1994 suburban help "chugging"

[klowninc89]

hey guys having issues here. my buddy welded up a part of my frame because it was pretty bad. we had the neg cable off and not touching anything. well long story short after all welding was done when he connected the neg back on it had a good size spark? thought neg did not do that? it took few turns but started "thought was loss of fuel?" but had rough idle in rev. then when to go down the drive it stall 3 time no engine light? wee then put little sea foam in did little better. we then took around the block few times it was then "drivable" i drove home did well at speed no issues stopped at sheetz for sub lol started right back up. but had little miss again. I'm confused? the truck is a 1994 k1500 5.7L 350 4L60e. i gave a tune up this am no help idk what the issue is? please help?

 

[klowninc89]

it also get worse with accessories on like lights, fans, defrost....it will just miss and put it in gear it dies...wtf?

 

[Fordum]

Well, any electrical load on an alternator is also a mechanical load on the engine. But, there is another possibility.
If the alt is not putting out, then you voltage might be going so low the electronics is not running right.

Hooking up any battery cable is liable to produce a spark. Jumper cables usually say to hook up the negative last, not because it will not produce a spark, but because it can be hooked up to ground away from the battery and its explosive gas.

94 just might be new enough to have the adaptive computer system. On the newer systems, the computer learns how to run the engine as it drives.

When you disconnect the battery, it forgets all that it learned, and has to relearn it.

But, sometimes some data remains, and can be corrupted.

You might try disconnecting the positive cable and hooking it to ground for a few minutes to drain any capacitors and erasing all memories.

Then, hook it back up and crank the engine.

There is a procedure for letting the computer relearn faster, but its been a while since I saw a copy of it.

If I remember right, you crank the engine without touching the gas pedal. Just let it idle.
Don't try to help it if it stalls.
Just recrank it without the gas until it keeps running.

Let it idle a few minutes, then, if its an auto, put your foot on the brake and drop it in gear, again without giving it gas.

That is about all I remember. If I can find a copy of the official procedure, I'll post it.

 

[klowninc89]

thanks i will try

 

[klowninc89]

ok that did not work....ahh wtf im so pissed....any other ideas?

 

[Blue85]

it also get worse with accessories on like lights, fans, defrost....it will just miss and put it in gear it dies...wtf?

Check all the ground straps - one may have been destroyed. May I ask where you were welding and what the ground was clamped to? What runs along the frame in that vicinity? Maybe something was in the way, disconnected and not put back correctly?

 

[klowninc89]

nothing on that side was welding up crack/hole boxed the frame....i looked nothing there i can see he grounded right to the plate he was welding. i look at grounds i did not see anything.....that i could see

 

[klowninc89]

changed fuel filter and coil...runs like a brand new truck