Tbi 350 has no power on the road

[L31MaxExpress]

Given the fact the 02 sensor shows over 900 mv under throttle, it is not a lack of fuel issue. Do you have a known good distributor and coil to swap into this truck? Perhaps from the same truck that you tested the TBI off. I do not even trust new ones out of the box now.

Years ago I had a L03 F-car that was ******* down hard with throttle but would start and idle ok. Was messing around with stuff and spent several hours of checking things. What ended up being the issue was an aftermarket reman distributor. The pickup coil had been replaced and it did not have the GM style connector on it. The pickup coil was plugged into the module backwards. When the EST circuit was connected to the ECM after setting the initial timing, the timing was actually being retarded. For some reason that I still do not understand, flipping those wires made the timing advance rather than retard when the ECM was reconnected. After flipping the pickup coil connector, the car ran perfectly.

 

[L31MaxExpress]

I cannot help but find it WEIRD that lay or maybe it was dog with an ing on the end is ***** out like it was a curse word. Literally was trying to imply that the engine was falling over or bogging out.

 

[df2x4]

I cannot help but find it WEIRD that lay or maybe it was dog with an ing on the end is ***** out like it was a curse word. Literally was trying to imply that the engine was falling over or bogging out.

That is unnecessary for sure. Do a test post and figure out which word is blocked in this thread, I'm sure the admins will remove it from the list.

https://www.gmt400.com/threads/censored-words-needing-unblocked.54292/

 

[L31MaxExpress]

That is unnecessary for sure. Do a test post and figure out which word is blocked in this thread, I'm sure the admins will remove it from the list.

https://www.gmt400.com/threads/censored-words-needing-unblocked.54292/

I actually posted, then looked up that word. Apparantly it has a completely different meaning coming from a sex act common in the UK now rather than how it was always used in the past relating to a vehicle. Refer to an engine as a dog and it means it is sluggish or weak. To dog on an engine or car meant to run the snot out of it all the time.

 

[JDGMC]

I will be checking my cams lift this weekend, I'm not a complete noob to this, I went to college for automotive technology, and worked at a dealership for 3 years, that was 9 years ago. now I'm a linemen working on the road, bought the modis is 2018 when I flagged down a random snapon dealer to warranty my ratchet. Honestly only used the scope, maybe one time for a wheel speed sensor, if I'm able to save and upload the graphs, I have no idea how that's done, will do some googling and maybe be able to get good data logs for you guys.
Btw I've ruled out misfire with my "cylinder deactivation load test"
I've sprayed carb cleaner all over to try and find a intake leak, found none
The data is shown 15 degrees advance at 44 mph yes
I've pulled plugs 3 weeks ago and they all looked the same, a bit black, they got cleaned and gapped b4 they went back in
I'd like to add, the more and more I think of this, I've feel like I've covered everything, except mechanical, the cam makes logical sense in my mind, and not a thing I've done or the previous owner has done has made a bit of difference. Maybe if I was older and had more experience with the sbc, diagnosing mechanical issues would be easier. I do appreciate everyone's input, and I thank you for the ideas, except the ls swop idea, that's not going to happen, lol

I will be checking my cams lift this weekend, I'm not a complete noob to this, I went to college for automotive technology, and worked at a dealership for 3 years, that was 9 years ago. now I'm a linemen working on the road, bought the modis is 2018 when I flagged down a random snapon dealer to warranty my ratchet. Honestly only used the scope, maybe one time for a wheel speed sensor, if I'm able to save and upload the graphs, I have no idea how that's done, will do some googling and maybe be able to get good data logs for you guys.
Btw I've ruled out misfire with my "cylinder deactivation load test"
I've sprayed carb cleaner all over to try and find a intake leak, found none
The data is shown 15 degrees advance at 44 mph yes
I've pulled plugs 3 weeks ago and they all looked the same, a bit black, they got cleaned and gapped b4 they went back in
I'd like to add, the more and more I think of this, I've feel like I've covered everything, except mechanical, the cam makes logical sense in my mind, and not a thing I've done or the previous owner has done has made a bit of difference. Maybe if I was older and had more experience with the sbc, diagnosing mechanical issues would be easier. I do appreciate everyone's input, and I thank you for the ideas, except the ls swop idea, that's not going to happen, lol

It’s all good. Do what ya gotta do to get that truck rolling down the road proper. For us arm chair analyst with or without experience, it’s often a puzzle with missing pieces. A chess game from a distance. What’s the next move? You can see the board and it’s piece's. When you find one that doesn’t fit, someone here will provide you with the next move if you need it.

 

[Hipster]

Carbon tracking in cap from improper phased distibutor? No missfires, no codes etc, Kinda f-ing around in circles at this point. 3 teeth off might put it firing the next cylinder but might not register as misfire. You've already indicted a possible issue with this.. Contrary to popular belief, FSM's are very specific in Dist. install, placement, which direction stuff is supposed to point/face, etc. without getting into the details of "why", Can the high-tech tools solve a basic assembly/install issue that you may be missing the point on.? There is no adjusting out of phase. No amount of turning dist. to dial in initial timing that corrects it. Whether you wrap your head around it and willing to correct/check it is a different story.

 

[L31MaxExpress]

Carbon tracking in cap from improper phased distibutor? No missfires, no codes etc, Kinda f-ing around in circles at this point. 3 teeth off might put it firing the next cylinder but might not register as misfire. You've already indicted a possible issue with this.. Contrary to popular belief, FSM's are very specific in Dist. install, placement, which direction stuff is supposed to point/face, etc. without getting into the details of "why", Can the high-tech tools solve a basic assembly/install issue that you may be missing the point on.? There is no adjusting out of phase. No amount of turning dist. to dial in initial timing that corrects it. Whether you wrap your head around it and willing to correct/check it is a different story.

The FSM is also very specific about wire routing as well to prevent inductive crossfiring.

 

[Hipster]

The FSM is also very specific about wire routing as well to prevent inductive crossfiring.

yeah, this stuff has to be right or you end up chasing your tail.

 

[Hipster]

Thank You!! @L31MaxExpress

 

[L31MaxExpress]

yeah, this stuff has to be right or you end up chasing your tail.

Very true. I cringe everytime I see someone grab a handful of plug wires and put a few zip ties on them to bundle them together to keep them off their manifolds or headers. Well intentioned but not realizing what they are doing can cause big issues.