This topic contains 9 replies, has 7 voices, and was last updated by 
killman 11 years, 4 months ago.
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Topic
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Having trouble starting my 2000 Chevy Venture, unless I give it a lil gas. Then in order to keep it from stalling once started, I have to be sure to keep the gas pedal pressed.
What could be the problem? Should I start with the fuel filter? Fuel pump? Charcoal cannister? Or any other ideas you can give me?
Thanks for any information you could help me with!!
Tom
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First thing is that I would start with cleaning the throttle body. They tend to get gunked up. Since you have fuel injection you should not have to give it gas. When you start it the throttle body should let a little air passed it for idle, one other thing is the idle air control valve (IAC) could be dirty, that may need a little cleaning. Cost is just throttle body cleaner, Is your air filter clean? Do you have any other symptoms when you are driving? The reason I ask is that if there are other thing going on with drivability that could help with diagnosis.
+1 on the advice given above.
Is there a check engine light on?
On newer fuel injected vehicles, if your stepping on the accelerator pedal during cranking, you are actually putting the vehicle in a clear flood mode which in essence means that the starti
Thanks for the advice from the two responses I’ve received thus far. I am going to do those suggestions and see if it helps.
Just went out to the van this morning, it started up fine, didnt have to press on gas pedal to get it going, no issues. So thinking that perhaps after driving, shutting off, driving again, it starts to act up.
I’ll be back to check later on this and see if I have any other responses. I appreciate the thoughts above, gives me a lil more perspective. I do have an auto mechanics degree from college, but just haven’t passed enough state licenses yet, so I’m not like an expert… but given the right advice and ideas, I can probably get the problem fixed.
Thanks,
Tom
That fact that it’s intermittent sounds electrical not mechanical, those were some excellent suggestions listed above. I would also check to see if there are any codes stored just to be sure. My suspect at this point would be the IAC but I would want more evidence before I commited to that. Keep us posted.
Thanks!
Well I’m leaning towards the IAT sensor.
After the van had been sitting for a long period of time, I hooked up my scan tool, my engine coolant was 102 and the IAT valve was 97. According to my mechanics book these should be within 5 degrees of one another. I looked for damage on the IAT. Then it instructed me to get the voltage of the IAT. The voltage I got was 2.02. According to the chart in my mechanics book, temperature between 86-104 should be measureing volts at 2.97-3.46. With the volts being 2.02, lower… is this suggesting the possibility that IAT sensor is bad?
Then based on reading what the intake air temperature sensor does, it makes a lot of sense of what issues I’m having that it COULD be the possible culprit. It doesn’t look like the cost for the IAT sensors are too much, so I might just try that and PRAY it fixes my problem. If not, I can look at some of the other options mentioned.
Again, thanks to everyone!
TomI think you would be better to check your temps when the engine is cold rather than hot as there really is no way for those readings to be the same with the engine hot. I don’t suspect the IAT however as it’s really just there for ‘fine tuening’ of the fuel mixture, it’s not really a major player when it comes to calculating the mix and I don’t believe it would cause the problem your having. I do however like that you are taking the time to do some testing before you start to replace anything, well done! Personally I’m leaning toward the IAC valve, if that is not in the right position when you start the vehicle it will offset the mix enough to make it run poorly, try tapping on it while the condition is present to see if the idle changes, if it does you might want to clean or replace that valve.
I suggest checking the fuel pressure regulator, they are a well known problem. They are most likely to act up after a hot soak, one thing you can check is to remove the vacuum line from the regulator and see if there is gas in it. If there is your regulator is likely bad. I used to work at a GM dealer and we sold lots of them.
Wore out electrodes on plugs will make starting difficult, making the gap wider per say
Thrasher
The IAT will not cause the problems that you have mentioned above. Usually a harsh shifting transmission is common if there is a problem in the circuit on GM vehicles.
Ditto on checking the FPR for a ruptured diaphragm. This is a very common problem on GM vehicles, especially on the 3100/3400 series of engines. Use a Mity-VAC or a long clear piece of aquarium tubing so that you can see a slug of gasoline coming at you when you are sucking on it. A good FPR will hold vacuum without any gasoline.
There should be a SES light and a trouble code if the IAC is too much out of whack. Try cleaning the IAC and the throttle body with TB cleaner. Think about cleaning the MAF while you are at it if you have a fine enough touch and a can of MAF sensor cleaner.
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