I have searched various threads, and would appreciate some clarity: 1. Although I am told not to rev the engine with the allen wrench in the mixture screw, can I adjust the screw, without revving, but while the engine is idling, or should I turn off the engine, adjust, restart? I have the CO tester from Eastern tools, and want to do some bit of adjustment on my own, and obviously don't want to damage the air flow sensor unit. 2. If I push down the spring loaded mixture screw, push down so it seats and engages while the engine is running, the engine will stall, before I can actually turn the screw. Per 1., did I do something I shouldn't have? 3. How much impact does the mixture crew have on readings? How far out of adjustment would be considered within range of the screw to adjust for? 4. Why do I test with the o2 sensor disconnected? The emmisions test would test with it on? If it is in compliance with the o2 sensor off, will it by design remain in compliance with the o2 reconnected? 5. I have a hyper cat, and have no port to test pre-cat, like I think the oem cat had. And the emmisions tester tests after cat? Thanks to anyone who can clarify.
Andy, if your 3.2 is failing emissions I would encourage you to take a comprehensive view of the potential fixes. In other words, attempting to adjust the mixture may just be a poor patch for some other failure in the system. A 3.2 with all fuel related fixtures working properly is a very, very clean burning engine. My 3.2 easily passes emissions without any cat at all. Have you checked all the other relevant components of the fuel/emissions system to make sure you don't have a failure somewhere before attempting to adjust the mixture? For example, if you have a failed O2 sensor then your car won't pass. There are a lot of components in the fuel/emissions system that must be functioning perfectly. And, if they are, it's highly unlikely you'll have to mess with the mixture adjustment. Just my $.02.
Can you give us the CO2 and HC readings those will go a long way to tell what is going on inside your engine.
Like he said. My 328 passes with no issues at all, there has to be other reasons I'd think. You do have pre cat testing ports unless some modification has been done, one per cylinder.
I have a simple co sniffer (really a co2 sniffer). New hyper cat and o2 sensor (i.e. less than 5,000km on it), new dist caps, wires, plugs. Oil change, air filter, etc. all basic items done. Car had a major at 40km, now has 50kms. The car runs well, maybe a slight barely dicernable blip of a misfire on occasison at idle. CO at idle was too high (I think 200ppm), HC too high (I think over 100ppm) as well, nox was in spec. I will post more actual data when I get home, but for various reasons (ok, I admit bumbling around with the mixture screw while doing an idle adjustment before I was properly researched and now I am trying to get back to what previously was emmission compliant settings). This is why I am fairly confident it is just an screw adjustment. I do have the individual exhaust port access, but this would measure just one cylinder?, but it is easy access, is this where I should put the tester? Another thread using my gastester just says put it in one of the outer exhaust pipes, but may have been a non-cat car being tested. But in the end, the provincial test just sniffs the post cat exhaust, with the o2 sensor on, so hence some of my questions about what spec to set and where to measure. Given the obvious things have been done, and my bumbling, I would like to try the mixture adjustment. If this is not successful, then I will think about the coils, injectors clogged, various other emmissions equipment, maybe a failed cat even if its nearly new, maybe a plug wire extender or dist. cap wire connection, etc.
Looking at the CO numbers you are running a little bit rich. The HC numbers look great no sign of a misfire there. A slight mixture adjustment should do the trick. The CO is the % of partly burnt fuel The HC is the amount of unburnt fuel in the exhaust stream
I was adjsuting the mixture screw, and with the engine idle, push the screw in and quickly turn, as the engine nearly stalls, then catch, do this two or three times. Sometimes the engine starts, need to crank a bit to start up again. Reading all wonky on the reader. Noticed getting warm, see a bit of smoke coming from the exhaust, good gracious the cat I think was glowing red hot!! Actually flickering like a light at 8pm at night here. Might have been the header pipe just before the cat. after a bit of cool down, i shot an infrared thermometer at the header and the cat, and both were still near 2000 F. Needless to say, I shut things down, misted the whole thing to avoid a car fire/house burn down. Have I so badly screwed up this adjustment, that I ran so rich, and the constant near stall/restart dumped fuel? Or was I so lean I caused the problem? I let the car cool, it will start and run, but I am now scared. Have I just ruined the cat? Fried hoses or belts? Is there some sort of default number of turns on the mixture screw from so I can at least get it ballpark back to something like normal, and I can drive the car to a dealer. At this point, I would probably get the vehicle towed. I guess I should only adjust the mixture screw when the engine is off. Answered one of my own questions the hard way. This is very disheartening, I went from a perfectly fine running car to near disaster.
If the reading you gave us are after the cat who knows what is happening upstream. If you have a dwell meter or a duty cycle meter adjust it for 50%. Having only one sampling port wont do you much good. We always adjust the CIS lambda cars by duty cycle anyway.
Brian- Should he do a compression check to make sure he does not have a burned valve? The idle misfire is what my 308 had when one of the exhaust valves was burned. Taz Terry Phillips
Compression problems do not drive CO too high. That is a pure and simple mixture problem. If leaning it does not bring the other gasses in line further diagnosis is required and suggests a different problem. Mixture is often set badly on fuel injected cars because there are still people out there that think it can be set by ear. I am a pretty good carburetor guy and set 6x2's all the time by ear but wouldn't dream of setting FI that way.
No, you are really illequipped to do this. Before you do serious damage you really ought to consider getting it to someone who knows what to do.
When I now start the car, it is clearly running on 4 cylinders, this must be what caused the cat to overheat, maybe had nothing to do with mixture adjustment antics. Is this some bizzare coincidence that while adjusting mixture, a coil failed? Could my pushing in and adjusting the mixture screw to a near stall condition have caused a coil to fail? Could I have damaged the microplex? But for my own education, I want to know one important thing - Does one adjust the mixture screw while the car is idling? Given that trying to adjust it stalls the vehicle, makes sense to turn engine off, adjust and restart. Is this correct? Have I damaged the fuel distirbution unit in some way by adjusting with the engine running? At this point, I want the most information anyone can share so when I explain all this to a mechanic, they have some sense of what might be wrong. In Toronto, it is not so easy to get a knowledgeable guy to work on these cars, especially in summer when all the exotics are out for play and service. Don't be too hard on me for trying to deal witgh a simple mixture adjustment.
It needs to be adjusted with motor running. It sounds as though you adjusted it the wrong way and in addition if you are manipulating the adjustment correctly it will not stall the motor.
Thanks for clarifying. But to be clear, when I push down the spring loaded screw with the 3mm allen wrench, once the screw has been pushed so the allen wrench will actually seat and adjust, the engine stalls. Just pushing down the screw stalls things. I am not sure what manipulation would prevent this. Any thoughts on the linkage between the adjustment and half the engine now shut down? When I describe all this to a mechanic, the focus will I presume be on the bank of cylinders not working, not fuel mixture.
Replaced failed coil (tested by taking coil wire off the good coil bank that ran, car wouldn't start), car runs fine now, but back to square one on mixture setting. Car appears drivable to get it to a dealer for proper assessment... With a cat fire, should I presume the metallic hyper cat is toast, and put back on the oem cat (with 40km on it, I presume it will be good for a while). I presume the o2 sensor would be damaged, and would replace that as well. Cat warning sensor likely damaged as well, or can it handle the heat? In the Mondial, anything else likely damaged by the cat, its kind of under the trunk and not too much else really close by...
Try using 97 ron unleaded full take of fuel then take it to dealer...worked for me...i got an idle speed problem, she keeps cutting out when at t lights, in addition keep having a lack of pwer as a spark plug lead keeps becoming detached you got any ideas for that
Went to an expert, he suggested the coil failure was a coincidence, nothing to do with mixture adjustment. Replaced coil, changed oil, plugs from gas fouling, put on old oem cat plus new o2 sensor (old hyper cat loked fine inside, probably ok, anyone want to buy it, with o2 sensor which probably is also ok?). Without any adjustment from what is was at when I brought it in, heres the emmissions test results: Idle: HC ppm 17, CO% 0.0% (!) ASM22525: HC ppm 14, CO% 0.0%, NO ppm 292 I had set this up perfectly using my gas tester!! (At least for emmission test purposes, I see the point of testing pre-cat for proper set up, and the old cat does have the test plug. The hyper cat does not, this is a design oversight on the part of hyper cat). So, here what I learned: 1. Mixture is adjusted with engine off. Anyone who says otherwise must have some different setup for the screw adjuster than a Swiss model1988 mondial. 2. Not in over my head, although this might be possible in some instances, but not in this case. Just some problems that appeared linked, but probably were not. 3. Cat fire is really serious stuff, not much time from a bank of cylinders failing to a major fire. This looks like a pretty poor design by Ferrari, instead of a slow down light, there should be a control that stops the gas from going into the dead bank of cylinders, or a fuel pump cut-off or something more than an idiot light for this type of problem. 4. No reason for these cars not to run really clean.
