'93 Lexus ES300 Fuel in Exhaust/Runs Rough

[barnold37]

I just bought a '93 Lexus ES300. It runs rough most of the time with raw fuel and white vapor comming from the exhaust. Occasionally it runs well with none of those symptoms, but that doesn't last long. The previous owner replaced the pre-injector and the #6 injector. He also replaced the ECM with a junkyard unit from a cross-referenced Camry. These repairs made no difference, and the pre-injector has to remain unplugged to keep massive amounts of fuel from pouring out the tailpipe. There is no significant water loss from the radiator, no water in the oil and the engine does not overheat. I'm planning on running a compression check this weekend to rule out the head gasket. Can a head gasket be bad without any of these other symptoms? Is it possible I have another bad ECM and/or injectors? If anyone has any experience or knowledge of something like this, there info would be greatly appreciated.

[rhandwor]

I would check the fuel pressure a leaking pressure regulator will allow excessive fuel into the engine.
Pull the vacuum hose for this regulator if it has fuel in it replace the regulator. They can fail other ways but this is a common problem of a rich running engine.

[barnold37]

Thanks! I will check the pressure regulator. I am not very hopeful, though, as that would be WAY to easy! I do appreciate any ideas, however, and will certainly check it.

[lexluther1]

ha what's good look.. not a lexus pro..but i'm learning as i go read me.. i bought a 94 es300 2 yrs ago.. never had not even a honda so lexus was a big challege for me to pick up. This car had like 200 things wrong with it from all the struts gone to my computer went out causeing my transmission not wanting to shift into overdrive. This guy didnt change the hoses on the car since it was built and later water leak turnt big leading to me blowing a head gasket.....damn...... so after a year and half going behind this guy doing mantence on this car rebulit the engine with the cheap mexican dude got a computer put struts on here...thought i was finish...check engine light came on again... o.k took autozone found it was my OXY sensors.. got them replace ( note you have 4 on this car easy to change get a Oxy sensor socket to take it off) light went off ran find.. and the white fog coming form your tail pipe my man... that's a good thing means your engine got good compression... mine's do the same but check engine light ca eon again... damn here we go...... EGR.. put a value on there..and i learnt you also need to replace VACUUM VALUE You got 3 on this car simple right there wher eyour injectors at my man... dont go to lexus get this part go to toyota ask for the camry now my light is off and it run so good... but real talk my man not really sure what's wrong with your's but take your time replace things like oxy sensors... egr value..( autozone 140.00) and the vacuum value set hear me i paid 160.00 for the set... if you get them seprate all each cost 100.00 so the set cant go wrong..also bro... replace yoru fuel filter that's not to easy to do pay some one shoot some B12 in your intake... take your air filter cover off while idlein shoot b12 as you rasie your engine at the same time... clean out some carbon try these things my man