vltjr

Recently my '91 LS400 has been experiencing a tach problem that is slightly different than those that I've read about in these forums. On start-up the needle jumps to 500rpm and just stays there regardless of what the actual engine speed is. Before this problem occurred, I was having some intermittent problems with the tach just sitting at zero for a short time after starting (twenty seconds or less). Any ideas? Thanks.

I replaced my wife's '94 LS400 water pump this weekend with all but one thing going smoothly. When putting the right side distibutor cap cover back on, I apparently left one of the spark plug wires loose or misrouted. When I started the car I heard a flapping sound coming from under the cover, and later discovered that I cleanly sheared a plug wire. Since my ignition wire set is practically new (and I haven't found anyone to sell me a single wire), my question is: can I repair this wire by splicing it back together, or buy some generic ignition wire and reuse my connectors to create a replacement? Does anyone have any experience with this? I've seen generic ignition wire kits that require cutting to required length and then crimping on connectors, but I've never done it myself. Any help would be greatly appreciated by me and my wife. Thanks.

Last night my daughter's '90 LS400 stalled out, preceded by usual loss of power symptoms (headlights and dash lights dimming, gauges zeroing out). When she tried to restart it, it seemed that she had a dead battery. I went out this morning prepared to change out the battery and get it moved to the house, and much to my surprise it started right up. I should mention here that the reason I was prepared to switch batteries is that about a month ago I replaced the alternator with a Denso rebuild, and my suspicion was that I perhaps got a lemon. When I got the car home I checked the battery, and the alternator output, and everything seems okay. My daughter is understandably afraid to drive the car until I diagnose and correct whatever caused this malfunction, but I'm at a loss as to how to proceed. I've been driving the car all day hoping that the problem would recur, but it has been starting and driving perfectly. Anyone have any ideas? Thanks.

Sorry I haven't posted since I decided to order a rebuilt Denso from an Ebay rebuilder (not surprisingly located in Southern Cal.). I ordered it on Tuesday and it arrived yesterday. I installed it today and so far, so good. It cost me $110 total, and the seller assures that he will warrant it for 12 months. I too was a bit leary of placing an order from a shop so distant from me, but after comparing prices both for an already rebuilt one, or having mine rebuilt, I decided to take the chance. I'll post further regarding my experience (positive or negative) after putting some mileage on it and retesting. Thanks for everyone's input.

I checked out Ebay after reading mejojo's post and found some rebuilt Denso alternators in the $80-$90 range and was wondering if anyone here has any experience with any of the sellers.

I always like having original parts rebuilt when possible. Does anyone have an idea what it costs to have this done? Jerry? The best price I've found for a Denso rebuild (from someone I trust) is $186+$40 core charge with free shipping (except for the core return, which I haven't yet determined). If a local rebuild is competitive, I'd prefer to go that route. Thanks.

Car was cold when I tested it. The RPMs ranged from 800-1500 and the reading stayed constant at 11.9v.

OK--with a freshly charged battery (which read 12.75v) I started the car and measured the voltage at the battery terminals at various RPMs. My meter showed 11.9v pretty much constantly. Unless I hear otherwise, I'm assuming it's time to price an alternator. Can anyone steer me to a reasonably priced (but also reliable) rebuild? I'm also in need of instruction on how to do the removal/replacement. Last year I had to remove and repair the PS pump and high-pressure hose, and I recall it being quite a chore getting a wrench into that area. Any hints? Thanks.

At least I do know about the danger of running the thing without the battery connected. Thanks for the info, and I'll keep you posted as to the results.

I think I'm going to go with measuring the alternator output in-vehicle with a meter, while running the thing at your suggested 1500 RPMs. I'll post the results. By the way, while the voltage regulator is located in the body of the alternator, it is separately removable and replaceable. That's the reason for my persistence in asking about a testing procedure for that component. Am I correct in assuming that if there is some measurable output from the alternator, and that output is increased/decreased when the RPMs are increased/decresed that the voltage regulator is faulty? Thanks again for all your help (and patience) Jerry.

Well, I had the battery load tested today and it seems it checks out OK. I'm not sure how to proceed from here, such as how to test the alternator or voltage regulator. Any suggestions (preferably specific instructions/directions) will be greatly appreciated. ThaNKS.

Thanks Jerry. I'll have to wait untill the morning to have the battery load tested. In the mean time, is there any way to determine whether the alternator output is correct? Thanks again.

My '91 LS400 died this morning while my daughter was driving to school. The first symptoms were that the dash lights flickered and then got dim, then the radio cut out, and lastly the car died. After I got the car home I charged the battery, and the car started, and everything worked normally. My question is: how do I determine where the problem is? How do I test the voltage regulator separately from the alternator? Any help will be greatly appreciately.

LScott400 - Thanks for the link--attempted to reset repeatedly with no success. Finally I noticed the code was not 41, but 31, which seems to indicate a problem with the center air bag sensor. I don't even know where this sensor is, let alone how to pinpoint the exact problem. Anybody have any suggestions? Thanks.

No, that's not exactly the procedure that I followed. The sequence is slightly different. I believe what I got was scanned from a 1992 manual. I'll try yours this afternoon after work. Thanks, and I'll post my results this evening.

I performed some work which required disconnecting the battery for more than a few hours then discovered that my air bag warning light would not go out after starting and driving the car. After searching the forums I found instructions for resetting a '92 LS, and followed them, without good results. I read a few posts where the posters warned that the procedure for one year model may not be applicable to any others. My LS is a '91. Anyone able to help? Thanks.

Thanks to some muscle (to move the fusible link block away from the main fuse block), and my wife's little hands (to thread the little hex bolts), I was able to change the 120A fuse. Now all I have to do is reset the "Air Bag" warning light. If I can help someone else with this problem, send me a message.

What I still need to learn is how to remove the small block holding the fusible links/cartridge fuses in order to get to the second bolt anchoring the 120A fuse. Searched the forum and couldn't find anything that specific. Thanks.

As will become very apparent, I'm new both to this forum and to my 1991 LS400. To make the description of my problem short, I'll just say that while performing an unrelated job, I blew out the 120A cartridge fuse, rendering my alternator useless. After searching through the forums, I am unable to locate any specific information on removal and replacement of cartridge fuses. Being new to these particular fuses, I'm looking for VERY specific instructions and any other useful advice. Thanks.