William Kisselstein

94 G20, 4L60E trans, OBD-1.

The other night the battery leaned over and welded the positive terminal to a radiator support brace, killed the engine. Somehow had slid out of place.

I restarted it after getting the battery back where it belonged and it was okay except the ABS would pump just a bit each time I hit the brakes.

Let it sit and get cold and a few hours later I drive it and it slips real bad in D and OD. Acts like low fluid. I check the stick and it seems low, so I added some today. Test drive, it shifted up to OD and was fine - once. I stopped to turn to come back home and it immediately went back to 2nd, slipped or just lugging for the 2nd gear start. and now will not shift past 2nd. Seems to be in limp mode.

Reading up there's umpteen things that can cause this but I am getting other odd electrical things. I turned the fan up to see if it was warm, with headlights on, and the radio turned off, did this two or three times. ABS light came on. Turned lights off and did the fan deal and radio stayed on, then turned lights back on, radio stayed on.

Turned it off, started it, CEL comes on as it should. No codes set. Remember, OBD-1 so I can't put a scanner on here and look for problems.

Speedo needle does jump a bit, very sporadic but I've noticed it. Maybe needs a speed sensor?

My guess is when the battery shorted out it damaged something else, the only thing I can think of that might be related to ABS and the trans shifting is that sensor. This has 4WAL ABS but I believe the rear is one circuit, as there is only one rear hose.

My local pick yard now has two '93s so I can go pull some used parts to try to diagnose the problem.

William Kisselstein

been thinking on this. Drivability manual says a VSS low voltage issue can cause it to go to 2nd gear only limp mode. Code clears when ignition turned off, so maybe it doesn't set a CEL.

Low voltage could be a factor of ground issues. Perhaps one got hot or damaged when the battery shorted. Seems like the neg cable goes to the block. So it would have been arcing back through whatever other grounds connect to the engine/trans. 91 has one on the trans bellhousing bolt right side.

If it was loose or very weak maybe it would cause this, although why it would continue to run fine at the same time I've no idea, unless the TBI stuff doesn't rely on a ground through the engine to work.

William Kisselstein

Found ground strap on the back of the engine completely severed, looks like might have melted on the frame side.