93 LS idle/clutch/electrical

ASSISTANCE Electrical & Entertainment Systems
1

Hi.
The car is a 1993 LS. I think my problems are related somehow but I am stumped.
Recently rebuilt the engine with OEM parts.

The problem(s):
When I am driving the car, all accessories off, get up to 5k rpms and push in the clutch (gear doesn’t matter) the car dies if I hold the clutch in and let the rpms fall. The needle drops like a rock. No check engine light. Just the oil light and battery light. It only dies with the accessories off at high rpm and shifting. At low rpm shifts, it works fine.

If I drive with the accessories and lights on, I can push in the clutch (any rpm and any gear) the car will either:

  1. Drop but idle from 500 prm to 1100 rpm back to 500 rpm and it just bounces.
  2. Or, it dies the same as the high rpm and no accessories on.

Base idle is set at 1100 rpms. When I push in the clutch (warmed up in the driveway) it drops to 500 rpms with the accessories off. Accessories on and doing this the idle drops to 500 and does the bouncing thing or dies. It feels like the accessories take the power from the engine… It idles fine when accessories are on and clutch is out. Lights never dim or flicker…

Took the battery and alternator to auto parts store and both tested great (alternator put out various amps but constant voltage). Replaced grounds. Double checked all wiring harnesses and hoses. New ignitor, coil, cap, rotor, plugs, wires, etc. Even did the IACV and FTIV cleanings. Idled smoother but no change in overall problem.
Is there something simple I am missing? What controls my idle when I push in the clutch?
If I had a camcorder I would just make a video and I bet one of you would know right away… I am planning on getting a new alternator in 2 weeks. That is the only thing that I have never replaced but is it normal for an alternator to put out a good voltage but fluctuating amperage? Amperage was all over the board with 10 being low and 35 for a high. No change with accessories on…
Any suggestions are appreciated.

2

I would say the alt. or voltage regulator or maybe brushes in alt. are bad, amperage should not be all over the place it should be steady and increase with RPM same with voltage, should be about 13.5V at idle and go no higher then 14.4V.
Also alt. should be checked under load in the car with motor running.

I am not sure why stepping on the clutch is having an effect, unless you have cruse control there is only one electrical switch, CIS, [clutch interlock switch] on the clutch lever, and all it is doing is supplying a ground to the starter relays coil, and is no load unless cranking to start.

You have checked to make sure there are no wires being pinched or pulled when you step on the clutch, right?:hmm:94

3

fixed

I replaced the alternator. Nothing changed. I rewired the ignition, the grounds, all wires involved in the charging system loop. Nothing changed.

I broke down and paid the dealership (Insert swear word here… I hate letting someone touch my car…). It turns out it is the thrust washers have failed and need to be replaced or the crankshaft has too much endplay in general and needs to be replaced. An issue which has haunted me with this car… I went from stage 2 clutch to a stage 1 and still I am getting failures…

Thanks for the info though, I was hitting wires with my foot due to a relocated ignition system (which fixed a different problem^^)