Auto Trans Shift Points

[mwesten]

Hey everybody. First post ever here but certainly not the last!

Think I need the auto governor rebuilt. Reverse works fine and when I shift to D I do get forward acceleration, but best I can tell I?m either staying in 1st, or starting in 2nd and staying there. I did do tons of research here and it sounds like the governor to me (so far). But can someone help me with:

1) How would I know if I?m starting off in 1st or 2nd?
2) What are the typical RPM (or speed) shift points for the 3-speed auto?

[Iznodmad]

In 3rd gear by 35 mph under 1/4 throttle. Don?t continue to drive it if you think it isn?t shifting, you will cause damage in a short amount of time.

[Iznodmad]

Oh, row through the gears ?manually? by using 1,2, then D. Or find the posts that tell you how to set up a ?test light? to visually see when the ?computer? shifts for you.

[Rich]

Read the second paragraph of this knowledgebase article (http://support.delorean.com/kb/a69/automatic-transmission-shifting.aspx) - see if your car?s symptoms match up.

The whole article is informative.

[Ron]

How to set up the test lights is in post 6 (https://dmctalk.org/showthread.php?350-Automatic-Transmission-Governor&p=26804&viewfull=1#post26804) of the following thread:

https://dmctalk.org/showthread.php?350-Automatic-Transmission-Governor (https://dmctalk.org/showthread.php?350-Automatic-Transmission-Governor&p=26804&viewfull=1#post26804)

[mwesten]

Thx guys. I?m going to try to run some tests like you called out. I did fail to mention that, while rolling, I can move from D to N and back without issue. However manually dropping to 1 then moving to 2 didn?t do anything (but still maintained forward acceleration. At this point I?m just not sure if I?m rolling in 2nd or 1st.

[David T]

First do all of the external on-car checks like fluid level, throttle adjustment, etc. Inspect the wiring harness to the shift computer aka governor. Sometimes they get burnt because it runs close to the exhaust. If it still isn't shifting right build a light box and hook it up. There is a small chart somewhere (maybe in the FAQ's) that shows the shift points and RPM's for each gear. One is for the 5-speed and the other is the auto. Most of the time the problem is either a burnt wiring harness or a blown shift computer and sometimes both. There are articles to fix the shift computer. Start with the light box and tell us what does or doesn't light up and when. The most common failure mode of the shift computer is erratic shifting and if the wiring burnt up then you can have blown 1 or both output transistors.

[mwesten]

First do all of the external on-car checks like fluid level, throttle adjustment, etc. Inspect the wiring harness to the shift computer aka governor. Sometimes they get burnt because it runs close to the exhaust. If it still isn't shifting right build a light box and hook it up. There is a small chart somewhere (maybe in the FAQ's) that shows the shift points and RPM's for each gear. One is for the 5-speed and the other is the auto. Most of the time the problem is either a burnt wiring harness or a blown shift computer and sometimes both. There are articles to fix the shift computer. Start with the light box and tell us what does or doesn't light up and when. The most common failure mode of the shift computer is erratic shifting and if the wiring burnt up then you can have blown 1 or both output transistors.

Thanks for this. I think where I?m sorta hesitating but need confirmation is how to wire a light box. I?ve seen write ups like this thread (https://dmctalk.org/showthread.php?17520-auto-trans-throttle-spool/page2) for example - but I?m hedging on just getting some wire and doing it because I haven?t actually seen it done? just read about it and seen small schematics. Does anyone have a pic of how you rigged yours?

[David T]

Thanks for this. I think where I?m sorta hesitating but need confirmation is how to wire a light box. I?ve seen write ups like this thread (https://dmctalk.org/showthread.php?17520-auto-trans-throttle-spool/page2) for example - but I?m hedging on just getting some wire and doing it because I haven?t actually seen it done? just read about it and seen small schematics. Does anyone have a pic of how you rigged yours?

It's really simple. It's just two 12 volt bulbs wired with a common wire. The box is just to hold them. Make your wire long enough so you can plug it in and put the lights inside the car so you can see them while you are driving. Any low voltage 3 lead wire (like thermostat wire) will do. Use incandescent bulbs. I don't know how it will work with LED's.

[mwesten]

It's really simple. It's just two 12 volt bulbs wired with a common wire. The box is just to hold them. Make your wire long enough so you can plug it in and put the lights inside the car so you can see them while you are driving. Any low voltage 3 lead wire (like thermostat wire) will do. Use incandescent bulbs. I don't know how it will work with LED's.

Ok that?s helpful and about what I was thinking. So it?s just B to one bulb, D to another, nothing going to/from C? correct?

[Ron]

Ok that?s helpful and about what I was thinking. So it?s just B to one bulb, D to another, nothing going to/from C? correct?You have to connect C to both bulbs also. (See post 5 above.)

[mwesten]

You have to connect C to both bulbs also. (See post 5 above.)

Right on. Sorry if I come across dense on this one. Electrical isn?t my forte? which means I have my work cut out for me haha.