Lazy acceleration: 911 3.2

My 911 hesitates under medium to hard acceleration until it reaches about 4000 rpm... Then it seems to smooth out. I also notice a 'pulsing' until it gets to 4000, too... Anyone have any suggestions to correct?

Thanks for all of the great info so far!

Adam

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Adam Nitti
www.adamnitti.com
'85 Carrera
'74 3.0 CS

adam-
i had the same situation and took my car to the local porsche dealer, e-mail me and i'll tell you what they said.


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-jeff 84 carrera cab.

Fine, just keep the rest of us 3.2 owners wondering.

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Mark Szabo
1986 911 Targa 3.2

don't take it so seriously mark, i'll e-mail you tomorrow. i'm just tired of all the wise-crack responses to personal experiences and suggestions of late, and this is one of those situations that will "leave the door wide open."

You may want to try and run a bottle of Techron thru your fuel system
You may have dirty injectors etc.

I will try the Techron; Could spark plugs be to blame?

Also, I initially failed emissions when I got the car and had to have that adjusted. Could the proper fuel/air mixture have been disturbed?

Thanks everyone-

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Adam Nitti
www.adamnitti.com
'85 Carrera
'74 3.0 CS

My 86 Carrera also failed the California emission test when I first got it. Seems the mixture was set too rich and was doing the same thing your car was doing until I leaned the mixture on the AFM.

Not only did it pass emissions but it became much peppier on the lower RPMs and a lot more fun to drive.

Joe Garcia
Redwood PCA since 1976

Great to hear of your success with the mixture change... What is the AFM? Is this something I can do myself, or do I need to take her in?

Thanks-

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Adam Nitti
www.adamnitti.com
'85 Carrera
'74 3.0 CS

The AFM is the Air Flow Meter and if you are not familiar with it, you might leave it with a knowlegable P-wrench who could set it up for you.

On my Carrera, after years of experimentation, I have found the optimum settings on my AFM that give me the best drivability, no bucking at 2200rpm, instant tip in throttle response, and 30mpg on the freeway which is hard to beat.

So, the Air Flow Meter is very adjustable, but it takes someone with the knowledge and patience to get it right on your car.

Joe Garcia
Redwood PCA since 1976

Thanks for the info, Joe!

In your opinion, should I still investigate the spark plug replacement issue or some other replacement of ignition components first before taking it in for an AFM adjustment?



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Adam Nitti
www.adamnitti.com
'85 Carrera
'74 3.0 CS

I would replace my plugs before I attemted anything more complicated or expensive.

I find it curious that in these days of computer-controlled engines, and advertising hype stating tune-up intervals of 100K miles, that dealerships (including Cadillac -- the ones' that tout 100K tune-ups for their Northstars) still point at the sparkplugs as causing problems, FIRST, every time! A friend's wife took a rough-running, stalling car into their friendly Cadillac dealer when he was out of town, and was charged $200 for a sparkplug change and nothing else was done -- no ignition scope, no diagnostic computer printout -- nothing but change the plugs while she waited 45 minutes, and two hours after she had the car back, it still had the same problem ... the mechanic hadn't even taken it for a test drive with her to find out what the 'complaint' was about -- took a bit of wrangling to get $150 taken off the bill, after hubby got back to town, but at least they learned not to trust that dealership service department!!!

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Warren Hall
1973 911S Targa

Did you get to the bottom of your problem? What was the fix? Thanks!

how do you adjust the mixture, I have a 84 911.

As I recall from my 88, there is a dial switch inside the DME box which controls the mixture. I don't think it can be adjusted on the motor because the computer will override it. Back on the Rennlist a year or so ago someone posted the 7 positions and what they were relative to the mixture, but I didn't save it. You might check the archive at www.rennlist.org

Vic
87 930

I'm in agreement with Warren, I think. Today's scopes can tell if your ash tray is too full. Rather than guess, take it to someone who has the equipment and has done hundreds. But then I'm intimidated by the more modern fuel systems. What a difference a year makes.

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'83 SC