Ya gotta love these OBD-II systems - they don't let you get away with anything.

OK - lets start with the basics. You replaced both hoses - got it. Did you have the code cleared afterwards with the tool or did you just disconnect the battery for awhile?

After the code came back, did you look at your LTFT/STFT and other related info? If so, what were the readings?

If you're sure the 02 sensor wiring is correct, can you access it's live data while the engine is running? If not, we'll get back to that later.

Now, onto your manifold question....You need to pull off the heat shield that is bolted to the exhaust manifold to inspect the upper portion of it (four 10mm hex head screws/bolts). You will wind up pulling out that 02 sensor again to get the heat shield off, as well a possibly the EGR pipe if your engine has it. While that 02 sensor is out, check it for any sign of contamination - what I'm getting at here is possible indications of poor engine mechanical condition (oil, etc...) Good time to also re-check the spliced connections and the main connector to the harness.

Take a good bright flashlight and look over all portions of the exposed exhaust manifold for any cracks. Give it good inspection.

Then crawl under the front of the car and inspect the lower portion of the manifold. Pay particular attention to where the manifold and pre-catalytic converter are bolted together for any soot or blowby that might indicate a leak. If none are found, put everything back together.

FYI - my cracked manifold did NOT produce this code. I just replaced it because it was a potential safety hazard and annoying.

Again - go with the basic stuff, if your fuel trims are high like before, think simple and work up. I've noticed that vacuum hoses that connect to the intake look fine until you move them around and such. Go back up to the symptom chart I posted earlier and look at the possibilities. Basic engine mechanical condition should always be verified first before getting into the sensor side (unless the symptoms/codes dictate otherwise). I have seen other members on this board have issues with their intake manifolds/gaskets and VICS systems (don't know if your car has this variable intake system - research it). An air leak around the throttle body or intake gasket (or even the intake manifold itself) can be a b*#$% to track if it's there - just takes detective work.

Have you checked the compression on this engine lately? How many miles on it?

The next item I would definitely look at is your fuel pressure. Unfortunately (at least in my case), there is no convenient schrader valve on the fuel rail to hook up to - you have to pop the fuel line off and rig in a test valve to a gauge - another great idea. This isn't something you should try unless you are familiar with how to bleed off pressure in the system before you crack it open. These systems run at around 30-45 psi which can make for a bad day if the bleedoff is not done properly beforehand.

The fact that you say the underside of that plastic hose connector is worse than the exterior view makes me curious. You been driving through acid rain or something? Ha. How did the inside of the large hose look (especially around the plastic elbow)? You said earlier that your MAF sensor was sooty as well. Potential clues?...

OK - I could go on and on, but the main point is to look at the simple stuff first. Sometimes the problem is staring right at me, but I fail to see it initially because I get ahead of myself and start looking at the more complex items.

I'll check in with you later. Good Luck...

J

 

I cleared the code, didn't disconnect the battery. And the tool I have doesnt give live data, so I can only go off the freeze frame data, and that always shows a LTFT of +25, and STFT of 0 although I believe that is because it's running in open loop.

And I did actually rig my o2 sensor to my multimeter. I got it warmed up with it plugged in first, but then I disconnected it and probed it with a couple small wires. It seemed to do fine but may have not been warm enough to be completely ready. I guess I'm going to go through all the vacuum hoses in the next few days and inspect them...

And I've owned the car for a year but haven't checked the compression myself yet. It has 185000KM, so that's about 115K miles. And the small connector... I hostly have no clue how it got like that, everything around it was fine. I checked the larger hose and didn't notice anything unusual on the inside.

Thanks again for all your help

 

Un,

Just for the heck of it, try disconnecting the negative battery cable for about 10 mins then reconnect it and take it for a good drive. With the replacement of the 02 sensor and the cleaning of the MAF, there may be some residual Keep Alive Memory effect that prompts the code to come on so quickly. I fully expect the code to come back, but I am curious as to how long it will take (depends on when the IM monitors set). When ECU input sensors are replaced/cleaned, it is always a good idea to reset the computer and let it relearn the performance of the new or cleaned components. If/when the code comes back, or another one pops up, look at the STFT and LTFT again and let me know.

In the meantime, check those hoses and look over the other items we've been discussing.

Stay with it man - you'll find it.....

J

 

Ok, so I haven't been looking for the problem in the past month, but the ELM 327 bluetooth thing I bought off ebay finally came in. I've been testing it out and took it for a long run today, on my way up to school.

I noticed something that I don't believe is related to everything I've posted previously, but my car is running hot. Like, very hot.. It gets up to 235 degrees, (farenheit). This seems pretty extreme to me. The guage doesn't begin to go up until about 230-235, and it hardly goes up at all. I was getting worried, so I turned on the heater full blast (thank god it wasnt too hot today..) and the temp went down to about 205-210, which I think is still too hot.

It kind of seems like the fans might not be coming on, usually went they do the RPMs jump up from 700 to 800, but lately I havent noticed that. Do you have any idea where the fan switch is located/ how the fans are switched on? I am going to try and check it out tonight, as well as the fan fuse. But they may just be coming on without an RPM jump, I can't tell.

So anyways, my temps are much higher than normal, right? I've included the txt file with the raw data from half the trip, the first half got deleted by accident. If you open it in excel, it should display properly.

 

Un,

Glad to see you're still out there. First things first - do you still have the 1170 code? If the engine is truly running hot, the two issues may be related as a lean running engine will tend to run hotter. The factory thermostat setting is around the 190-200 Deg F range. Assuming your Engine Coolant Temp (ECT) sensor is working properly, then you are indeed running hotter than you should be.

The engine cooling and condenser fans are activated by separate relays inside the black fuse/relay box under your hood near the battery on the driver side of the engine compartment. Looking at the relay/fuses in this box from the front of the car (once the cover is removed), the cooling fan relay is the one at the very bottom (closest to the radiator) and furthest to the left (passenger side of box). The condenser fan relay sits just to the right of the cooling fan relay. The fans are commanded on by the computer through these relays depending on whether the A/C switch is engaged or the ECT input to the computer is high (high coolant temp).

Quick way to see if both fans come on is to warm up the car and turn on the A/C. Both fans should run. If one or both don't turn on, then you have to check whether the fans are good or the relays are bad (or vice-versa), as well as the the fuses you mentioned.

FYI - the condenser fan is the one closest to the passenger side of the vehicle.

OK - with all that said, what are the other things to check? Well- radiator cap condition, coolant level (as well as coolant quality), radiator (check for debris that may cause airflow restrictions outside or corrosion/junk buildup inside the radiator that would inhibit water flow), water pump drive belt tension, faulty coolant hoses (soft or spongy), faulty thermostat, and the water pump itself.

Of course, there may be other contributing factors here such as incorrect ignition/cam timing, overall engine mechanical condition or the previously mentioned vacuum leaks that could cause the overheat situation.

Lastly, the ECT sensor could certainly be providing incorrect info. FYI - the ECT sensor is located near (behind -I think) the thermostat housing. The sensor should produce the following resistance readings during testing with the sensor tip submerged in water:

at 68 Deg F, it should read between 2.2 to 2.6 Kilo-ohms
at 176 Deg F, it should read between 0.29 to 0.34 Kilo-ohms

Remember - check the simple stuff first....

J

 

Ok, I'm going to try and check what I can. I actually already bought a new thermostat, because my Dad thought that's what could be causing the problem. So when I replace that I'll check the ECT sensor.

The weird thing is though, the fans seem not to be working for awhile, maybe a couple trips, then they come on for a couple trips. I haven't looked at the relays yet, but how can I test them if they work sometimes and not others...

So many possibilities x.x I may just try and take it to a mechanic to see what's wrong with it. Any idea how much they charge for a diagnosis, if they even do such a thing?

Thanks for all the continued help.

 

Thought I would just mention that the new thermostat appears to have solved the problem of my car running hot.. Now there's just the original problem to solve still. I need to go get it checked out or something. I'm never going to find the cause.

 

p1170 ho2s 11-inversion for mazda 626 2001 kombi when i diagnosis this car this above mentioned trouble code appears after that i clear it ok but the problem is the car engine rpm raise up and fall down not fixed what do you think of this problem ?
please any body knows help me

 

Nazih it means you have a lean condition. Too much air or not enough fuel. In most cases it is too much air. Look for a vacuum leak. There are various methods to look for a vacuum leak. Search Youtube.

 

Uhmm! I know this is a little late for UNSPLOSION but it could help someone else. The most common reason that I have found for this type of lean condition is a phantom air leak. One that comes in after the metering. Most common place is the oil dipstick. The rubber O ring wears flat and air leaks in. On the road I just wrap a little plastic from a thin bag like a dog poo-bag around it to make a better seal and start it up again. A new O ring and some rubber grease is the way to go. Also check the oil cap and its seal. Any air leak into the motor gets into the intake manifold.