325e running warm, High NOX HELP!

[86beast325e]

So, my car is running warm, not quite over heating but it passes the midpoint while I am driving. It wont pass smog and I have searched and am all out of ideas. I bought the car over a month ago and the car runs great other than this issue with it warming up.

The smog guy told me that it failed because of high NOX.

I have replaced all of the belts, the water pump, 80 degree thermostat, spark plugs, cables, cap, rotor, fan clutch, all the hoses, coolant, and replaced the plastic intake chamber. I cleaned out the MAF sensor and the throttle body, I just ran some sea foam through the intake and got quite a bit of white smoke out of it but its still heating up. I previously ran half a can of sea foam through the gas tank and it runs better but I have no idea what else to do with the exception of messing with the timing...HELP!

[Balleristic31]

Check your ground to the temp gauge to make sure your gauge is reading correctly. If the temp is a little hot but consistent I'd guess gauge problem.

Try new o2 for smog or new cat

[Stanley Rockafella]

did you warm the car up properly before testing?

mine warms up to that temp regularly but I dont' gaf,the car is fine aside from what the needle says

EDIT: I also failed my first run (as I've never ha dto do anything like that before with any car I've owned). I went for a hard drive for about 20 minutes through the mountains and a lot of high revving, all to come back and get far better than average scores.

[jlevie]

Check the head temperature with an IR or contact thermometer. If the engine is truly running hot, replace the radiator.

High NOX will be an engine that is running lean or a bad catalytic converter. The appearance of the plugs is usually a good enough diagnostic for a lean condition.

[86beast325e]

I already changed out the cat and the o2 sensor and the smog test guy did indicate that it appeared to be running lean. I am fairly certain that it temp gauge is reading correctly because the coolant was hot enough to pop a small hose connected to the intake manifold. Its running a bit cooler since I ran the sea foam through it so I am going to try and sea foam the crap out of it and see what my results are.

[SmokeE30]

Dont keep puting deadpan in there, it's not gonna make it run any cooler. You Need to get an actual temp reading like Jim said, useing a thermometer, that will tell you how hot it actually is and if it's cause for concern or if the cluster mounted gauge is just innacurate. Also pull your spark plugs out and look at them, you can tell a lot about how an engine is running by the look of the plug, pull em and check em out or post a pic here for us to tell you what we think.

Also when you say you already replaced the cat, what brand and how long ago? The magnaflow ones have been known to only last a year or so before needing replaced again.

[86beast325e]

Any tips on a cheap way to check the temp? Ive never had to do this and I dont want to spend a ton on a IR thermostat. I guess first off, how much does one cost? The Cat and every other part mentioned are no older than 10 days. The old plugs had a fairly consistent burn, no oil or anything crazy.

There is definitely some vacum leaks somewhere because the seafoam smoke was coming out of the engine bay quite a bit. I found a leak in the gasket from the header to the cat, (Two Gaskets). There is also smoke from under the intake manifold but I couldnt pin point it so I am thinking of doing the ol' cigar smoke test to find the leaks. I assume that the vacum leak is contributing to it car running lean. I appreciate all the help so far!

[86beast325e]

Okay, found a cheap IR thermometer. Will update as I find more.

[SmokeE30]

Yes intake leaks will do that. I would have a proper smoke test run at a shop to be sure you pinpoint them all, being able to hold the system under pressure makes it easier.

[86beast325e]

Well, the car is running hot. I am assuming that the high nox and heat are not directly related. I ordered a new radiator which is the last piece in the coolant puzzle to replace. My original plan to fight the vacuum leaks was to remove the intake manifold and replace all the vacuum hoses and intake gaskets. Its a lot of work but I dont know how much they typically charge to find and fix vacuum leaks.

[bmwman91]

You can have a shop do a smoke test to look for vacuum leaks.

Personally, I have used duct tape and a bike pump to seal up the TB/ICV and put a little air into the vacuum-side. I then listen for leaks. It is harder than the smoke test, but cheaper.