hard start when hot

[928vette]

My g/f has a 2000 Isuzu Amigo with the 3.2 V6 and auto transmission, 36k miles.
When the engine has been running and hot, it's hard to start after sitting for a short period of time. The starter spins fine, and the motor tries to start and then just kinda dies off. It will start up on the second try, but usually has to crank for a good 2 or 3 seconds. When it starts, the rpms are slow to come up. Once running, its fine and is not lagging in power. When the engine is cold, its fires right up with no hesitation at all. My first thoughts were in the fuel department, such as a fuel filter, but I am not really sure.
Any ideas on where to start investigating??
Thanks in advance for your help!!

 

[Amkeer]

Take it to the dealer! It should still be covered under the warranty. Its best to let them diagnose a fuel issue like that since it could be numerous things.


Daily Drives
-2003 Toyota Tacoma PreRunner XtraCab, Impulse Red, Peppy 2.7 Liter 4 Banger, Running Mobil 1 Synthetics SS 5w30.
ODO 5300 Miles.
-1995 Toyota 4-Runner, Evergreen, 3.0 V6, Running Mobil 1 Synthetic SS 10w30.
ODO 82300 Miles.

 

[rpn453]

I would take a guess that it is a fuel system problem. My '87 Grand Am experiences the same problem - I think it is maybe a little bit of vapour lock. It hasn't caused me enough problem to worry about it though.
Like Amkeer said: go to the dealer if it's still under warranty.

 

[got boost?]

sounds like it is too rich when it is started warm. it could be a coolant temp sensor, or a bunch of other things. If the car is hard to start whenever it is hot the CTS is probably it. if it is only after sitting, it will take some work to diagnose. do you get a code?

[ October 15, 2003, 02:45 AM: Message edited by: got boost? ]

 

[Z Licious]

I had a similar problem with a mitsubishi eclipse. Turned out that it was the gasoline used. The gas had alot of ethanol in it and would cause some type of vapor lock. Try switching to a good brand of gas like Chevron and see if this can help.

[ October 15, 2003, 03:22 PM: Message edited by: Z Licious ]

 

[DavoNF]

I agree, try a different brand of gas first.

 

[LM]

There are several possibilities, and tests would have to be performed to pinpoint

One thing that springs to mind is a loss of residual fuel pressure, which can be tested for with a fuel pressure gauge and proper fittings (can usually build DIY pretty cheap), and drop-down specs would be available (in a service manual or wherever)

Possible causes would include (if applicable to your vehicle) a faulty fuel pump check valve, internal or external fuel injector leak, fuel pressure regulator leaking or diaphram failing, fuel line leak - including the fuel pump fittings, fuel filter fittings, fuel rail fittings, fuel line itself

Also, as already mentioned, a bad CTS aka NTC sensor (usually easily tested with a DMM and cold/hot resistance specs). Or any sensor involved with starting and fuel mixture

Or early signs of an electrical/ignition component failing when hot-soaked