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1993 454 TBI Problems!!

  • lvoithoffer
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06 Apr 2019 20:30 #28474 by lvoithoffer
1993 454 TBI Problems!! was created by lvoithoffer
I have a 1993 k3500 454 NV4500... The engine is a semi fresh rebuild(50K miles) with a small cam. I have replaced the following some parts multiple times... The truck has a stumbling rough idle. Seems to lack power to me but im not sure. If i take the truck for a short drive when i come back and go to instantly restart it has no fire from injectors....hit it with a little ether and shes up and running again. Im fairly positive i have that narrowed down to a weak oil pressure sensor.(changing it tomorrow). The truck runs pig rich and never seems to go into Open loop.(i think heated 02 will change that). I AM OPEN TO ALL SUGGESTIONS.. out of ideas myself.

I have a ALDL cable with WinALDL & Tuner pro rt but quite frankly do not know what i am looking for I have attached a copy of my logs at a idle.
docs.google.com/spreadsheets/d/1ZuvfldSA...U/edit#gid=361545408

Parts replaced less than 300 miles ago.( All new with AC Delco parts)

Completely Rebuilt TBI unit with 2 inch spacer

New TPS & IAC i did my best to calibrate them

New map sensor

Pickup Coil ( Timed at 4 degrees BTDC with connector unplugged)

Cap rotor & Plugs & Wires

ICM

Ignition coil

o2 sensor ( Re wired from ecu wire was broke assuming when they reinstalled the engine)
*** I plan on switching to a heated o2 due to my long tubes.

CTS

Knock sensor (Wire was also broken)

Newer fuel pump & Filter 15k ago with all new lines

Im sure there is plenty others im forgetting. The EGR is deleted as are all other vac lines except MAP,PCV. I am at my wits edge with this truck but i love it very dearly. Hopefully the geniuses on here can help me figure it out. At this point any direction is better than none.

Thank you very much you can email me at This email address is being protected from spambots. You need JavaScript enabled to view it. Or text me at 724-570-8672 if that is easier.

Lucas

Picture of said truck causing all the heartache
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  • cheryl hartkorn
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07 Apr 2019 14:08 #28491 by cheryl hartkorn
Replied by cheryl hartkorn on topic 1993 454 TBI Problems!!
so it stays in closed loop? if so thats good. what are the oxygen sensors doing when its running rich? can you force them rich and lean? what is the engine coolant temperature sensor reading??

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07 Apr 2019 14:47 - 07 Apr 2019 15:17 #28492 by guafa
Replied by guafa on topic 1993 454 TBI Problems!!
Hi ivoithoffer,

What tool/method are you using to realize injectors are not firing when restarting?

Are all your diagnostic inputs coming from aldl software?
Last edit: 07 Apr 2019 15:17 by guafa.

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08 Apr 2019 15:12 - 08 Apr 2019 15:13 #28518 by chief eaglebear
Replied by chief eaglebear on topic 1993 454 TBI Problems!!
was there feedback control in 93?????? also lets look at trims at 2500
Last edit: 08 Apr 2019 15:13 by chief eaglebear.

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