Intermittent crank/no start issue

[Matt Allen]

First off – thanks to ETCG for some great videos! I’m a 30 year veteran of the IT industry and I used to work on cars in HS but always relied on others that knew more than I. With 2 kids in college, I now have four cars to maintain and I find doing the work rewarding and fun, and certainly cheaper than paying others. Thanks to the great vids from ETCG I have the necessary confidence to better understand my car’s systems and lunge forward with my home style maintenance and repairs in my own driveway. I even asked for an impact wrench for Christmas, I have a feeling it’ll get opened this weekend however!

To Eric – you’re not charging enough for your premium membership but then again the low price was a no-brainer for me so I signed up right away.

Now on to my problem. My son has a 2002 Ford Taurus v6 LE with about 268k miles. The engine was actually replaced before I bought the car ($300) so it’s not original motor. With more frequency, he is having an issue where he will go to start the car and it’ll crank but it won’t ignite. Last month his battery died, I had it tested at AutoZone, confirmed bad, and replaced it under warranty from Wal*Mart, it was only about 15 months old. After putting in new battery, the car wouldn’t start. It cranked just fine. Came back the next day, car started right up. This failure repeated itself two days ago. Then again last night he had the same thing happen, but after a no-start, he shut off ignition, waited several minutes, then it started right up, so in that case he did not have to wait several hours or next day. I have noticed during these incidents, I cannot smell fuel near the engine compartment, no flooding, no gas whatsoever which seems odd to me. Also I cannot hear the fuel pump but that is true even when it is working, I think is near the rear passenger seat. I also placed my ear on the fuel filler and couldn’t hear the pump go on, or off. Again this is true whetheer the car starts, or not. It seems to me if the intermittent problem was a fuel filter, or fuel pump, it wouldn’t be intermittent. Also, if it was an inertia sensor switch, that would stay off until reset, not be intermittent. Do you guys think I might have a bad fuel pump relay? How could I check that if it’s intermittent? Thinking maybe I should just replace that and see if it helps. Because it’s so intermittent, I’m not sure what to test. I did get a Fuel Pump pressure tester from AutoZone (on loan) but heck, I can’t even locate the schrader valve on the fuel rail. Even if I could, the car is starting now so there is no failure to test for. Lastly, I do have an ELM327 OBD2 Bluetooth adapter and I’ve loaded up several apps on my smartphone but didn’t see anything out of the ordinary and of course there are no error codes or CEL or MIL to check. I’m at a loss about what to look at now.

I apologize for the long thread, but wanted to provide detail so you could assist. Thank you in advance for your time and suggestions.

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[none]

Fuel pumps can fail on an intermittent basis. If the pressure tester auto zone provided any extra fittings, you might be able to tap inline between the supply line and the rail. You might want to try between the filter and the fuel line as well. Being able to tap in anywhere with the pressure gauge is what gets you moving in the diagnosis. Testing a relay on the cheap is as simple as switching the fuel pump relay with another one already in the fuse block and try starting the engine. Because it’s a Taurus, I’d want to start with fuel, but you could check for spark if that’s all the farther you can chase at the moment.

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