HarleyMH

I have a 91 4runner with the 3.0 v6 with performance injectors that are possibly factory with 8 as the number for them and an after market air filter that's having issues. I can drive it for 20 minutes or more n its fine. I shut it off for 15 minutes it will start but try to die if I don't get the rpms over 4k in time. When it dies it doesn't even try to start again until it's cooled off. Then it fires up and I can smell unburnt fuel mixed with the exhaust. New coil plugs and plug wires. Doesn't miss. Anyone know the issue?

rworegon

Jennygirl and a couple of others have been experiencing similar issues recently. They'll likely chime in.

Welcome to YT!

jennygirl

Did this just start happening? Done anything to your car recently, or did you just get it?

And yes welcome

HarleyMH

I've had it since April n it came with the issue. Thought it was the coil but it wasn't.

jennygirl

First and foremost I would check TPS, I think it's likely that is your cuplrit. I would also pull and check the plugs, post a pic here if you are unsure at all. Enough running rich and they will foul. Make sure TPS is good first, though, before replacing plugs.

The best instructions online for TPS can be found here:
http://4crawler.com/4x4/CheapTricks/TPS/index.shtml

Godspeed

HarleyMH

Hope that's it. N that it just needs adjusted.

HarleyMH

Is there anything else it could be that I could test? I found what may be fuel in air breather right before it hit the intake. Its not in the filter or close to the air flow sensor.

HarleyMH

Could it be the thermostat? I just ran it n it got overly hot n was close to dying. I didn't have enough water in the radiator but the engine is just barley warm.

jennygirl

I dunno, did you check the TPS? Anything to report there?

What do the spark plugs look like when it's doing its thing?

HarleyMH

Haven't had the chance to. The radiator get really hot n starts spewing n my temp gauge maxed out. The motor and intake were cool to the touch.

HarleyMH

Was not the thermostat. I replaced it and it continues to do the same thing. I've noticed it missing on one mabe two cylinders. Once it gets going it fires on all cylinders.

HarleyMH

I have the tps unplugged n it starts n runs. I'm about to check if it still has its issue.

Cyberhorn The Dragon

did you find the issue?
i was about to chime in that it could be a leaky cold start injector or the cold start timer switch soulds like its flooding the engine when you shut it off warm the CSI or the CST think the engine is 'cold' an are dumping fuel in so it can run cold

HarleyMH

I unplugged the tps n left it unplugged. It seems to have been the problem. It will start n run fine. Rpms are a little high though.

Cyberhorn The Dragon

just a temp fix though the ecu isnt getting a signal from it so its running nearly in a limp mode wastin fuel as well id bet

there are tests to check the TPS if its faulty id give it a check
but its likely not the issue

the cold start injector if it is leaking once the engine is up to temp unplug it then let it sit a bit like you've done before if it still does the hard start issue leaky injector its dribbling fuel line pressure into the plenum till the line is empty
now if it doesnt have an issue id look at the CST it may need to be cleaned or replaced

HarleyMH

Would I have to plug the tps back in? Another detail I should add. When it's cold outside n I start it it smells like it's flooding out. After it warms up its fine.

Cyberhorn The Dragon

yes you'll have to plug it in, when its cold its really pouring fuel in there to help the engine start an run as EFI dont have a choke to make the air fuel mix rich in the cylinders so they dump fuel into the plenum so its drawn into the bores with the air then more fuel is added via the injectors at the head lower manifold junction

newer cars make longer sprays with the injectors soaking the valve face instead of a cold start injector dumping into the plenum

i would first pull the CST from the engine an check it see if it responds to hot water (as it would the coolant) correctly if its fine then its your CSI leaking just so you know in cold weather your engine cools off faster so the engine goes back to cold start mode engine doent mind a bit of extra fuel cold plenum take a bit to warm it up so it gets fed in gradually

in summer heat the engine doesent like that extra fuel an behaves like its flooded as the fuel evaporates in a thick cloud inside the plenum thus hard to start wont run right the 02 sensor reporting way too rich condition leans off the injectors which makes it stumble an run like crud till the excess fuel in the plenum has been run through then 'miraculusly' it just runs right again

HarleyMH

What is the cst?

Cyberhorn The Dragon

Cold Start Timer screwed into a water jacket electrical connector on it pull the wires deep wall socket fits right over it

HarleyMH

I ran it to temp then when I shut it off I unplugged the cold start injector n waited then tried to start it and it sputtered but fired up n ran at the normal rpms.