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Eric Fowler
03-03-2000, 12:20 PM
My 88 750 is not even coming close to passing emissions. Besides taking it to a dealer and paying out the wazoo, what are my other options? I am thinking of doing plugs/wires b/c it probably needs them anyway. Any other suggestions? It is supposed to have new O2 sensors. It was my immpression that Cats were either 100% good or 100% bad, no in between. Mine have not overheated or clogged up so could these really be the cause? Any help would be appreciated. Thanks.<i><br></i>

sam
03-03-2000, 01:28 PM
There's a number of ways to get away with emissions. Clean the intakes very good (two person needed for the v12). make sure the air<br>filters are clean, make sure the pcv valves, its hose, and connections are not clogged. Theres<br>some stuff you can buy at the auto store that helps lower emissions (pour in tank). <br>Cat's get clogged but you'd really notice the lack of power.<p>My 90 mustang lx would pretty much pass without cats (haha) but of course they look under the car, and well , it ended up costing $125 for a "Guaranteed pass" at a seedy neighborhood. $125 for two years of smog here (atlanta) is not bad considering its cheaper than having cat's put on and losing the power. If you have any muscle car head-friends, ask them for a place that will Certainly pass you're car , if *all else fails*. <p>Be nice to your 750 and tune it up. air filters, intake cleaner,plugs,clean the distributor/caps, should all be good. If the O2's are bad you'll be getting a check engine light.<p>sam<p><br><i>: My 88 750 is not even coming close to passing emissions. Besides taking it to a dealer and paying out the wazoo, what are my other options? I am thinking of doing plugs/wires b/c it probably needs them anyway. Any other suggestions? It is supposed to have new O2 sensors. It was my immpression that Cats were either 100% good or 100% bad, no in between. Mine have not overheated or clogged up so could these really be the cause? Any help would be appreciated. Thanks.<p></i>

scott
03-03-2000, 01:51 PM
As far as your cats go, they can usually tell if they are working by putting a temp probe on them. If they are working, they achieve a certain temp. Don't know the exact temp, but do know that the catalytic reation is exothermic (i.e gives off heat).<br>Other than that, look at what you were exceeding.<br>Too much fuel could cause excess HC. This could be leaky injectors, etc. I also hear that O2 sensors are always good to replace if they have miles on them. Definitely don't purchase these from a dealer. Even if you have a dealer install them, you can supply the parts.<br>However, if you are that much over the limit, I'm not sure if a basic tune up is going to get you where you need to go. A good independent shop that deals in BMWs may be the ticket. I found dealers were not that great with the 12 cyl cars.<p>Good luck

John
03-03-2000, 05:32 PM
Eric<p>We're just taking stabs in the dark on this one. My 88 735iL with 226K passes at the same readings I got in 1992 with 112K. These are usually not that hard to pass. So, under the guise of having something else checked out, like and oil and filter change, take it to the dealer and have them read the fault codes from the diagnostic port.<p>If you insist on trying to slug it out alone here is a list:<p>Air and fuel filters<br>Spark plugs and wires.<br>Do the V-12's have hydraulic lifters? If not, adjust.<br>Check the fuel injection rail pressure.<br>Check for vacuum leaks.<br>Check position sensor (crankshaft).<br>Check the air box flow meter.<br>Pull one injector and take it to a specialized injection service shop and have them test it for leakage and spray patern. Although one bad injector will knock you out of an E test, on high mileage cars they all degrade pretty much the same. You can, also hit the injectors with the "bomb" like the dealers do (injector system flush).<p>If it points to the cats, I have pity on you. You might have to buy a ranch in Montana to establish residency and register it there. It would be cheaper than tackling that exhaust system!!<p>Looks like a long weekend,<br>John 88 735iL (226K)<br>79 320i (250K)<br>95 Disco<p><p>As I recall, the 88 750 O2 sensors are a bear to get at.<p><br><i>: My 88 750 is not even coming close to passing emissions. Besides taking it to a dealer and paying out the wazoo, what are my other options? I am thinking of doing plugs/wires b/c it probably needs them anyway. Any other suggestions? It is supposed to have new O2 sensors. It was my immpression that Cats were either 100% good or 100% bad, no in between. Mine have not overheated or clogged up so could these really be the cause? Any help would be appreciated. Thanks.<p></i>

Gilbert
03-03-2000, 07:09 PM
You might even try one of those $3.00 cans of fuel treatment they sell at auto parts stores that are guaranteed to get you passed. I've been told they worked, but don't really know. And they may be outlawed in California.<br>Good Luck.<p><p><i>: My 88 750 is not even coming close to passing emissions. Besides taking it to a dealer and paying out the wazoo, what are my other options? I am thinking of doing plugs/wires b/c it probably needs them anyway. Any other suggestions? It is supposed to have new O2 sensors. It was my immpression that Cats were either 100% good or 100% bad, no in between. Mine have not overheated or clogged up so could these really be the cause? Any help would be appreciated. Thanks.<p></i>

BD
03-03-2000, 11:21 PM
<i> Why would you confess in a public forum to breaking a Federal law ?

sss
03-03-2000, 11:27 PM
hmm okay i forgot to type "Hypothetically" in the message. my bad :), i was just talking hypothethically. Better? nobody would want to break a law :) kinda like when i take my car Hypothetically up to 140mph on the road, i wouldn't really do that, whats the point?<p>sam<br>s<i>: Why would you confess in a public forum to breaking a Federal law ?<p></i>

Eric Fowler
03-06-2000, 03:12 PM
Thanks to all those that posted. I realize that this question was probably pretty bad since it was pretty general. After looking at things for a short period of time this weekend, I decided there are so many factors, that I would rather just take it into Dinan and let them figure it out. I would rather spend time working on building the motor on my Camaro which I do understand and has much fewer factors. I did think that it was funny how easily it passed in comparison to the BMW!!!! I will post the results on Wed. when I get the car back.<p><i>: hmm okay i forgot to type "Hypothetically" in the message. my bad :), i was just talking hypothethically. Better? nobody would want to break a law :) kinda like when i take my car Hypothetically up to 140mph on the road, i wouldn't really do that, whats the point?<p>: sam<br>: s: Why would you confess in a public forum to breaking a Federal law ?<p></i>


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