I have just built in my Corvette 1971 a LS3 376/480 crate engine, and with plug and play kit 19201327 (pcm # 19201790)
When I start the car it has the right idle, and run and sounds well in free gear.
When I put the 400th automatic gearbox in drive (pure mechanical no sensors connected with the engine etc ) the engine stops at once (same like try to driving away with a stick in third or fourth gear)
When managed to drive away the idle get higher and engine is running around 1500 and 1800 rpm, and without using the throtle the speed become 30-40 mph
When I start to push the accelerator I miss total the promissed horsepower wich it shows in free gear, (and compare with my former old standard engine)
This is for now a problem of the second degree, but maybe it had to do with the First problem .
In the dark you can see the Mill light shines very very weak.
I bought a predator to test things, and found no problems

Communication will be a bit slow because of the time difference , so hope you will be please patient with me.
Anybody who think can help?
T.I.A
PC

 

Are you using the proper flexplate and spacer setup for that combination?

Was this a transmission known to be a good working part ahead of time?

 

Thanks for reply
Yes proper flexplate and spacer and transmission is also O.K.
Found it complete mystery that the engine stops suddenly, while it
has not any electronical connections with aut. gearbox .

 

Are you sure that the torque converter is completely seated in the trans?

 

Thanks reaction.
Yes, start to doubt myself and built in the "old" engine back and tranmission is oke.
Now the LS3 engine is back built in and problem is also back
T.I.A.
PC

 

Isn't there a wire you have to hook up from the computer to the gear selector to tell the computer the car is in gear?

 

Not to my knowledge , but it is a old fashion 400th automatic gearbox
with no wires.

 

This may help.
https://ls1tech.com/forums/automatic...questions.html

 

Many thanks I have looked many days on Google, forums etc to find this kind of info, I must read and study this first and will come back later this week (or next weekend when I think I had to do some modefications on the car )

PC

 

It said something about putting a 6-speed tune in it, to clear the ses codes.
That may trick the PCM. Hopes everthing works out for you.

 

What's the stall on your converter? What does GM recommend for a stall speed with that engine?

 

Thanks for reaction, I have lot of questions and suggestions for this weekend
when I can work on the car.

 

Stall is standard

 

The converter and all is ok, idle 850 rpm oke but engine died at instant when I put it in drive

 

I think that the pcm needs a signal from the VSS. You can add one using a Dakota signal generator on the speed-o cable. That's what's I used on my 350 turbo.


http://www.dakotadigital.com/index.c...rod&prd109.htm

 

Thanks for this suggestion, think it take a few weeks before its will arive when ordered .

In the mean time somebody suggest that maybe the ignition fires is a bit too late.
I have a test predator, but doubt if I can make (electronical) changes on the ignition time to make it fires earlier, and would it be interesting

 

[QUOTE=JJFarmer;14609764]I think that the pcm needs a signal from the VSS. You can add one using a Dakota signal generator on the speed-o cable. That's what's I used on my 350 turbo.


Hi,
Have lent and tested a dakota signal generator in the hope it was working on the pcm, while I got a 400th automatic transmission.
But without results.

Can the ignition timing be late ???
Problem: Idle 850 rpm oke but engine died at instant when I put it in drive