87 454 tbi black smoke

[bigblockdually]

i'm pretty dam sure that my truck wants to be a diesel it has a slight engine knock that goes away when warmed up and it smokes BLACK if you tap the throttle quick and repeadtly it will smoke or if you just nail it from a stop and let off when you get to the floor it will run rough until you rev it up and hold it steadt i can get it smoking pretty dam bad sometimes to the point it looks like the truck is on fire if i just keep on tapping the throttle in gear it gets all caught up in itself and just smokes like hell so if anyone knows why its doing this it would help and you can also just romp the hell out of it burning out launching it or just reving it it wont do it

[87 STEPPER]

Hey welcome to the board.

The first thing i'd check is the fuel pressure regulator diaphragm and spring if either are defective and the fuel pressure isn't regulated properly the fuel pressure will be to high causing a rich condition thats why you are seeing all that black smoke.

This requires thking apart your TBI assembly.

If you google model 220 TBI you can find a complete brake down of the TBI unit.

Good luck.

[bigblockdually]

yea i'll take a look at that that might account for the burning a 1/4 tank in 15 minutes

[rfmaster]

Originally Posted by bigblockdually

i'm pretty dam sure that my truck wants to be a diesel it has a slight engine knock that goes away when warmed up and it smokes BLACK if you tap the throttle quick and repeadtly it will smoke or if you just nail it from a stop and let off when you get to the floor it will run rough until you rev it up and hold it steadt i can get it smoking pretty dam bad sometimes to the point it looks like the truck is on fire if i just keep on tapping the throttle in gear it gets all caught up in itself and just smokes like hell so if anyone knows why its doing this it would help and you can also just romp the hell out of it burning out launching it or just reving it it wont do it

BigBlock
You'll have to do basic troubleshooting with your truck. Your TBI system has an ECM which controls fueling and timing depending on sensor inputs.

1st Check codes - you can do this a with paper clip by shorting Pins A & B on ALDL connector. This will force your ECM to blink SES light, reveling error codes. It should blink code 12 (three times) followed by any other stored trouble codes. Do this basic check first.

2nd the most common cause for rich TBI operation is an open coolant temperature sensor (CTS) located next to the thermostat housing (two pin connector). When this sensor fails (usually happens after many years in service ) ECM sees open circuit which corresponds to very cold temperature. This results in rich mixture condition.

Check codes first.

//RF

[Rippin-J]

randomly happened onto your thread ...I am no expert, but your point about the motor running rough for a bit when you applied throttle sounded familiar.

my motor has been doing the same thing and the net result was a valve issue in the heads. why it sputtered (and blew smoke) so badly when I applied throttle was that there was at least one cylinder that wasn't combusting correctly. BUT, if I increased the rpms is 'appeared' to smooth itself out. my theory there is that the motor is firing fast enough that that one (or more) bad cylinders became less noticeable.

my other new theory is that I also heard a 'knocking' sound, but perhaps my untrained ears mistook an actual knocking sound for 150psi of pressure escaping through the tiny leaks in my valves (which if muffled by things like an intake manifold or exhaust headers) may sound deceivingly like a 'knock.'

I don't mean to underestimate your ability to sonically diagnose anything, but this is all stuff I have recently discovered and figured I would share considering our symptoms seemed to be somewhat related. honestly you're probably better off if the computer will fix it for you vs having to tear apart the motor!

[pig rig]

being a tbi engine I would start with the tbi its self just cause you can regulate the fuel with opening a closing the throttle and nothing was said about throwing any codes. so my money is your screens on your injectors are pluged go buy a tbi rebuild kit theirs nothing to a tbi to rebuild its amatter of taking it apart and putting it back together

napa tbi rebuild kit # is 2-1751

[bigblockdually]

thanks guys i think i'll try rebuilding the tbi since it is the least costly rippin-j your diagnoses seems pretty convincing and makes good points but i think i'll hold off on a top end job until i rebuild the tbi and if that fails then i'll pull the heads!!!

[Rippin-J]

no worries bro, I would do the same thing.

if it comes to rebuilding the heads, check out my thread for 'in-truck head removal.' I just completed doing it myself for the first time and it worked! Not as bad as I had imagined, and fun to learn that much about the motor.

good luck, keep us updated!