Ive recently had a problem with my lexus ls400 1992 a few months ago, it wouldnt start. I had it looked at and was told that the starter went out. The starters located under the intake manifold and i had to remove everything from the manifold to the fuel rail and finally the starter, located in the valley in the engine. It was a DIY. I had to replace many hoses that broke and the o rings of the fuel injectors. Although, after i put it back together and tried to start it, it occasionally backfires, most times turning over yet not starting. So i looked around and figured out the timing has become advanced, the thing is i didnt touch the belts, or mess with the cams at all, only taking off the manifold to get to the starter. I havent touched any distributors or the sparkplugs. I need help ASAP, does anyone have any info that could be of use?

 

this might help
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Here is a firing order diagram to help assist you.

 

The only thing to do with the fuel rail is disconnect any lines to it. It is totally unnecessary to remove it, it should just stay on the manifold. Yeah the wires need to be disconnected but nothing else, all removing that all does is cost more time and money. And that's the problem all the things messed with that were not needed to be messed with. First things I say to check are ruined wires or ruined connectors. Maybe dirt introduced into the injectors etc. Unless you modified the engine position sensors positions or the t belt theres not much you can do to advance the timing.