Engine Doesn't Get Enough Fuel on Hot Days

When you get into your, "2000 black cavalier", turn the key to the on position, and listen for the fuel pump. You should hear it whirring and then stopping when the system is charged.

Or wait 10 seconds and then try to start.

Or, take it to the shop.

Question: how do you know it's running out of fuel?

What tests have you done to indicate it's running out of fuel?

Even with the car in the sun, with all systems working right, temps should not affect it. You need to do some basic tests to see what's going on; fuel pressure, volume and delivery for a start, plus ignition checks and a basic scan of the data stream.

Perform the basic tests and go from there. Let us know what happens.

Looks to me as "Vapor lock"... Google now...Wangito

Hi buzneg,

Good advice from donzi (was that the name, sorry). It may pay you to check to see if there is any 'gunk' on the inside of the fuel cap, stopping it from letting air in? Give it a good clean and possibly a very light oil on the working spring etc. (Not sure about that because I have not had time to check it out).

I believe you have a 'Solex' 'carb' on your engine. If so you may find this page very helpful. It explains in detain all the workings and possible faults, some of which you can check for yourself.

http://www.thesamba.com/vw/archives/manuals/32phn.php <<<<<< This is a brilliant site if you have a solex carburettor!

Check the fuel line and look for joints where air may be drawn in. Like where the rubber hose changes to a metal pipe just before the carburettor?

Check your fuel pump. It may be the tank end of the fuel pipe has been knocked and is not directly under the fuel every time you start, like on an incline for instance. Has the car had any 'bumps' at the back which could have knocked the tank?

Good luck and keep in touch.

My 1999 Cavalier 4 cylinder is sequential port injection. There are times when the engine is still hot that if I miss my "que" and release the key too soon, I'll have to turn the engine over for another 15 - 20 seconds to make it start. Otherwise it always starts within 3 seconds.

Hello JerryNH,

Thank you for you reply post.

I did a pretty good search and, I know the spec' of this Cavalier 4 cylinder differs depending on your and Country so I can only choose what I thought to be the most likely spec'? ................. So yours is fuel injection then? Are most of the US versions the same as yours?

I had a car with a rubber diaphragm which was the vacuum for the carb'. It had a pin hole in it. I checked it several times, and my car would go for a few miles after I had, only to come to a 'kangaroo' halt. I had the problem very late and very early as I drove to work, so checking it was not easy as I was working by 'touch'. After about 10 stops I dismantled the carb' took this diaphragm out stretched it and found the problem. You could never see anything wrong just looking at the carb though! PITA!

Take care.

Lets sort fact from fiction. It sounds like a fuel problem now does it look and smell like one.The working theory is lack of fuel so we trust but not assume that the car is mechanically functional, in good repair and is displaying no codes. Before starting and with the no one in the drivers seat ID your fuel pressure regulator and pull off the vacuum sensing line there should be no fuel in it or leaking from the diaphragm (common problem). You can't vapor lock a pressurized fuel system so check your fuel rail pressure. Connect your gauge set before turning on the key so you can watch the pressure climb then look to see if it holds. (This is the hum in your trunk.) Anything sketchy here or intermittent not a good sign. Pressure should rise quickly and remain solid. Fuel pressure will remain steady it does not fluctuate. It will vary a few pounds with load and throttle setting but not swing from a high to a low or jump around while the engine is idling. These are some quick fuel system checks it does not discount any electrical problems i.e. sensors etc. Again we are trusting the OBD II will pick up and display any intermittent or hard failures.

Fuel caps can cause some bizzare problems. A cap that is loose will code, an evaporative purge valve that has gone bad will code. On a hot day fuel preassure will rise in a closed system, up to a point, not go into a vacum.

Once upon a time clothes pins and a wet t-shirt may have been the answer but those days are long gone.

UPDATE:

So it happened again today, over an hour I tryed starting it every 10-15 mins. everytime it got a little gas and then stopped except for once. I took out the gas cap and tryed it, it didn't even get gas, then I put it back in and tried it, and it started.

And after it starts like this the passlock light stays on. My passager side lock is damaged like somone tried to break into it.

Hello buzneg,

This could be directly related to the fuel pump or pipe in the fuel tank. There may be rust or some other bit 'floating' about in the tank which only occasionally is caught by the end of the fuel pipe. It may happen when your fuel is lower?

It may happen because of fuel with water or other stuff mixed in which you may get from a particular Garage? Have you thought about this Garage link? With one of my cars A tiny part of rubber, I think from the filler cap, gave the same sort of intermittent problems you describe.

Let you fuel get lower and siphon some into a clear container to see if the is and 'foreign body' in it.

Take care.

I may have too much time on my hands.

If a person were to take 5-6 small sandwich sized plastic bags and force them into the filler neck of your gas tank, there would be problems. As the fuel pump is running the plastic bags could get caught by the suction action of the pump. This would cause the bag to wrap around the pickup strainer until it starves the engine of sufficient fuel to run on. After the engine stops and the pump stops running, the bag will slowly settle to the bottom of the tank again. This would allow the engine to run again until a bag gets caught in the fuel movement again.

I do not think your symptoms match the expected symptoms caused by bagging a tank, but, who hates you?

I do think that a fuel pressure check is called for. Good luck.

I don't think that the bag scenario will work. I'm 99&44/100ths % sure that the end of the pump is covered with a "sock" and just lays on the bottom of the tank.

And you don't think those bags could find that sock?

Could we duplicate the test with smaller pieces in a spray bottle?

Or are you going to force me to baggie my boss's car?

Absolutely try it on your boss's car! I think that the pump can and will draw the bag to the sock. What I find unlikely is that the bag will be small enough to be drawn in and captured and still large enough with correct orientation to completely cover the filter.

Wait for a really cold, wet, miserable day to drop the tank outside. This will insure that there will be no bag in the tank, but you will break the straps that hold the tank up and / or the wires to power the pump / gas gage.

Works for me every time!

A cold day here is anything below 50 degrees.

You really need to do some basic testing, as mentioned in several posts, to resolve this problem. Odds are you'll never solve it unless you do.