Solid Crank, Zero Start - Ideas?

[phattyduck]

The 4runner don't prime the fuel pump with the key in acc. It only runs the pump while cranking. I'd now jump the pump connector to see if you can get the pump to work.

Agreed. I'll be the third one to say it on this thread. The fuel pump doesn't prime and won't prime. It only runs in the the START position OR if the key is on AND the engine is running. If the engine stalls for any reason (or key is turned off), the fuel pump runs for 1-2 seconds after that then turns off.

-Charlie

 

[ShakenBake]

Thanks everyone for your responses and help.

The replies stating that the fuel pump only runs when the engine runs was useful.

I was either busy with work or too lazy to do any of the recommended testing until today and here's my update.

I first checked with my OBD2 dongle and I found that it IS able to communicate with the ECU and there are NO codes. this effort also showed RPM >0 when attempting to start it. That leads me to believe that the crankshaft position sensor that I replaced is working as well as the ECU. The one I replaced was also probably working but oh well. This one should be good for another 235K miles.

Next, per the factory service manual, I checked the resistance on the fuel pump but I'm not 100% certain I did this as prescribed. I used a multimeter to check the resistance on pins #4 and #5 at the connection to the fuel pump via the access hatch underneath the rear seats. As stated, this was done at the access hatch connection, not the pump itself (I didn't want to drop the tank just yet). The result I got was "OL". Full disclaimer, I'm more of an idiot when it comes to electrical than an electrician. This result would indicate that the pump is bad but the FSM says to do this test with 12V supplied and I'm not sure that's what I did because I did this test with the hatch connection disconnected. I assume the multimeter supplies some voltage to be able to do this test. Did I do this correctly?

Next, I tried jumping the pump. Per the FSM, I connected the positive battery terminal to pin #4 and negative to pin #5 and nothing. No noise or vibration.

Based on this, can I safely assume the DeatschWerks fuel pump shit the bed after 5 years? If so, I'm a little gun shy about going with a non-Denso fuel pump. The OEM one I replaced for the Deatschwerks fuel pump was still going strong after 23 years. I did some research and discovered that the 4th gen 4Runners have a higher flow OEM Denso fuel pump with identical dimensions and connections. The only difference being the prefilter. Assuming I properly diagnosed this, I may buy the stock Denso pump and appurtenances (prefilter) and the 4th gen Denso pump.

Does this make sense or did I do this wrong?

 

[T4R2014]

Sounds right. That brand pump is popular in the aftermarket scene for some godforsaken reason. It's probably just a Euro sounding name on bulk AliBaba junk. I have zero interest in dropping fuel tanks twice so the 4th Gen V8 Denso pump is a good call.

 

[2TH4IST]

Yeah sounds like a dead pump. When you ohm out something OL means either an open circuit or resistance so high it can be/or is registered as and open.

Hell if you need to boost your pump, I've used the aeromotive fuel pump speed controller and the Kenny bell boost a pump. But either of those costs more then probably 3-4 stock denso fuel pumps lol. 1jz single turbo Cressida.

Most denso pumps use the same inlet strainer size. So you can get a 3rd gen and clip it onto the 4th gen pump

Denso fuel pump strainer

Save a bit and just get the pump with out the strainer and buy the 3rd gen strainer.

 

[ShakenBake]

Sorry for taking so long to provide an update, it took me a few weeks to get the correct pigtail for the fuel pump. I finally replaced the fuel pump and it's running again. Thanks to everyone for helping me figure this out.

I ended up going with the Denso 951-0024 fuel pump which is for the 4th Gen 4Runner V6 and V8 figuring it provides higher flow rates than stock. Everything is pretty much identical to the stock pump except for the electrical connection at the top. The stock pump has a smaller gauge blade style connection. To make it work, I got the "Import Direct Fuel Pump Wiring Harness - Z11061" from O'Reilly's and spliced it with the stock harness. FWIW, It looked like the wiring harness for the Deatschwerks 200 that I replaced would have worked as well.

 

[2TH4IST]

Glade we all could help. Good to hear it's up and running again!