91 Ls 400 ignition timing

[erwinmj]

anyone willing to share how to adjust ignition timing on 91 ls 400 ?

 

[Lextreme II]

There is a Group Purchase on the adjustable Cam gear. That will help. Some piggyback computer can also alter timing.

 

[Peewee]

You can't alter timing on the factory ecu.
I'm actually thinking of making an adjustable setup for the crank angle sensor.
Just to alter the timing 2-4 degrees.
Give it a bit more pep for us boys who run premium fuel.

Thoughts?

 

[Lextreme II]

Peewee,

Would adjustable cam pully would work? BSEE is trying to get a group purchase together.

 

[Peewee]

Adjustable Cam pulley will change cam timing, not ignition timing.
Two very different things.

 

[erwinmj]

the problem i have is trying to identify the source of back fire , the story is i have 91 ls 400 with 149,000 miles purchased used a year and half ago everything works well engine and trans then one day the water pump leak so i replaced the water pump and since i was gonna open the engine i decided to change all the major maintenance parts, timing belt , cam seals, valve cover gasket , idlers , tensioner, thermostat , toyota ignition wires , cap and rotors , spark plugs,air filter pcv...( also cleaned throttle with rag and throttle body cleaner , did not remove throttle body) ( found out also that evrything was still original parts never been serviced)
i set the timing belt just like in the procedure that was in the manual that was posted here, crank at " 0 " and 2 cams aligned with the engine timing marks , rotated the engine several times and timing marks still right on the money put back all together start engine engine idles well , road test it felt not picking up when going up hill and started back fire and noticed trans fluid burning hot ( pulling trans dip stick )
i thought trans needs flush so i changed the trans filter and type iv toyota fluid about
3 quarts and checked cooler lines ok. road test still back fire and not picking up the accelarator, continued my trouble shooting , on idle i have around 15 vacuum, ,my vacuum gauge does not fluctuate so it is not sticky valve and raise rpm 2000 hold for 1 minute vacuum did not change so it is not clogged converter but i think 15 vacuum is on the border line to be normal in idle....
anyway i checked the ignition coils and saw the one in the left side is kind of greasy kind of melting even after cleaning so i replaced both ignition coils and road test it and still have the back fire on high rpm on steady and car not picking up when load with A/c or trans on drive....so i thought i need to adjust the ignition timing ..
please advise...

btw when i removed the timing belt , crank at "0" the 2 cam pulley's mark are a little inward from the engine timing marks about a tooth....is this how lexus do the cam shaft timing ....may be i need to put it a tooth in on both cams please advise.....

 

[Peewee]

Get someone to check your cam timing.
Or take a photo of the two cams with the crank on 0

 

[Lextreme II]

You better read this http://www.lextreme.com/timing2.html