| Author |
Message |
Bill V. (Doc)
Junior Member
Username: Doc
Post Number: 135
Registered: 9-2001
| | Posted on Friday, September 13, 2002 - 5:32 pm: | |
The reason I bring this topic up is because when I got my car, the previous owner had it tweeked, by way of disconnecting the O2 sensor and richening the fuel mixture. Set up this way , the car idled and ran smoother--ie steady, even idle and no rpm surging at low speed , steady-throttle driving in traffic. Since I got the car, a Ferrari dealer noted this and returned the setting to stock spec and reconnecting the O2 sensor. Now, although the car runs fine once it gets rolling, the idle is rough , with rpm surging noted. So, i was thinking of returnng it to the "tweeked"state--it really did idle /perform more smoothly and evenly. So, do you see any problem with my dc'ing the O2 sensor again and very minutely richening the mixture ? I do realize that such adjustments need to be tiny. |
Richelson (Richelson)
Member
Username: Richelson
Post Number: 817
Registered: 12-2001
| | Posted on Friday, September 13, 2002 - 10:32 am: | |
Bill I wouldn't turn the mixture screw yourself especially without the proper CO machine to test it with. Brian is completely right. Turning it a slight bit can cause a large difference that you may not be able to notice. Are you still running your Cats, emissions too? If so you don't want it to be too rich. You may want to ask your mechanic where he set the CO level and compare. HTHs. |
Brian stewart (Eurocardoc)
Member
Username: Eurocardoc
Post Number: 375
Registered: 11-2001
| | Posted on Friday, September 13, 2002 - 10:13 am: | |
Plugging the hole tightly may be the only problem, try that first. The adjustment screw is a 3mm allen head, clockwise for richer, as I said a tiny amount can be a huge difference, maybe a 1/10th of a turn. |
Bill V. (Doc)
Junior Member
Username: Doc
Post Number: 134
Registered: 9-2001
| | Posted on Friday, September 13, 2002 - 6:57 am: | |
Thanks , Brian. I do know that the adjustment was tweeked by the last owner of my car and I recently had it returned to stock specs. However, it definitely was not tightly blocked by thatt 10mm bolt--as I mentioned, it just loosely fit into the hole. Although the mix was adjusted to stock spec, it feels a bit too lean and I was wondering in what direction one adjusts the screw to richen it slightly. Also, what size screw is in that adjustment hole--is it an Allen head? It's difficult to see. Maybe my just plugging the hole will solve the lean -feel. |
Brian stewart (Eurocardoc)
Member
Username: Eurocardoc
Post Number: 374
Registered: 11-2001
| | Posted on Thursday, September 12, 2002 - 9:45 pm: | |
Simply put, the hole is to access the fuel metering adjustment, it should be blocked off at all times otherwise the fuel mixture will be wrong due to air leaking via that hole. Also EPA laws state that the plug should be intact for emmissions testing and compliance. Lastly, without proper tester, do not attempt to adjust, a very small degree of movement can make a big difference. |
Bill V. (Doc)
Junior Member
Username: Doc
Post Number: 133
Registered: 9-2001
| | Posted on Thursday, September 12, 2002 - 8:47 pm: | |
I 'm still getting acquainted with my '85 308 and i just noticed a hole on the right side ( looking down from the rear of the car) of the fuel injection unit right next to the air cleaner housing. In fact , there is an indenture at that point on the air cleaner in order to get at it, I presume. Anyway, there was a 10 mm bolt sitting loosely in the hole and, when I attempted to tighten it in, it just spun freely as it seemed to hit a shelf about 1/2 into the hole. Although my first thought was that it was a mounting bolt for the unit, it apparently isn't. Can anyone tell me what that hole is there for? Is this the adjustment area for the fuel mixture by any chance?
Second Q--if this isn't where to get at the fuel/air adjuster, where is it located and how does one adjust the mixture ? |
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