Starting Problem--please Help

[leshan]

98 taurus se 155k. These days are hot(90F more). My taurus got a start problem. After driving then parking for about 20 minutes under sunshine, I tried to start my car again, sometimes I can not start it. When I turned the key, it cranked, but won't get ignition. Even got start, the RPM was only 500rpm and unstable, engine shut down itself within 5 seconds. When the engine was runing unstable and hesitatly, I tried to push the gas pedal, the RPM won't change, Seems the gas pedal didn't work.
So, I turned the key to off, took out the key, opened the hood for about 30 seconds, then I tried to start the car again. It start normally, everything works well.
It happened severl times, all in hot days. Could you please tell me which parts probably need to be replaced or what can I do?
Thanks.

[jmira29]

It sounds like you have a temperature issue. What does the temperature gauge read when it won't start? It could be something as simple as a stuck thermostat.

[leshan]

temperature gauge read normally. Thermostat should not be stuck. I replaced it at about 120k. But I will check it.

[Mediarocker543]

Originally Posted by leshan

temperature gauge read normally. Thermostat should not be stuck. I replaced it at about 120k. But I will check it.

I'll look into this in the morning.

[Huney1]

Sounds like it's starving for fuel. The fuel filter should be replaced every 30K mi and some say 20K. Is the mass air flow sensor clean? If it hasn't been cleaned lately do it.

[leshan]

Yes, I'm worring about the mass air flow sensor. It's clean. But I used to use sensitive electronic cleaner to clean it by spraying several times. Two times was just after driving. But the cleaning thing happended 20k miles ago. I don't know if the cleaning will affect the sensor. Will a bad mass air flow sensor act like this? It's expensive.
The fuel filter is new, I replace the filter less than every 30k. The fuel pump should be in good condition. I replaced it 10k ago.
On more question. I saw two sensors very close to the Thermostat. I believe one of them should be coolant temperature sensor. But I don't which one, and what is the other one. Thanks.

[Huney1]

WARNING: Do not remove the Idle Control Valve (ICV) Electrical Connector with the engine running. This risks sending a power surge through the Electronic Control Unit (ECU/Motronic) and destroying it. This is caused by a Voltage Spike being generated (exceeding the maximum voltage threshold that the ECU can withstand) when the connector is disconnected/reconnected.

As I understand it, the MAFS wires are VERY sensitive and should never be touched by anything, just sprayed off with a good electrical cleaner, let it dry then spray again, do that a few times and should be good to go. I know they're $130. which is why I cleaned mine. If it's not working right or got touched that could be the problem. If it was 20K mi ago then buy some CRC MAFS cleaner and do it with the right stuff, It worked wonders for mine along with cleaning the ICV.

"I saw two sensors very close to the Thermostat. I believe one of them should be coolant temperature sensor. But I don't which one, and what is the other one." One on the left looks like temp sensor but other is a metal tubing elbow that goes toward the fierwall then down behind the engine, no idea what it is but it contains coolant because has a rubber hose clamped to the tubing. Ours is 03 Vulcan SES.

I wonder if you got a tank of bad gas and the filter got stopped up enough so's it starves the engine for fuel . . . ??

WHEW! 102F heat index and 52% humidity - monkey weather out there.

[MyTaurus8AChevy]

Originally Posted by leshan

I don't know if the cleaning will affect the sensor.

Don't use the electrical cleaner, as they will leave a residue after drying. Use the CRC MAF cleaner mentioned above.

The fuel pump should be in good condition. I replaced it 10k ago.

Was it replaced with the original Ford part, or an aftermarket pump? Aftermarket pumps do not last very long. If you search this forum you'll read many posts from other people who have stated that they have gone through 3-4 aftermarket pumps until they got tired of replacing them, and then went to Ford to buy it and then never had any problems since. The point is, just because you replaced it doesn't mean it's good There is a BIG difference in quality between the Ford fuel pump and the aftermarket ones. Also a pump that is about to go bad will typically have the symptoms you're mentioning, so keep that in mind.

Also don't discount the bad gas idea either. A lot of states do not check for gas quality, and we've talked with many mechanics that say that one of the biggest reasons why people bring their cars in deals with bad gas. For example; we thought our fuel pump was bad because we just replaced the fuel filter less than 10K ago. That was back when we used to buy 'cheap' gas. Our fuel pump cost around 350.00 so we figured we had nothing to lose by replacing the fuel filter first (which we'd have to replace anyway after replacing the pump). Guess what? Even though our filter was relatively new, after replacing it all of our symptoms went away, and we didn't have to replace the pump Most likely the new filter got clogged or damaged from using the cheap gas, so we now only buy Shell gas and haven't had any problems since.

[leshan]

I'm ot sure if the MAFS is working right. But I did not touch it, just spray. I just wondering if the sensitive electronic cleaner is ok for MAFS? I did not know MAFS cleaner before I saw it in store last week. So, I used to use sensitive electronic cleaner to clean the MAFS several times. IF the MAFS is bad, will the check engine light come on? My check engine light did not come on. I will try the MAFS cleaner first, then coolant temperature sensor.

[MyTaurus8AChevy]

Originally Posted by leshan

I did not know MAFS cleaner before I saw it in store last week.

Yes it is relatively new, but it does work a LOT better than electronic cleaner. Well worth the cost. You should also get much better gas milage afterward. Spray it once and let it sit for a few minutes (to soak in and loosen dirt) and then spray a few more times. Allow to AIR dry before reinstalling.

IF the MAFS is bad, will the check engine light come on? My check engine light did not come on.

Yes I would think so. Whenever we clean our MAFS the light does come on, so unless your light isn't working correctly it should sense that the MAFS was removed. The light might even STAY ON after you clean it. This is normal. It will go off again in around 50 miles or several fill ups, whichever comes last.

[leshan]

Thank you.
The fuel pump is aftermarket one from autozone. Last year, I can not start my car, I thought it's because of the fuel pump, so I went to autozone to get one and put it on. But I still can not start my car. Follow the autozone guy's advice, turns out that because of the crank position sensor. I'm worring about the fuel pump now. Is there any other way to change the pump without take off the tank?

[MyTaurus8AChevy]

Originally Posted by leshan

Is there any other way to change the pump without take off the tank?

It's inside the tank, so I would think not

[leshan]

I just bought the CRC MAFS cleaner. I will do the cleaning tomorow, and then watch and wait. In the past month, It only happened twice. If it will not happen more often, I will stay with it. I hate to replace the fuel pump with jack stands.

[MyTaurus8AChevy]

We just cleaned our MAFS again too. We clean it every 2-3 months Keep a diary of what happens with your car; where you buy gas, what happens just before the problem starts, how long the car was running before it happened, etc. It will help you to trace down the problem if it happens again. It's probably a gas problem but could still be something with the ignition. I have my car specially wired up so that if someone tries to steal it the fuel pump shuts off. When this happens the engine studders just before it dies like what you explained in your first post. This is why it sounds like a fuel problem to me, but it could still be something else. I don't think a dirty MAFS could cause the engine to die, but a defective one certainly could. If you need to buy a new one then you can get it at wholesale by going here.

[Huney1]

Originally Posted by leshan

I hate to replace the fuel pump with jack stands.

The trick is to run it almost dry on gas before taking the tank off.
Remember, gas weighs 8 lbs per gallon.

Get a couple of your buddys to help. Run it almost dry on gas then get it off the ground so the tank will clear the car when lowered. Have a buddy on each side and loosen the straps then lower it easy to the ground. Open the top and the pump is right there. The top comes off with a flat head screw driver like it is screwed on so use a soft hammer and tap the scredriver sideway in a circular motion. Ritey titey - lefty loosey. Keep the washers in order so everything goes back the same way it came off. Some pumps don't come with a new pump filter so get one if needed.