Confirm Fuel pump failure on crank no start

[lo_jack]

So coronavirus happened and I got ISTA+.


I checked EWS and it says everything is good. Key enabled, starter enabled. There's no diagnostic the the EWS menu I could find for fuel pump, however. Read state says they are on the same code and the key is active.



I tested the fuel system for leaks with INPA...tested within spec on the pressure test. But I didn't see a pump diagnostic test.



I queried it about the battery terminal safety thing, and it says no fault codes stored for that.


My battery light is on, according to INPA, it sits at 11.68v connected to the charger (10a) and when I crank it goes to 10. So maybe that's still no good.


But it still looks like I am getting no fuel to the rail.

[andrewwynn]

Like you said. No electricity no pumping.

My foxwell will direct command the pump. I'm pretty sure ISTA will also.

See if you can command the pump on.

Lift the back seat and the sound is obvious.

If no power at the pump even with command test then hotwire the pump (I usually use an M12 Milwaukee drill battery but you can use the cigarette lighter port). If the car will start with hotwire pump, at least your car isn't veto the fuel/spark you prob just have a broken wire

[andrewwynn]

(one time when I was charging an AC system that refused to engage they clutch I just fed it 12v with a drill battery). I discovered afterwards the low pressure switch failed open but after putting in 7 cans of R134a I really didn't feel like starting the whole process over so that car now has a paperclip for a low pressure sensor!

[upallnight]

Originally Posted by andrewwynn

(one time when I was charging an AC system that refused to engage they clutch I just fed it 12v with a drill battery). I discovered afterwards the low pressure switch failed open but after putting in 7 cans of R134a I really didn't feel like starting the whole process over so that car now has a paperclip for a low pressure sensor!

I think your system is overcharged, not unless you have a huge leak. Even 7 cans into a completely empty system the system is over charged.

[andrewwynn]

Yikes! Not my car. It was a Chevy suburban with a rear evaporator. I was quite surprised that it didn't start cooling after 3-4 cans but when I looked up the requirements it needed like 6. Can't get all of a can out with a non pump system so needed 7 I think.

[lo_jack]

Back from the dead. Using INPA first, and then another machine with ISTA, I checked EWS alignment. Both keys are registered and EWS is not my problem.

So I replaced the fuel pump relay and all the related fuses, just for fun. 47 in the glove box and the one in the little holder next to the computer.

I put a new fuel pump in, key on--no sound.
But the fuel pump fuse that I just put in is blown.

Why would I be blowing fuel pump fuses? The pump clearly won't prime if the 47 fuse is blown.

[andrewwynn]

Indications are a short in the wiring measure the Ω from each pin at the pump to ground. If you get a low resistance on the power means it's shorted

[lo_jack]

Ok, I'll check the ohms on the connector. Does that lead run under the car or inside it--do you know offhand?

[andrewwynn]

I think it's inside the people part. The wire goes through the inside outside seal plate

[lo_jack]

Could this be a result of a bad/improper engine ground? Like the engine wiring harness has a short in it?