E4OD issue

[BW42]

Hokay -- here goes. early '93 350 7.3 IDI Diesel, no turbo, 123K on truck. Rebuilt E4OD, shift kit installed, new neutral safety switch with corresponding new harness, new solenoid pack, upgraded pack connector. TPS adjusted. New tranny runs and shifts better than the last 20 years that I have driven the truck. Except -- when humidity is high, or raining, computer puts tranny in limp mode. Checked dome light, fuse, speed sensor, all lights, everything working except dial light in radio. Don't use radio anyway, as I lose radio settings everytime I take ground cables off the batteries to reset computer. Tranny also goes into L mode when driving under high voltage wires, or when cop triggers radio in my vicinity. Checked and cleaned two ground points under hood, including motor-to-chassis ground on firewall. Any ideas? At this point I might even consider voodoo -- BW

 

[Noiseydiesel]

Two ground points?
Uh, you might desire to research it a bit more.
One on each inner fender kick panel, one at the tail gate on the left side. One on the firewall at the right hinge, One at the . . . left battery . . . Then there is the trans unit itself plus the TCM ground(S) and I know I am missing at least another one. Not to mention the ground strap behind the right cylinder head.
Currently my drive train is out so I might be missing one in my list. . . .

 

[BW42]

Hi -- thanks for the info -- been under the weather for a week, got tested Friday with negative results for Covid, so I haven't been able to run those new points down. I did find out the the TCM has two special, isolated ground points on the driver's side that are necessary to eleminate electronic interference. I've also got three new ground straps to install -- one motor-to-chassis, one chassis to frame, and one frame to rear axle. Got to find my round-to-its first - again, thanks for the info -- BW

 

[joshtee]

Have you checked you tachometer sensor?

 

[BW42]

About the tack sensor -- Haven't checked it yet -- years ago, all dash gauges went crazy -- replaced the VSS and fixed that. Since then, everything in the dash has been very steady. I'll check the sensor when I get back to work on the problem -- Thanks -- BW