75 Eldorado in Sport Mode

[pplaut]

I replaced the modulator. Changed fluid.
Things are so much better.
However, the car shifts at 30 and 50 mph and not a moment before.  If I accelerate to 50 and then let it shift into 3rd gear, I can then drive around 40-45mph in 3rd gear. Letting off the throttle prior to 50, the thing will not shift into 3rd gear. :O
It reminds me of putting my wife's car in sport mode where it shifts at the upper end of the rpm scale.
The throttle kickdown has been disconnected and does not seem to make a difference connected - or not.
I appreciate any ideas here.
Thanks!
~P.

[Barry M Wheeler #2189]

My 20K mile '91 Seville shifts into second gear at 14 MPH (and not before.) It also shifts into high at about 40 MPH. It may be that the shift points are programmed at certain speeds. My street is rough because of three years of sewer line replacement, so I don't speed up much when going to the super market a block away. (I "know", but I'm getting old.) But it is kind of a pain to "wait."

[Dave Shepherd]

You need full vacuum to the modulator for proper up shifts, even an out of tune engine can cause delayed upshifts.

[pplaut]

The car would not shift out of first gear until I replaced the modulator and vacuum lines. So, at least it now shifts out of first gear, but just seems delayed. The modulator I purchased said it was for the 75 Eldorado.

[Dave Shepherd]

Possible it is wrong,  adjustable modulator maybe the answer.

[35-709]

Or maybe it is an adjustable modulator that needs further adjusting.  If you put a small flat blade screwdriver in the vacuum nipple do you "feel" a screw in there?  If so, you can turn the screw inside the modulator counter-clockwise to soften the shift and make it come in earlier.  An adjustable modulator usually has a red band around the body.  If adjustable, try 3/4 of a turn counter-clockwise and see what you get, fine tune from there.  MAKE SURE you have manifold vacuum there.

[pplaut]

I have to pull the modulator out and check. Unfortunately, this was a 12.00 part from O'Re**ys. I doubt for 12 dollars it is adjustable. As a side note. I have very little faith in a 12.00 part but they said the 30.00 part was no longer available.

[bcroe]

There is a 6 cyl and a slightly smaller V8 modulator.  It takes a somewhat
fine screwdriver (I ground a custom) but all the replacements I see are
adjustable.  My experience is, not very sensitive, I would turn it out
5 turns and see what happens.  I keep track of the turns, otherwise
I would lose track of this multi step tuning process. 

Bruce Roe

[35-709]

You don't have to remove the modulator to check to see if it is adjustable (or adjust it), just remove the vacuum hose and insert a small, flat blade screwdriver in the hole.  If you feel the screwdriver blade fall into a slot and/or it has a red stripe around the body, you have an adjustable modulator.  After that it is trial and error to get the shift where you want.  If you DO NOT have an adjustable modulator, they are readily available, probably at NAPA, etc. but certainly here ---

https://www.summitracing.com/parts/bmm-20234?seid=srese1&cm_mmc=pla-google-_-shopping-_-srese1-_-b-m&gclid=EAIaIQobChMItJOip_bu2wIVyrfACh1Legi4EAQYASABEgKl6_D_BwE

https://shop.advanceautoparts.com/p/atp-at-modulator-valve-jx-66/11239193-p?c3ch=PLA&c3nid=11239193-P&adtype=pla_with_promotion&gclid=EAIaIQobChMItJOip_bu2wIVyrfACh1Legi4EAQYAiABEgJoifD_BwE&gclsrc=aw.ds

https://www.speedwaymotors.com/TCI-350001-GM-TH350-TH400-Adjustable-Vacuum-Modulator-Valve,334375.html?sku=282350001&utm_medium=CSEGoogle&utm_source=CSE&utm_campaign=CSEGOOGLE&gclid=EAIaIQobChMItJOip_bu2wIVyrfACh1Legi4EAQYAyABEgKFVfD_BwE 

[pplaut]

Thanks!