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Masturbater
95 ES, 97 M3
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32 Posts
Discussion Starter · #1 ·
Hello all,

I have a 99 4runner 6cyl w/ 66k miles and I'm experiencing warm start issues. When engine is cold, starting is not a problem, but if the engine is warm (after a drive and shutting down for 10 min), the engine doesn't want to start unless throttle is depressed.

Recent tuneup was done, including spark plugs, cleaned MAF, cleaned intake manifold, and changed fluids. I am thinking it's fuel related problems, either injector, FPR, fuel pump, main relay, or...

Does anyone else have the same problem? What seem to be the issue here?

TIA
 

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Toyota Fanboy
Joined
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4,486 Posts
It could be one of the following:
1.) Air filter dirty.
2.) Fuel not reaching fuel injectors. Check for vapor lock situation, brought about by clogged fuel tank vent lines.
3.) Bad engine ground connection.
4.) Defective pickup coil distributor
5.) Fault with fuel injection or engine management system
 

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Registered
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342 Posts
Seems to me your MAF meter is on it's way out.
Even though you cleaned it. It still might be telling the ecu to lean it out. Causing it to hard start.
And if you applied throttle. ECU see's the load the TPS is reading and gives it more fuel.Therefore finally starting the vehicle.

You're not experiencing it at cold engine because you're in open loop.Meaning you're fuel trim is up there until normal operating are met.Then it will run stoich.
 

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4Runner X's 4
2001 4Runner Sport
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7 Posts
Had a '94 with the same problem. It was cold start injector and cold start switch - must replace both. Cold start system is getting wrong message and it is sending fuel when it is not needed. Try this before MAF Meter because that cost $650!
 

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Vendor
Joined
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243 Posts
wimpwgn said:
Hello all,

I have a 99 4runner 6cyl w/ 66k miles and I'm experiencing warm start issues. When engine is cold, starting is not a problem, but if the engine is warm (after a drive and shutting down for 10 min), the engine doesn't want to start unless throttle is depressed.

Recent tuneup was done, including spark plugs, cleaned MAF, cleaned intake manifold, and changed fluids. I am thinking it's fuel related problems, either injector, FPR, fuel pump, main relay, or...

Does anyone else have the same problem? What seem to be the issue here?

TIA
When it does start, do you see black smoke coming out of the tail pipe?

If so, do an injector leak down test. If the injectors are leaking it will flood the engine making it hard to start when warm.

This is not much of a problem when cold. A cold engine will fire pig rich where a warm engine will not.

There could be a lot of other things, but black smoke is a dead giveaway for leaky injectors.

Gadget

www.URDUSA.com
 

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25 Posts
good post... I have a similar sounding problem, been that way for going on 3 years now. To this point, I've just dealt with it.

And as for Gadget's point... no black smoke for me.
 
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