Balancing Throttle Body Openings

[DrumrBoy]

When adjusting the screw on the linkage between the throttle bodies, you want to ensure that the left butterfly (left as seen from the driver's position) opens slightly before the right one.

I've tried several different "gaps" between the screw end and the plate it contacts but haven't gotten it right yet...the car is still bucking and banging at low rpms or under no-load conditions. No problem when you give it gas, just annoying.

It started out with zero gap and I've tried several different gaps but haven't tried extremes yet (pretty much stuck to 1/32 - 1/16 gap) - should the gap be significantly bigger than that?

 

[ViperJohn]

Perhaps you have a bad TPS or TPS ground?

Also, are you resetting your computer after making the throttle body adjustments?

I was told that having the set screw space about the thickness of a dime. While not perfect, it was a dramatic improvement from what I had before.

Make sure you reset the computer and then turn the car to the "on" position without starting it. Press the accelerator pedal through a full range of motion.

Hope this helps.

 

[PhoenixGTS]

Try not looking at the linkage. It might be steering you wrong. Take the smooth tubes off and stick your thumbs into the throttle bodies so they are pushed against the bottoms of the butterflies. Have someone barely push the throttle. You want the driver's side butterfly to move ever so slightly before the passenger side. Keep adjusting it. You will get it.

 

[DrumrBoy]

Thanks for the ideas.

I didn't think about resetting the PCM. I was lazy enough to try it without removing the tubes....shame on me!

I'll post when I get it figured out with any additional tips I discover - for the next guy.

 

[RoadiJeff]

Okay, I've been following this thread for a few days with one question that I figured someone else would have asked by now. Anyway, why don't we want both throttle bodies to open at exactly the same time? It seems that the optimum adjustment, according to what I've read here, is for the left side to start opening slightly first.

I have a '99 RR/10 that I bought about a month ago. I haven't really studied anything under the hood yet and I figure I'll get into that when I change the plugs and wires out soon. Maybe this will all make more sense then.

All the service manual says on the throttle body adjustment is to place a 1.0 mm shim under the accelerator pedal down stop with the pedal pressed against it and adjust the cable tension until full WOT is achieved on the throttle bodies.

 

[klamathpro]

Okay, I've been following this thread for a few days with one question that I figured someone else would have asked by now. Anyway, why don't we want both throttle bodies to open at exactly the same time?

Because we only have one TPS and that's on the driver side. If the passenger TB starts opening first, even slightly, more air flows into the driver side bank without more fuel, causing the low throttle bucking when one bank has the right amount of fuel and the other doesn't. Then a split second later, the TPS tells the PCM to give all the injectors more fuel and the leaner bank receives that needed fuel adjustment too late and bam, the other half of the bucking.

 

[PhoenixGTS]

Because we only have one TPS and that's on the driver side. If the passenger TB starts opening first, even slightly, more air flows into the driver side bank without more fuel, causing the low throttle bucking when one bank has the right amount of fuel and the other doesn't. Then a split second later, the TPS tells the PCM to give all the injectors more fuel and the leaner bank receives that needed fuel adjustment too late and bam, the other half of the bucking.

That TOTALLY makes sense. I has always thought of is being related to the IAC solenoid being on the passenger side and idle air for the pasenger side cylinders having to go through the idle air passege over to the driver's side plenum (which feds the passenger side cylinders), but what you are saying makes total sense - UNTIL - you think about low speed bucking being when both throttle bodies are open at least a little bit. Then neither idea makes as much sense.