Cranks but wont start... 2000 2.7L...

Strange one here. My kid's 2000 PreRunner with 2.7L 4-banger had difficulty starting after he put half a tank of gas in it. Took 3-4 attempts and then it finally ignited and ran. He drove it about 10 miles to a friend's house and it ran fine the whole way. Parked it for about 5-7 minutes and came out to find it would crank but not start. Let it sit for 9 hours, came back and it fired right up and drove 10 miles home without a hitch.

Any ideas?

 

Look at the starter. Might need replacing or the wires are loose.
Check spark plugs, sparkplug wires.

 

I'd check for bad gas first since it started right after a fill up.

 

Not a bad thought, but it runs like a champ now. It's something intermittent.

 

Is it consistantly hard to start shortly (within 15 minutes) after shutting off?

 

I would check/ clean the IACV.

 

Well if it cranks, but won't start it will NOT be your starter that's bad. I would think it may be your fuel pump. Turn key to on position without starting and listen if fuel pump is working.

 

Also check for spark when it doesn't start... if you have spark, your problem is not in the ignition system.

 

I'm in the process of feeling things out right now. Not sure exactly what it's doing on a regular basis yet because it just did it for the first time last night. After driving it home, I went out and tried it 3 or 4 times after letting it sit 10-15 mins each time and all was back to normal.

One of the first things I thought of was a stuck EGR valve but these aren't the old school types where you can reach in and check if the diaphragm is pulled up.

I also thought, since the fuel filter looks original at 160K miles, that I might replace it and see if that makes any difference.

I agree though, I need to dig in when it's malfunctioning and see if I've got a fuel or spark problem. My guess is fuel.

 

Not having a distributor, what do the 2000 2.7L trucks use to sense crankshaft rotation? Is there a crank angle sensor? Cam sensor? Where is it mounted? Could my cranks but wont start be related to an intermittently faulty sensor of this type?

Could also be a fuel pump relay.

 

fuel pump

 

Is that a guess or have you seen these pumps act tempermental like this truck is doing? I always thought fuel pumps were either dead or alive without much in between.

 

just a guess.

But if the motor cranks, and as long as you can make sure its getting spark...its a fuel problem.

when is the last time you changed the fuel filter?

 

Never. But I just got it for my kid at 157K and it's got 160K on it now.
It's on the replace immediately list.

One thing I did find in another thread is the mention of the ECU relay. I suspect without that relay functioning you would probably not get fuel or spark. Unless the fuel pump is not controlled by the ECU. Hmmm...

 

Drove my 2000 3.4 to the mall. Came out 2 hours later. Would crank but not start. Towed home. No spark. No strong fuel smell at exhaust pipe when cranked, so I don't think ejectors were firing. No blown fuses. EFI really checked good. No fault code from 'DIAGNOSIS' OBD1 (undergood) or from ODB2 (underdash) scan. Problem found: Both wires at Crank Angle Sensor connector were broken. Probably vibration over the years. Pic attached. Spliced in $3 connector pigtail from local part store. Truck runs fine again.

 

Wow. Nice work. That would be pretty easy to miss if you weren't looking for it, I imagine.