car won't start :(

[ac97gt]

this morning my car was running beauitfully, two hour ride home on the highway, parked it in the parking lot, all seemed well. went out like 7 hours later, tried to start it and it stalled out right away. everytime you start it, it stalls out right away. if you start it and give it gas right away it will try hard to rev up, then finally it will rev and as long as you keep giving it alot of gas you can get it to rev... but it has like NO power at all. if you hold the gas down pretty far you can get it to simulate like an idle, but you have to hold the gas alot, and again, no power at all. when you push the gas alot and get it to rev, it SOUNDS ok, like it sounds real smooth and pretty much like it should sound, and even when my friend held the throttle to simulate an idle, inside the car i thought it was fixed, but when he let go, it stalled right out still.

i dont know a real lot about cars, but the best analogy i can give to explain the problem is like a parking brake. its like theres a parking brake on the engine. you know when you drive with your e-brake on, its like you have no power and it doesnt wanna run right at all, thats what it feels like, an e-brake on the engine, you need to give extra gas to get it to even stay on, and it has no power. since it had been raining my first thought was maybe somethin in the distributer or something, but it all looks dry down there. other thoughts maybe fuel filter, fuel pump?

i dont know what to do... any suggestions please?

[Snakeman]

sounds like what my car did when a vacuum hose came loose

[ac97gt]

yeah that also definitely sounds possible, thanks for idea.... ill check into it tomorrow... other than peeking around inside the hood and listening/looking, how can i check for that?

[Snakeman]

tug on hoses, check the big ones first since your car is having such a hard time.
make sure the air intake is unobstructed. if you sucked a plastic bag into the intake it would mess things up too...

[surfbeast]

Check for any lose hoses connected to the intake plenum. It sounds like it may be a fuel filter. Since at higher fuel preassure it runs but at low fuel preassure it dies. They are cheap and easy to replace. Don't run it to much if the fuel filter is the problem, it can burn up the fuel pump. Check the filter first. then go from there

[Hammer]

Check your induction hoses that connect to your intake...
Make sure everything is clear from the air silencer before the air filter all the way to the intake. It sounds like there is a vacuum leak...

[WHITE_SVT_SNAKE]

Heres a couple of things to take into consideration:

1. Loose or damaged wire harness connections at distributor (5.0L) or Coil Packs (4.6L) Or the Alternator... Engine Controls, Computer and or connections to the computer... u probably shouldn't mess with all that, but if u really want too u can check the connections going to the computer... its behind the passenger side kickpanel (I.E. To the right of the Passengers Right foot... )

2. Intake manifold vacuum leaks. Make sure all mounting bolts/nuts are tight and all vacuum hoses connected to the manifold are attached properly and in good condition. Make sure there is nothing obstructing the air filter, also make sure nothing has gotten through the airfilter and possibly stopping up the MAF.

3. Insufficient fuel pressure. A variety of things could cause this... But seeing as how your not SEC certified or a master mechanic, lets just look over the small things... First check the Fuel pump switch or "inertia Switch" which is what kills the fuel pump if a collsion occurs (or maybe even if something hit a collision sensor, or maybe something could have even hit the pump or switch it self). This switch is in the trunk on the left side behind the carpet... it is a red button with a plug underneath it... Make sure the plug is connected securely, and then press the red button to reset the switch... Next if that doesn't solve the problem, check fuel filter, its fairly simple to replace and shouldn't cost more than 10 bucks or so... You are supposed to relieve the fuel pressure before changing the filter, but seeing as how the car wont run thats going to be hard to do considering u have to unplug the inertia switch and let the car run until it quits... but i guess u can't exactly do that... so just try and change it without relieving fuel pressure... Its infront of the gas tank underneath the car and its has connectors which common sense should tell u how to take it off... Anything else that could cause this insufficient fuel pressure isn't something that you should really be messing with so i'll skip to the next stuff....

4. Check the coil packs and the spark plug wires going to them... and make sure they are connected securely... Allso check to make sure the spark plug wires are connected securely to the spark plugs... Make sure they haven't gotten wet... Make sure you have the correct gapped spark plugs as well... Check the battery and alternator thoroughly... Check engine ground (probably not this, but i guess it could be).

5. Make sure your emissions system components aren't faulty... The only thing i can think of that would cause this is maybe bad O2 Sensors in the exhaust system... Anything other than that you don't wanna mess with...

6. Idle speed could be incorrect, Check the TPS (throttle position sensor) and replace if nessessary.

7. and last but not least, Something to do with the fuel injection could be malfunctioning... This you really really don't wanna mess with unless you know what your doing...


If none of this helps you might wanna get a professional to look at the car... Hope this helps... Good luck

[xxxBlakexxx]

Hey white snake, thanks for the great mechanic lesson! That was really helpful.

I had a problem like this with my car and it turned out to be a bad TPS (Throttle Position Sensor). It was about $30 at Pep Boys. I knew right away what the problem was becuase I thought I damaged it when I changed my Throttle Body. A bad TPS will cause your car to do all kinds of crazy things.

QUESTION: How do I know if I have the correct vacuum? Can it be measured?

Blake

[WHITE_SVT_SNAKE]

Yeah, a bad TPS is like a good case of the clap... You don't want one... ... As to your question about vacuum yes it can be tested and it doesn't cost much to do this... All u need is a Vacuum gauge... u can get them almost anywhere (car related)... Any car parts place should have them... The only thing you have to worry about and that is difficult about this is how do u interpret the results of the gauge... Some general info and instructions on how to do this are as follows:


A vacuum gauge provides valuable information about what is going on in the engine at a low cost. You can check for worn rings or cylinder walls, leaking head or intake manifold gaskets, incorrect Carburetor or TB adjustments, restricted exhaust, stuck or burned valves, weak valve springs, improper ignition or valve timing and ignition problems... among a few other things i may have forgotten...

Unfortunately vacuum gauge readings are easy to misinterpret, so they should be used in conjunction with other tests to confirm the diagnosis.

Both the absolute readings and the rate of needle movement are important for accurate interpretation. Most gauges measure vacuum in inches of mercury (in-Hg). The following references to vacuum assume the diagnosis is being performed at sea level. As elevation increases (or atmoshperic pressure decreases), the reading will decrease. For every 1,000 foot increase in elevation above approximately 2000 feet, the gauge readings will decrease about one inch of mercury.

Connect the vacuum gauge directly to intake manifold vacuum, not to ported (throttle body) vacuum. Be sure no hoses are left disconnected during the test or false readings will result.

Before you begin the test, allow the engine to warm up completely. Block the wheels and set the parking brake. With the transmission in park, start the engine and allow it to run at normal idle speed.

Read the vacuum gauge; an average, healthy engine should normally produce about 17 to 22 inches of vacuum with a fairly steady needle.

Here are a couple of gauge readings and what they indicate about the engines condition.

1. A low steady reading usually indicates a leaking gasket between the intake manifold and cylinder heads or throttle body, a leaky vacuum hose, late ignition timing or incorrect camshaft timing. Check ignition timing then eliminate other possiblities...

2. If the reading is three to eight inches below normal and it fluctuates at that low reading, suspect an intake manifold gasket leak at an intake port or a faulty fuel injector.

3. If the needle has regular drops of about two-to-four inches at a steady rate, the valves are probably leaking. Perform a compression test or leak-down test to confirm this.

4. An irregular drop or down-flick of the needle can be caused by a sticking valve or an ignition misfire. Perform a compression check or leak-down test and read the spark plugs.

5. A rapid vibration of about four in.-Hg vibration at idle combined with exhaust smoke indicates worn valve guides. Perform a leak-down test to confirm this. If the rapid vibration occurs with an increase in engine speed, check for a leaking intake manifold gasket or head gasket, weak valve springs, burned valves or ignition misfire.

6. A slight fluctuation, say one inch up and down, may mean ignition problems. check all the usual tune-up items and, if necessary, run the engine on an ignition analyzer.

7. if there is a large fluctuation, perform a compression or leak-down test to look for a weak or dead cylinder or a blown head gasket.

8. If the needle moves slowly through a wide range, check for a clogged pcv system, incorrect idle fuel mixture, carb/TB or intake manifold gasket leaks.

9. Check for a slow return after revving the engine by quickly snapping the trottle open until the engine reaches about 2,500 rpm and let it shut. Normally the reading should drop to near zero, rise above normal idle reading (about 5 in.-Hg over) and then return to the previouse idle reading. If the vacuum returns slowly and doesn't peak when the throttle is snapped shut, ,the rings may be worn. If there is a long delay, look for a restricted exhaust system (often the muffler or catalytic converter). An easy way to check this is to termporarily disconnect the exhaust ahead of the suspected part and redo the test.


that should about do it... I hope this answers your question... I got kinda technical sounding but its not to difficult... if you have any questions drop me a line here at the forums or @ svt_snake@hotmail.com

David

[ac97gt]

thanks for all the help and suggestions guys. heres the update. i started the car the day after and it did the same thing. i started it again and figured i would give it gas and it let struggle a bit, i wanted to see how far i could take it (could it get to red line?) and it did.. as i did this it seemed to get more and more power, so i tried to simulate an idle by holding the gas in. i held it at like 1k and let it sit and gradually i could take my foot off the gas until it seemed ok. everything was alright then... i revved it up and then took it for a spin around the parking lot.. it ran fine. im figured something clogged in the fuel dept, filter, injectors, somethin. i replaced the fuel filter (without relieving the pressure? oops) and i put injector cleaner in. it has been running perfect for the last couple days ever since, so im thinkin its cleared up. thanks again.

[xxxBlakexxx]

ac97gt:

I am glad to hear that things are running better for you and I hope they stay that way. This summer, I could not get my car started after 12 or so attempts. I let it sit, got it started, and then added HEET to the tank. That cleared up the problem.

Did the fuel filter seem plugged when you removed it? I have a replacement for my car. I should get it done this weekend. Car has 42k on the original filter. I am asking for trouble, I think.

[WHITE_SVT_SNAKE]

Blake,

The need for changing the fuel filter has a few things about it... 50K is about average... but i recommend every 25k... for as little as it costs ($7-$15) it sure can save you a lot time, money, and trouble... If you drive aggressive all the time for the most part (there are always anomoly situations) your filter will be cleaner then if you drive slow... because of fuel pressure in the filter... the higher the pressure over a period of time would make it less likely for buildup to occure in the filter... Now if you use regular unleaded gas, there tends to be more "biproducts" in the fuel... whereas premium tends to have less... For the most part anyway... and if for no other reason because the fuels production process and its level of combustability... but thats all another days lesson,... lots of technicall mubojumbo... anyway hope this helps...

By the way, Always use Premium gas if you have the means, its been proven that it burns cooler (believe it or not), more efficiently, and more completely (so you have less build up of carbon and "junk" in your motor). I.E. better performance and life from the motor...