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All my crazy Lexus issues SOLVED!! (ECU-leaking capacitor)

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Old 06-14-14, 05:29 AM   #841
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I'm looking at a LS 400 for sale and the owner tells me that the instrument cluster's engine temperature gauge reads high (& has read high for over a year) but that his mechanic tells him that the engine isn't really overheating so he just ignored it.

There is no check engine light on.

Do you guys think that this is a case of malfunctioning capacitors in the ECU? Or something else.

I don't want to buy a car with potential expensive repairs. But I would plan on doing the ECU anyway on any LS 400 i bought.
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Old 06-14-14, 07:56 AM   #842
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Originally Posted by Salted View Post
Do you guys think that this is a case of malfunctioning capacitors in the ECU? Or something else.
I don't think so.
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Old 06-14-14, 09:08 AM   #843
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Quote:
Originally Posted by Salted View Post
I'm looking at a LS 400 for sale and the owner tells me that the instrument cluster's engine temperature gauge reads high (& has read high for over a year) but that his mechanic tells him that the engine isn't really overheating so he just ignored it.

There is no check engine light on.

Do you guys think that this is a case of malfunctioning capacitors in the ECU? Or something else.

I don't want to buy a car with potential expensive repairs. But I would plan on doing the ECU anyway on any LS 400 i bought.
Another member in a thread had a problem of it reading too low all the time and it ended up being his ECT ( Engine Coolant Temperature ) sensor.
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Old 06-14-14, 12:54 PM   #844
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Quote:
Originally Posted by Salted View Post
I'm looking at a LS 400 for sale and the owner tells me that the instrument cluster's engine temperature gauge reads high (& has read high for over a year) but that his mechanic tells him that the engine isn't really overheating so he just ignored it.

There is no check engine light on.

Do you guys think that this is a case of malfunctioning capacitors in the ECU? Or something else.

I don't want to buy a car with potential expensive repairs. But I would plan on doing the ECU anyway on any LS 400 i bought.
The probability of the ECU caps are a typical repair item as these cars age. That is a consideration to have in mind with the car. It is a low cost fix. The ECT is another and that couples with poor MPG as a symptom but that also goes with vacuum leaks.

Basically, any of these LS's are going to need a going through and a handful of parts to insure good running. Typical parts like: O2 sensors, tune up with caps, rotors, wires, plugs and the prior mentioned. Engine aside, the usual suspension parts.
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Old 06-17-14, 06:00 PM   #845
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Yes in these engines there are TWO Coolant temp sensors in the front of the engine; in the front water bridge between the heads. One is for the Gauge and the other is to read temp. for ECU and the injection system and the one for your injection is very touchy and must be really accurate because if it reads low the computer thinks the engine is cold and constantly gives rich mixture killing mileage. I changed mine in my '95 LS400 and along with the new caps in the ECU it now runs like a new car it starts great and slowly reduces the idle speed as it warms up. These little engines are a joy to behold when you give them proper information. And do not scrimp on the sensors either get Good sensors like came in there not fly by night auto like "PepBoys" or Auto zone You will waste your time and really waste your efforts because "you get what you pay for" these parts are not expensive; Get the real Japanese good parts you wont be sorry.
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Old 06-17-14, 06:37 PM   #846
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I took pics of a car that came into work that was a 91..with 411,000 miles on it,he has owned it since around 100,000 miles..never done the ecu,has only changed the tranny fluid twice,oil leaking everywhere..did the timing belt once at 250,000..coolant leaking..inside was beat up..exterior was trashed...guess what,still starts and runs with no check engine light
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Old 06-18-14, 11:58 AM   #847
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^ many stories out here like that. i see so many still on the road and i'm sure more of them have no ECU rework. this is cali though, where it's less susceptible, and junkyards flow with parts galore.
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Old 06-18-14, 05:09 PM   #848
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So I've been having a lot of trouble with the car lately. Trying everything I could think of to fix the issues I'm having. I rebuilt the ECU last year per this thread. All new caps and from digikey. I did the ripple test today just to verify the ECU. The ripple test said no more than 40mv. Mine is reading a lot higher than that. I'm testing the right ports and also using a 47uf capacitor.

I pulled the ECU and checked it. Everything looks OK but the readings were crazy high.

Issues I'm having are, a severe bogging down and no power. Idle is high also. Unplug the AFM and it runs halfway decent. If I have to replace it, I'm thinking about going with megasquirt and not even dealing with it at all. Here's a video.

https://www.youtube.com/watch?v=s2Dj...ature=youtu.be
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Old 06-18-14, 09:01 PM   #849
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I am new to this forum and have been a Lexus owner only for a few months.

I told myself that I was no longer going to purchase cheep fixer uppers and finally go with something NICE for a change.
Along came this gorgeous 1997 Lexus LS400 with only 127k miles on it. the Interior and exterior were in perfect shape. This car ran like a dream. I was so overwhelmed that I test drove it 3 times then got a loan for it.

The day I drove my new (to me) Lexus off the lot people right and left of me were goggling at me from blocks away. Yah it looks that nice. I made it 3 blocks when I noticed the gas light came on.
On any of my previous cars I never let the fuel get that low. I had thought the fuel gauge was faulty. Ez fix for me. I stopped and put premium shell gas in it and topped the tank off. The guage was right on. The dealership had drained all the extra fuel from the car. It had 3/4 a tank just 1 day prior to me getting it.

I made it home that day with no problems. the next day I started it up and, spitting and sputtering, bucking and jerking. I figured damn I must have sucked junk from the fuel tank. No biggie. I changed the filter, took her to the shop and had the top end flushed. The check engine light came on so I had it scanned. Random misfire in cylinders 2,3,5 and 6.

This was when all Heck broke loose. After the top end flush I checked the plugs. There was water in EVERY spark plug sleeve up to the top of the cover.The dealership told me they detailed the car and steamed the engine bay for me. they obviously Pressure Washed the Engine Bay! After I used a shop vac to get all the water out I was able to go to work with a Complete tune up. Well complete in my book.

There were Copper Plugs in MY car!! I was hot. If that was the case I changed everything. Ordered the good NGK's at 12 bucks a pop, the Denso caps,rotors and wire sets. both Toyota coils. I was NOT messing around with this. I went online and ordered the transmission fluid and filter from a Lexus dealer. ( it was a little brown)

Guess what happened next. From all the raw fuel that got dumped down my exhaust (from the misfiring), when I finally fired it up with all my new components I blew the cones out of both cats. and the problems with misfiring were never fixed. I parked the car. New cats, got all the remains out from the y pipe, buttoned her back up. Same problem with the misfiring. Also it has no power going up a hill, it shifts late from 1st to 2nd, and slips from 2nd to 3rd. If I try start it and it cranks for more than 10 seconds it will die every time. Then it will fire right up and have TONS of power for about 2 min. Also if it is running good and I turn on the AC, well lets just say a turtle can get from 0-60 faster than I can.

Reading this forums I have hope, and have ordered all the specified Caps from post#1 along with the required tools. I paid 4,600 out the door for this Beautiful car, over 2,000 in parts and labor later. Yah lets just say I was a little upset.
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Old 06-18-14, 09:46 PM   #850
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I would have just took this car back under the lemon law and been done with it.
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Old 06-18-14, 10:02 PM   #851
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usoff89 - It should be a 0.47 uF cap, not 47 uF. Perhaps just a typo, but it would increase the measured ripple by passing more low frequency.
sha4000 - AFAIK, lemon laws do not apply to used cars, but each state law may vary.
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Old 06-19-14, 05:52 AM   #852
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gene, that was just a typo. it was a .47uf. I'll double check it too when I get home just to make sure.
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Old 06-19-14, 12:06 PM   #853
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gene, that was just a typo. it was a .47uf. I'll double check it too when I get home just to make sure.
If you bought it via the links on the first page, I'm sure you probably got it right.
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Old 06-19-14, 01:20 PM   #854
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welllll..looks like ive had all of these issues at one point or another now...dammit ive been in denial haha
someone sell me a repaired one for the low ;D
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Old 06-19-14, 06:21 PM   #855
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So...... I double checked my capacitor when I got home. Apperantly I bought a .047uf..... FML, I'll have to get another one and recheck it again.
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Old 06-19-14, 06:21 PM
 
 
 
 
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