front 02 sensor was replaced last year and this year, may have been the cause, then took a look at the flex joint on the original manifold:

My old Manifold Flex Joint:



I don't see any nuts the manifold and the cat together on the underside of the bolts. Shouldn't there be nuts locking the bolts together?

The manifold I'm looking at from FCP:



Is it just me or are those gaps in the flex joint of my old manifold? Can't get underneath the car right now to take a pic of the underside, but the original manifold is still on the car (The muffler and tail pipe were replaced last year with a Starla). The Pro Parts Sweden Exhaust Manifold is less expensive than the Genuine Volvo manifold and comes with gaskets and bolts. FCP is a site sponsor here, right? I know that eEuroparts is. I'd rather buy from a site sponsor, whenever possible.

There are no vacuum leaks. The Distributor Cap, Rotor, and plug wires have all been replaced and the plugs will be replaced with genuine Volvo Spark plugs, this evening. Next up was going to be the ignition coil until the CEL hit again today.

[abscate]

I was wondering if the cable extension to the front 02 sensor not being replaced when the front 02 sensor was replaced last year and this year, may have been the cause

I don't think the right part has an extender - it is cabled to fit precisely.

O2 sensors are not a place to go aftermarket - you can chase your tail with these for a long time.

[DARK_BLU]

So, if they used an adapter harness like this one:


for the front 02 sensor, that means it's not genuine Bosch? Hmmm.... The Bosch 02 sensor in this pic looks just like mine and isn't long enough to reach without the "adapter harness":



Since they were replaced twice and the P0133 and P0140 keep coming back, it's possible that they aren't Bosch. But since the plug wire replacement and plugging in that disconnected vacuum hose to the secondary air pump, the gas mileage is no longer horrible, like it had been (Getting 22mpg City and 32mpg Highway at 306,700 miles on the odometer, now). At this point, buying a Professional Parts Sweden Exhaust Manifold is probably a good idea, since the original manifold looks to be worn and I've already done the muffler and tail pipe. New plugs go in, this evening. At 306,700 miles, it's time to replace it anyway.... I'll get that front 02 sensor replaced with a Genuine Volvo/Bosch next, and replace the adapter harness, too. Perhaps this is coincidence, but since my last oil change in March where I installed a K&N Filter, this back and forth with the 02 sensors has been happening. Normally, I use Mahle or Mann. Could that have anything to do with it?

[abscate]

I don't know the 1996 model year well enough to know if there is an adapter on the O2 sensor stock or not. I do know these cars are picky about a few things, and O2 sensors are one of them

[Ozark Lee]

There was a TSB that added an extender to the oxygen sensors but I can't remember the exact year and models that were included in the bulletin.

...Lee

[DARK_BLU]

My 96 has the extender, so it's possible that they replaced the 02 sensor and not the extender and the extender not being replaced along with the 02 sensor could be the cause of the P0133? I can't remember where I read that the extender is supposed to be replaced too. "The Shop" should've known to replace the extender. It doesn't say on any of the receipts that the extender was replaced.

I read another thread that indicated that the P0133 from the front 02 sensor is what causes the P0140 on the rear 02 sensor.