355 Throttle

I've tried it all. I replaced the circular throttle cable assembly on top of the
engine, lubed cable, etc. etc..

It is a "vacuum-thing" when opening the throttle. It is especially apparent at slower speeds.

Not much you can do.

AZFerrari

 

http://www.ferrarichat.com/forum/showthread.php?t=81739

http://www.ferrarichat.com/forum/showthread.php?p=134882747

 

Well, I have driven a couple 95's and they did not do this...so not all of them do it...so there might be some way around it.

 

The most common "throttle" problem on Ferraris is the floor mats pressing against the accelerator pedal.

Seriously.

 

Mine is perfect whenever it comes back from service, starts to stick a little bit when due for next service - maybe its a mechanical service indicator

 

Not the 1995 355 specific "sticky throttle" issue. This is very different...it relates to the "tip in" as you first depress the throttle....it will be a bit jerky and difficult to modulate smoothly.

 

Its a vac. issue and cleaning / adjusting the throttle plates eliminates it. I have heard the linkage mods help but I believe that is a bandaid repair bypassing the origional cause.
Dave

 

Mr. Helms is correct(as usuaul hahaha), get monometer and spend some time balancing the throttle plates and adjusting the bypass screws, it appears to be a vacuum balance problem between the outer and inner sides of the throttle plates. Please, Dave or Brian correct me if I am incorrect here but it seemed to work for me om my CH car. It feels like a sticking throttle but it is not, if you sit at idle and bump the throtttle a bit with your foot it should rev fine. it only happened on my car when I was in gear and moving the car and stepping into the throttle ie; engine being under load. Regards, Vern

 

Depends on the amount of carbon build up and how the throttle plates are adjusted. Can be bad at an idle and UN-useable on the road. NOT an easy job to do correctly as it get quite hot in the wheel wells by the time they are all adjusted correctly. Even with the exhaust fan on full speed, 8 Mercury columns jumping around, and the heat of the engine, one starts to see double before the job is done. Just when I thought updating and correcting the throttle settings on a 348 was rough, along came the 355 issues. Makes one long for the C-4 Webers........ right up until you jump into the 355 and feel what it is supposed to feel like. Advancements in technology, isnt it great?!

Dave

 

What is the basic problem? Mine is fine sometimes and other times not. When you say it is a vacuum problem, what do you mean and how do you correct it and have it stay corrected? I have done the change of the linkage parts and helped alittle. I can't believe the challenge cars would have had this problem and still be driven smoothly.

 

Have to laugh Dave at your above discription of heat and the difficult time I had adjusting the throttle plates on mine, crap what a furness those cars can be. I finally did it in stages. Adjusting the throttle plates first then letting it cool and then doing the air bleed screws and then the throttle progression last, by the way that seemed to be where the problem on my car was. Agree on the 348 balance, piece of cake compared to the 355. I guess you have to look at Ferraris as being an interesting challenge. Regards, Vern

 

I don't see how the throttle plates and air bleeds can get out of adjustment that much to cause this issue unless they have a wear issue, seems a regular diet of Techron is neccessary as well to keep them from sticking.

 

Josh, I think you would clean the throttle plates first, if they are dirty you are going to get different air flow readings than you would with them clean. Regards, Vern

 

Agreed, but they seem to mine runs better now than it did before I went back to adjust. The mercury columns were of quite a bit off when I started. What showed to be off the most was the progression adjustment. Techron isn't going to help the throttle bodies on the 355 because they control air only there is no fuel going over them. Techron would help the injectors stay clean but, that isn't where the problem seems to be. Regards, vern

 

everyone seems to be on the right track, for the basic checks, but also beware on the throttle plates, check for small ridges on the housings,caused by rapid opening/closing of the throttle, i.e "blipping", we have see this cause sticking.

 

There are times when my car runs so strong. I have GruppeM intake, Hyperflow cats computer chip off a challenge car. The throttle response is right there in any gear and the car really pulls and any slight movenment of the throttle causes a surge that pushes you back in the seat--even in 6th at 3000rpm. Then there are other times when it seems like there is play in the throttle off idle and it stumbles alittle and the throttle response is not nearly as crisp. Is this a throttle adjustment, throttle position sensor?

 

Just out of curiousity anyone running a K&N filter having the sticky throttle issues?

My car does not experience any throttle issues, it has a few times bumped up a few rpm off idle then settled down this has happened when I first got as it had been sitting for a period but has not done it since.

 

I have the GruppeM intake an it has K&N filters and I still have the throttle problems.

 

Is anyone aware of a documented procedure to do all this? If not, anyone feel like writing one?

Thanks, Dave