I'm also a member of a Mercedes forum and saw where someone was able to adjust the CO2 setting on his fuel injected straight six MBZ. He said it helped the idle quality tremendously. Is there any such animal on the Camaro 305 TBI's?

Anyway, when go out back and I listen to my exhaust I hear a putt-putt and the idle's much rougher than I'd like. First...I assume these engines can be made to purr...right? Second, I've checked and triple checked the plugs/wires for arc'ing but can't pinpoint anything. Any other ideas this fine Saturday morning? Thanks. Dave

 

Its a chevy V8, it will likely never idle like a merc.

You can do a cyl drop test, to see if you are missing.

Not sure what a CO2 setting is, that is not a gas any one every really checks for, exept an emmisions testing, if you are talking about O2, then that is a diffrent story.

 

Alot of German cars with the Bosch fuel injection system have a POT on the Mass Air Flow sensor to adjust the idle CO reading. It adjusts the Idle air/fuel mixture. It is most commonly seen on older cars with the Vane style Mass Air. You can get an adjustable MAP sensor for a TBI, but for the money you mights as well get a prom burner.

Before I cammed my 305 engine, it would idle so smooth at 475 RPM you could barely tell it was running. It now runs nearly as smooth at 600 rpm.

There is no reason a chevy won't idle as well as a mercedes. The chevy is getting the same number of power pulses and they are spaced the same as the mercedes. If everything is balanced correctly it will idle very smooth. When was the last time it was tuned up? What is your fuel pressure? What is the timing set at? Are your valves adjusted right. What about your plug gap?

 

Thanks very for the comments ...now at least I know there's an idle quality I can shoot for. By the way...I've looked for "cylinder drop test" info and haven't found anything yet. Can you explain the test in 25 words or less?

As for a tune-up...everything's fairly fresh and as close to specs as can be...I just thought I could attack the putt-putt exhaust noise by going after this or that rather than doing a complete tune-up over again. Knowing me, if I did something wrong the first time I'll probably set it up the same way the second time. And if the putt-putt goes away, which would be good...I really won't know why. Thanks again. Dave

 

Welll this is a good start to make you motor purr.....

https://www.thirdgen.org/techbb2/sho...hreadid=245398


You did the tune-up but have you changed any sensors? Like the O2 or the IAC? Sensors are what tell your computer(ecm) what is going on in the motor. With age they can send improper readings making the ecm make adjustments that you would not normally need. Learning DATA LOGGING will let you know what is going on in your motor.

GOOD LUCK!

 

As a matter of fact, the O2 and the IAC are new as well. (As I age I often realize my sensors are subject to rot and corrosion from disuse and neglect.) But I never let my car feel neglected.

And I have a pretty good scanner....that gives me both codes and operational data.

Of course, THE RIGHT THING to do would be to follow your advice and learn and then DO some data logging; and, follow your advice re: DIY PROMs. You're correct...there is a ton of very useful information here at the forum.

Now... for those of us who are time-challenged and ended up with a TBI without knowing it would require data logging and DYI PROM's to do a tune-up.... all I'm trying to do is get an idle quality improvement so my wife's car isn't the subject of family meetings, fer Christ's sake........

Sorry for the outburst...I'm all relaxed now...

I'm not sure now if I should begin data logging my car or psycho-analyzing my head.

With tongue planted firmly in cheek, I remain a loyal member. Thanks for the input. Dave