Engine won't run. Dies after brief start.

[Lacy923]

I need help! I have a 2002 Tundra v8 4x4. Let me first give you a little history. The O2 sensor (sensor1/bank1) went out about 6 months ago. I finally got around to replacing last week. I also changed the plugs. After about 300 miles on the new equipment, my truck lost power and died. After repeated attempts, it would not start. Now to the good stuff With the key in the "ON" position, I hear a constant high pitched humming sound from the throttle body assemby. I first thought it was the fuel pump or a relay, (I have not tested yet) but low and behold, my truck started this morning and ran about 10 seconds (the check engine light was not on) before sputtering and finally dying. It would not restart. I am now leaning toward an extremely dirty engine. If the sensor allowed the fuel mixture to run rich for the last 6 months, it stands to reason that the throttle body and all other parts (fuel injectors, etc) are covered with gunk. Does this sound like the problem or could it be something else. Please give me some input so I can isolate and correct the problem. If it turns out to be dirty, what ius the best way to clean it?

[Puffnstuff]

After I read this I began to wonder if the problem might be with the drive by wire throttle. Could it be that it isn't opening the butterfly up and choking the engine? I would clean out the tb and make sure the butterfly isn't being hindered by build up.

[Lacy923]

Thanks for the advice. After reading your post, it stands to reason that if the butterfly valve cannot open or fully open due to build up that the motor could humm. I will clean it this afternoon and report back.

[Lacy923]

Well,

I cleaned the TB and no luck. What is the easiest way to determine if the fuel pump is working? I have a Hayes manual and it says that you should be able to hear the fuel pump engage for about 2 seconds when the key is turned on. I cannot hear anything from the fuel tank, but I can hear something from the engine??? Last night, I loosened the nuts that contect the fuel filter and tried to start the truck. I did not see any change in the fuel dripping from the filer ends (I would have expected it to spray if the pump engaged). So I am leaning toward the pump not functioning properly. That brings up the other question....could it be the fuel pump relay or the EFI relay? Both are over $50 and non-returnable. Is there a way to test either of them? Is there a better test to isolate the fuel pump as the culprit? Please respond if you can think of anything.

[Picasso]

Welcome to TundraSolutions Lacy923.

What is the easiest way to determine if the fuel pump is working? I have a Hayes manual and it says that you should be able to hear the fuel pump engage for about 2 seconds when the key is turned on. I cannot hear anything from the fuel tank, but I can hear something from the engine???

I just went down to my truck and turned the ignition to the ON position without starting it. I heard the whine/humming sound from either the throttle body or starter. Could not hear a thing from the fuel pump in the tank. (With the exception of slightly clogged fuel injectors, my truck runs fine.)

Last night, I loosened the nuts that contect the fuel filter and tried to start the truck. I did not see any change in the fuel dripping from the filer ends (I would have expected it to spray if the pump engaged).

If you are saying that you unscrewed one or both of the lines at the fuel filter, and nothing sprayed out when you turned the ignition on after doing so, then you definitely have narrowed down the problem. Just to narrow this down a little further, did you unscrew the line at the filter that goes to the fuel pump? I'm trying to eliminate the possibility of a severely clogged fuel filter with this question.

So I am leaning toward the pump not functioning properly. That brings up the other question....could it be the fuel pump relay or the EFI relay? Both are over $50 and non-returnable.

Very possible but I don't think likely. When electrical relays go, they typically go for good. You stated earlier that your truck started again after dying.

Is there a way to test either of them?

Yes. Do you have a digital volt/ohm meter with a continuity circuit tester?


When your truck won't start, does the starter sound like it's engaging or is there just dead silence when you turn on the ignition? Has anything else recently happened or been done to your truck, whether you think it is related to your problem or not?

Right at the moment, I do not believe that your symptoms have anything to do with your O2 sensor, but with a little more info I'm certain we can find the problem.


Paul

[Lacy923]

I think I have isolated it to the fuel pump. I borrowed the fuel relay and the EFI relay from a friends truck and put them in mine. NO luck. So, I switched the EFI with the open relay (they are the same) and still no luck. I noticed a small mention in the Hayes repair manual regarding fuel pump operation. Apparently on the v8, the fuel dampening sensor will engage and a small screw will slightly raise when the pump is functioning. I checked on the working Tundra and this was true. When I checked on mine while attempting to start, the screw was recessed and did not move. So, I am 99% positive I have isolated it to the FP. My only question is after I remove the tank, can I take a meter and check the connection to see if a curcuit exist to power the pump? If not, it could something more isolated and possibley severe. If a current exists, I need to replace the FP. Does this sound like a good plan? Could it be anything else at this point? And yes, it attempts to crank, but does not start.

[Flashgordon]

Yes, you can check to see that you have voltage at the FP connector. The thing is though you also want to make sure you have amperage. You might have 12v. but not enough amps to work the FP. A wiring problem might exist then...resistance.

I agree with your assessment that it is a FP problem though.
What a lot of people don't know is that it's very important not to let the level of gas drop below a quarter tank.
The gas is what keeps the pump cool and prevents an early failure.

Good luck!

[Lacy923]

Below a 1/4 tank???? That would explain it. I typically drive around with the low fuel light on! Any suggestion on a new pump? Dealer is about $350-$400. I found a new one on EBAY for $50.00 with a new screen. It is a Bosch OEM for my year model. What are your thoughts?

[Flashgordon]

You might be OK with the one from eBay and it sounds like a fair price. I can't comment on Bosch FP, never used one.
If you are at all concerned, go to a Napa Auto parts, CarQuest, etc.

Good luck!

[Lacy923]

OK, I made the final step. I have removed the gas tank and am waiting on the fuel pump to arrive. I am a bit disturbed by some of my findings last night. The Hayes repair manual stated that the fuel pumpo should come on when the key is in the "ON" position. I started at the relay box and checked for power in the EFI relay socket. After inserting the EFI relay, I had power at the C/Open relay socket. After inserting the relay in the C/Open socket, I checked for power in the Fuel Pump Relay socket. Low and behold, it does not exist. However, when the key is turned to start (turn over) the motor, I have power. When I disengage the starter, I lose power. I also get the same result at the fuel pump. Since earlier test showed that the fuel pump was not working at any point, I was not too worried. But, if the pump does not work in the "ON" position, how will the truck maintain fuel pressure????? Am I still OK?

[lou_lams]

its been awhile since I have worked on cars but, I use too work at a toyota dealer years ago. are you able to get a hold of another tundra and try cracking the fuel line on that one and have key on, engine off and see if u have constant pressure? make sure you have towels handy and covering the cracked line, and maybe even a bucket underneath just incase. to kinda answer the earlier question about the o2, when it goes out, the computer goes into a fail safe mode, inputing its own values of what it thinks it should be at based on your prior driving habits, so it should not be getting that kinda of build up where it won't start again. at least thats what I rememberoh and the other thing about relays, I have seen some with intermitent problems

[Lacy923]

I replaced the fuel pump and we are up and running good as new. After getting the old FP out, I noticed that the pump screen was extremely dirty and the in-line filter was almost impossible to blow through. The pump I purchased on EBAY was only $50.00. The dealership wanted almost $600 for the job.

A note to all you out there. If you do have to replace a fuel pump, make sure you reset the computer. Apparently, mine was so starved for good gas flow that it was way out of whack when I finally got it to work correct. After resetting the computer, everything was fine!

[Flashgordon]

Thats great news Lacy!

Most of the OBD II vehicles will run the fuel pump for about 5 seconds with just the key "on" then the pump will shut off. A prime so to speak.
This is normal until a start condition is detected then the pump will run as normal.

Since you said your tank and screen were rather dirty, get some Chevron Techron Fuel Injector Cleaner (best cleaner on the market!) and wait till your tank is damn near empty. Add the cleaner per instructions and fill with a good quality premium gas (Amoco Gold, etc.)
This will really clean you injectors and your vehicle will run smoother.

Contrary to what I said above, remember to fill your tank when it reaches 1/4 tank.

Glad you're up and running........................