d21 auto adjustments

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J_Dub
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d21 auto adjustments

Postby J_Dub » Sat Apr 18, 2015 3:31 pm

So after getting the truck running again I know need to make some adjustments.

There is no kickdown at all, so I have to manually select the gears...

And at foot to the floor it only revs until 3000rpm before changing in every gear.

Lastly, because of the above issues, it won't hold in overdrive at all realy, it will change from 3rd to overdrive then lockup in seconds.. So the problem I get from this and by having no kickdown is approaching a hill and I want to hold speed, it means switching overdrive off which puts it back in 3rd which at 90kms its revving its tits off..

Where should I start?
Is the kickdown cable the lower cable of the 2 on the injector pump?

Some research suggests adjusting the tps will change the revs at which the box will change gear??

Also read that the vacuum solonoid could be a culprit.

Would be good to get a discussion going as a lot of searching ive done doesn't realy give hard n true facts on what's fixed what.

Cheers

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Re: d21 auto adjustments

Postby Crash bandicoot » Sat Apr 18, 2015 3:42 pm

Since it has tried to go into over drive, start with adjusting the TPS first, it seems it may only be out by a degree or two.
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Re: d21 auto adjustments

Postby J_Dub » Sat Apr 18, 2015 4:39 pm

Well that worked a treat, adjusted it to get the gears to change at a touch over 4000rpm. No point going higher, still no kickdown at anything higher than 60kmh.

All I want is to be able to kick down at 100kmh to disengage lockup and keep it in over drive, so I can maintain 100kmh on a slight incline, to chop to 3rd at 100ks is a bit to much revs

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Re: d21 auto adjustments

Postby Crash bandicoot » Sat Apr 18, 2015 5:07 pm

um might be a dumb point, but the ecu you put in.... did the truck it came from have the (economy/power) switch on the dash? it might be economy by default if its not hooked up.
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Re: d21 auto adjustments

Postby J_Dub » Sat Apr 18, 2015 5:23 pm

I'm thinking this could be a problem.
Not so much the new ecu but the power/hold switch, the switch itself has power to it, ie is illuminated but there's no indication on the dash itself and the switch does nothing. Power or hold don't affect gear changes, maybe that's stuck in hold?

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Re: d21 auto adjustments

Postby Crash bandicoot » Sat Apr 18, 2015 5:27 pm

yeah we do need to illiminate that as the cause.. i'll dig out the wiring diagram and see what wire we need to put a switch in to drop it out of lock up when in O/D but not drop back to third.
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Re: d21 auto adjustments

Postby J_Dub » Sat Apr 18, 2015 5:52 pm

I've found that mate.
Blue wire brown plug drivers side of engine bay, mite do that tomorrow

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Re: d21 auto adjustments

Postby Crash bandicoot » Sat Apr 18, 2015 5:58 pm

okay

anyway might aswell not waste the research, for any one elses benefit

after a little dig, on the RL4Ro1A ecu the OD and lockup solenoid on the trans loom leading up to the engine bay,by the looks it will be pin 3(or blue wire as Jdub as described) on the brown 8 pin plug in the engine bay, and pin 115 on the ecu, as this is a D21 make sure you confirm it first as it is slightly different to the R20 RE4 that have.
on the RE4' ecu, it is pin 5 on the brown plug (red wire for the 98 era)and different pin again on the ecu ( pin 3 ).

basicaly we need to interupt this line to unlock the torque converter but still have the trans in O/D. (or 4th)

below is the brown plug, and below that again is the switch arrangement on mine.
T/C lockup
Line pressure dump
and middle is normal.
the bottom switch is for 1st and 2nd without shifting the stick back, it is quite harsh on the driveline though as it is done at full line pressure so wouldn't advise that one unless the ground is real soft under foot.
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Re: d21 auto adjustments

Postby J_Dub » Sat Apr 18, 2015 7:13 pm

Cheers crash.
I've read u can adjust kickdown on these via cable then I've read some say u can't, is the cable below the throttle cable for kickdown?
On mine its directly below throttle cable on injector pump and goes back into firewall about mid-way, above engine?

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Re: d21 auto adjustments

Postby Crash bandicoot » Sat Apr 18, 2015 7:22 pm

J_Dub wrote:Cheers crash.
I've read u can adjust kickdown on these via cable then I've read some say u can't, is the cable below the throttle cable for kickdown?
On mine its directly below throttle cable on injector pump and goes back into firewall about mid-way, above engine?


I would have thought the extra linkage on the pump is for the choke cable on the older td27 then the vacum operated choke on the not so early ones.
there is a diagram in the manual for the linkage but that's to adjust the gearshift. i beleive the kickdown switch is on the accelerator pedal.
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Re: d21 auto adjustments

Postby ChurchurDan » Sat Apr 18, 2015 8:50 pm

The second cable is the hand throttle.

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Re: d21 auto adjustments

Postby J_Dub » Sun Apr 19, 2015 4:34 pm

Just an update.
Adjusted tps a bit more.
Much better again..
I was thinking before the last adjustment, if it's programmed to change at 3000rpm, then the kickdown would be less sensitive, as the computer thinks its doing higher revs anyway so it want kickdown. I noticed an improvement when I adjusted the changes to happen at 4000rpm but no kickdown in top gear.. So I adjusted again to change at 4500rpm foot to the floor.. Now I have very good kickdown across every gear at any speed..

Still won't hold overdrive for long but this is typical for these boxes and a lot of old autos so not fussed, the hold switch mod will fix this.

All n all for future reference, adjusting tps gives longer gears and improves sensitivity for kickdown

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