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Smog test in CA

I took my 2003 325i BMW sedan for the first ever smog test.It failed:reason low RPM at low speed.The tech explained that the RPM was too low at 25 MPH while it was okay at higher speed.The test was aborted.The car has done 43300 miles, maintained per schedule.I called BMW and they want to run diagnostic test at a cost of 160 dollars /hr.!Any suggestion? Thanks


Would like to help but your post is so CA. specfic that I cannot. My logical mind says “failing a test for too low RPM at 25 mph,how can that be?”

If the test said “failed due to low IDLE rpm” well thats a different story

If you want for me to look into this try to post all info you can (what RPM is min. to pass?) and I will try to help by looking at CA. info on the net. (I am ex BMW Tech)

$160/hour sounds like what you should expect when you buy a Beemer. I suggest you shop around for a reliable independent mechanic, especially if this is not a warranty issue. The dealer will probably waive the diagnostic fee if there is something wrong with the car and they fix it. If it is under warranty, the only risk is that you will have to pay if there is nothing wrong with the car, which is unlikely.

This rejection criterion is so weird, so strange, and so California that I simply cannot comprehend it. I’ll be interested to hear what it all means.

Wish I could help. Sorry.

I believe when theyb start the car the RPM has to be between 600 and 1500 and if it is below they will not run the test.The tech suggested I get my RPM set higher when starting.

Now this is making more sense,you are dealing with a low idle situation,this should be easy to diagnosis,seek a qualified mechanic,the Dealer,or in CA there are special “smog” stations.

Your inital post made it appear the car failed for having low rpm’s at 25 mph,which made no sense at all.

There is no “adjustment” for idle speed (this feature was taken away long ago on all cars) the speed is controlled through components and computers.
Is you car ideling below 600 rpm (what does the inside tach say?) how low is your idle?

I’m with Oldschool on this, it makes sense now.

While it seems like a possibly unneeded expense, the diagnosis recommended will be the first step to uncover why the engine is idling so low.

The problem is an easy one, at least. Not that it won’t cost you a little money. Sometimes, you just have to spend and you’re done for another two years.

Trying to clarify here; did you fail the 25mph test, or the rpm was too low at that speed. They usually give you the print out and it states the emissions at each speed; did you pass the emissions (CO, NO, etc)?

If indeed the car is idling too slowly, check all the air tubes from the mass airflow sensor up, and clean the idle air control valve while you have the tubes off it. This sounds easy but is a pain because of the location where they hide the idle air control valve on BMWs. Also check the throttle position sensor.

I rather suspect, however, that there may be nothing wrong with the car. The smog station told my daughter that the timing was off on her 328, and they failed the car. BOGUS. How could the timing be off on these cars? I took it to another station and it passed.

Test was aborted as the RPM was too low when they started the test,I believe at 25 MPH

I spoke to the technician.Now he says: The car did okay at 15MPH and at 25 “did not shift” and the test was aborted automatically.Am I correct if I say the idle RPM was not the problem?

I spoke to the technician today.Now he says: The car did okay at 15MPH and at 25 “did not shift” and the test was aborted automatically.Am I correct if I say the idle RPM was not the problem?

Not shifting should make for higher rpm,this gets more confusing.We hear you when you say problem is not low idle rpm.