99 Cavalier RS Won't Start Unless You Have Foot on Gas

None of the above, Maybe the throttle position sensor, adjust the idle, etc.

There is no idle speed adjustment.

Actually there is, at least that's what I would call the little screw at the base of the throttle body. Granted with electronic control it does not normally need adjustment and should be done by a professional. I also should have added checking for vacuum hose leaks as well

I should have said no user adjustable idle speed controls.

the fuel filter is in no way connected to your accelerator pedal.......so probably not, the fuel only pumps from electricity, not your foot motions like an accelerator pump in a carburated engine. if you see black smoke that indicates fuel that is short of oxygen (too rich), if the smoke is white , its oil or coolant related

I would remove and clean the throttle body, and replace the throttle position sensor...and if the injectors have never been cleaned, then I would do that at some point....

OK. The simplest solution is to list the car on an internet auction site (name withheld). After a few days, someone will take the car away.

I had a similar problem with a Vectra but only when the engine was warm but not hot. It acted as though it was over-fueling as suggested in an earlier post, holding the accelerator down increases the air flow to even this out.

Possibly a temperature sensor telling the ECU that the engine is hot when it is not. First stage would be to check for fault codes.

Experience says bad fuel pump, plugged filter, other engine control modules NS, but before you do any of that have a diagnosis performed.

First off, is the service engine soon light on when the car is running? If yes then have the system scanned for trouble codes. It could very well be the Mass airflow sensor, MAP(manifold absolute pressure sensor), Throttle position sensor, or even a clogged up air filter. The first three will definitely trigger the SES(service engine soon light).

No the service engine soon light doesnt come on, it's just hard to start at first,but once it warms up then when u shut it off it will restart with out givin it gas. Just turn the key and off ya go. Has everyone lost on what it could be . But Ty all for your input. Greatly appreciated.

Have you tried hooking it up to a reader? Just because you are not getting a light does not mean there isn't a code in the computer.
I had similar problem with one of my cars. No warning lights but same issue. Turned out a couple of sensors involving the fuel system were bad but no warning lights just a error code in the computer.

Ok. Have you opened the air cleaner and removed and inspected the air filter, or checked the whole system for a blockage? I would disconnect the duct at the throttlebody and see if the car will start normally. If it does there must be a blockage. Also check for carbon/crud build-up on the inside of the throttlebody. Check both sides of the throttle plate. If there is, buy a can of carb/throttlebody cleaner and spray it in there. I would even buy a new air filter, they're under $15 at your local autoparts store. It is pretty damn hard to diagnose something over the internet. Take some photos and post them, it might help.

Uh-oh, I'd better run there right away and put my foot on the gas!

(Sorry, couldn't resist.)

Check oxy sensor in the exhaust.

Some can be cleaned. Most need replacing.

Stu.

http://www.chacha.com/question/how-much-money-will-a-scrap-yard-give-me-for-a-1999-chevy-cavalier

I remember the days when you had to push the pedal to the floor before you cranked it to set the choke and have the accelerator pump splash some extra gas into the intake manifold. Then you might have to give it just a little throttle when you cranked it. Or if you managed to flood it, you would hold it wide open as you cranked it. Those things had vacuum dashpots and electric heaters to manage the choke plate. I don't really miss carburetors.

I wouldn't waste any time looking at the fuel filter. It's probably fine.

In my admittedly somewhat short lifetime of only fifty years, half a million miles, nine or ten motorcycles, six cars, two trucks, one RV, a boat and dozen or so pieces of powered equipment, I still have yet to see a clogged fuel filter.

I replaced them from time to time thinking it was a good thing to do, then I cut a few open. What really surprised me was that even after 100,000 miles, there was very little in them in terms of particulates and no evidence of varnish or gum or anything. The quality of our fuels over the last several decades is very good (ethanol not withstanding) and the filters are only there to protect the vehicle from some extremis situation. But generally a clogged filter will provide enough fuel for low-load situations but starve the engine while climbing a hill or other high load situation. This doesn't sound like your problem.

You should hang around with me then. I more than make up for you experiences with plugged fuel filters. It's an ever and ongoing issue around here.

Tank rust and fuel varnish are the #1 things I deal with on a regular basis for clogged filters and fuel lines and it does not seem to matter what machine or where the fuel came from.

Give everything enough time and it clogs a fuel filter or fuel line with a fine yellow/white or rusty orange grease like varnish.

I could understand tank rust. The last steel fuel tank I had was an '89 Plymouth mini-van. Even with the steel tank, it must have been coated well, because when I had to drop the tank to change the fuel pump, there was no rust in it. Some of the fine sediment I did see may have come from a gas station. So many of the tanks now are polyethylene so rust from the vehicle tank is becoming a thing of the past.

It might be that in the mid-West, the fuel supply may not be as well maintained as in the large east coast metro areas where the service stations tend to be newer and the fuel never sits around for more than a couple of days or so.

I wonder if there is any data on the quality of fuels by regions?

Cheers !!

It sounds like the ECM is not seeing the correct temperature of the engine when it is cold and therefore is not allowing enough fuel into the cylinder to sustain cold operation.

Pressing the gas pedal down and opening the throttle plate allows more air to flow past the Mass Air Flow sensor which in turn increases the injector control pulse width resulting in more fuel being introduced into the cylinder.

This allows a rich fuel-air mixture which is required for cold temperature engine operation and is not needed once the engine reaches operating temperature.

I would replace the engine temperature sensor that reports to the ECM as it is low cost and easy to replace.

If this doesn't solve the problem I would pursue all of the other solutions listed in the many posts one at a time starting with the lowest cost and working my way up the list.

Use of an engine analyzer will not usually reveal the cause of the issue unless the feedback signal is "out-of- acceptable-limits".

There is a myriad of ohmic tests that can be performed by a knowledgable technician to verify engine sensors operating status but it requires a high level skill set so you may have to get help from a professional.

Good luck!

Thank you all for your input,very helpful information. I'm gonna try to get it in the garage as soon as I get paid.:)

If you have one or more injectors that leak, you might get the same conditions. When you shut off the engine, the fuel pressure is at 60 psi. if it sits long enough, this fuel will leak into the induction system. As the engine cools, this fuel will puddle in the intake. When the engine is next started, too much raw fuel is dumped in to the intake (still leaking injector) combined with the puddle of fuel from sitting leaves an over rich mixture that needs more air. The leaking fuel might also wet the spark plug, also hurting starting.

After the engine is warm, the hot engine helps boil off the leaking fuel, helping to start a rich mixture.

after the car sits over night, try pulling the spark plugs, and looking for wet plugs. If no wet plugs are found, disable the ignition system, and have someone turn over the engine, while watching for what is blown out of the plug holes. BE VERY CAREFULL. That is gasoline flying out.

it will catch fire, if there is a spark from the ignition system. Good luck.

Hey Bob,

Been a while.

GA.

Cheers,

Stu.

Sorry. I got drunk, and passed out for a while.