Although I’m not often a gambler, I’d wager large sums of money that every Previa in existence which has never had the fuel injectors serviced has lower insulators which have turned to rubble.
How important is it to deal with this? Not very. The insulators stop the injectors from bouncing around in the bore and making noise (which you probably can't hear anyway). However, if you have a reason to take the injectors out, do yourself a favor and order four 23291-75020 parts ahead of time.
There is a pic near the end of this thread... https://www.toyotavantech.com/forum/...=fuel+injector ...with part numbers for the other rubber parts if you just got a large christmas bonus and want to order all of them, but most likely you don't need them.
Below are some photos and notes from doing this today on 32 year old, 297K miles injectors...
If, like me, you're a first timer taking injectors out, take the gas cap off to release any pressure. I didn't crack a fuel line joint forward of the fuel pump to release more pressure, but it's perhaps a good idea. To access the injectors this is a passenger seat out, engine cover off job.
After you've got the electrical connectors unclipped, which, unusually, is fairly easy, and the injector holders off, it's time to pull out the injectors. They're just held in by the friction of the o-rings around the injectors. With your fingers pulling gently on the electrical connector boss, and some narrow profile pliers pulling gently on the stem, rotate back and forth and it should come out with only cave-man force. If you have to use gorilla force, gawd help you not break anything. Try to get them out reeealllll slowly so you don't get a spurt of gas in your face, especially if you didn't crack a joint.
#1 cylinder. I thought this was bad.
Attachment 12401
I stuck a piece of emission control hose in the hole to stop the pieces falling into the cylinder.
Attachment 12402
An unwound paper clip with grease on the end worked well to fish out the detritus.
Attachment 12407
#2 cylinder. Yeah, this one's bad
Attachment 12403
#3 cylinder. Hahahaha.
The paperclip and grease even worked well on this rubber-fuel sludge.
Attachment 12404
#4 cylinder
Attachment 12405
When pushing the injectors back in, put a very thin smear of grease on the bores in the fuel rail, and on the injector o-rings - it really helps them go in without damage.
