2012 Malibu, intermittent crank but no start

Maintenance/Repairs
1

2012 Malibu, 140k. Started about 1-2 months ago. It cranks but doesn’t start. The lights, radio, etc, come on just fine. I replaced the battery first off. The parts shop said the battery was borderline, it was due, so I replaced it. Still having it. Sometimes it starts and runs fine. Sometimes it cranks but doesn’t start. Sometimes it starts for a second but then dies. Sometimes it starts and rumbles and shakes like crazy, and then dies.
I’ve had the fuel pump relay changed twice. My shop is saying the fuel pump is testing ok. Earlier tonight, when it was cranking but not starting, I took out the fuel pump relay, did nothing to it, and put it back in 5 seconds later. It started right up.
Any ideas?

EDIT: It has cranked but not started for the shop too. That’s when the changed the fuel pump relay

EDIT 2: Took it to an electrical shop. They found a burnt out wire leading to the fuel pump relay. Changed it out. Working so far. Fingers crossed

2

A failing crankshaft position sensor can cause the problem you describe.

Tester

3

+1 for possible Crankshaft Position Sensor…

Sounds like it be time to find another shop, depending on if it is not starting for the shop or not… Or invest in a scanner that has Live Data to check it yourself…

Remember though, if your shop is testing it while the vehicle is starting, it will most likely test good, it has to be cranking and not starting to find a crank, no start problem… So you might have to leave it for a while depending on how often it no starts…

4

I’ve never had a warning light with it. With no light, would anything show up on a scanner?

6

You would be checking Live Data, not checking the codes… Live data on a scanner shows your vehicle’s real-time sensor readings and system statuses (like RPM, speed, temps, O2 sensor voltage) as it runs…

Disclaimer, I only watched a few seconds of the video, but it shows Live Data anyway…

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7

Not that this makes a difference, but is your’s a push-button start Malibu?

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8

It’s keyed.

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9

One more item ruled at least.

Yeah, I prefer good old-fashion stick-a-key-in-the-ignition cars.

(waiting for all the obnoxious “Of course YOU would!” static to begin)

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10

This may not be your problem, but I will leave this TSB it might help someone in the future.

It says if one or more of the symptoms listed is something that you may be having

It may be caused by the body harness making hard contact against the floor panel’s edge under the left rear seat cushion.

15-08-45-001 1..2

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11

Sure, crank sensor which is cheap. I changed mine just preemptively. About $50 total. But I’m a fuel pump guy with Gm. Sure it tests fine when it runs but what about when it’s not starting. I’ve had them go out on almost an annual basis. A5 th3 gas station wouldn’t stsrt, put the pressure guage on it and zip. Banged on the tank with a 5 lb hammer, and started. Towed from the ramp and started when it hit the shop. Have had bad contacts at the pump and three new ones fail out if th3 box. I don’t trust them at all.

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12

You must be related to Han Solo :joy:

How’d he get the Falcon started in a jam!

13

Delphi is the Only Fuel Pump assembly I will put in a GM vehicle, the rest are junk, don’t remember ever having a bad out of the box or having to warranty a Delphi fuel pump assembly… Can’t say the same for the others, AutoZone’s and Airtex were the worse…

It is an old trick to get the brushes or whatever to vibrated enough to work again for a time, same as hitting a starter to get it spin enough again to start the vehicle…
Hitting something can sometimes jar whatever just enough to make electrical contact to work again for the time being, often doesn’t last long…

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