After my Silverado got totaled I purchased a 2008 Tundra 5.7 gas with a good deal of deferred maintenance. It has a hot start issue where once it’s warm it turned over like an old flooded carb engine and if I open the butterfly it helps a good deal.

I replaced the fuel injectors and it was MUCH better than before but the hot start issue still existed. Perfectly fine when cold, fine for short periods like filling up with gas, but after about 15 minutes and up to 4 hours it has to crank for a good five seconds, which is forever in starter years.

I realized that I installed Flex fuel injectors instead of regular gas injectors. I know the FF flow more but are there other compatibility issues?

O2 sensor readings are in spec and the fuel trim levels don’t deviate very far from zero.

TIA!

I have no experience with the Tundra or any of its parts.

BUT - did you buy OEM injectors or ebay chinesium knockoffs? It's possible you may still have a rich condition at hot start due to one or more leaky ("new") injectors. There's a lot of garbage injectors out there being sold as direct replacements but they're just junk.

If there's 2 different OEM part numbers there's a reason. If you used known good quality injectors (OEM, or equivalent), then I'd be suspicious that using the flex fuel injectors could be the problem. Just because the flow rate is close enough to run fine most of the time doesn't mean that it's going to be good enough under all operating conditions.

Probably only way to prove it would be to get the correct parts and see if the problem is solved.

Not the EBay junk, but refurbished OEM units from Rock Auto.

I know the FF can flow more but not sure if they do flow more always due to a phasing or pulsing compatibility.

New OEM would be lovely but at $1k for a shot in the dark I was hoping for some experience from a tuner here.

Funny enough, I’ve asked on the Tundra forums and such but the extent of their tech savvy stops at which is the loudest muffler available. This place seriously has some of the best gear heads around.

They do have separate part numbers so I’m headed in that direction.

dont know much about that motor but the flex fuel vehicles either have a sensor to know what fuel is in it or it uses the O2 sensor etc to figure out what fuel is in it and what the injector should be doing. so is this a flex fuel vehicle? if not then it may be opening the injector based on the fuel trim it should have with the standard injector which would mean it is flowing more. if it is a flex vehicle it could be that it thinks it has E85 in it when it doesnt. if you think it is bleeding fuel in when shut off you could hook a pressure gauge up and see how fast it drops pressure which may indicate that a injector is leaking or being held open. on the other hand you say it has to turn over for a while when hot so are you sure it is firing the injectors when hot? maybe it is spinning over looking for a specific signal that is taking a while to trigger when hot, say a cam sensor which is only used on start up. just guessing as I am not an electronics expert.

Not a tundra guy but can you see the IAC action and is there a known issue with the passage getting plugged up. I assume you did the usual tune up first before trying to diagnose anything.

Definitely not a Tundra guy either, but most elec fuel inj systems have a Clear Flood mode activated by pressing the accelerator all the way down while cranking. Clear Flood mode shuts off the injectors. If equipped, it may help with starter wear until you get the root cause addressed.

If there's a fuel press regulator on the fuel rail with a vacuum hose attached, pull the hose and see if it's wet inside. If the regulator diaphragm has a leak, it will travel down the hose into the intake flooding the eng.