HELP 99 taco won’t start when 90+ degrees..

No, mine is a round shape, on the drivers side.

As for the hiss, I will study that more closely and if need be replace the cap.

Thinking this is not the correct thread for me to post in, didn't realize the OP has a V-6 whereas I have a 4 cyl. If need be i will start a separate thread? If not I'll continue on here?

One thing we found on mine. We pulled the injectors on mine & applied 9v to open them. Ran carb cleaner through them and one injector had visually discernable metal shavings or fragments coming out of it. < that cannot be a good sign.

I have noticed when I deliberately alter the shutoff time, restart difficulty varies. Shut it off and restart within 30 seconds, it starts normally. Wait 2-3 minutes it starts a bit harder. 5 minutes? It's getting hard to start. Wait 15+ minute to 20 minutes, you can tell it's flooded and very hard to start.
Wait 45 minutes to an hour, it starts normally even if it's still warm but less than operating temp per the temp gauge.

I don't know how to isolate the fuel rail & injectors under pressure to do a bleed down test with a guage, so I tried varying the shut off time to see what result would come from that. Ie: the longer it sits the longer fuel has time to leak through the injectors and flood the engine.

With what I'm seeing, it appears that is what is going on, longer it sits the more fuel leaks through the injectors until it stops leaking and it's had time for the fuel to evaporate via residual engine heat and makes for easier starting. ie: let it sit for 45+ minutes then it starts normally.

Also tried the trick of pulling the inlet air temp sensor to put the truck in limp mode, did not change the current starting difficulty at all.

It did have I suspect a failed engine temp sensor and that's already been replaced, using limp mode originally helped the starting but since we changed that sensor it's still this situation.

Also the 'check engine' light went out by itself both times after putting it in limp mode, that light is currently off albeit functioning normally, comes on with key on and goes out after starting.

We have replaced the VSV and cleaned the the EGR temp sensor & EGR passages & valve & throttle body. As well as removing the injectors and running carb cleaner & some compressed air through them. We did find a lot of solids coming out as well as the aforementioned metal shavings.

Idle is smoother than before and the hot restart past 15 minutes it seems like the truck is trying harder than before to start but it's still a battle to clear what appears to be a flooded engine.

 

@atticus finch
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