Help, IAC Valve problem
#16
Intermediate
Thread Starter
I am pro at soldering, I have also ordered capacitors from digi-key, which I will be installing in the ecu myself. I have read a few more threads and came to the conclusion. Either it's a bad ignition coil or bad ECU or clogged Cat. Tomorrow in the morning I am going to change ignition coils. If the problem goes away, I will return CATS, if the problem persist then I will change CATS and swapped the ECU with the one that I ordered from eBay and rebuilt it's original ECU myself once I receive the capacitors.
#17
Intermediate
Thread Starter
Problem with buying an ECU...
1. The "New" ECU you just ordered is likely still using the stock caps, they will likely be bad as well, this is a common problem with the capacitors being over 25 years old, you will need a rebuild to fix it.
2. That "new" ECU is not tied to your vehicle and will cause issues with your security system and will require reprogramming.
Just use the one in your car, get it sent out for professional overhaul by someone that knows what they are doing, and you get to disregard both 1 & 2.
I currently have my ECU out for the same exact issue you are having... not joking, this is why I have been commenting on your thread, I am dealing with it right now. My ECU is currently on it's way to LSCowboy for overhaul with brand new Nichicon, high ripple, low ESR caps. The cost for me was $248 which includes RETURN shipping, you must pay for outgoing.
1. The "New" ECU you just ordered is likely still using the stock caps, they will likely be bad as well, this is a common problem with the capacitors being over 25 years old, you will need a rebuild to fix it.
2. That "new" ECU is not tied to your vehicle and will cause issues with your security system and will require reprogramming.
Just use the one in your car, get it sent out for professional overhaul by someone that knows what they are doing, and you get to disregard both 1 & 2.
I currently have my ECU out for the same exact issue you are having... not joking, this is why I have been commenting on your thread, I am dealing with it right now. My ECU is currently on it's way to LSCowboy for overhaul with brand new Nichicon, high ripple, low ESR caps. The cost for me was $248 which includes RETURN shipping, you must pay for outgoing.
#18
I would have done the job myself but all of my soldering equipment is basic as I rarely have to repair motherboards or PCB connections, I just send them back to the MFGR to deal with it.
As for the cost... meh, he has a great reputation on Facebook and on multiple forums for this stuff, and it's still cheaper than other repair shops, he is also meticulous in his work, and I have spent quite some time talking to him over facebook in a private chat. Ex NASA electrical engineer doing work on my ECU, hell yeah I will take that.
Thanks for the offer however. As for your issues, if you have not done a tune up on that car recently, just get that out of the way as well, certainly can't hurt. New NGK Iridium plugs, new plug wires, distributor caps, rotors, coils, that should do it.
As for the cost... meh, he has a great reputation on Facebook and on multiple forums for this stuff, and it's still cheaper than other repair shops, he is also meticulous in his work, and I have spent quite some time talking to him over facebook in a private chat. Ex NASA electrical engineer doing work on my ECU, hell yeah I will take that.
Thanks for the offer however. As for your issues, if you have not done a tune up on that car recently, just get that out of the way as well, certainly can't hurt. New NGK Iridium plugs, new plug wires, distributor caps, rotors, coils, that should do it.
#19
Intermediate
Thread Starter
I would have done the job myself but all of my soldering equipment is basic as I rarely have to repair motherboards or PCB connections, I just send them back to the MFGR to deal with it.
As for the cost... meh, he has a great reputation on Facebook and on multiple forums for this stuff, and it's still cheaper than other repair shops, he is also meticulous in his work, and I have spent quite some time talking to him over facebook in a private chat. Ex NASA electrical engineer doing work on my ECU, hell yeah I will take that.
Thanks for the offer however. As for your issues, if you have not done a tune up on that car recently, just get that out of the way as well, certainly can't hurt. New NGK Iridium plugs, new plug wires, distributor caps, rotors, coils, that should do it.
As for the cost... meh, he has a great reputation on Facebook and on multiple forums for this stuff, and it's still cheaper than other repair shops, he is also meticulous in his work, and I have spent quite some time talking to him over facebook in a private chat. Ex NASA electrical engineer doing work on my ECU, hell yeah I will take that.
Thanks for the offer however. As for your issues, if you have not done a tune up on that car recently, just get that out of the way as well, certainly can't hurt. New NGK Iridium plugs, new plug wires, distributor caps, rotors, coils, that should do it.
#20
Have done that tune up 4 months ago. All wires, spark plugs, throttle body and the whole nine yard. Well you paid for the NASA brand , You know what you should buy one ECU from eBay also and keep it for emergency. Since you said your car is 92, good thing is 92 ECU don't need programming keys or anything else. It's plug and play.
I still need to do my oil change, 4 new Cooper CS5 Ultra Touring tires with balance, and a tune up (because I want to, last tune up was 15K miles ago and 6 years ago), the guy (original owner) that had the car before me was in hospice, so it never got driven much recently until I purchased it.
the real fun is going to be redoing the seals....
#21
Intermediate
Thread Starter
Currently the biggest thing I fear about my car is the other drivers on the road... the value of these LS400's in the eyes of insurance companies is jack ****, so they total it out even with minor damage.
I still need to do my oil change, 4 new Cooper CS5 Ultra Touring tires with balance, and a tune up (because I want to, last tune up was 15K miles ago and 6 years ago), the guy (original owner) that had the car before me was in hospice, so it never got driven much recently until I purchased it.
the real fun is going to be redoing the seals....
I still need to do my oil change, 4 new Cooper CS5 Ultra Touring tires with balance, and a tune up (because I want to, last tune up was 15K miles ago and 6 years ago), the guy (original owner) that had the car before me was in hospice, so it never got driven much recently until I purchased it.
the real fun is going to be redoing the seals....
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UNCNOR (08-18-17)
#22
Since you bought the car, I would suggest use the hell out of it and enjoy driving it as much as you can because if you don't utilize it then it's not worth buying it. I bought my LS400 to give some rest to my Toyota Land Cruiser. I work in mining industry and wear my expensive watch at work. My coworkers tell me that I shouldn't be using expensive watch for work. I told them I spend most of my time at work and if I don't utilize my watch at work then there is no point of keeping it. I am getting old and getting closer to my death every second, I should enjoy each and every second of the items that I bought it for my pleasure while I am alive. After I die I wouldn't be able to take them to grave with me and enjoy them in grave. Sorry for my bad English, English is not my first language but I hope you got my point.
#23
Intermediate
Thread Starter
I performed the ignition coil test as described in the picture, passenger side ignition coil failed the secondary test and driver side coil passed both test. I got this test diagram from Autozone, they didn't had coil in stock but they printed this paper for me which was a great help. Then I went to Oreilly, they had one in stock which was cheap made in china iginition coil, I bought the coil and tested it with the mulitimeter and it passed the test but when I installed it in the car, it didn't make any difference and the car smelled like unburnt fuel and struggling to run. So I return the coil and order used oem from eBay. Now waiting on coil. I also changed the rear catalytic converter which was a little bit clogged but not too bad.
#24
I performed the ignition coil test as described in the picture, passenger side ignition coil failed the secondary test and driver side coil passed both test. I got this test diagram from Autozone, they didn't had coil in stock but they printed this paper for me which was a great help. Then I went to Oreilly, they had one in stock which was cheap made in china iginition coil, I bought the coil and tested it with the mulitimeter and it passed the test but when I installed it in the car, it didn't make any difference and the car smelled like unburnt fuel and struggling to run. So I return the coil and order used oem from eBay. Now waiting on coil. I also changed the rear catalytic converter which was a little bit clogged but not too bad.
Not sure if that "new" ECU you just bought is going to help, you might want to reference that "ECU, now all my weird problems are fixed" link I posted earlier to ensure you get the right caps.
#25
Intermediate
Thread Starter
I did order the chips needed for the ECU that was described in the link you provided. I received their shipment notification as well. I am going to try out this eBay ECU that I bought for 25 bucks and at the mean time rebuild original ECU using those capacitors. But I believe ignition coil has major hand in my car's problem.
#26
I did order the chips needed for the ECU that was described in the link you provided. I received their shipment notification as well. I am going to try out this eBay ECU that I bought for 25 bucks and at the mean time rebuild original ECU using those capacitors. But I believe ignition coil has major hand in my car's problem.
#27
Intermediate
Thread Starter
This car made me 50 percent Lexus certified mechanic lols. I may have messed up ECU because few months ago the blower motor sucked a candy rapper and it was making wierd noise. I had to unplug lots of wires in order to reach the blower motor and ECU harness was one of those wires. I didn't disconnected the battery either while I was disconnecting wires under the dash.
#28
Intermediate
Thread Starter
Since I am waiting on the parts that I ordered on eBay i.e ECU and ignition coil. I had replaced the spark plugs, wires and cleaned up the TB 5 months ago, but I didn't had time to replace the distributor cap and rotors because reaching them is also pain in the ***. So today I decided to check out the condition of the distributor rotor and caps as well and I found them in very bad shape. Hopefully this will solve my problem. Distributor rotor tips has also cracked plastic.
#29
Intermediate
Thread Starter
Found the left coil wire damaged. I tested resistance of the wire, which was alright but I wonder if this can cause red hot catalytic and no power. I am still waiting for distributor caps and rotors to arrive until then I am not going to put the car back togather. I checked the ECU also, it's chip-set is in pristine condition and no leaky acid or inflated capacitors.
#30
Found the left coil wire damaged. I tested resistance of the wire, which was alright but I wonder if this can cause red hot catalytic and no power. I am still waiting for distributor caps and rotors to arrive until then I am not going to put the car back togather. I checked the ECU also, it's chip-set is in pristine condition and no leaky acid or inflated capacitors.
As for that coil wire, definitely replace that.