fsuguy

Maybe I'll try this solution on my master key -- it stopped working on my main trunk/glove compartment locking device some time back, although it works on everything else including ignition!! Thanks for letting us know! The surprising thing is, after looking thoroughly into the locking mechanism itself, there don't appear to be any electrical contacts (at least in the '92LS400) that the key blade itself must break - the lock has the usual spring loaded bits and pieces that need to be depressed just so to allow clearance(???)

succinct, indeed!! Thanks for letting us know what it was.

Oops, Never mind!

I just realized this was a suggestion of what to check instead of the actual problem!!

hi,

If you had any loose wiring leading to the fuel pump (it is the disk behind the rear seat!), then that is very likely the culprit if your FP is not whirring merrily away!!

You can do a simple test, using the ODBC connectors under the dash by the driver's kick panel or the one under the hood, to see if the FP is functioning.

hope this helps

SRK,

Can you post a quick method to test the pressure system? I have a suspicion my pressure is low, but not sure where to make the connection of the pressure gauge, etc.

Thks

UNDR8D,

Glad you got it resolved and posted your findings. Can you let us know who did the rebuild/repair of the ECU for you?

TIA

I agree with curiousB about fixing the thing.

However, these same farseeing engineers put the durn alternator in a most disagreeable spot if the PS springs a leak!! I would (I actually have used a metal shield) take the precaution of using a shield, but using spacers to keep the plastic away from the alternator body to allow air circulation.

pierce1,

Do you know if the ignition coil was defective before it was replaced? If one of your coils had gone bad, you would experience the symptoms you described - engine smoking from near the firewall, rough running, etc. Also, one side effect of the coil going bad is combustion of gases in the catalytic converter (and possible damage to the front Oxygen sensors and either the #25 or #26, or both codes being triggered).

If you check your Oxygen sensors first, you may be able to narrow down the problem. You probably already are aware that the O2 sensor input to the ECU regulates the fuel flow (together with input from several other sensors - MAF, Temperature, etc.)

Also, can you post whether anything unusual happened before all these things came up?

Hope this helps.

landar,

Thank you for the link and explanation... also, now that you mention it, the locking tabs on the TPS connector did break off and I have used electrical tape to hold it in place - that may be my problem!! I think I will get another new TPS, though, just to be certain. Any ideas on where I can get replacement harness connectors for the TPS?

curiousB, that is a good idea - to put in another ground - will do that and post any findings. I had gone through the trunk hinge harness and repaired a couple of broken wires that fixed a couple of other problems. It was a chore trying to find the broken wires inside the insulators, but I finally hit on the idea of using a simple continuity probe - the one with the sharp point on one end and an alligator clip on the other - worked like a charm! Did not find more than three broken wires (two yellow and one white).

landar (and curiousB, and Paul A),

Thanks for asking... in a previous posting, someone suggested that occasional hesitation may be due to a loose ground wire in the engine bay. I know from my own experience with a '86 Honda Prelude that this is very possible - a ground lead at the end of the fuel rail was loose on the Honda, which caused all sorts of diagnostic issues, since everything else worked perfectly. Finally, entire bolt came off and I could see sparks from the loose ground wire when it made contact with the fuel rail. Once I replaced the bolt, everything was smooth sailing again, but it was devil to diagnose until I knew where the problem lay.

With my '92 LS, I don't have any MIL/CEL lights, and do have what I can only describe as a sort of hesitation on occasion - sort of a dropping out of gear, or engine cut out, or fuel interruption (something like that, but not exactly sure, since RPMs don't drop to 0) - it is not a violent shudder - just as if the car is coasting to a stop, then it resumes as if nothing is wrong, unless I immediately step on the gas, then there is a slightly noticeable shock of engagement, as if something is forcing the engine or transmission to engage(?) This behavior only began after I had a Toyota dealership (Thomasville Toyouta in Georgia - the closest dealership with whom I have not had a lousy repair/maintenance experience) change my valve cover gaskets and fix a leak in the rear water bypass; they did a pretty bad job, since the insulation on the rear wiring harness under the heater control valve was not replaced, bolts were not replaced, and the hose to the water heater valve was tightened to the point where it was cut through and leaked water all over the harness (I had to get a new hose and clamps from Sewell and fixed it myself!)

For what it's worth, as part of my routine maintenance I have had the water pump, timing belt, rotors, caps, wires, and plugs changed. I also changed the fuel pump resistor, both coils (coils went bad at different times), TPS (it went bad as indicated by Cruise control failing to hold), water outlet and thermostat, serpentine belt; so none of these can be the culprit, at least I am hoping so. Also had the transmission rebuilt, and replaced solenoids #1 and #2 to fix shifting problems.

I have, after much searching, managed to find a M12 double banjo bolt and union (ntxtools.com) and plan on testing my fuel pressure and regulator to rule those out as a possible cause. If it is fuel related, I think I may also need to test my fuel pump relay. One additional helpful note - When the cruise control is engaged, the problem does not manifest itself(?) So if any of you think the ground may be a solution, or anything else, I would appreciate it very much.

...and 924S, just want to point out that often posters asking for help on this forum don't always explain the problem they are having, so asking why is intended to elicit more background information on the problem that usually helps those who may have very useful information relevant to the problem not provide incorrect solutions; at least that is my experience, so don't think of it as reluctance.

curiousB,

Thank you for posting this pic. I don't think it should be significantly different for the earlier models. You are wealth of information, and I, for one, and very, very glad you are a member of this forum and share your experience and knowledge with the rest of us!!

Does anyone have a clear idea of how many ground leads the '92 LS400 engine has, and where they all are? I would dearly like to know this information, if possible!

thx

Gsmith400,

No reverse is probably due to seals being shot in the tranny. My '92 had over time begun to lose reverse - it would take more and more time before it would go into reverse, but it would do so eventually. finally, when it began to lose front gears, I had the tranny rebuilt, and no more problems. The shop owner (very reputable) told me the seals were hardened and needed to be replaced. If you do have the tranny redone (most likely any replacement - read that used will also have the seals losing their flexibilty due the environment or abuse!), make sure to have the shifter solenoids changed as well, or you will have shifting problems - the A341E is apparently notorious for having these solenoids getting clogged up over time.

By the way is your starting problem resolved? From what you have described, you may simply have a low battery problem. These cars have a heavy load requirement, in my opinion. Try borrowing a new battery and see whether your problem resolves, and let us know.

ehabmarco,

Is your question about how to test the oxygen sensor? If so, I can post the diagnostic procedures from the '92 Repair Manual. Not sure whether the procedures are applicable across all 1st gen models, though. Let me know and I will post them.

I don't want to alarm you, but if this bunch is the same as ATE, there was some very negative feedback in Clublexus (pictures were provided) about ECU repair. Pictures showed very poor quality, and the person who posted said he never got the problem resolved. Hope your experience is better!

Good work ehabmarco. To quote a phrase, "If you eliminate the impossible..., whatever remains, however improbable, must be the truth!"

I agree with what curiousb points out. Also, I have experienced the exact problems you have described - twice, and both times it was the coil. Although, there is a good possibility of the ECUs going south - the capacitors used in these models appear to have limited survival based on some pictures of open ECU cases and circuit boards that I have seen. Consensus in some circles is that after about 15 to 18 years, the caps need replacing. In your case, if you have opened up the ECU case and have not noticed misshapen or leaking capacitors, then it is all the more reason to check your coils - first the driver side one, then the other. Also, the FP resistor may be on the way out. If you do check the resistor, do so when it is hot...and let us know what your final solution is!!

HTH

Hi,

I hope you did some research on the repairing entity in the US. If not, you could be seriously disappointed. Check out what some other folk have found, or at least, pay heed to who you need to avoid. If you cannot find anything on this forum, check out clublexus. It may save you some grief!!

kajman,

good for you! Thank you for posting your solution!!

I recently had occasion to replace my tach ('92 LS400 & sticky tach issue) and in the process moved my speedometer needle a bit. Now it is off by about 15mph. I have not fixed it yet since I will have to take out the instrument cluster (PITA!! because of the connector plugs, but will do so as soon as I get my replacment cluster indicator bulbs) but I think that it will be simple to fix - there appears to be a sort of stop inside the mechanism to prevent the needle going below zero mph; it looks like if you move the needle manually, it is possible to move back beyond this point resulting in the needle dropping to below the zero mark. I think the fix is to very gently lift the needle and turn it clockwise so that it is in front of the backstop and pointing at zero. The tach fix was similar.

HTH

Kajman,

Sorry about the post missing that attachment - I sketched a picture of the underside of the junction block #1, giving the layout of the relays, from the repair manual. However, I don't see any way to attach it to this post. There does not appear to be a simple way for me to attach the pic through this system(?)

If you drop the fuse plate, however, there are 6 relays, one of which is the "B" relay for your windows. There should be two screws holding the plate in position. The relay of interest is one of the nearest two relays near these two screws.

Seems like back in the heyday of the cold war we bought into some philosophy called mutually assured destruction - piled up enough nukes and more or less let the other side believe that if they so much as snorted, we would let loose with an overwhelming response, and then they would do the same, thus assuring total destruction on both sides. The end result was neither side used any nukes. The same result would have been achieved if neither side had nukes at all, but at a huge economic gain.

In the case of the DRL, my belief is that if I don't blind the other guy, he will be in a much better position to see me coming, and anyone else that he needs to be able to see so he does not swerve suddenly into my path. I can only speak from my own experience, but many times I have had to look away from oncoming traffic because of the glare - usually from the higher vehicles, and occasionally from those sporting the HIDs, etc.

...but, it would interesting to hear from the OP what his reasons are!

jtbel,

Thanks for the tip. Will try that and let all know what happens.

Kajman,

In the '92 LS400, the power window relay is beneath the driver side dash on the reverse side where the fuses are laid out (junction block #1A&B). You have to unscrew a couple of bolts/screws to drop the junction block, on the reverse side are about 5 relays. "B" is the window relay.

I would suggest you try a known good battery before you go through all the trouble of dropping all the panels, etc., to potentially save yourself some time.

I am attaching a sketch of the junction block (1992 LS400)with the placement of the relays - it's only a sketch since I have no way of copying the diagram. The layout is:`

A. Tail light control relay

B. Power Window

C. Defogger relay

D. Fog Light Relay

E. Turn Signal Relay

F. Integration Relay

Kajman,

Have you checked that your battery is putting out enough voltage? On my '92, when the battery was on its way out, quirky things began happening, and all cleared up with a new battery! The onset of the cold weather and concurrent electrical problems appear to be related in the case of your '92. Will try to locate the diagram and post a pic later tonight or tomorrow.

I do not like DRLs both on my own vehicles, and especially on those that are oncoming! SUVs, truck, etc., because of their height difference to lower riding cars, have their lights drill right through the rear windows, and when oncoming, straight into ones skull! Now when these are modified to HID, etc., one can imagine the discomfort. These things are a hazard, and a truly unbiased analysis of the benefits of having them installed on US vehicles, given the normal conditions (read that daytime lighting or natural illumination) on US roads, will not be able to justify the additional costs imposed on the user. In some European and northern scandinavian countries where normal conditions are different, I suppose a case for their use could be made.

Besides, having your lights on all the time places an additinal drain on the alternator, which places an additional drain on the engine. So, from a purely efficiency perspective, it makes sense to disable them.

'Nuff said.