[PsychoSupra]

Hey everyone! It's been a little while since I've had to make another post, but after searching through the forum the last few weeks and trying and testing a few different things--I'm completely stumped.
When the problem first started I was able to drive about 15-20 minutes before the car would start bucking during acceleration and the EFI relay and IGN Main relay in the fusebox under the hood would start heating up pretty bad. If I continued driving the bucking problem would get worse, happening even when just cruising at a constant speed, until finally the relays would be too hot and the engine would shut off--unable to turn over again until it sat for about 20-30 mins.
I started searching for similar problems and solutions on the forum. Since then I tested it with another ECU, problem persisted. I changed out the igniter and coil, problem persisted. I switched in a different set of relays, the problem didn't occur as quickly at first, but it has started happening again just the same. I checked the under side of the fusebox#3 and all of the connectors were sturdy with no problems. The fuel pump is fairly new and the pre-filter is brand new. For a moment I thought it might be a wire from the fuel pump shorting out, because when I turned my key to the start position without turning the engine over and short the fuel pump check connector for a few minutes the relays started to heat up pretty bad. However, I stopped shorting the check connector and left the key in the Start position for a while longer and they got even hotter.
Wouldn't this mean there's got to be a short or something between the ignition, starter, and those relays? If it was the voltage regulator on the alternator wouldn't other electrical systems/components be affected? Any input or suggestions/ advice are greatly appreciated!

 

[AJ]

Have you checked the charging voltage?? At each of those ie starter, alternator, ignition etc...

My gut reaction is overcharging condition...

Then improper grounds....

 

[PsychoSupra]

Is the charging voltage just the voltage at each component while the engine is running? and the overcharging condition is caused by the voltage regulator malfunctioning? Is there anything specific that can cause that to happen? Besides age, of course.. I did the "Big 3" wiring upgrade at the beginning of this year, could this have contributed to the problem?

Most of the ground points have been disconnected, cleaned, and reconnected. However, some of the ground wires might possibly have corrosion under the insulation, but everything I've tested so far has grounded out just fine..

 

[dannoxyz]

Ground problems would result in lack-of-flow issues. What you've got with overheating is opposite, too much flow.

Very simple test. Go straight to source.

Measure actual current flow out of relay that gets hot. How many amps?

Could just be short on circuit that relay feeds.

 

[RedP85]

What is the voltage at battery with engine held at 2-3K rpm?

 

[Flyin' Hawaiian]

Could just be short on circuit that relay feeds.

Or added items on that relay that's overpowering that circuit. After checking battery and alternator voltage, start tracing things that relay powers. It may be one of the things hooked to it that's got a bad ground and is now pulling a much higher current from the relay's output voltage.