I have a friend who has a truck with a 305 TBI in it and is having a problem keeping it started so I need your help.

The truck will start up and stay started in park but as soon as you put it in drive it stalls. so far he has changed the plugs, wires, cap rotor, computer, o2 sensors, idle air sensor, and a few other things.

Now here is the strange part, if I remember right he said that if he disconnects the wire that runs from the computer to the coil the truck will stay started in drive but will run like crap. (being why he swaped out the computer).

I figured it was bad rings or something but if that was the case it wouldn't do what it does with that wire disconnected.

The SES light is also on but when checked it isn't throwing any codes. He has brought it to GM certified mechanics and they can't figure out the problem.

Any help would be greatly appreciated

Thanks
John

 

I'd check the ignition timing, the MAP sensor, and maybe the injectors. Some better auto part stores will clean and flow injectors for about $10 each.
But if the timing is off and the computer adds more it would explain why it would run better if unplugged...
Also try unplugging the torque converter lock up switch or "TCC" the square plug on the side of the trans. If it's bad it will stay locked up and stall in drive.

 

Maybe the idle is set too low?

 

im having a similar problem but it wont even stay started in park, only when i hold the gas down.

 

OK some more developement, after he took off the timing wire it fried his altinator and possibly ignition coil. He says that when it did start you could drive it but you had to use two feet and constantly give it gas. He has already checked the timing, vaccuum leaks, and cleaned his injectors.

Being over here in Germany the cops are trying to get him to junk it and its a good truck when it runs properly.

Any help is greatly appreciated

thnaks
John

 

Two things to check:

1) Unplug the square connector on the side of the transmission, the TCC solenoid. If it's bad the torque converter will remain locked up and it'll seem as if it's in high gear.

2) unbolt the exhaust before the "catalytic converter" if it's had an internal meltdown it'll cause too much back pressure and run real sluggish and stall.

How does it run in "Park"?? smooth? or misses?

Does it seem to run too rich, too much fuel?
A bad coolant temp sender, O2 sensor, or weak spark can cause this.

Too lean?
Check for a clogged fuel filter, contaminated fuel etc.

Give more details....