Full parts cannon and still runs rough

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Schurkey

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Getting current codes can be done with a paper clip. If you're REALLY clever, you can find out if the engine is running in open or closed loop, and whether it's running rich or lean. None of that is enormously helpful, or this would be fixed already.

Verifying sensors and computer outputs, getting pending codes, and bi-directional control are beyond what a paper clip can do. This vehicle is beyond repair with a paper clip. You need a scan tool, or an oversized amount of both perseverance, and luck.
 

TylerZ281500

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Yea I thought the starter took a **** so I replaced it and same thing then thought it might need shims but nope. When I noticed it was an injector is when I turned the key the last time and heard the injector spray fuel on the prime. That’s when I looked and the throttle body was full of gas. Pulled the plugs spun it over a bunch. Replaced the injectors and it ran great for the first few days then all of these problems started happening and over time they’ve gotten worse I’ve replaced half of the parts because they were bad.

The ground straps are fairly corroded, they have that green tint all the way up them so I’m going to replaced them for sure.

So how long should it take for the ecu to start learning a new fuel table? A few miles or days?

ecu doesnt learn anything its essentially binary and you input what you want it to acheive and it tries or it throws codes
Scan tool would be great, it an OBD1 and the paperclip and count the blinks is the only way I know how to read codes.
Even using the paper clip trick it still might shine some light on the issue.

i never had luck with scan tools on tbis you really need tunerpro and moates has gone under now soooooo not sure at all
 

Schurkey

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ecu doesnt learn anything its essentially binary and you input what you want it to acheive and it tries or it throws codes
Fuel trims aren't learned?

i never had luck with scan tools on tbis
Name the scan tools you didn't have "luck" with.

I do just fine with a Snap-On Solus Pro, and before that, an MTG2500.
 

RichLo

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ecu doesnt learn anything its essentially binary and you input what you want it to acheive and it tries or it throws codes

I can take this two ways, one your going so deep into computing that your right Computers cant 'Learn' like humans can. Or two you have a fundamental misunderstanding of ECUs.

Long Term Fuel Trim, Short Term Fuel Trim, and Knock retard are all examples of the computer learning and adjusting for optimal performance. It only throws codes when the engine is doing something that will make it fail an emissions test which is usually something that will also make it run badly.
 

PlayingWithTBI

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Long Term Fuel Trim, Short Term Fuel Trim, and Knock retard are all examples of the computer learning and adjusting for optimal performance.
Exactly, the "binary" side is part of the hardware and can't be modified. The binary side of the Scalars, Switches, and Tables can be modified by "Burning" or "Flashing". Other things like STFT and LTFT, KCs, etc are stored/modified in volatile memory which will be lost when power is removed from the ECM/PCM. Kinda like ROM and RAM in your PC. At least, this is how I understand it :33:
 

df2x4

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moates has gone under now soooooo

BoostedNW.com has Moates alternatives and replacement parts. I believe they were messaging the admins about potentially becoming a supported vendor here but I haven't heard anything in a while.

 

tsr2185

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did this problem exist prior to the new engine? what is the new engine, factory replacement kind of deal?

have you checked to ensure the grounds at the waterneck and back of the head are good, no breaks. the one on the back of the head will do some wierd stuff as your facing if that breaks. took me a long time to figure that one out on my old 93.

ground straps too are important, grab some off amazon for cheap and traingulate, frame, engine and body if youre uncertain
What kind of issues have you seen with a bad head ground cable on a TBI?

Just curious for future reference, mine isnt in the best shape but its still connected.
 

Blp378

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I know it’s getting old now but I thought I’d give you guys and update. Replaced wires and knock sensor it definitely helped it seems to be running better now off idle. However, at an idle like at red light it has a very low idle still and surges like it has a decent sized cam. Pretty much anything above idle it smoothed out instantly. Still smells to be running rich tho not nearly as bad.


I have noticed another problem. My Speedo seems to have a constant/consistent twitch to it. I have noticed that is a ground wire is removed from the battery it will do something similar. So could I harm anything by doubling my grounds. Like adding extras to the current locations or adding more locations?
 

drdoom1337

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I know it’s getting old now but I thought I’d give you guys and update. Replaced wires and knock sensor it definitely helped it seems to be running better now off idle. However, at an idle like at red light it has a very low idle still and surges like it has a decent sized cam. Pretty much anything above idle it smoothed out instantly. Still smells to be running rich tho not nearly as bad.


I have noticed another problem. My Speedo seems to have a constant/consistent twitch to it. I have noticed that is a ground wire is removed from the battery it will do something similar. So could I harm anything by doubling my grounds. Like adding extras to the current locations or adding more locations?

I would implore you to check the timing on the truck. On a TBI motor you HAVE to disconnect the wiring behind the glove box in order for the timing to stick. Then you can plug the wire back in. I believe it's brown. On the squarebody trucks it was on the firewall. I'm 100% certain this is the issue.
 
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