Aggressive throttle

[59ghia]

Hello fellow ZERS'

Does anybody out there suffer from aggressive throttle syndrome? No, not the need to mash the throttle down at any given opportunity although I do tend to suffer from it on occasion:classic: This one is your starting out, push down on accelerator (pretend theres a cop next to you) no response, alittle harder and it snaps open, not full throttle mind you, maybe 2krpm. I've lubed all fittings, thats not it. In looking at the linkadge, I think its in the design, just to Roob Goldberg. Has anybody done a mod to remedy this? Maybe a helper spring or something? I can feather the clutch and get around it, but when rounding a corner and dropping into second it's really annoying.

Thanks Dave

[Daniel]

I wondered when this would come up.The problem is the linkage part that attaches the carbs to the assembley on the balance tubes.It's about 5" with the snap white balls on it.If you look close you see that the entire assembly is almost a straight line when at rest.When you apply the gas you have to "break" from straight.Thats your surge.The fix I made was to use the firewall linkage part from a 280z,it might have been zx.Anyway you'll know when yousee it.It has an adjustment on it .It's the piece that goes from the firewall mount to the gas pedal linkage.I put a small bend in the part,then adjusted it so the length is the same as the 240 part, it is just curved now.When in place the straight line is now gone and so is the surge.I hope I am clear if not let me know. Have fun!! Daniel

[biker]

You may be talking about the jerkiness of the throttle. I suffer from it as well and may do something about it one day.

There is an article at the following site

http://www.zhome.com/

Look up under Technical Articles Index. It talks about throttle linkage problems under intake.

:classic:

[kmack]

I have this same problem. Makes starts from a dead stop (while next to Mr. Officer) a real chore.

Daniel, do you have any pictures of what you did to correct yours? Or what the parts look like?

Biker, I've seen that article before and it pasically says to cut the welds of the top arm on the throttle linkage bellcrank mounted on the firewall. If someone doesn't have a welder it makes putting it back together a little tricky. I'm looking to try it, but I want a spare bellcrank first before I go hacking up my good one.

Anybody have any other solutions?

[Daniel]

I'll get a photo tomorrow.It's that short linkage rod that connects the carbs to the throttle stuff that mounts on the carb balance tube.When you use the one I mentioned from the 280 and bend it kinda like a hockey stick it changes the action.The 240 kinda goes down then left.Thats the problem.The hockey stick fix(think we now have a name)Cause's the action to always go left.I think the part is 280zx.It's been years ago but,for awhile I was making them for alot of guys.I would raid the boneyards for that zx part.

[carguyinok]

Anybody have any other solutions?

Its called fuel Injection

Sorry I had to. I know a few people that have spent what seems like days on the linkage. One of them had found that the return spring\springs where way to strong. He put new springs on that where not wound as tight and it helped. (note I said helped not fixed) But when dealing with 30+ year old plastic parts helped maybe worth it. VS, broken linkage. :tapemouth

[2ManyZs]

Before you start taking it apart and replacing parts, the question I have is have you tried to lube the linkage? Not just the plastic ball ends, but the pivot on the firewall as well? Take the E-clip off, unhook you ball ends and lift it off the mount, and see if it is rusty under there, clean it up and lube the *%# out of it and put it back together and see how it works then....I had one that was stiff, lubed everything and then took the "bellcrank" or whatever you wish to call it off the mount on the firewall, and voila, it was rusted terribly. Guess at one time or another the washer line sprung a leak and soaked it with windshield washer fluid as I found "blue goo" under the pivot.....

[Victor Laury]

I can only add,

I didn't have this problem until last month when I installed my Ztherapy total restoration. Everything is lubed. As a matter of fact, the throttle pedal is way lighter now, As if ZT sent me lighter return springs. Well, If I try to creep at below 5 MPH - Wow! do I ever get into a surge cycle! I believe I've bruised a collar bone with my shoulder belt. I think I'm going to change my pedal height (rod length through the fire wall) and see if that helps. Too bad, my pedal is now right where I like it and can easily "heel toe" in it's current position.

[59ghia]

Daniel,

Sounds like a good idea, Next time I'm at the wreckers I'll look for that piece. Question, is since you refer to it as a hockey stick, is the bend high, (at the balance tube ) or low at the carb cross shaft? 2many, I've dis-assemled and lubed the piece you are refering to, (when I first got the car roadworthy) and it made a difference, but I still have the problem, just not as severe.

Dave

[kmack]

I have lubed mine also. Specifically the bell crank (polished the shaft on it even) and the piece mounted on the balance tube. I got very little improvement in doing this.

I thought about this on the way to work this morning, has anybody thought about or tried a secondary helper spring? We already have the return springs, what about a helper spring to help overcome the initial "sticky-ness"?

[beandip]

:classic: I am not sure just what you are having trouble with , however I was having a surging of rpm from a standing start , say from idle at a signal and then a flat spot after , then smooth increase in rpm there after. I changed to 20wt oil in the dampners and it all cleared up. I went to 20 wt fork oil from a Cycle shop.

[59ghia]

Hello fellow Zers'

Kudos to Daniel on the "hockey stick fix" ! Throttle is nice and smooth now

Thanks again!

Dave