Turns over but won't start - already used "search"

Looking for some advice of where to look next. I have a 2001 Cab that stranded my wife the other day at the grocery store. It would turn over, start and run very rough, and then die about 5 seconds later. Using the throttle would not increase the revs at all and now it will not start at all, it simply turns over and over. I got the car towed home and hit the "search" feature on this forum. It seemed like a common theme was the "Crank Position Sensor". I ordered the new sensor and replaced it with confidence yesterday thinking it would solve my problem; it didn't. So now I'm just looking for a little advice of where to look next. I do hear the fuel pump kick on when I turn on the ignition and the carpet is NOT wet under the seats. Any suggestions...? Travis

Silly question but..........how much fuel is in the tank?

I just laughed out loud at that question but only because that's the first thing my wife asked me... It shows it has plenty of fuel and just to be sure I added about a half gallon yesterday once I had it up on jack stands. I'll probably go ahead and add a full gallon or so just to completely rule out a faulty fuel gauge. Although the gauge does show it has close to a quarter tank.

Basically three things make an engine run: air, fuel, spark. Gets way more complicated after that. Sneaky Pete is correct to ask the question. Doubtful it has anything to do with air. Also, is it throwing any CEL codes? How is it if you turn on the ignition but not to start? Dash light up and all appears ready to go, or is anything amiss? Anything electrically strange happening? I agree the CPS was the place to start, but now you have eliminated that so you are going to have to find out if you have fuel pressure in the rails and spark at the plugs. Might require some patience but you will find the problem. Check all fuses. Pull the negative cable on the battery, wait ten minutes, reconnect and that will reset the DME.

I appreciate both your responses, I only laughed at Sneaky Pete's question because my wife asked the same thing. It was a totally legitimate question, and the obvious one to ask first. I don't know if it threw any new codes because the CEL was already on due to a "bad" secondary air injection pump. I don't have a code reader and normally just go to the auto parts store to have them read the codes. Maybe I should buy a code reader but since I've disconnected the battery will it show anything? I'll check for fuel pressure and the fuses when I get home this evening. Is there a fitting on the fuel rail that I can depress to see if fuel sprays out under pressure? Yes, patience is important when working on cars. Thank you!

Disconnect the hoses to the secondary pump and try to start it. Only a WAG

Darn! Since you disconnected the battery it probably cleared any codes. Still would not hurt to have an OBDII reader and check. You can get one at the auto parts store for $50-60. Might come into play next time you attempt to start and it doesn't start. It might throw a code at that point. Aside from a clogged fuel filter, I'm leaning towards something wrong with spark, or a blown fuse. Double check the connection of the CPS. Next up, throttle position sensor, MAF, and idle control valve. I would leave the fuel pressure for a bit later since it is tricky to connect a gauge and check pressure.

I'll try both of your suggestions and report back this evening. Fuel filter was changed about 1k miles ago along with RMS, IMS bearing, clutch, spark plugs, plug tubes, AOS, brake pads, 2 window regulators, transmission rebuild, steering column stalk, etc... Been running great since I put it back on the ground a couple of months ago until now... The SAI pump runs so it's got to be a valve somewhere. There's always something to do on these cars. Thanks again.

Is yours a C4? The gas gauge shows the car's best guess on how much fuel is left once you start to get closer to empty, and sometimes the guess SUCKS.

No. It's a 2001 Cab

Two other thoughts came to mind to check: when you are checking the fuses, check to make sure the wiring and switches are connected on the clutch pedal lever (assuming you have a manual), and also check that the accelerator control pedal sensor hasn't gotten kicked loose or disconnected. The accelerator control pedal sensor is under the dash...the cable for it comes out of the top of the accelerator pedal. When you press on the accelerator, does it move the TB connector in the engine bay?

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Yeah, I saw that, but I wasn't sure whether or not yours was a C4 (they made 'em in '01) and thus you were cursed with the stupid hump tank. Keep us posted - I'm curious about the cause. When it happened to me, it was the fuel pump.

Agree with others you need a scanner to retrieve the error code(s). Try to get a scanner that also reads real-time sensor data values. If you use an Android phone, you can get the cheap bluetooth OBDII dongle.

Really reads like a fuel pump (or fuel pump relay) is at fault. You sure you are hearing the fuel pump run when you turn the key to on? It might be worth replacing the fuel pump relay. (I borrowed a fuel pump bypass/test relay from a Porsche tech to confirm my car's relay was ok.) If you are sure you are hearing the fuel pump run when you turn the key to on do you hear the pump continue to run if you wiggle the key in the ignition? (I'm of course thinking maybe the ignition switch is at fault.) Is the battery in good shape? A bad battery can crank the engine but may not have enough juice to light the spark plugs.

BTW, even if you can hear the fuel pump running, still doesn't mean it's delivering enough fuel and fuel pressure. Really need to check the pressure and flow rate at the fuel rail to properly confirm the fuel pump is good. How old is the fuel filter? You need to check if you have sparks and fuel to diagnose it further. Also check the C2 fuse.

First thing I would do is check fuse C4 (3rd row from top, 4th fuse from left). I pull mine often to turn the motor over (w/o cranking it) and pump up the oil pressure in th 4-6 tensioner to prevent chain slap.

I'm printing out the string of responses so that I can try them when I get home from work tonight. I'm also going by the auto parts store to borrow a code scanner tonight. I'll report back this evening. Thanks everyone for their help. Travis

Ok. A little update. Checked fuses = all good I was incorrect; the fuel pump does NOT turn on. Need to test the fuel pump relay. Searching how to do that now.

Oops

Jump pins 30 and 87 of the fuel pump relay (position #13) socket the fuel pump should turn ON. If not, it's likely the fuel pump is dead or there's a wiring problem. Edit: actually the fuel pump relay is not the generic type so it can't be swapped with other relays. When you crank, does the tachometer needle shake at all trying to rise?

Tried jumping the terminals and the pump does NOT turn on. Then I used a voltmeter to check the voltage at the relay socket for terminals 30 and 87 and I have no voltage. Must be upstream of the relay panel.

Pin 87 is connected directly to the fuel pump so it should not have voltage when the relay is unplugged. Pin 30 should have 12v at all times and it gets power from fuse C4. Have you unplugged fuse C4 and check for continuity?

I think maybe I checked the voltage incorrectly. Let me go see if grounding the voltmeter and then checking one of the terminals gives me a reading. Electrical components are something I do NOT understand... Mechanical makes sense

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If you do get 12v at pin 30, you can try swapping out the relays like I suggested above.

Ok, now that I've tested for voltage at the relay socket correctly, I know that I have 12 volts going to the relay. I ground out on the door hinge and checked voltage at terminal 30 on the relay socket and had 12 volts. When jumping terminal 30 and 87 my fuel pump does NOT turn on so I guess that means my fuel pump has crapped out. Sound right?

I'll try swapping out the relays as Ahsai suggested just to confirm.

Also, check resistance between pin 87 and the chassis, which measures the resistance of the fuel pump, which should be quite low. If you get an open circuit, your fuel pump is toasted or there's wiring problem between the relay panel and the fuel pump side (less likely).

Ahsai, thank you for walking me through that; electrical stuff frustrates me because I don't understand it. I checked the resistance between pin 87 and the chassis and definitely have an open circuit. Since I DO have voltage at the relay socket and can't get the fuel pump to turn on by jumping the pins, it must be a bad fuel pump. If anyone sees I've missed anything please let me know. If not I'll order the pump and replace it. Thanks again!

You're doing great! I also hope you found an open circuit on the fuel pump side. To be 100% sure since the fuel pump is not cheap nor is it an easy job, you should make sure the OPEN circuit is inside the fuel pump as opposed to be between the fuel pump relay pin 87 and the fuel pump or between the ground and the fuel pump. You are not quite home free yet but getting very close. Now you need to go to the fuel pump connector (4 pins), unplug it and check if the resistance between pin 4 and pin 1 (where the Brown wire and Green/White wire go into) indeed are OPEN circuit. Those two pins are connected to the pump. If you get some low resistance, the fuel pump may be OK. See Figure 3 here for the 4 pin connector (2 pins are the fuel pump and the other 2 pins are for the fuel level sensor). Make sure you test the right pins!! http://www.pelicanparts.com/techarti..._Fuel_Pump.htm Edit: added the wiring diagram for clarity. junk.pdf

You are awesome. I'll check that tomorrow evening and report back.

Didn't get around to checking the actual pump itself last night. I'll definitely report back once I get to it. Probably going to be a few days.

I put in the replacement fuel pump this evening and IT RUNS!!!! Thank you everyone for your tips and advice and thank you Ahsai for your step by step diagnosis. Travis

Glad you got it sorted out. So it's the fuel pump after all. You could also ohm out the old fuel pump now that it's out.