SilverSurfer

Hello! I have a 1977 280Z stock 5-speed manual transmition. The original AFM seemed like it was having some issues. The engine was running rich (you could smell it and I was getting horrible gas mileage), at idle the engine did not run steady/consistent (it revved up and down sort of like ooooOOOOooooOOOOoooo ... if that makes any sense ... and the tach would move with it below 1000 RPMs to slightly about 1000 RPMs), and, lastly, sometimes when going slow in third gear the car would hit a point where it would jerk until you either sped up or slowed down even further.

I had a spare (used) AFM and swapped it out today. The first thing I noticed is the car idled smoothly/evenly right about about 1000 RPMs. This is the best this car's sounded since I've had it. So, I took it for a ride. That's when I ran across a different problem. The car seemed to do great when driving in the city (no jerking when running slowly in 3rd gear), but I ran into a problem when I went on the highway. The entrance ramp I was using is slightly steep (uphill) and the car chugged (moved sluggishly). I could barely get 'er over 35 MPH and so I could not get up to highway speed. Once on the highway I was able to get her going, albeit slowly. Once up to speed, she had a lot more pep.

I am assuming that she is now running a tad lean? But I am no mechanic. Not by a long shot. Obviously the new AFM made a difference, solving a few issues and introducing a new one. So, where do I go from here? What should I check? And how do I tweak this?

Any help would be appreciated. Thanks.

Skully

AFMrebuild Is a good read, if you want to know more about the AFM. I have had to adjust the carbon track on mine, not saying that is your issue, but just read through that article anyways its good.

SilverSurfer

Thanks!

rogerz

keep your revs up. the l28 is not a puller engine it is designed to be used at higher revs. use your gears. from what you wrote you seem to like going slow in third gear. Not what was intended by the designer. Try that ramp in second.

SilverSurfer

Thanks for the reply. I did not intend to indicate that I was using 3rd gear at slow speeds. Sorry about that.

With the previous AFM I was able to zoom up the inclined entrance ramp with no issue, entering the highway at 55+. So, my main question here is that there is a major difference between the two AFMs. Somewhere between the two seems like it would be a sweet spot.

rogerz

you can always take the AFM apart but many who have tried had a monumental FAIL