My 2001 Chevy Venture hesitates to start when the engine is hot. The engine cranks well any time, cold or hot. When the car is park for a few minutes after a longer drive and the engine is hot (normal operating temperature).
There is no problem with starting when the engine is cold or needs to be restarted right after it has been turned off.
I was told that it may have something to do with fuel vapor lock in the fuel line?
Any suggestions anybody?
mark
It’s possible there may be a vapor lock (although I never came across this problem with my 2000 Silo). (Identical engine)
There are other reasons too, such as: a dirty air filter, faulty emissions system, bad engine ground, a loose ignition connection and perhaps even a low battery (or dirty battery cable connections).
These 3.4l engines are not known for starter heat soak faults.
The engine cranks well all the time, but do not start immediately when it is hot (when the engine is turned off for a few minutes after a longer drive). It seams to me like there is no fuel delivered or ignition is not working correctly. One needs to crank the engine a litle bit longer when the engine hesitates to start. When it starts and is running, everything works grate. The mechanics at GM replaced the battery, but did not find any thing wrong with the car. There is no engine check light, the engine starts immediately when the car is parked for a longer time, overnight or it is restarted in a minute or less.
mark
Some faults don’t always show a cel (code) which makes diagnosing a bit more difficult.
I think there would be a CEL on and a code available if there were coil pack faults.
Perhaps a weak fuel pump or leaking fuel pressure regulator (do you ever get the smell of raw gas when it won’t start?)
Try parking the van facing into a breeze one time, so if there are fumes they will be directed to the cabin.
Not pleasant, but at least you’ll know there is a leak.
My van intermittently (once or twice a month) gives me a hard time (instantly) starting when hot as well.
I found that pressing gently on the accelerator (while cranking) enables a start. So that tells me there may be a leak back through the check (one way) valve or the fuel pressure regulator.
The check valve is in the fuel pump which is in the fuel tank. Yep, the tank has to be dropped to check/ remove the fuel pump.
When the fuel gauge quit, I had to replace the sending unit (in the tank) and that cost me almost $300 (CDN)
FYI, the fuel pressure regulator/injectors and fuel rail is under the UPPER intake manifold.
Let me know what you find, Mark. I’d appreciate it along with anyone else trying to correct the same fault.
I will try to turn the ignition key on and wait a little till the fuel pressure builds up and then crank the engine, doing that will check if the pressure check valve is working properly. When the engine is cold over night and the check valve is bad, the fuel pressure should be very low after several hours, but the engine starts immediately then, I do not think that it has to do anything with the fuel valve? I think I have checked that before and did not see any difference, but I will try it again.
Thanks a lot for your suggestions, but there is no fuel smell. This problem started a long time ago when the car was under the warranty, but my GM mechanics must not be the best, so they just replaced the battery. I was thinking that there is an additional injector or so that is activated during the cold or hot engine start. I push the gas pedal a little when I cannot start the motor and it helps, I think?
mark
Hey Mark,
I have a 96 3.4L with the EXACT same problem. This is my wifes van so I need to get it fixed to keep my happy home.
Your description is dead on. Runs great except on hot days after its been driven and sits for a while. The “vapor lock” problem you mentioned is not the first time I’ve heard that. It was suggested that I try a better quality gasoline because the winter blends that are still out there at the cheap stations have a tendancy to boil at lower temperatures. The heat under the hood after parking it hot is enough to boil the fuel in the lines after sitting for a while.
I haven’t tried the better fuel yet. I am experimenting by hosing down the fuel lines before starting it. It’s 90 degrees here today (Denver) so I’ll post my results. Please let me know what you find as well.
Qwazi
I have the exact same problem with my 2000 Chevy Venture. Starts and runs fine every time between September and April when it is cooler here in PA, even if I have driven a long distance. But when it’s above 75 or 80 degrees outside, even just a few short trips around town, and it may not start. The other day when it was 95 degrees out, I ran some errands; wouldn’t start after my second stop. Have to wait about two hours before it will start again.
When this happens, it’s as if the car wants to start and will sometimes seem to “turn over” when I turn the ignition key, but acts like it is starved for gas, as though it’s trying to run on “fumes.” Once that happens, it won’t start again for 2-3 hours, no matter what I do. A couple of times I have run down the battery trying to start it. Now, I’ve learned to just leave it alone for a couple of hours. Then it will start and run fine, like nothing ever happened.
Like one poster suggested, maybe the fuel is boiling in the fuel line. I’ve had it to a mechanic a couple of times. No results. Bottom line is: Can’t depend on the car to start after driving it on hot days. Problem started two summers ago; has happened three or four times already this spring. So it’s getting worse. Will have to get rid of it if I can’t figure it out.
Any further suggestions from you “car guys?”
I was thinking about warping the fuel line in some heat shield tape that will shield the fuel line from the engine heat, but it is not ease to do. The lines are very well hidden there. Did any body try to replace a temperature sensor or reprogram the computer?
A lot of people are willing to talk about the problem, and theorize about what might be happening; but, is anyone willing to do some testing?!
It does seem to be a fuel problem. Do a little test to throw a little light on it: attach a fuel pressure test gauge to the engine; use a long hose and attach the fuel pressure test gauge to the windshield or outside rear-view mirror.
Start the engine and record the fuel pressure. Drive the car at highway speed and record the fuel pressure. Stop the car/engine and record. Wait a few minuets and record the fuel pressure. Wait an hour and record the fuel pressure.
What happened to the fuel pressure in each instance? Perform test. Report. Discuss.
Mark,
Does the engine always start when you push a little on the gas pedal?
If so, get some throttle body spray cleaner. Disconnect the air intake to it and clean the throttle body and let us know what happens.
Roadrunner,
I am not sure if pressing the gas pedal has anything to do with the starting or not.
I really cannot tell. I can not repeat the problem unless I drive the car again for a while.
When the engine starts the problem do not exist anymore unless I heat up the engine again and park the car.
I will install a fuel pressure gage and a spark plug and check witch one is the trouble.
My theory is:
If the check valve does not hold the fuel at the correct pressure, it may be the problem
(the fuel pressure is low enough for the fuel to start boiling, after few minutes, when the engine is hot and stopped and there is no cooling or ventilation in the engine compartment).
Do you know the operating range for the fuel pressure?
I will get to it as soon as I buy the fuel pressure gage.
I will let you know about my progress.
mark
I agree, you got to do some fuel pressure testing but you may have a pump going south. Also could have the pump relay failing when its hot. Need to do some testing to rule things out or take it somewhere.
Key ON and engine OFF : 52-59 psi (according to my Haynes manual)
I have a 2000 Venture with the same problem. I first thought the problem to be fuel related. As the gas gauge had not worked for some time, I went ahead and replaced the fuel pump assembly. This corrected the fuel gauge problem, however ‘starting’ problem remains. I pulled a spark plug when the car would not start and found: NO spark. Seems there are 3 likely culprits for this. Ignition Control Module (ICM), Crankcase Sensor, or Powertrain Control Module (PCM). Today I replaced the ICM $86.00, same problem. Tomorrow I will be replacing the (Lower (7x))Crankcase sensor $17.00. If this does not work, PCM is $285.00. Problem could also be wiring. I will ohm this out and flex wires before $$ for PCM.
No resolution yet
HELLO MESIEFY!
Did the new crankcase sensor fix the problem?
Thank you.