Crank but not starting

Hi all,

My truck is cranking but not starting. It also happened a month ago and I tapped the fuel tank and got it to start and it has been running ever since. Now it happened again two days ago and have not been able to start successfully. I am not super well versed with codes and did a bit of research but maybe can get some extra suggestions. My guess is this may be fuel pump related. I got codes P0440 and P0174 from OBDII reader.

 

Two possibilities.

If you smacked the tank and it ran, that's classic sign of a fuel pump failure. BUT we also know rats/mice LOVE to chew the fuel supply/return lines on top of the tank, and build nests on top of the tank, which could cause fuel delivery issues too.

Absense of nests DOES NOT mean they didn't chew shit up. If I had a dollar for every person on here who's had rats chew up the lines on our truck's tanks, it'd pay for a weekend's worth of beer.

Two things here:

• The EVAP code (P0440) is suggestive of rodent chewing also, it's telling you the tank and/or the fuel delivery/return/vapor lines are cracked, loose, missing (or it can be a bad gas cap, or a cracked rubber line). Your tank and fuel delivery system needs to be able to hold vacuum.
• The fact you slapped the tank and it ran again, that can be a classic sign your fuel pump is dying. And if it's ever been replaced, especially with a store brand part, it's no surprise, non-OEM pumps usually only last a couple of years at best, if they don't die within the first month or two.

What would I do?

1. I'd get someone to slap the tank repeatedly while I was cranking the truck again, to see if you can get it to catch.
2. I'd get a mirror out and look all over the (A) fuel filler neck, between where you stick the gas nozzle in, down to the tank and (B) all over the top of the tank, every corner, every line or barb you see coming up, inspecting for signs of chewing or holes.
3. Based on the results, I'd take action.

And by "results", I mean ... if you find evidence of chewing, your pump is probably fine, but you need to deal with your rat problem, and you need to replace or repair whatever they chewed on. If you find zero evidence of chewing on stuff, then it's probably time to replace the fuel pump. DENSO was the OEM manufacturer of the fuel pumps for our trucks. It's really hard to get them these days, but you (I think?) can still buy them from Toyota.

 

I can fix that

 

Thanks shifty, I am going to get some help from the father in law to tap the tank again and see if we can get it going again. Otherwise I'll definitely be taking a look for evidence of chewing. This truck is new to me passed onto me from my dad shortly after he got it. We don't really know the history of the truck besides the recalls that were completed by toyota. New battery 3k miles ago, Ball joints(upper and lower oem), timing belt, water pump, pulleys and seals were all done in the last 1k miles.

 

Definitely start here if you haven’t already: https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

Just know you need to do the timing belt/tensioner/water pump every 100k miles or 10yrs, whichever comes 1st, looks like you know this I see. And NEVER use aftermarket lower ball joints (and always use fresh hardware when replacing), OEM lower ball joints should be replaced every 125k-150k, failure is catastrophic, I see you know this already too, it seems. Lastly, Radiator should be swapped every 125k-150k (and coolant done at 100k if using pink long-life) to avoid coolant getting into your transmission fluid. If 4WD you need to grease up all zerks on the driveshafts every 5k miles to avoid premature failure, using a moly-impregnated NGLI2 grease. The rest is mostly just oil changes…

 

Have you checked the ignition fuse? I always used to remove mine on the 3.4l as a theft prevention.