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Join Date: Jul 2011
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I took my car for a drive yesterday and the balancing of the throttle bodies did have an effect but I decided to redo the balancing again as I thought my process could be better as I did not compare all cylinders.
My original process was to balance cyl 1,2,3,4 and then use 1,2 as reference and balance 5,6 so
and then I left it at that assuming the setup was balanced.
So I took the M out for a drive to warm up the engine, hooked up the Carbtune and checked the settings.
With cylinders 1,2,3,4 I see that the readings were all slightly off so I balanced them all again to 22cmHg.
Then I measured cylinders 1,2,5,6 and adjusted all to 22cmHg.
I found that I was wrong to assume that they would be balanced. My oversight the first time is not understanding that adjusting one set of throttles would impact the vacuum of the others, I didn't think this would be the case but it is happening. Maybe my setup has a leak or something else needs to be replaced/adjusted, but when I measured 3,4,5,6 cylinders 3 & 4 were slightly off, so I adjusted them to 22cmHg.
Then I went back and checked 1,2,3,4 and needed to tweak 1,2 ever so slightly to match at 22cmHg.
I checked 1,2,5,6 and 3,4,5,6 and all readings were at 22cmHg.
I took the car out for a drive and the car drove even better than after the first adjustment. Throttle response was immediate and smooth vs. the jerky delivery of power the car initially exhibited prior to balancing.
Before balancing, when I was coasting in gear the car would have a tendency to lunge (feels like you stepped on the brakes hard for a split second) when the RPMs dropped to a certain point, so combined with the jerky acceleration make for a rough drive. These symptoms have been fixed and the car accelerates and coasts very smoothly now.
So I do suggest to everyone who is doing a throttle body balance to do the extra steps to make sure all of your throttles match up perfectly to get the best results.