Engine cutting off, hard cranking, bouncy volt meter

[94 Silverado]

I have these problems which I feel are all related but I'm not sure what to do about them. My truck always acts like it's lugging when I crank it. Like it doesn't get enough juice. It has a fairly new battery, alternator, and starter, and I've had the charging system tested. It seems to be fine. Then sometimes the truck will just cut off randomly and won't fire back up for a few minutes. I know I have spark and fuel because I've tested them when it's doing this. The volt meter also bouces when the blinker is on and goes really low with the A/C on high. I feel like it's a bad ground but I'm not sure which one. I relocated the ground on the thermostat housing to another bolt but I think the actual wires may be bad. What's the best way to go about replacing that connector and finding a better grounding spot to rule that one out?

 

[LPG PWRD]

You can never have too many grounds, add some more beefy grounds and go from there.

 

[daddy_dandy]

You have 3 main grounds.

They run:
Battery to the front of the block.
Battery to pass fender.
Rear of passenger head to frame. (near starter on frame)

There's also a ground strap on the hood.

Check to make sure all those are in good condition. Many many many people upgrade these grounds with a larger gauge wire. PERSONALLY I prefer to purchase a beefier ground strap. They are readily available at Summit and probably at your local speed shop.

Regarding the harness ground you mentioned, as long as it is connected to a solid grounding point, you should be fine. Where exactly did you relocate it too?

I've had the same lugging problem when starting. It began as a loose connection to the solenoid on the starter which eventually killed the solenoid. I know it's a major pain in the ass (I HATE starters) but pull that starter down and make sure everything is well connected and in good shape.

 

[94 Silverado]

The thermostat housing ground was relocated to a bolt on the A/C compressor bracket I believe. The shop did it, not me. So I thought they knew what they were doing. But it wasn't long after this that it started acting up. I took it back once but of course they acted like it wasn't their fault. I'll look into getting a grounding strap and checking all my grounds. I think it also could be the actual O connector on that ground because it looks kind of greyish and the wire sheilding is torn in a few spots.

 

[daddy_dandy]

Fix the damaged wire and relocate it back to the waterneck.

Here's a quote from here: http://www.pacificp.com/forum/viewtopic.php?p=6949

The big problem on the 98 was oxidation between the alt. bracket & the motor, it was just enough to not ground the alt properly & reduce its effectiveness. Really hard to find, Remove / Replace alt & things were good for a couple of days, then the dimming of lights would start. I finally chased all the grounds as PSwired stated & once I attached ground cable from the alt mtg bolt directly to the ground lug on the block everything was fine. I can run the high beams, Driving lights, AC, dual electric cooling fans, 2 amps & all the int, lights & no dimming at all on the 205 amp alt. Finally found the corrosion when I rebuilt the motor, the back side of the alt bracket was all ate up with oxidation everywhere it touched the eng. block. I also up the wire size on the line coming from the alt, to the battery, just be sure to fuse it also.

Boosted

Speeder from that forum also describes (in a different thread) how corrosion can buildup between the lug and nut for the + connection to the alternator. May be worth taking it off and checking it out. Also, if you're using a stock battery, there is a lead washer which collapses when you tighten it. It's a 1 use only and if you've ever over tightened the connection, it could now be slightly loose which could also cause your problem.

 

[daddy_dandy]

Most people also add a ground from the alternator bracket to the frame. I suppose this is mostly due to the corrosion Boosted describes.