Car is still not starting. Need suggestions

[BATMAN]

Alright here is the deal. I am not sure where the problem is and Bill is out of town so i can't get him to run over here and help me. So, hopefully this is something i can fix on my own.

On my way home, my car started to stutter a little. I saw my fuel preasure gauge fluxcuate, but not the way your thing... i was loosing fuel preasure and then it would jump back to 45psi where it was supposed to be at. So its not boost related. So needle was basically bouncing. I could hear the whine of my fuel pump decrease with the loos of fuel preasure and increas with the preasure gain. I made it home and the turned off the car. Turned it on again and saw no problems. A couple hours later, i went to turn on the car and it wouldn't turn. Kinda like when your starter goes out.

I thought it might be the battery so i started to charge it. After charging it for about half hour, it still wouldn't turn. I gave it one last try and varoom the car started... but not even a minute into it i could hear my fuel pump whine down and see my fuel preasure drop and then i saw the needle drop from half take to empty and the car turned off. Now i can't get it to turn again. I know the problem is definately fuel related.

Now i read the tech database. Do you think its the fuel relay? What i tried is going into my fuse box and switching the AC relay with my fuel relay (the little grey boxs). THey had the same part number, but that didn't work. I thought it might be the fuse on the wire going to the external fuel pump, but thats not it either. do you think its PCM related? Do you think its the air fuel ratio not being read right? I'm not very technical when it comes to the fuel.

Now...based on the Engine tech database...it sounds like my car is not staying in closed loop. The last thing that happened to me was that i bottomed out and i messed up my catalytic converter again. I wonder if i damaged my o2 sensor...if it is damaged is it possible that it is not reading the correct air fuel ratio and then not going into closed loop? I would think that a code would be thrown out for that and i am not getting any codes. There are people with no cats and the car still runs so thats why i am ruling that out. Again i am not a fuel expert so i am just throwing that out there.


In my case, my car is supercharged so i do have an fmu, an external fuel pump. The external fuel pump is running off the same power source as the stock fuel pump from what Bill told me. He can't really tell me whats going on without seeing it himself so i have to wait till he gets back. Now... i have 50,000.00 miles on my car and i haven't changed the fuel filter yet. Could that be it?

Any ideas? Let me know.

HEre is the excerpt from the tech database:


3800 PCM Operation

The 3800 computer has several Modes of operation:

STARTING MODE

When the ignition is turned ON the PCM energizes the fuel pump relay for two seconds, allowing the fuel pump to build up pressure. The PCM then checks the Engine Coolant temperature (ECT) sensor and the Throttle Position (TP) sensor. During cranking, the PCM checks the crankshaft position signal in order to determine the proper air/fuel ratio for starting. The PCM controls the amount of fuel delivered in the STARTING Mode by changing how long the fuel injectors are energized. This is done by pulsing the fuel injectors for very short times.

RUN MODE

The RUN Mode has two CONDITIONS called Open Loop and Closed Loop. When the engine is first started and engine speed is above 725 RPM, the system is in Open Loop operation. In Open Loop the PCM ignores the signal from the Heated Oxygen Sensor (HO2S), and calculates the air/fuel ratio based on inputs from the TP, ECT, MAF sensors. The system remains in Open Loop until the following conditions are met:

1. The HO2S has a varying voltage output showing that it is hot enough to operate properly (this depends on temperature).
2. The ECT has reached a specific temperature (reported to be 170 degrees).
3. A specific amount of time has passed since starting the engine.

When these conditions are met, the system enters Closed Loop. In Closed Loop the PCM changes fuel injector on-time based on the signal from the HO2S. This allows the air/fuel ratio to stay very close to 14.7:1.

[ November 02, 2003: Message edited by: BATMAN ]</p>

[Tiago]

actually I would check the alternator first, see if its ok then move on from there.

[Magnus]

alternator.

also, advanced tech is not about minor car fixes and troubleshooting so I'm moving this to general.

[black98V6]

well it could just be your stock fuel pump going out, since you have a fuel pressure guage you have a little more to work with than most people. I would say either your pump isn't getting enough juice because of either bad wire or bad ground OR the pump is on it's way out. Now as far as the car not even turning over makes me want to lean toward a power issue. check your ground from the battery to the block make sure it's tight. You could have knocked something loose on that bump you hit when you messed up the convo.

Yeah now that I think about it i'd check both the hot and the ground connections from the battery.

[slacker69]

Yeah i was gonna say check the stock fuel pump maybe hook a volameter to it and see whats happing.

[Riles]

it seems like one of the pumps, because even if your car is not in closed loop, your fmu should raise the pressure regardless of the pcm or the injectors (assuming you had some boost). Try using your fmu to raise the pressure using compressed air- see if your pump can still go up in pressure.

I would seriously check your stock pump, or even your in-line- if the inline pump is not on (or failed), can the stock pump push it through the inline without a pressure drop? I dont know much about inlines-i use an intank walbro. But, it sounds kind of like the symptoms of something that spins that is having touble spinning (like fuel pumps).

[Magnus]

his motor wouldn't even turn... means no juice.. not lack of fuel.

i bet when you DO get the car running your volt meter goes down slowly, then when its too low your car just dies..

cause you have no juice..

cause your alternator is not charging.

[BATMAN]

actually there is nothing wrong with the voltage. I already thought of that and tested it. Infact the voltage stays strong, just the fuel preasure drops and car stops.

When i meant it doesn't turn... i meant it doesn't turn on. You can hear it trying but doesn't turn on all the way and when it does turn on, it turns off after a minute of running.

[Magnus]

Car is off... put the key in the ingition, turn it to on position.. what does yoru fuel pressure go to? in about 2 seconds it should drop... what does it drop too?

wait 10 more seconds, where is the fuel pressure at now?

[WickEdSix9838]

you've driven your car 50000 miles w/o changing the fuel filter?????? i think that would be a good start...

[BATMAN]

Changed the fuel filter this weekend. The car is still not starting. Its cranking, but not starting.

Magnus. I tried what you said. I turned the key on and my fuel preassure on my stock gauge goes up to about 3/8s of a full tank. It used to go up all the way to half a tank but i lost some fuel when i changed the filter and from all the attempts at starting the car i am sure thats why its lower. It doesn't drop though. i waited 10 senconds and it just sits there. However my autometer fuel preassure sits at 0. Nothing happens. However i don't think thats going to read anything till the car starts.

What do you guys think? I think its my external fuel pump. I mean if it was power to my internal then i wouldn't see any preassure on my stock gauge right?

Could it be bad fuel? I thought about syphoning out some fuel to see if there was water in it.

Any ideas?
How could i see if my fuses are still good?

Is the grey block in my fuse box the fuse or the relay for the fuel pump?

[FunkZ]

Um, the amount of fuel in your tank has nothing to do with the pressure, hehe unless it's empty.

I was going to say alternator also, especially at 50k miles (that's about when mine went out) and the gauges will go crazy and not read correctly when the voltage drops. Using a volt meter, what is your battery reading with the engine off? Also if you can get it running again, what is the battery reading then? Should be around 12 and 14.4 (off and running)

If you're sure your alternator is not the problem, then I would check for spark and fuel. Pull one of your spark plug wires off a plug, stick a screwdriver in the end and hold it close to the block/heads while somebody cranks the motor. To check for fuel, pull that plug and see if the tip is wet with gas.

[Riles]

The fuel pump or pumps are not working. He said his autometer fuel pressure gauge is not moving when he turns the key. It should flash up to full pressure for a couple seconds. He has NO fuel pressure.

Check to see if voltage gets to the pumps. If so, then one of the pumps is probably not working.

[camaro_speedemon]

Do you hear the fuel pump come on when you turn the key to "on" That's a good indicator right there if you don't.

[Magnus]

you should have fuel pressure when you put the key in the on position.

You have 0.

You have a bad pump or relay.