How to adjust 2nd to 3rd upshift for 94 E320 sedan

3798 Views 12 Replies 2 Participants Last post by Clarkz71, Dec 17, 2013

e320Fred

Discussion Starter · Dec 3, 2013

How do you just adjust 2nd to 3rd upshift (94 E320 sedan) when I want it to shift sooner... seems to be revving higher and then shifts for about a long second, versus a quicker and lower rpm transition... Gas mileage has suffered and I think this is the issue.

the trans was soft rebuilt 3k ago... 3rd to 4th shifts perfect, never seen 1st (good for45 degree inclines, I guess

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Clarkz71

· #2 · Dec 3, 2013

e320Fred said:
seems to be revving higher and then shifts for about a long second, versus a quicker and lower rpm transition... Gas mileage has suffered and I think this is the issue.

You're not talking about the shift delay that's normal until the engine temp comes up, are you?
It's to warm up the catalytic conveter faster.

Or does this delay happen all the time?

The control pressure cable will affect the shift timing of all gears.

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Clarkz71

· #3 · Dec 4, 2013 (Edited)

From the FSM............

Transmission upshift delay

In order for the catalyst to reach its operating
temperature faster, the no load or partial !oad
2 - 3 upshift is delayed for a maximum of 90
seconds after engine start at engine coolant
temperatures between 0°C and 40°C. Therefore.
the upshift takes place at a higher englne rpm.
The delayed upshift controlled by the engine
control module HFM (N314) via the upshift delay
switchover valve Y3/3. see group 14.
The engine control module processes the
following information for this purpose:

Engine coolant temperature,

Vehicle speed signal (via CAN),

Transmission range 'D" (via CAN),

Elapsed time after start.

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Clarkz71

· #5 · Dec 4, 2013

Possible, either that or the vacuum can at the transmission for the
bowden cable.

Disconnect the vacuum line at Y3/3 and plug it. See if that affects it.

The signal comes from the HFM module, but Y3/3 could be stuck.
Check it for power.

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Clarkz71

· #9 · Dec 16, 2013 (Edited)

Well, that may cause a code, but I don't know if it's the problem.

Keep us posted.

I circled the fitting to plug for anyone that wants to disable the shift delay.

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Clarkz71

· #11 · Dec 16, 2013

Flare and delay are two different things.

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Clarkz71

· #13 · Dec 17, 2013

e320Fred said:
Not sure if I have the right nomenclature?

The car is upshifting too late at 2750-3200 rpm (versus 2000-2500 rpm-- delay) with rpm spike and drop (flair-a long second) at that point.

I might video my dash with a good engine/car audio showing symptom then post.

Also, seems a slight change (sooner) in upshift after fixing vacuum tube elbow fix--after a day of work driving....

No, you have a delay in shift.

A flare is when the rpm rises suddenly and drops back down during a shift.

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