khoefer47 Posted March 29, 2011 Share Posted March 29, 2011 Ok so this is the story, I have a 93 Ls400. When it first started acting up it would get very quiet then the hesitation and running like a lawn mower type of deal would start till it eventually would just shut off. It would do this every 3 to 5 days at first then it became more frequent, it wouldn't crank back up right away so I would have to sit for a while crank it and try to get home befor it would shut off again. It has got come to the point where it just wouldn't start, some days it would but only for a while. I did a full tune up, coils, ignitors, maf sensor, altenator, battery, fuil filter. With no progress of doing those things I had the cats gutted, I have a friend who has the same year that gutted his and its running fine but anyhow still no luck. I went and pulled a ecu off one in the savage yard and it cranked after a few tries, you could barely turn the key and it would fire up. So that held up for bout 3 days then it gave me different problems ie. cats would turn red which are gutted mind you, and the crank somedays deal but no it just won't start. The guy who has it now can't figure it out, he's had it for about 10 months now, he said its got good compression and is firing, he checked the timing which was fine, also he tested certain parts from a running ls400 and still no changes far as the coils, ignitors, maf sensor. He wants me to test the ecu's out so im going to test them on a running ls400 to see if its that possibly the problem. If that doesn't work does anyone know anything that could help me solve this mystery. Only thing I could think of if this doesn't work is maybe a faulty wire in the harness or someone said something bout a fuel injection sensor but anyway I would appreciate the knowledge if you have any Ideas that could help me out. Thanks for taking the time to read this everlasting event. Quote Link to comment Share on other sites More sharing options...
1990LS400 Posted March 29, 2011 Share Posted March 29, 2011 About all I can contribute is to tell you that there are extremely detailed diagnostic procedures in the repair manuals for these cars. I've been driving LS400's for 21 years / 275,000+ miles and I have never had a problem that a trained Lexus mechanic could not diagnose in a few minutes. My only suggestion is for you to take your car to someone who has the diagnostic information, proper equipment and the training needed to diagnose problems with Lexus cars. Quote Link to comment Share on other sites More sharing options...
curiousB Posted March 29, 2011 Share Posted March 29, 2011 Well I would stop randomly changing parts in hopes of it fixing the problem. That is a very expensive way to repair your car. I suspect your about $500+ into and have yet to put in a useful part. Based on what you have done maybe its fuel starvation caused by a faulty fuel pump. Get a can of starter fluid and spray some in the air intake as someone cranks. If the engine catches for a bit (don't expect it to run for long) then it points to fuel issues. Quote Link to comment Share on other sites More sharing options...
landar Posted March 29, 2011 Share Posted March 29, 2011 I am not so sure gutting the cats was a wise move but what's done is done. Your report of red cats and running "like a lawnmower" sounds like a lot of folks who have had a bad coil(s). Red cats mean a rich gas mixture into the exhaust system which, in turn, points to an ignition problem, perhaps even timing. How old is your timing belt? How many miles on the car? Quote Link to comment Share on other sites More sharing options...
khoefer47 Posted March 29, 2011 Author Share Posted March 29, 2011 I am not so sure gutting the cats was a wise move but what's done is done. Your report of red cats and running "like a lawnmower" sounds like a lot of folks who have had a bad coil(s). Red cats mean a rich gas mixture into the exhaust system which, in turn, points to an ignition problem, perhaps even timing. How old is your timing belt? How many miles on the car? Timing belt was changed back in 03, I have 268,000 on it, Mostly highway miles. I would take it to the dealer but a hundred dollars an hour isn't cheap lol. I would rather put that 4 to 500 there gonna charge me to find the problem into another engine which would run me 560 plus shipping with 40 to 60k on it. Quote Link to comment Share on other sites More sharing options...
khoefer47 Posted March 29, 2011 Author Share Posted March 29, 2011 Well I would stop randomly changing parts in hopes of it fixing the problem. That is a very expensive way to repair your car. I suspect your about $500+ into and have yet to put in a useful part. Based on what you have done maybe its fuel starvation caused by a faulty fuel pump. Get a can of starter fluid and spray some in the air intake as someone cranks. If the engine catches for a bit (don't expect it to run for long) then it points to fuel issues. You know what I did that and it was catching but for a short period though, when it was running you could smell the fuel pretty good whether it started with starter fluid or not. Quote Link to comment Share on other sites More sharing options...
DANNYDOO Posted March 30, 2011 Share Posted March 30, 2011 GO INVEST IN A 29DOLLAR GLOBAL ECU READER AT SEARS.get the codes and see whats going on. When you switched ecu,you may have put the wrong one inside that made it run too lean or too rich.They are not all the same.It could have a completly different proogram if not exact number match. Its like a heart transplant.They need to learn how to run the car right..Or it gets rejected. Your got rejected i think. Check the fuel pump man!! if you have compression,you have spark,you have fuel..You should have a running car. These are electrical mnightmare yes. Could be a wire....goto library and get the electrical diagrams for the engine and ecu free and dive into it. 10months? DOes it start at all now? Quote Link to comment Share on other sites More sharing options...
khoefer47 Posted March 31, 2011 Author Share Posted March 31, 2011 GO INVEST IN A 29DOLLAR GLOBAL ECU READER AT SEARS.get the codes and see whats going on. When you switched ecu,you may have put the wrong one inside that made it run too lean or too rich.They are not all the same.It could have a completly different proogram if not exact number match. Its like a heart transplant.They need to learn how to run the car right..Or it gets rejected. Your got rejected i think. Check the fuel pump man!! if you have compression,you have spark,you have fuel..You should have a running car. These are electrical mnightmare yes. Could be a wire....goto library and get the electrical diagrams for the engine and ecu free and dive into it. 10months? DOes it start at all now? Ok ill hit sears up and see how it goes, no its not starting at all? I'll call the machanic tomorrow and see if he checked the fuel pump. Thanks for the info. man Quote Link to comment Share on other sites More sharing options...
curiousB Posted March 31, 2011 Share Posted March 31, 2011 If it isn't starting at all I'd try to find out why before you throw a lot of parts at it. If you can borrow a timing light you can check to see if cylinder 1 is firing and timing is correct while cranking the engine. If one cylinder is firing and in time then you can be sure others are in time if their wiring is not crossed and wires are good. You can spray some starter fluid into air intake while cranking to simulate fuel being delivered. If the engine starts even just for a second then it points to fuel issues. Could be fuel pump, could be fuel pump relay, or could be filter (although I think you said you changed filter). You need to narrow it down a bit or you could drop a lot of coin swapping parts out. Quote Link to comment Share on other sites More sharing options...
VBdenny Posted April 2, 2011 Share Posted April 2, 2011 Just an outside shot at something to consider. Restricted mufflers? Stranger things have happened but of course 90% of the time, problems are electrical. Quote Link to comment Share on other sites More sharing options...
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