Philes' Forum by Vic Lucariello

Hello Bimmerphiles! This month I have an update on what I have learned about the new New Jersey emissions inspection. I know I promised to have Part I of the saga of Big Al’s limp alternator, but with all the controversy of late regarding the new emissions test, I thought it appropriate to let limp alternators lie for another month.

Last month I reported that I had taken my 1980 320is through the new inspection and had not received the dynamometer test but rather an idle emissions test similar to that given at DMV since the early seventies. Moreover, I reported that I had been told by the DMV inspectors that BMWs do not receive the dyno test . Subsequent info indicates that I was misinformed. I composed last month’s DMV report on newsletter deadline day [Indeed, I inserted it into my already-completed column.], so I didn’t have time to corroborate what I had been told at DMV. I also requested that any of you who went to inspection contact me to share your experiences.

Three Bimmerphiles were kind enough to contact me . Bob Butchko, Pedro Reyes, and 1999 NJ Chapter President Gary Bossert all went to inspection since the inception of the new system and report that their Bimmers did indeed receive the dyno test. I requested that they send me copies of the test printout [This is the only way to tell for sure whether your Bimmer underwent the new ‘Loaded-Mode’ test on the dyno or a single- or two-speed idle test], although at this juncture I am quite sure they did get the dyno test. If any other of you Bimmerphiles could help me with this, I will greatly appreciate it. The test printout shows which test was run along with the emissions measured and their respective pass/fail criteria. My mailing address appears in the masthead. I would like to create a database of dyno test results so that we can compare a given Bimmer’s emissions to a baseline for that particular model.

Another Bimmerphile, Don Fields of Autosport Performance [Englewood, NJ; 201 816 0911], was kind enough to do some research and report that 81> 2WD Bimmers should get the dyno test provided that, if they are equipped with traction control, the control can be switched off. Don and I think, as does BMW Super Tech Bill Wiedmuller at Hunterdon BMW [Lebanon, NJ; 908 236 6302], that all traction control-equipped BMWs have an instrument panel switch for this purpose, so this tells me that 81>, gasoline-fueled, non 325ixs are supposed to get the dyno test.

I had the opportunity to witness and participate in a NJDMV-certified dyno emissions test, and I learned a lot of stuff you folks should be interested in. Unfortunately, this particular test was performed on a FWD 1994 Chevy Corsica with 3.1 l V-6 and auto trans., but hey, any port in a storm! Here are my observations and comments: The inspector must have a special state license to perform the test.

The inspector’s credential data must be scanned or manually entered into the emission test computer along with the vehicle’s pertinent data. On our test, the scanner picked up the inspector’s data, but we had to manually enter the vehicle’s. This manual entry added maybe 5 minutes to the inspection time. Included in the vehicle data are the vehicle gross weight rating and odometer reading [114,000 miles in our case].

The emissions test requires engine RPM as one of the data inputs. This is the reason for the RPM sensor I mentioned last month. The sensor DMV used on my 320i was placed on the hood and slid [OUCH!] around until it picked up a reading. The machine we used on the Chevy had such a sensor, but also an inductive sensor which clips onto a spark plug wire like a timing light’s. We used the clip-on sensor. The inspector told me that the hood sensor is unreliable, and if the RPM signal is lost during the emissions test, the test is aborted and has to be redone. I don’t know if the DMV inspection stations have the clip-on sensors, but you can be sure I will ask them to use it if they have one.

After we had everything hooked up and data entered, we proceeded to do the evaporative emissions test. Depending upon the year of the vehicle, this will be a gas cap test or an actual test of the integrity of the fuel tank’s gasoline vapor recovery system. The Corsica got the gas cap test, [as did my 320i], which consists of removing the cap and checking to ensure it holds a prescribed pressure.

Next up was the actual dyno emissions test, which requires that the vehicle be maintained at an indicated 14-16 MPH at an engine RPM not exceeding 2500. The dyno’s rollers, which are driven by the test vehicle’s drive wheels, are loaded to simulate driving the vehicle at a steady 15 MPH up an incline. [This is why we needed to enter the vehicle weight] The tester’s computer screen indicates both speed and RPM values via mimics of an analog tachometer and analog speedometer. Also displayed are the drive wheel torque and horsepower along with ambient temperature, barometric pressure and relative humidity. If the inspector, who is sitting in the car ‘driving’ it on the dyno, allows the speed or RPM to deviate from the prescribed values, the test is aborted. Once the speed and RPM are OK, the computer starts a timer and begins a 15 second or so ‘conditioning’ period. Two purposes for this are to ensure the vehicle’s catalytic converter[s] is at operating temperature and to ensure the ‘loaded-mode’ emissions are reaching the gas analyzer [I believe the analyzer is also checking the sample’s Oxygen and Carbon Dioxide levels at this time to ensure it is receiving a ‘proper’ exhaust gas sample].

After the conditioning period, the actual emissions test begins. This lasts about 50 seconds and again requires that the speed and RPM remain at their prescribed values. I found it interesting that the computer screen was not displaying any emissions values. Indeed, it never did. The whole emissions test, including carefully driving the Corsica up onto the dyno [DMV uses a drive-over dyno which is a bit faster to position the vehicle on.] took about 20 minutes, including the delay due to not being able to scan the vehicle data and having to root around for a new windshield sticker.

After the test, the computer indicated that the Corsica had passed, and we put a new sticker on the windshield. We were required to enter the sticker serial number into the computer, which then indicated it was transmitting the results of the test to the main DMV computer in Trenton. Only after all this was done did we get a printout of the test results [we had to specifically ask the computer for one], which showed that the NOx [Oxides of Nitrogen], CO [Carbon Monoxide], and HC [Unburned Hydrocarbons] were far below their respective limits, which were also indicated on the printout. This on a fleet vehicle which had received MAYBE one set of new spark plugs in 114,000 miles. Spark plug wires, etc., looked to be original. The Corsica did, however, have fresh oil in the crankcase.

The way to tell for sure if your car received the loaded-mode dyno test versus a single- or two-speed idle test is to examine the printout. If the printout has a limit shown in the NOx column [ours was 1150 PPM], you got the dyno test. The idle tests do not have a NOx pass/fail criterion, so the report will have a blank or dash in this area.

I hope this was as informative and interesting for you Bimmerphiles as it has been for me. In next month’s column I hope to tell you that Joanne’s 1986 325 [2.7 l Eta Motor], passed its dyno test as easily as did the Corsica.

Again, I will really appreciate receiving copies of your emissions test printouts. Thank you in advance!

Anyone wishing to contribute to Philes' Forum should contact me via the info on the masthead. I'm interested in tech tips, repair /maintenance questions and/or tips, dealer horror stories, product evaluations, etc. Please call before 8 PM, and if you leave a message, PLEASE INCLUDE A PHONE NUMBER WHERE I CAN REACH YOU DURING THE DAY ON WEEKDAYS. Also, please be patient, I try to return every phone call, but it sometimes takes a while. If you don’t hear back from me within a few days, please call again. The best way to contact me is via e-mail.

Copyright 2000 - V.M. Lucariello, PE