i own a 1998 cavalier w/70,000 miles.

when i start it in the morning, it won't start the first attempt, it sounds like it wants to. then on the second attempt, after i turn the key off, it starts right up. also after i get where i'm going. if i try to start it, it starts right up.

i just had the fuel pump replaced about 1 month ago., because the car wouldn't stay running at all.

the car was fine for awhile, after the fuel pump was replaced. just start doing this a week ago. i tried fuel system cleaner already.

any ideas??

 

Given you have a good working pump and the filter is in good serviceable condition, it would probably be your fuel pressure regulator or the water temp sensor for the computer.


Here is an Autozone link to give you an idea of what you're looking for.

http://www.autozone.com/az/cds/en_us...rInfoPages.htm

Hope this helps,

Bob

 

i changed the sparkplugs out over the weekend. just because i knew it probably needed done.

which would you try first the the fuel pressure reg or the water temp sensor?

remember after the car is warmed up it runs perfectly.

 

temp sensor makes more sense...make sure wherever you go for the part that they understand that you want the sensor that is for the onboard system (OBD II) and NOT the one for the gauge or light.

 

well, i do not quite understand how water temp sensor will prevent your engine from starting, i am all for learning new things though.
anyways, if i understood you correctly, you have fail start from the 1st few cranks, though it feels as if engine catches but won't catch well enough? then you turn the key back to off, and turn it back to on again, and it starts right on? and then it runs/starts fine?
look here:
http://www.2carpros.com/first_things..._excessive.htm
and here:
http://www.2carpros.com/first_things...wont_start.htm

as you will notice, it all goes down to basic things: poor fuel pressure, poor fuel mix, too much air coming into the combustion chambers, poor spark.
so, even that you just had fule pump replaced, does not mean that it works fine. i had 3 alternators failing on me in one night, outta da box, from a parts store that used to be around 8 yrs ago.
is your car parked outside? i think what you have is cold engine start problem. in my opinion, you have combination of few things: poor fuel pressure+poor spark+possibly air leak into intake manifold(new spark plugs+bad wires/ignition coils=bad spark).
it just sounds like at the 1st crank, there is not enough fuel in combustion chambers to "catch". then, when you let it go, and start over, you have enough, as you have leftover from the 1st crank plus new spray from the
2nd crank. plus, in cold engine, fuel does not stratify as good as it does in warm one, has tendency to coaless into larger droplets, and those are harder to combust.
try this: turn your ingnition key all the way to on, so that dashboard lights come up, then let it sit like this for maybe 10 seconds. pump with gas pedal maybe five times, all the way down to the floor. keep gentle pressure on the gas pedal, just a little bit, and crank then. see what happens.
sometimes, when you do this, you can hear gentle wrrooom from the back - that's your fuel punp building up pressure. all you doing is you are letting it enough time to build up pressure, plus adding some oxygen with open throttle, and letting richer fuel mix with slightly open throttle.
btw, how bad is your air filter?

 

i do not quite understand how water temp sensor will prevent your engine from starting

coolant temp is the primary input for cold start in all fuel injected cars.

poor fuel pressure, poor fuel mix, too much air coming into the combustion chambers,

all of these are the same thing...a too lean fuel mixture...which is what happens when the temp sensor reports a temp that is warmer then actual

try this: turn your ingnition key all the way to on, so that dashboard lights come up, then let it sit like this for maybe 10 seconds. pump with gas pedal maybe five times, all the way down to the floor. keep gentle pressure on the gas pedal, just a little bit, and crank then. see what happens.
sometimes, when you do this, you can hear gentle wrrooom from the back - that's your fuel punp building up pressure. all you doing is you are letting it enough time to build up pressure, plus adding some oxygen with open throttle, and letting richer fuel mix with slightly open throttle.
btw, how bad is your air filter?

the fuel pump runs for 2-3 seconds when the ignition is turned on to pressurize the lines... waiting more time will have no effect after that 2-3 second interval passes.

pumping the accelerator pedal has no effect whatsoever on fuel injected engines, correct starting procedure is with the foot off of the pedal.

opening the throttle during cranking does not richen the fuel mixture, it leans it...more O2 is leaner.

a dirty air filter causes a richer condition.

ideally here, to prove whether it's a fuel pressure/supply issue or a sensor input issue, diagnostic testing should occur. scan first after an overnight soak to see if the coolant sensor is accurate or not. if it is accurate, then a fuel pressure and volume test is in order. it is true that a new pump may not be getting the job done...also the filter should have been replaced when the pump was done. i'm not so sure that it could be the regulator as I believe that you'd have other driveability issues...regulators don't just screw up during cranking the first time of the day.

make sure that the fuel pump does run for 2-3 seconds when the key is first turned on (don't try to start it, just key on)...if you have to stick a funnel in the fuel filler neck and listen while a helper turns the key on for you.

 

Per OP: Car starts on 2nd try after he lets off the key. Could he have a perpetually weak spark condition due to ?, and the reason it stays running when warm is that warmed up gas/engine can fire easier even on weak spark?

 

i reread the post several times...i don't see where it starts when he lets off the key...but rather he attempts to start, it doesn't, he turns off the key, reattempts and then it starts.

weak spark doesn't fit to me either...what difference does it make how many times you try to start cold...it would still have a weak spark.

best i can offer is a gut feeling based on description and experience...it sounds more fuel related than anything else. but i've been wrong before...

 

I am more of an old car (pre fuel inj )guy, but the temp sensor makes the most sense to me as it acts just like the choke on a carborated car. unless he has carbon build up on the valves acting like a sponge for initial fuel spray.
remember Murphy was an optimist

 

thanks to all for your responses.
i went ahead and changed out the water temp sensor.
do i need to disconnect the battery for a few minutes to reset the computer?

 

no you do not have to disconnect the battery, my guess would be low fuel pressure also if you still have the problem would suggest you check fuel pressure after setting overnight as the only thing that is really changing from turning the key on and attempting to start the car and turning it back on and it starts is the fuel pump has a few more seconds to build up pressure and likely cycling the key on and off a few times before even attempting to crank the engine over would likely accompolish the same thing and the vehicle would start right up if the fuel filter wasnt replaced with the pump would probably start there.

 

My bad. I was influenced in my thinking by some other recent post where someone tried to start their car, and when they let off the key, to "on", is when it started, and not when they actually had the key to "start".

I have a cold and must have been brain dead when I posted that, since now when I also reread the OP just now, I completely see it your way.

 

the problem was a bad fuel pump they put in. wasn't holding pressure after awhile. the garage that put it in, put a new fuel pump in free of charge. good business practice. i wouldn't have went back if they charged me, the second time. they are gonna make alot more money off of me in the years to come.