What's new
By:
Filters

Ex 6.5 4l80e van with a treefiddy constantly stalls

AK_F250

AK_F250

Red Rocket
Joined
May 19, 2020
Member Number
178
Messages
741
Loc
Alaska
We have a float truck. Pic because no one knows wtf it is. It lifts the plane and drives it into the water. All homemade.

80019A2D-963C-4921-A09E-E93F64D7039B.jpeg


So it’s originally a 4x4 6.5 van with a 4l80e. The diesel was toast so dad tossed a carb’d 350 in there. The issue is going into drive the engine stalls. I’m not a gm guy, and from what dad was told by his tranny shop owner buddy running it manually would default to 2nd forward.

75% of the time when it’s put into gear, regardless of rpm, it stalls. Is this a transmission issue or carb tuning? This thing only has to drive 200 yards out of the hanger to the lake and then back again. I’m carb and gm dumb, is there a simple fix?
 
yozsi said:
Sounds like a little of both. Almost sounds like the TCC is stalling out the motor sometimes and maybe you aren't running enough initial timing advance.
Click to expand...
The tcc issue was my first though. If it’s trying to go from shitty carb idle to 2nd would that stall it?
 
yozsi said:
Possible. Depending how shitty it's running. Have you checked the timing?
Click to expand...
The timing seems fine before and after it’s in gear. But like I said, Carb tuning is foreign to me in 4 stroke engines. The engine came out of a 80’s half ton with a th350 and ran fine.
 
This is from a forum i just found

4L80E behind a carbureted engine? - Chevy Message Forum - Restoration and Repair Help

Re: 4L80E behind a carbureted engine?
09-06-02 01:46 AM - Post#123477
In response to BBT

As far as the electronics, you'll need an aftermarket (or adapted factory) ECU, harness, a wiring jumper to get an RPM signal, and a kit to mount a TPS (throttle position sensor) onto your carburetor. That is it.
If you are doing this to payback with fuel economy you will need to do a lot of driving!

I love the ones I have used with the aftermarket ECUs.
Click to expand...

That was the first response and there are more
 
First off, your dad and his tranny are sick, but my Christian soul wants to help you.


Ya got 2 easy options
1) replace the trans with a th350 and manual throw out
2) replace the TB with a high rpm stall
 
M92PV4U said:
So it never worked after the engine change?
Click to expand...
No clue, he got the van with a bad engine. But it was all computer controlled. Once the 350 went in there was no computer anything. My dad will trip over a dollar to save a dime, I’ve pointed him to standalone shit that will solve the problem but…
 
Some one on pirate and possibly here was selling a full manual shifter kit that took a conventional trans and made it fmvb with his designed shifter handle that had intregal switches to handle the elec controls required.


Th350 is a bad conversion choice simply because of the spline issues will dictate a tcase swap or shaft swap as well as the drivelines.

Th400 would be more dirrect if you find the right one.


The tc shouldnt be locked at all. I have a fmvb 4l80 with zero elec and i can add the tclu if i want but that is a very expensive and full tear down solution.
 
AK_F250 said:
No clue, he got the van with a bad engine. But it was all computer controlled. Once the 350 went in there was no computer anything. My dad will trip over a dollar to save a dime, I’ve pointed him to standalone shit that will solve the problem but…
Click to expand...
Yeah... it's probably an electronic issue with the computer controlled transmission not getting the computer inputs.
 
Replace the van with a trailer coupler and use your skid steer?

One less thing to maintain.
 
Lol does the tranny stick out past the cab on that thing.

We need more pictures of that thing once the plane is unloaded.
 
Ummduh said:
Is there any wiring left still attached to the trans? If there is, unplug everything.
Click to expand...
this

and if that don't work try pulling the VB and making sure all the TCC valvey stuff moves freely, it should default to unlocked
 
What a waste of what would have been a pretty nice van. Seems like any generic mini-van, or even a 4wd truck, would have been a much better donor.
 
larboc said:
What a waste of what would have been a pretty nice van. Seems like any generic mini-van, or even a 4wd truck, would have been a much better donor.
Click to expand...

All vans are better as a donor. I've driven those 6.5 vans, and they're miserable crap. Not to mention every single one leaks gallons of oil because it costs a fortune to chase the new leaks every week.

That's the one vehicle I fully support chopping down in every form, mini-van to full size, they're all miserable to drive. Only acceptable form is the cab and chassis dually with a tall 12' KUV body for the slightly tighter turning radius compared to a truck chassis.
 
If the converter isn't locking and the trans isn't locked up nothing is going to cause the engine to stall when you put the trans in drive.

Your shitbox 350 is probably idling at 300rpm or the carb is goofed up. Did you rev up the engine real high and then pop it into gear at all? That's the right way to make this work long-term.
 
I had a th400 converter go bad, and it has no lockup, but it was killing the motor when you put it in gear. replaced it and back to normal. only other thing that might do it is if the valves are too tight. had that on one as well a long time ago, but not real likely on hydraulic lifters.
 
Had a 93 6.2 diesel with the 4L80-E. Had a standalone computer for the trans as the engine was mechanical. It had an adjustable throttle position sensor on the injection pump only for the transmission. When it went bad that 4L80 was a whole different animal.
 
You must log in or register to reply here.
Top Back Refresh