S-10 2.8 TBI runs rough midway through warmup

[AuroraGirl]

recently bought the truck from a parts store lackey that could not get it running after a motor swap and proceeded to throw the kitchen sink at it and replace every sensor, distrubutor, injectors, fuel pump, temp senders, MAP, the whole works.

never be kyle, kids.

 

[Blackbeard44]

I replaced all the vacum lines today and was staring at the injectors when I noticed fuel leaking from a gasket into the venturi (maybe metering block) not sure if a TBI has one? but thats kinda what it looks like to me, I tightened the torx screws a few turns, ( I circled 2 out of them of them in the screenshot) they were not tight at all, the leak stopped and the motor instantly started to purr all nice and smooth.

I am crossing my fingers it runs like it should tomorrow when I fire it up.

 

[AuroraGirl]

I replaced all the vacum lines today and was staring at the injectors when I noticed fuel leaking from a gasket into the venturi (maybe metering block) not sure if a TBI has one? but thats kinda what it looks like to me, I tightened the torx screws a few turns, ( I circled 2 out of them of them in the screenshot) they were not tight at all, the leak stopped and the motor instantly started to purr all nice and smooth.

I am crossing my fingers it runs like it should tomorrow when I fire it up.

Im glad thats working for you (you know what i mean)

 

[Blackbeard44]

Finally got it, the TPS was bad, the new one that was on there was sloppy, I did test it and it was within range but it would fluctuate voltage without the throttle plat moving, yesterday I put the old one on there and adjusted it, and today the truck ran flawlessly through a warm-up cycle, now thats its running right I am going to start using it. THANKS to everyone that chimed in

 

[Blackbeard44]

well I thought for sure I had it licked, but today I fired it up and it high idled for about 10 seconds and started chugging again. I started wiggiling connectors and the wire harness in various places, nothing changed. i pushed on the EGR diaphram and It didnt cut out as much as it did before, so I unplugged the vacum to it and the truck started running great. I got to looking and wondering why it would open at idle, the port from the TB is higher than the throttle plates and it didnt makes sense to have so much vacum at an idle, than I thought to see if the idle screw cap was in place or drilled out, and like a true genius he drilled it out, I started unscrewing it to lower the idle and the damn thing started idling higher as less vacum was coming from the "J" port on the throttle body, about 3 turns out and the EGR quit opening at an idle.

I am wondering about the electronic vacum control unit, if its messed up, I may be wrong, but it doesnt make sense to have any vacum going to it at an idle, it may need to be adressed more though

the truck is running good and everytime I unfunk something it gets a little bit better everyday, Im not sure if todays battle was the final one but its running very nice.

I did do the idle reset process for the computer set it to as close to 625 RPMS and re adjusted the TPS again as well, so I guess we will see what tomorrows cold start brings.

 

[Blackbeard44]

It's been a couple of days now and the truck has performed flawlessly, I think the issues stemmed from a few new faulty parts and people adjusting things they shouldnt, I have drove it about 150 miles this week and its running great.