4.3 tbi

[badco]

Ok so I have ran into a problem with a 90 4.3 5SPD truck. Has serious flooding issues and injectors look almost stuck static. New distributor, new temp sender, rebuilt throttle body and swapped to a later TPS main body due to a lil to much shaft wear on the original. Retained same injector tower and even made regulator adjustable. Fuel sits at 12-13. Tried a coil, throttle body, spark control, map, pcm and whatever we could off a running truck. Had some hot plugs and set of msd race wires I put on it jus trying even. Can unplug one injector and will run ok.

 

[PlayingWithTBI]

Can unplug one injector and will run ok.

Maybe the wire going from that injector to the ECM is shorted to ground somewhere? When you turn the key on (KOEO) do they start spraying without cranking?

 

[badco]

Maybe the wire going from that injector to the ECM is shorted to ground somewhere? When you turn the key on (KOEO) do they start spraying without cranking?

No they dont spray until crank it. Weird deal is I can't get fuel pressure any lower than 12 now, I had extra regulator and cut spring just to try and still wont. Thinking may have restriction in return. Air goes through it but that dont tell me if its partially blocked

 

[badco]

It spraying fuel like its wot trying to start it. It was running fine one day and next day started this. They trying to get me to put a carb on it or swap it to a SBC with carb. I know customer really well and a carb is last thing they need. They drive normal, not fast or hard and never even pull anything except a lawn mower couple times a yr. I dont care for tbi but it's simple and usually reliable.

 

[evilunclegrimace]

See if you have an open coolant temp circuit or a slewed CTS, meaning it is telling the ECM that the coolant is very cold .

 

[DerekTheGreat]

Have you hooked a scanner into it? I'd be interested to see what the ECM is seeing, something is commanding the injectors to dump fuel in... New parts don't always equate to solved problems or things you can cross off a list.