Help.... Truck not running

[Green Machine 92]

I wake up go out to start my truck to go get it inspected. To my horrible surprise its not starting. The only way it'll crank is if i have the pedal to the floor. If i let off the gas it putters out and dies. Black smoke is coming out the tailpipes, and runs rough as hell. I checked all the vacuum hoses they are all fine. I checked the injectors and the aren't clogged and are spraying. I did unplugg one of them and cranked it. It cranked right up (without giving it gas) and ran better with one plugged in than two. I was unplugging ang plugging in my battery alot yesterday ( trying to get my subs working) idk if it may have shorted out something. It ran like a champ the day before and alll it did is sit in the driveway now it wont start. Its a freshly rebuilt motor only 60 miles on it. I need some help finding the problem.

 

[chevy_man]

Some truck specs would be a good start.


But if I had to guess since you can see the injectors that you're dealing with TBI. Sounds like your injectors are flowing way to much fuel. Could be the injectors themselves or a computer issue, although when I lost a computer mine wouldn't open at all. The black smoke is because it's running super rich.

If you hooked your battery cables up backwards once it will turn your computer into junk. (My ex's dad did this to me when I was putting a transmission in at his shop, er) I'd be tempted to start by swapping with a known good computer (it only takes about 10 minutes and a 9/32nd's socket to take out the glovebox).

 

[shelbyt.67]

If u do have obd1 then try resetting the ecm wit a jumper at the data plug.

 

[chevy_man]

If u do have obd1 then try resetting the ecm wit a jumper at the data plug.

From 87 to 95 the trucks had OBD1. However, all the jumper will do is flash the codes. To reset it you need to disconnect the battery for a few hours.