Hello all . I have a 1990 LS400 that 3 year ago I seriously messed up and after all that time I've finally gotten my hands back on it and I'm looking for some insight;
For some background ; I had bought an LS400 with 146k miles on it . I attempted to do a full tuneup/timing job on it , along with replacing the oil pump for some reason , but I had an issue with timing belt tension. I moved after the first 5 tries , now 3 years later I'm back at it .

Here is my problem ; I have verified I have the right timing belt , the tensioner is working properly with the proper protrusion , it has the proper idler/tensioner pulleys, and a (proper?) 209 tooth count gates belt.

The belt has so much slack that the tensioner is not able to take it up. Makes the timing sloppy and prone to jumping teeth

I took off the oil pump I had previously put on because since then I heard about how 2UZ oil pumps have different offsets and I have no idea what the pump is off of. I pulled the pump off a 1995 LS400, but now comparing them they are identical . I've found a pair of part numbers for oil pumps for 1989-1994 1UZ vehicles , but everything I see says its interchangeable with the one I got from the junkyard .

My question;
Is there anything that I haven't checked here that you would ? Do you know if there actually is a difference in the pumps from 94 back to 95 forward ? Are there any different components in that space ? Any insight would be greatly appreciated .