91ls400guy

Hi every this is my first thread I recently bought a 91 Lexus ls400 and I absolutely love it runs amazing smooth very healthy 190k miles but i cannot figure out what wrong it will be perfect no problems for a day or two then it will not start it starts when ever it wants to. I will drive it and then I shut it off and it only cranks and cranks It's not getting spark when it's doing this I've changed so much stuff. It's making me crazy !! It will start within 15 minutes of sitting and randomly trying to start it or all day it will not start. Sometimes it will start within the next crank. Like I said it starts when it wants to and some days it's perfect I've gone over all my grounds and cleaned them checked relays all fuses removed both fuse boxes check every single control unit box for bad capacitors or burnt circuits I got a junk yard ECU and mine and the other ECU look perfect and both didn't help I've replaced both cam sensor and I've replaced the crank sensor. I replaced both ignitors I replaced the ignition. It has a rather new starter and a newer alternator and brand new battery will all connections cleaned. No check engine lights I've unplugged my cam and crank sensors and I won't get a cel / check engine light. I absolutely love my car and I'm a single dad and this is my daily I really need help and would greatly appreciate it more than anything ! Thank you all in advance again runs cherry spark wires plugs injectors etc are fine I've checked everything I can think of about to buy a remanufactured ECU on line but both of my ecus look flawless

deanshark

Instead of buying a reman ECU I would send in one of yours to get it rebuilt. It'd be cheaper anyway. Even if the ECUs look good they can very well be bad. The caps don't need to leak to be bad. In the past, one of my ECUs did the same thing, (random no start) don't remember which one cuz I messed with about 4 of em. But I do know it didn't throw a code cuz the ECU was bad. After I changed the ECU, with a known good one, it always started, no more of that problem.

91ls400guy

Thank you so much for the speedy response I will definitely try that I appreciate it brother I love this lexus more than any car ive owned I'm keep updates posted