Hey guys, I have fixed lots of small problems and replaced a couple parts that all together were causing bigger problems.
Cleared out some old codes and now light came back on with 3 codes...

P1129 - Long term fuel trim system too rich Bank 2

P1476 - EVAP Control system LDP Malfunction/insufficient vacuum.

P0432 - Catalyst system efficiency below threshold Bank 2

I know some of these problems mean a faulty O2 sensor but I don't which one is bad. There are 4, 2 post catalytic and 2 pre and are about $120 each. I only want to replace the culprit.
Can anyone help me out?

 

None of those codes state that your O2 sensors are bad. That's not to say that they might not be bad, but these codes do not point the finger at the O2 sensors.


P1129: Long Term Fuel Trim mult.,Bank2 System too Rich

This means your bank 2 primary O2 sensor is sensing too much fuel. It can be caused by a leaky injector, a stuck open EVAP valve, a missfire on load, a clogged cat, or a bad MAF. Compare the multi fuel trim for bank 2 to bank 1. if they are both high, suspect a bad MAF. If just bank 2 is high, suspect a clogged cat, especially with your P0432 code.


P1476: EVAP Emission Contr.LDP Circ Malfunction/Insufficient Vacuum

Likely a clogged vacuum line to the LDP (leak detection pump). They often get clogged, crusty, kinked, or break with age. Check the lines to the LDP (RR fender well). You'll need a VAGcom to help you diagnose and short-test this component.


P0432: Main Catalyst,Bank2 Efficiency Below Threshold.

Two likely causes: either your cat is bad (likely if you have over 100K miles on the original cats, clogged or broken monolith) or the cat simply can't handle the excess fuel being dumped into it from your over-fueling (rich condition, P1129) issue. If the second is the case, it's only a matter of time before the cat is no good.

Hope this helps.

 

How to I diagnose a leaky injector or a stuck open EVAP valve? Both my MAF and bank 2 cat are basically new. Woudn't a bad cat make a rattling sound tho? I do feel like I'm getting back pressure.

My bank 1 cat is original but my bank 2 is new.....What happens if I remove both cats?? Can I leave both flex parts and run a straight pipe to the muffler? That would solve my clogged/back pressure problem...lol

 

Dead-head the fuel pressure and check for a loss in fuel pressure after the car is shut off. This will tell you if you have a leak. You could also remove the rail and injectors as a unit to physically look for a dripping injector while there is pressure in the rail.

It's also called an N80. You can use a VAGcom to run an output test and listen for a click. You can also check it with a 12V source and a vacuum gauge. Listen for a click and you can use the vacuum gauge to check if it closes.

Is the MAF definitely the right one? Only suspect the MAF or N80 if Bank 1 is also on the rich side, as these will affect both banks.

Is the cat aftermarket? Why was the cat replaced? A bad cat will only rattle if the monolith breaks up.

You'd have a permanent MIL unless you reprogrammed the ECM to remove the secondary O2s (cat efficiency) or used non-foulers (search "test-pipe" and "non-foulers").

If your cat was recently replaced and you still have a code for it, you may have a cat that isn't up to the necessary standards or the cat is failing due to an over-fueling issue.

Since your codes are only on one bank, suspect something particular to that bank. You really need a VAGcom to read out your fuel trims to compare to bank 1 to help you diagnose this.

Another few things to check:
-pull the front-most engine cover. Replace the vacuum lines that are torn up or rotting that actuate the secondary intake flaps.
-try Seafoaming the intake. You might have some carbon-stuck ports
-check your spark plugs for signs of fouling or old age

 

Sorry I'm still learning alot....I don't what dead head is.

If you're talking about the purge valve located on top of the airbox.....I don't have a vagcom yet but it does click for a couple of seconds on and off.

The MAF is correct and cat(magnaflow aftermarket) was replaced because of a broken monolith after driving a couple of blocks on a misfire.

I did not have any codes for the cat after I installed awhile ago, light came on for this recently so I guess its a rich/over fueling problem.

I've replaced many hoses if not all in the engine compartment

I've seafoamed once before gas tank, intake and crankcase. But I sucked the seafoam through the vacuum pump, I think its wrong right?

Spark plugs is a major headache, all the time they get carbon or oil underneath...
I KNOW it's not valve cover or the spark plug well gaskets I've replaced. Might be valve stems or guides? I'm going to check them to see how the new ones look.

Thanks!!

 

It just means test your fuel pressure.

If you're talking about the purge valve located on top of the airbox.....I don't have a vagcom yet but it does click for a couple of seconds on and off.

The MAF is correct and cat(magnaflow aftermarket) was replaced because of a broken monolith after driving a couple of blocks on a misfire.

I did not have any codes for the cat after I installed awhile ago, light came on for this recently so I guess its a rich/over fueling problem.

I've replaced many hoses if not all in the engine compartment

I've seafoamed once before gas tank, intake and crankcase. But I sucked the seafoam through the vacuum pump, I think its wrong right?

Spark plugs is a major headache, all the time they get carbon or oil underneath...
I KNOW it's not valve cover or the spark plug well gaskets I've replaced. Might be valve stems or guides? I'm going to check them to see how the new ones look.

Thanks!![/QUOTE]

 

It just means test your fuel pressure. Some setups require you to tap in-line with the fuel rail to test it, others give you a schrader valve. Dead-head means you tap into the rail in such a way that allows you to test the loss in pressure after the fuel has been pressurized. Lets put that on the back burner for a bit.

That's the one. If you hear a click, I'm satisfied for the moment, lets also put that on eon hold.

Ok, now we're getting close. What was determined as the cause for the misfire? Was it ever fixed? How long ago was this? How many miles ago?

Due to the one-sided (one bank) nature of your issue, I think we can eliminate vacuum leaks as a possibility for the moment.

Well, you should suck it through the vacuum lines on the intake, not the pump. You can try seafoam again, but keep reading.

Ah ha! Now we're getting somewhere! If there's oil around the base of the plug wells or the plugs are fouled, you've got an issue. Fix this first before moving on. Bad spark due to oily or fouled plugs will create a poor burn, and thus can throw such a code.

 

Yes the purge valve is clicking...

The misfire was never determined the cause....put in Bosch IR fusions and car misfired like crazy then put in NGK's and ran fine. No more misfire.

That oil ileak is the problem. I got 2 leaks in the back of the engine driver and passenger side. When engine gets hot, I start to see some smoke from those two places but can't pinpoint exactly where it's from. (No noticeable oil loss) (Might be camshaft gaskets and seal?)

And another oil leak on the spark plug wells. This one I'm almost %100 sure but please give me your opinion.
There is no visible oil inside the spark plug wells and valve cover gasket set was replaced. The only possible explanation are the valve stem seals.

How difficult would it be for me to accomplish this DIY (camshaft gaskets/seals and valve stem seals)? I need spring compressor. Air compressor, etc. If i replaced all these seals, do I have to replace VCGs again?

Thanks!

 

A little story: my father-in-law's '96 Saturn SL2 has been running hot and loosing coolant and oil for about 2 years. About a year ago, I began playing with it. I found oil in the #2 plug well. I cleaned it, replaced the plugs, topped the coolant and oil, and it ran fine. In September, he noticed it loosing oil and coolant again. Again, I found oil in the #2 plug well, but additionally, I found the radiator had a small leak. I cleaned it, topped the fluids, and it ran fine. Just before winter, it developed a misfire and blew the endtank off the radiator. It sat all winter.

After the winter, I replaced the valve cover gasket and spark plug well gaskets to alleviate the oil in the #2 plug well. I also Seafoamed the intake and crankcase. It ran fine for about 15 minutes, and then developed a misfire in cylinder #2. I again let the car sit until just this week.

The car ran fine for ten minutes after a bit of a smoke show. The exhaust cleared and the engine literally seized in single puff of smoke at the same moment it blew oil out of the side of the head. I removed the valve cover to find a massive crack running into the #2 plug well. I would have discovered the (at the time) small crack over a year ago with just a simple leakdown or compression test.

Now... this isn't to scare you or tell you that your head is cracked. Cracked heads are quite rare on Audis (unlike Saturn 4-bangers! Gr!). I just want to be sure you don't have a deeper issue that could be pinpointed and eliminated. Do a compression and leakdown test. Here's a good article to help you out. This test will help you determine if you possibly have a bad headgasket, piston rings, or valves, or it might help confirm that you have a lesser issue such as bad valve-stem seals.

http://www.carcraft.com/techarticles...ter/index.html

 

Yea I really doubt I could have this issue because the car runs exceptionally well even with all these problems... BUT I will definitely look into doing a compression and leakdown test.

Thanks bud