1.8T not starting with probable fuel pump problem

[duk3]

Hey I could use advice please.

Car won't start. I had it taken quite apart to replace a lot of hoses, thermostat, more. I took the electrical harness out and wrapped all the nearly dryrotted wiring with cloth tape and stuff like that. Basically, I could have messed up all kinds of stuff.

I have spark at all 4 plugs, the battery is strong, the engine cranks freely, it will do about half a chug every 5 seconds of cranking. The exhaust will do a single glub every 1 minute of cranking.

I took the fuel rail with injectors out of the intake manifold and while cranking, gas squirts out of them all equally. But when I hook a fuel pressure gauge to the Schrader valve, it doesn't even move the needle. And I hear dead silence from fuel pump even when my head is right next to it and it's cover is off.

Testing resistance across pin 1 and 4 of the pump reads 1.3 ohm. I heard that 1-3 was good. Testing volts DC at the harness for fuel pump while it's disconnected reads 3v while key is off, 3 while key is on, 12 while cranking.

So this means my fuel pump is bad? I hear literally zero sound from it. Weird that gas still makes it out of injectors but I don't know if normal.

Is it wrong that there's 3v to pump even with key off? If so maybe that is what killed the pump? Any advice on what to test or what to try or what you know in addition by reading this is appreciated much. Thanks!

[rocket1420]

If gas squirts out of the injectors, I would be hesitant to call it a fuel pump. I would disconnect the fuel line at the fuel rail and put that in a bottle. Crank the car.

What you are describing sounds like bad compression. Did the car overheat? What caused you to tear the engine bay apart? The engine will sound like a normal cranking engine if compression is good, whether or not it starts. Maybe a short video would help?

[EuroxS4]

If it ran before you fixed it.Go over everything you had apart.Make sure you didn't leave anything unplugged.

[BryMFL]

The fuel pump can still pump if bad. If if went out it could be running just enough to move gas but not enough to atomizer it to burn. Cars ignight vapors not liquid. And a pump can all the sudden die. It happened to me. Was out driving around and all of the sudden boom nothing. Had to change my pump in the parking lot of Wendy's after going to O'Reilly for a new pump. Longer to drive to get it than change out. If you can hear the pump running its probably bad. It's under the passenger rear seat. Pull the seat and listen for it.

Sent from my SAMSUNG-SM-N920A using Tapatalk

[duk3]

Boom! You guys are great thanks again for help.

For one thing, when I reported no sound from the pump, I meant that there was no sound even with the rear seat off and the pump area 3-screw cover removed. I couldn't hear it do anything even while cranking then nor when key was turned to accessory.

I'll make a video when I next work on the car, hopefully tonight though I can never know. I'll pull the fuel rail with injectors and put little containers under it to show the gas spray and get your impressions. I'll do it with a fuel pressure gauge connected too so you can see how the needle doesn't even move and then tell me if I'm an idiot for hooking it up wrong. I'll put the camera near fuel pump and show voltage readings, resistance readings, and lack of sounds from pump. What else should I depict?

Car was taken apart because I had done the timing belt and had no heat afterward. My idea was that the new water pump killed the thermostat. As long as I was replacing thermostat, I took intake manifold off, alternator off, re-hosed all the stuff that hadn't been replaced since I've owned the car. I hooked up an n249 properly for the first time since I've owned the car. The original one had a nipple snap off of it. I also changed j plug, bottom coolant hard pipe, all the coolant hoses except those from the heater core, new coolant temp sensors (x2.) I rewired the front left ABS wheel sensor to further troubleshoot a problem with ABS. I replaced trans mounts. I finally swapped out a broken axle. I adjusted my coilovers hoping to finally have an acceptable ride height, and probably some more that I'm forgetting.

[walky_talky20]

Wow, that's a lot of work. And great to include all the surrounding details of the recent service. That's helps us help you.

I'm sure it's discouraging to get all done and have a car that won't start. It sounds like you have a positive attitude about it though, which is half the battle won right there, in my opinion. There's a great crew here, I'm sure we can get you sorted.

</PepTalk>
<ActualAdvice>

It really sounds like the pump gave out. It should definitely make some noise with power applied. You can unplug it and apply power directly to the pump wires. You can even reverse the voltage to the pump. Sometimes that will get it to free up in a pinch - working it back and forth a couple times.

In the case the pump is actually fine - the only other thing I would think is fuel mixture is off. You changed the temp sensors. It is unlikely, but possible, to get a new sensor that is faulty. If you have VCDS you can check coolant temp in the ECU before you attempt to start it. Should be approximately ambient. If the reading is wacky, that can absolutely prevent it from starting.

[Luxus Panzer]

when my fuel pump went it would still move "some" fuel when it primed or I attempted to start the car. (removed the line at the pump and some fuel would pump out).

New pump and it fired right up.

[rocket1420]

The reason I suggested checking the actual fuel and not relying on a fuel pressure gauge is because I got hosed doing that. I chased a fuel pressure problem that didn't exist for days because I trusted the gauge I attached to the fuel rail.

It's really hard to hear the fuel pump while cranking. The fuel pump will prime the first time you turn the key to on, but after that, you have to actually crank the engine to get it to run. As someone else suggested, apply voltage directly to the pump harness. It's been awhile, but I think it's the two outside pins.

The final test would be to pull the fuel pump and apply voltage to it. If you don't know how, you basically need two pry bars. You cross them and put the ends on the tabs of the basket. Hard to describe, but as long as the tank is less than half full, it's not too bad.

I have the one I pulled out of my '03 if you want it. It works fine.

[duk3]

Oh that's so nice thank u! I'm going to put 12v directly to the pump for a test and if it works I'll also test w/ your other method and report back.

[Human Garbage]

Know anyone with VCDS? That might help narrow it down. I'm thinking it sounds like the pump, pun intended, if there is no sound at all. I can hear that thing buzz to prime sitting in the drivers seat. My hearing isn't that great either, loud music and flying airplanes with basically open headers four feet away from my head have taken their toll...

[duk3]

I have the poor man's VCDS because eBay 409.1 cable. It helps sometimes.

Progress! I ran 12v from battery to pump and it works! I guess I'll hook up my fuel pressure gauge and do it again to see the reading, then reply.

Re-connecting the harness to pump and turning key to on position didn't prime the pump.

[rocket1420]

Re-connecting the harness to pump and turning key to on position didn't prime the pump.

It's not necessarily supposed to. The only definitive way to check is to check voltage while cranking. You'll need back probes to do this.

I would probably pull the fuel rail and have each injector squirt into some kind of jar. Observe the spray pattern while you crank the car. If the spray pattern sucks, disconnect the fuel line from the fuel rail, and observe how much fuel comes out while cranking. If flow is insufficient, I would then disconnect the fuel line at the filter/regulator and observe how much fuel comes out while cranking. You'll eventually get to the flow problem (if there is one).

[duk3]

Yeah thanks. I was able to measure 12v at pump while cranking actually.

So I just disconnected the supply hose from the fuel rail and used the 12v I was supplying from battery to run the pump and 0 gas came out of the hose. So I suppose there's a blockage somewhere. Make sense?

Maybe I got hoses/plastic lines hooked up in wrong places for the return to fuel tank "system." Maybe I put a check valve on backward for this. I'll try to find out. And I'll probably also test fuel flow into fuel filter.

[rocket1420]

Yeah thanks. I was able to measure 12v at pump while cranking actually.

So I just disconnected the supply hose from the fuel rail and used the 12v I was supplying from battery to run the pump and 0 gas came out of the hose. So I suppose there's a blockage somewhere. Make sense?

Maybe I got hoses/plastic lines hooked up in wrong places for the return to fuel tank "system." Maybe I put a check valve on backward for this. I'll try to find out. And I'll probably also test fuel flow into fuel filter.

The arrow on the filter/regulator should point toward the front of the car. Remove both of the lines on the fuel tank side of the filter and crank (should probably feed them into a bottle). The line that shoots out gas goes on the outside connection. The other one goes in the middle.

EDIT: Are you sure there's gas in it?

[duk3]

I probably am out of gas fuck my life

[duk3]

Hi guys. I am proud to report that I wasn't out of gas. It was still a pain in my ass to figure out but in the end it turns out my fuel pump wasn't working right. It made noise when I gave it 12v but it wasn't pumping nearly enough gas. Troubleshot like this:

Dropping fuel filter a few inches and popping both lines off of the end that faces the trunk. Let them dangle and put 12v to pump. A working pump will spray out like a firehose from a 6" tall fireman. Mine was more like a weak garden hose from a 6" tall person filling a kid's pool.

Autozone had one for $230 which I bought because I could pick up same day and after install, car started fine.

Now I need to figure out why my lowbeams and blinkers don't work. It was great to be able to drive around the block at least.