Oh No! Help! 1/4 CEL and smog test!

I had just sorted out the 348 and went down and paid my taxes and got the temp plates for the smog test and found I have another issue. This afternoon I took the car on a nice 50 mile run. It ran perfectly and had no CEL's. I was preparing to go to get my emissions test in the morning. I decided to take the car out again around 8:00 tonight for another short run and to checkout the lighting etc. Shortly after the car got warm, around 10 miles or so I started getting an intermittent 1/4 CEL. It came on and off about 5 times and then stayed on. I parked the car for about ten minutes and then started driving again. I was immediately presented with the 1/4 light, which stayed on the whole drive home. I just pulled the codes:

1211 and 1114

This really sucks as the car has run beautifully for the last two weeks after I put in the new O2 sensors. I've cleaned all of the connections I can think of and the MAFs. The O2's are ungrounded however, but new. I really need to sort this before I go to the test. I can put it off for a few days but I am running on a 10-day temp. plate.

Any help would be great. I will try anything you have to share.

Thanks,

Mike

 

You know, now that you mention the O2 grounding thing, goth and I were wondering why my car has both O2 sensors grounded to the frame. Moreover, the ground wire was soldered on to the sensor - it did not come that way stock. The solder is pretty stout stuff (high temp) and a general home soldering iron won't cut it. I still wonder if these were added by someone in this situation... :-/

 

The only thing I can suggest is that at one time I had a recurring CEL light under similar circumstances, and it turned out that one of the rubber intake boots had popped part way off at the throttle position sensor on the right bank (I don't know how it happened, the clamp was tight but the boot wasn't entirely over its lip), and apparently the resulting vacuum leak was confusing the oxygen sensor on that bank. Once I got the boot back on correctly and erased the code, it hasn't happened again. Good luck with it.

 

I don't know for sure, but I don't think they have a way to hook up to an OBD-I car. I think the under-dash test port was added as part of the OBD-II spec. So for smog purposes, the absence of CEL is just going to be a visual check. You could pull the bulbs, and still probably pass a tailpipe sniffer.

Disclaimer - the above could be totally wrong. This is just a thought...

 

Will check that this morning! Thanks.

--Mike

 

I had thought of that, but if I'm throwing a CEL the odds are I won't pass the sniffer. I'm sure this is an electrical connection or some other small item. I don't think it is a part failure, hope I'm right.

--Mike

 

O.K. I took the car out again today and it threw the same codes. I switched the left and right O2's and got CELS on 5/8 and 1/4 instead of just 1/4. Switched back and got just the 1/4 again. I unplugged O2 on 1/4 and the CEL went off. Then checked the ground on the plug and the newly installed ground wire with a test light and confirmed the ground. The coolant is full and bled and the gauge read acurately, between the 145 and 195 marks. The MAF's and connections have been cleaned yet again. Should I assume my new O2 sensor on that side is bad? What is the test? Clock is ticking on this and I have no problem getting another. It is a Bosch Universal 15727 4-wire.

Thanks,

Mike

 

Hmmm...wonder if you can get through with the 1-4 O2 unplugged if that didn't trigger a light? I *think* on the OBD1 cars you still have to show them that your CEL comes on briefly at startup then goes off, and then pass the sniffer. That would be just temporary to pass the test with your temp plates before they expire...

 

Maybe. The local NAPA has another O2 in stock, but I really want to findout if this one is the cause before I go buy another. I really do need a solid test for the O2. I have tried everything else and the cars runs fine, just want to pass the emissions test.

UPDATE: I just pulled the 1/4 O2 connections and started the engine. Both 5/8 and 1/4 CELs come on as normal during start up. The 1/4 CEL does not come back on with the O2 disconnected. Also, I pulled the codes and got 4444, that was it.

--Mike

 

With regard to the emissions test, I once had to get my car smogged and it was throwing CEL's and running rich. I'm in a "Smogcheck II" zone in California, and I believe it is one of the strictest tests in the country. My car was able to pass, error codes and all. Our motors run very clean to begin with; if your catalytic convertors are in good shape, you may still pass if you can't get this issue sorted before your due date.

Brian C. had this to say about 1211 error codes a while back:

You can check the connections to your coolant temp sensors without having to remove the intake plenum (easier if you don't have big hands like me, lol). This thread has some pics of how to get to the coolant temp sensors:
http://www.ferrarichat.com/forum/showthread.php?t=229830

 

How do I know if the coolant sensors are bad? The gauge seems correct and the fans kick on when they should. I will clean the temp. sensor connectors however as they were never done. If this error keeps up i may just disconnect that banks O2 sensor and then go get my test. It acts normal without it connected so at least for the test I'll unplug it.

--Mike

 

There are several temp sensors on our cars; one does the gauge, another sends a signal to start the fans and the two I referenced in the link send data to the ECU. Make sure those two, with the blue connectors, have a solid connection, no broken wires, etc. If they send a signal to the ECU that the engine is still cold when it fact it has warmed up, it will result in a rich condition and could give a 1211 CEL. I can't recall the resistance value range off the top of my head, but you stick an OHM meter across the pins to get a reading.

 

OK now we are gtting somewhere. Lets say I just replace them, do you guys have a part number for the sensors that won't break the bank and I can get readily? I'm headed off to NAPA anyway.

I think I just found it BOSCH Part # 0280130026. Now one last question, Why would it be the temp sensors if the CEl gets cleared by unplugging the 02 sensor?


--Mike

 

From the link I posted earlier:

Bosch (OEM): 0 280 130 026
Airtex: 5S1483
Adelco: F1864
Standard Motor Products: TX18
Niehoff: TS25151

I would check the wiring first, it is rare for the OEM Bosch sensors to go bad.

 

I looked at the wiring and connections from the back after removing the airbox. I can't see where they go toward the front of the engine. I don't see any breaks and I tried giggling them during idle and the CEL stayed steady and the engine note did not change. The really tough part of all this is that after I changed out the O2's everything ran great for 50 miles. The 1/4 CEL is still intermittent at first and can be cleared by hitting the throttle a few times. Comes back in about 20 seconds or so. I still think this is a bad Bosch O2, but who knows. Still pulling 1211. 1114 is now gone and I haven't had it back.

--Mike

 

What I have done so far and I still can't clear this 1211 CEL on 1/4. The problem started 50 miles after new O2's installed to clear 5/8 and 1/4 CEL's for 1211. I am going to replace the O2 on the 1/4 side, hope that is it. If it's fouled then I have another issue as far as mixture. Can O2's be read like plugs? Should I just pull a plug and look?

1. Cleaned MAF's and connectors.
2. Cleaned O2 connections.
3. Cleaned Exhaust ECM connections
4. Cleaned Phase Sensor connection
5. Cleaned TPS Sensors and connections.
6. Changed out the coolant sensors for the ECMs under the intake. Bled the system afterward.
7. Cleaned the throttle bodies.
8. Cleaned the Crank Sensor connections.
9. Tightened and checked all of the hoses and intake piping clamps.
10. Re-initailized the system many times.
11. Did my best to check all of the wiring during the cleanings.

Thinking of swapping MAF's if I keep getting the 1/4 CEL after the new O2 gets put in. What else could this be? What should I check? Symptoms are as follows. If I reinitialize and let it idle I will get the CEL just after warm-up. Wait for the full 20 minutes, hit the throttle and the CEL clears for about 35-40 seconds then reappears. That is the current set of symptoms. When the issue presented itself I was at the end of a 50 or so mile drive when the 1/4 CEL came on intermittently until I throttled it, after about 10 minutes it stayed on.

--Mike

 

Out of curiosity, when was the last major service performed? Perhaps the problem is at the cam timing and combustion end?

 

June of 08. The car ran fine when we brought it home last January. It idles and runs fine or at least it did Starts right up and doesn't miss or smell wierd, but I have a sniffer test this coming week and I need this to pass. I still need to pick-up a new meter so I can check the MAF's, maybe they need adjustment.

--Mike

 

Before you buy another O2 sensor, swap the existing ones and see if your CEL changes sides. You can also check the resistance on your MAF sensors by placing the leads of an OHM meter on pins 1 & 6 - you should have a reading from each one very close to 383. You can also swap the ECU's behind your seats and see if the error changes sides (disconnect the battery before removing ECU's) - between swapping ECU's and O2 sensors (and checking codes between each step) you will be able to determine if the issue is with the sensor, with the wiring or with the ECU.

I have had many similar problems that you are experiencing, and in the end it was Dave Helm's connector kit that finally got rid of all my remaining issues. http://www.ferrarichat.com/forum/showthread.php?t=236795

 

Why, oh why did I not think of that? I'm off to swap O2's. I know about the MAF ohm readings, but I need to buy a new meter as mine went missing during the move.

--Mike

 

The ohm settings don't matter on the MAF unless it runs open loop. You will run Open loop at cold startup until the O2's get warmed up to operating temp. After that unless the O2's drop off your ECU will not read the MAF CO screw.

When I put in my new O2's, I found the stoichiometry (O2 output .5 - .6 volt) point to be at around 450-500 ohm. Above that you're running too lean (O2 drops to around .02V) and below that you're running rich (O2's at .8+V) and risking to burn out the cats if you drop an O2 on a drive.

The MAF's either work or don't, so swap them and see if the problem follows them. Don't buy one for a test as they're quite expensive.

 

Well I changed out the 1/4 O2 and drove it around this morning. I had my test at 2:30 this afternoon and she passed! I haven't seen the CEL since changing the O2 so mabye I got a bad one the first time around....we'll see. Either way I'm cleared to register the car in Connecticut!

--Mike

 

I had a similar experience with Bosch O2 pre cat O2 sensors on my BMW 540. I got a "check engine" light (actually BMW has a "service engine soon" light) that I scanned and the code is for a bad left side pre-cat O2 sensor. I decided to replace them both and a few days later I get a another light for the right side! Yup, bad sensor. So I replace the right side again, and now all is well. Fortunately the online parts source I use, happily credited my account. (www.autohausaz.com)

Good you have pre OBDII. If you have OBDII, and clear the codes after the repair, you still have to drive several cycles and rack up a bunch of miles to set all the "ready" parameters. If two or more parameters are showing "not ready", you will not pass the emission test, and they require you to come back after you have driven the car more. This is becoming standard in more states, the reason it to prevent people from simply clearing codes before taking the test. Basically you have to drive suffiently that if you had a fault, it would trip the "check engine" light.

 

Mike...did you go to Old Lyme? What was your impression?

 

I was pressed for time so I went to Portland Automotive, about 7 miles from me. I found them through F40 Motorsports, they have all of there cars done there. I was impressed with the service and the care for my 348. I have decided to let them do the services I don't want to do myself. They have a floor dyno as well. Thanks for the heads up on Old Lyme, may use them in the future.

--Mike