M30B35 Throttle Linkage Adjustment

[gte619n]

Hey fellas,

I went to drive the car this morning and after warming up, the car seems to stick at 2,200 rpm. Weird! So I investigate and the throttle linkage does not seem to be returning to rest on the adjustor screw:

When I lift it back up, all is well and usual. The springs seem to be working fine, so I'm suspecting some drift in the linkage. This is a FI (L-Jet, IIRC) converted car, so I'm trying to figure out how to adjust the rod. Here are a couple of picture of my setup:

Excellent modification of the bracket by PO... but I digress. Here is the adjustment mechanism:

Is there a locking pin or a spring clip or in the middle there? Do I push something down to unlock the lock nut before adjusting? Nothing seems to rotate or move freely, so I'm looking for a little direction before I start messing with it for real.

Does anyone know the source of this part as well?

Thanks!

E

 

[sfdon]

What is going on here?

you know what that piece of metal is?

its the throttle stop.
nothing is touching it.

 

[HB Chris]

I would lubricate the pivot on the motor mount and the four ball joints. The L shaped lever should be resting against the throttle stop. There is nothing to really adjust in that middle piece.

 

[gte619n]

What is going on here?

you know what that piece of metal is?

its the throttle stop.
nothing is touching it.

sfdon, the PO removed the stop there when he swapped the engine. I believe the throttle stop is at the top on the FI throttle body in this setup.

 

[gte619n]

I would lubricate the pivot on the motor mount and the four ball joints. The L shaped lever should be resting against the throttle stop. There is nothing to really adjust in that middle piece.

HB Chris,

I think this setup has it using the lock screw at the top on the throttle body? The L bracket at the bottom isn't even remotely close.

I did lubricate everything and it just won't return quite all the way to the idle adjustment screw on the throttle body.

I think I need to lengthen the rod and I'm wondering if that center thing is an adjustment? If not ... is it just some kind of flex joint?

Thanks,

E

 

[HB Chris]

The ball joints are adjustable to lengthen or shorten the rods. The L bracket prevents the pedal from traveling too far which isn’t your problem. The screw at throttle body is only to fine tune idle.

 

[TedS]

It worked before and now it's all of the sudden not? I wouldn't do anything drastic yet before making sure what you have is working right.

 

[gte619n]

It's just not QUITE hitting the idle adjustment screw. ALMOST hits it. When I pull the link up so that I stops against the idle adjustment screw, it idles at a perfect 700ish.

 

[HB Chris]

Idle should be 950 when warm.

 

[sfdon]

sfdon, the PO removed the stop there when he swapped the engine. I believe the throttle stop is at the top on the FI throttle body in this setup.

It certainly is not. That little 6mm BOLT (which does not belong there) is supposed to be slotted, it is there to adjust the gap between the butterfly and the throttle housing when the throttle lever (which is probably not what you think it is) is not at spec. It is NOT a throttle stop. It is not a idle adjustment screw.


" idles at a perfect 700ish."

Not even close..... See HB Chris above.

Your picture shows a mismatched throttle linkage intermediate lever mated to a throttle stop. Try using matched pieces.

 

[HB Chris]

I have the same Z shaped arm which I believe was used on all carb coupes and injected coupes used the L shaped arm. Either will work and the ball can be moved as an additional hole is provided. From the first pic the L is not resting against the Stop bracket which would indicate the arm from the pedal is too long as is the vertical rod. Here is a pic of my Z arm on my b35 injected motor. And I should have clarified as Don has said, that screw with the nut just fine tunes throttle butterfly opening which will affect idle.

 

[sfdon]

Furthermore…..
never install the bolt #10 into the lever #8 backwards…

your next WOT run may be your last one.

 

[Ohmess]

I think the adjustment mechanism you have pictured is a spring relief for situations where you have the pedal to the floor and are still pushing. I say this because the slots in the side appear to provide for some upward movement of the lower portion of the arm, without transmitting the upward force to the upper portion of the arm. My car has a cylindrical device that does this.

These stops and relief mechanisms protect more expensive parts, and ensure the linkage responds to your inputs. It is not fun when you let off the throttle and the rpms don't change.

 

[gte619n]

@Ohmess, gotcha. That must be what it is!

Thanks for all the advice boys! I'm going to adjust the rod length a touch and then start gathering the correct parts.

 

[sfdon]

You can start by researching the pedal dimensions in the footwell and verify that you have a throttle stop there.