Car won't start: no cranking/or fuel pump priming sound

[cmiguel32]

I've done a bit of research already on the issue so I'm looking for some validation/recommendations for my troubleshooting process.
The car just started giving me this issue 2 days ago. It would randomly start after a couple attempts, but now it does not start at all.

When turning the key to ACC, i'm not getting any sound from the fuel pump. When turning the key I get no sound from the starter/solenoid.

I opened up the ECU box to make sure I didn't have water in it (fuse 219 is newish) nothing visually suspicious.
Battery is only a few months old and voltage reads 12.1v

I'm leaning toward the issue being one of four things:

ECU communication to the fuel pump relay/starter (ECU relay, fuel pump relay)
Bad starter solenoid or wiring on the starter
Bad connection from wiring going to ecu relay socket
Faulty ignition switch

I've considered the lower clutch position sensor, however I don't think that would explain the lack of sound from the fuel pump with the Key at ACC on. I've also considered the crank position sensor, but the sensor is brand new and having had experience with a faulty one before, the car should crank (similar logic if considering a bad rear CTS sensor -- mine is also new).

I'll pull vagcom codes again tonight, but I didn't see anything out of the ordinary.

[5ktq]

ECU has nothing to do with the cranking, so you can rule that out, for cranking anyway.

batt > main fuse > some fuse > ign switch > interlock relay > starter solenoid > block > gnd strap

that's the circuit for the starter. clutch switch operates the interlock relay. fault has to be in there somewhere (or dead battery!)

[SJorge3442]

That 12.1 is a battery with only 50% charge on it. I would get it charged up and try again. You've been around here long enough to know that our cars can get super goofy with a low battery

[cmiguel32]

That 12.1 is a battery with only 50% charge on it. I would get it charged up and try again. You've been around here long enough to know that our cars can get super goofy with a low battery

Good point. I'll give the battery a bit of a charge.

For good measure, on my lunch break I picked up relay 219, 395 (under the ECU), relay 167 (fuel pump), and an ignition switch from a local yard that had them lightly used and in stock.

[thetikm]

Man if I had read this sooner I could have given you my old fuel pump relay.

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[rocket1420]

Connect the battery to the starter. Jump over everything else to see if the starter is bad. Work backwards from there.

[cmiguel32]

Replaced all relays except the fuel pump, replaced clutch switch and relays 219 and 395, replaced ignition switch. Still nothing. Charged battery too.

No fuel pump sound or cranking.

Pulled vagcom codes, nothing except a intermittent communications code with steering angle sensor.
Check ground points, cleaned the one on the firewall next to the 02 sensor harnesses.

Reloaded last tune file and there were no checksum errors.

Time to pull out the multimeter?

[5ktq]

Put 12V to the solenoid, see if it cranks

Not cranking has nothing to do with fuel pump or ECU at all. it's entirely separate.

[rocket1420]

Multimeter should've been the first tool you grabbed. As I said above, and 5ktq reiterated, put battery voltage to the starter solenoid.

STOP just replacing parts. You are just making it harder, as now you don't know if you replaced a working part with a bad one. The more you touch, the more variables you introduce. For example, did it start working because you fixed it, or because you jiggled a wire while you were in there?

[cmiguel32]

Multimeter should've been the first tool you grabbed. As I said above, and 5ktq reiterated, put battery voltage to the starter solenoid.

STOP just replacing parts. You are just making it harder, as now you don't know if you replaced a working part with a bad one. The more you touch, the more variables you introduce. For example, did it start working because you fixed it, or because you jiggled a wire while you were in there?

Thanks and you're right. I was just foolishly optimistic for an easier fix.

Relays all have power/ground where they need to. So I tested the hot wire to the starter solenoid at the connector (lots of corrosion) and got a spike of 13v that immediately dropped to 3v. I tested the wire itself and got 13v. I pulled the connector off the starter solenoid and ran 12 volts via a wire directly to the solenoid and still no start. So we can confirm the starter is indeed bad. Ordered a Bosch replacement, but still wondering what could be causing the fuel system not to prime with Key on acc. At least the cranking issue will be resolved!

[jpulll]

So we can confirm the starter is indeed bad. Ordered a Bosch replacement, but still wondering what could be causing the fuel system not to prime with Key on acc. At least the cranking issue will be resolved!

Have you checked engine management fuses?


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[rocket1420]

The fuel pump doesn't prime key on engine off. Well, I think technically it's supposed to the first time after a while. But in general, the fuel pump only gets voltage while cranking.

[RVCA1]

The fuel pump doesn't prime key on engine off. Well, I think technically it's supposed to the first time after a while. But in general, the fuel pump only gets voltage while cranking.

I agree with rocket1420. I just replaced my fuel pump the other day after running into similar symptoms; however, I knew mine was faulty due to the "insufficient" fuel gauge fall.

But to add to what rocket1420 said, the engine needs to be cranking at a specific RPM, which I don't know off the top of my head, in order for the sensor to signal the fuel pump relay to fire via the ECU. I don't know the specifics numbers, sorry.

Also, You wont get power to the fuse until this relay closes. You can jumper the relay to check the pump. If that works, you need to see why you're not getting the signal to the relay. As said, if the engine is not turning, the fuel pump relay will not be active. If you crank for a while without starting, the relay will disengage. If you have no crank or cam signal, the relay will disengage so check those. If you don't hear the pump when you jumper it, you have a dead pump.

"Best case" scenario is to check the cam position sensor.

Then again, I may be wrong. Just some notes I've read over as I could be just mumbling, but if not, then I hope it's as minor as a sensor. Good luck!

[cmiguel32]

Replaced starter, still nothing.
Tightened bolt for ground strap on passenger side engine mount and voila, it starts.

Guessing it wasn't torqued to spec when the engine was installed.

[SJorge3442]

Replaced starter, still nothing.
Tightened bolt for ground strap on passenger side engine mount and voila, it starts.

Guessing it wasn't torqued to spec when the engine was installed.

Ah, yeah those straps can suck to get to (atleast on the 3.0). Glad it was an easy fix, albeit it took a little while to figure it out.

[RVCA1]

Ah, yeah those straps can suck to get to (atleast on the 3.0). Glad it was an easy fix, albeit it took a little while to figure it out.

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