95ES-300

Hi all. Just picked up a 93 LS400 that is near mint in and out, just wish I could say the same for the electrical issues I am having.

I acquired the car from a mechanic that does my state inspections. The owner was tired of dumping money into this car to try and get it running, so he told him to sell it. He put new cam sensors and a crank angle sensor in it. Here are the issues....

Car sat for 6 months, started right up and drove home. Got it home, shut it off, let it sit for about 4 hours, started it back up, and the problems began.

At first the engine and trac light would flash off and on together, and every time they would flash, the car would bog down, and the tach would jump all over the place.

It has since gotten worse, engine light and trac light are on almost all the time now. Every once in awhile, the car will clear up for a brief second, lights will go out, and then it bogs down again.

So basically, I have noticed, that anytime the engine and trac light come on, the car immediately runs like crap, exhaust smells rich and lean at the same time, and the manifolds will glow red as well.

If you cut the car off, and turn the ignition switch to run, the system will be reset and the engine light will be out, as soon as I start cranking the car, it comes back on. I cannot pull codes either, I put the jumper wire where I was supposed to, but nothing happens. I also notice that the transmission stays in 2nd or third gear when the engine light is on, unless I shift it into gear manually.

DO you guys have any ideas for me? I am leaning towards a defective ECU? What do you all think? Any and all help is very much appreciated, i am banging my head against the wall at this point.....

Oh, and I went out to start it about an hour ago, started right up, ran great, no engine light, and after about 10 seconds, it came back on and started running like crap again.....

RA40

iTrader: (6)

How many miles on this thing? Take the car to get plugged in for the codes. My guess: O2 sensors, cats may be toasted and coolant sensor. Pull some plugs and see how they look. Among other issues, the EGR pipe is probably plugged along with EGR valve.

The car probably runs better when it is cold/first thing in the morning right? As it warms up, it is unhappy? What is the indicated operating temp on the temp gauge?

I hope you got a -really- good deal on this.

95ES-300

Car has 192,000 miles on it. I drove the car 25 miles with no problems. No engine light, or trac light. Temp gauge was right below the middle mark. Car runs the same cold or hot. When the engine light goes out, car runs smooth as silk.

It is a random problem, reason why it was at the mechanic. They said, sometimes it will go on for a few weeks acting like this, and then they said that it would run fine for a month without a hint of a problem. It's a very random problem, I am just trying to find the little gremlin that's doing this. Thanks!

AHJ

Maybe a loose / cut wire in the trunk. Along the left hinge.

95ES-300

Checked the wiring harness in the trunk. Seems to be in good shape. Just about to the point of pulling the engine out and dropping in a 2JZ. lol

95ES-300

Just wanted to check back in with everybody. The problem was the ECU and AFM. Went to a junkyard got both units for under $100.00 and the car runs like a champ! I got the AFM just incase. Plugged the new ECU in, ran good, but had a light. Was able to read codes this time. Sent me a AFM code, replaced AFM, lights are gone. Car runs like new again. Thanks everyone! Paul

idrivemb97

im a super noob at this but seems like i have the same problems with my car to. and had a question of where is the ecu and AFM located at and is it an easy job to swap out. and also what is AFM.

JAndersson

AFM=Air flow meter, measure the amount of air sucked in to the engine. The ECU uses this (and other) information to decide how much fuel to put into the engine.

For information on how to change the AFM see attached pdf. The Engine Control Module (ECU/ECM) is mounted on the front floor board on the right side of the passenger compartment.

idrivemb97

cool thanks, i have so much of those AFM. my dad bought them from junk yards but i do not know which ones are good or bad cause my dad passed away and so now im left here to continue trying to fix his car and soon put it on the road. is there any way at looking at them AFM and seeing if they are good or not

JAndersson

Yes.

1. Disconnect the Volume Air Flow Meter connector.



2. Using an ohmmeter, measure the resistance between terminals THA and E2. 10 - 20 k ohms at -20°C (-4°F) 4 - 7 k ohms at 0°C (32°F) 2 - 3 k ohms at 20°C (68°F) 0.9 - 1.3 k ohms at 40°C (104°F) 0.4 - 0.7 k ohms at 60°C (140°F) If the resistance is not as specified, replace the Volume Air Flow Meter.

3. Reconnect the Volume Air Flow Meter connector.

idrivemb97

omg thank you so much!!!

williamb82

im betting its the ecu

idrivemb97

i think it is ecu as well. probably gonna try to take it out and send it out to get it rebuilt

lev00221

iTrader: (28)

95-ES300..........for a noob you sure did a great job diagnosing and fixing your car. Very impressed.

95ES-300

Just wanted to check back in on this topic again. My junkyard ECU took a dump on me. Car had different issues this time. Car would start and run good with no engine lights, but if you gave it more than a 1/4 throttle, it would die out.

So, I assumed this ECU was trashed as well so I sent my original ECU in for a rebuild.

So, I found a company on E-bay that rebuilds them. ATE in TN, website is here....

http://www.autoecu.com/

They rebuilt my ECU for $150.00 and some change. Took them two days to do it. Quick turnaround time. Would highly recommend them.

Got it back Friday of last week, and the car runs better than it ever did. The 90-94 ECU's are most prone to failure, seems they have leaky caps. If your LS400 falls into this year range, and is acting stupid like mine was, more than likely your ECU needs a rebuild....Just an FYI......

Oh, and they also rebuild the climate control LCD's and back-lighting problems in our clusters.