Bad fuel pump, or relay?

**orttauq** · 06-02-2011 06:10 PM

*Problem solved, it was the crank position sensor*

What's up guys,

On my way home from work today cruising at about 60, the engine shut down with no warning. Pulled over and attempted to start it, nothing doing. I had recently switched ecm's and thought maybe that was the issue so I changed the ecm back on the side of the road. Cranked again, no start. As I'm contemplating where to tow it to, I thought I'd give it another try. Started right up.

Get home about 10 minutes later and go to back into my spot. As I'm backing up, bam...dies again. about 10 minutes later, started back up again.

So I know it's not ecm related. I'm thinking either fuel pump or relay. How would you determine which one though? My pump has given me no issues, and is completely silent. And after 10 minutes it starts up again. I know the fuel pump module might be over heating and shutting down, but there's no symptoms to think the pump is straining. Any ideas?

Thanks,
Chris

BTW, no MIL or faults in the system

**Alex818** · 06-03-2011 10:58 AM

Same thing happened to me. It was a weak fuel pump.

**VR6Bomber** · 06-03-2011 11:46 AM

I had the same issue. My car woul die randomly; going 60mph on the highway or sitting at a light, it would just totaly die.
Crank with no start. Wait 10 minutes and it would start up no problem. Then just die again somewhere again.
Fuel pump did buzz, but swapped that, also swapped the relay, issue persisted still.
It turned out to be the ECU.
I think have a stock fuel pump somewhere if you want it?

**ThirdStrike** · 06-03-2011 12:06 PM

I'd say if it were the FP relay your car wouldnt start at all. Replacing the pump is not too hard to do. Replace the filter too.

**NishadJoshi** · 06-03-2011 01:03 PM

Originally Posted by Alex818

Same thing happened to me. It was a weak fuel pump.

Useful, very useful.

Edit: So, did you fix it yourself or have a shop fix it? If shop, how much did it come out to? Thanks.

**Alex818** · 06-03-2011 01:40 PM

Originally Posted by NishadJoshi

Useful, very useful.

Edit: So, did you fix it yourself or have a shop fix it? If shop, how much did it come out to? Thanks.

WMS did it today. I haven't looked at the bill yet. (i kinda don't want to lol)

oh and i upgraded to an 044.

**AutoUnion1** · 06-03-2011 01:45 PM

Change your fuel pump fuse to rule that out.

**S4inMN** · 06-03-2011 05:36 PM

you don't generally see fuel pump relays go bad, if they do they are usually accompanied by multiple short to ground codes. A lot of other stuff gets power from that relay. I would also say possible intermittent CPS but, again, it would throw a implausible signal code and you said ECU was clear of faults. I'd put my money on fuel pump. If you can get it to kill while idling throw a fuel pressure gauge on the feed line. Crack a beer open and watch it, if pressure slowly fades and your car dies it needs a pump.

**orttauq** · 06-03-2011 05:54 PM

Originally Posted by S4inMN

you don't generally see fuel pump relays go bad, if they do they are usually accompanied by multiple short to ground codes. A lot of other stuff gets power from that relay. I would also say possible intermittent CPS but, again, it would throw a implausible signal code and you said ECU was clear of faults. I'd put my money on fuel pump. If you can get it to kill while idling throw a fuel pressure gauge on the feed line. Crack a beer open and watch it, if pressure slowly fades and your car dies it needs a pump.

That's basically what I've boiled everything down to. CPS almost always has an inherent fault and regularly be accompanied by an EPC light/lack of power. Zero faults still in the system. It sucks now because I have the car home and can't reproduce the problem. I was going to pull the feed line while it was dead and crank it, but I can't get it to fail again. My job/shop is 45 miles away from my house so I don't want to risk driving it and having it crap out permanently.

What fuel pumps are people going with these days? A buddy at work suggested just getting a walbro 255 but I've read about some issues with them in B5's. Bosch 044 the best option?

Thanks for everyones help!

**S4inMN** · 06-03-2011 06:15 PM

Originally Posted by orttauq

That's basically what I've boiled everything down to. CPS almost always has an inherent fault and regularly be accompanied by an EPC light/lack of power. Zero faults still in the system. It sucks now because I have the car home and can't reproduce the problem. I was going to pull the feed line while it was dead and crank it, but I can't get it to fail again. My job/shop is 45 miles away from my house so I don't want to risk driving it and having it crap out permanently.

What fuel pumps are people going with these days? A buddy at work suggested just getting a walbro 255 but I've read about some issues with them in B5's. Bosch 044 the best option?

Thanks for everyones help!

Sounds like an S4, when you want it to die it wont. When you need it the most it doesn't hesitate to give you the finger. 044 is the chosen pump, good flow at high pressure. I've heard good things about Deatchewerk pumps. I think VAST is selling them now? 300lph iirc. You have to buy some misc. fittings to make the 044 a 'drop in' pump. 034 just released a pretty bad ass surge tank with the 044 included. That would require a working, stock in-tank pump though lol

**orttauq** · 06-03-2011 06:46 PM

I can't complain, this s4 has been uncharacteristically reliable! I might have to go with used OEM to get it going quickly then just move on to an 044. Thanks for all your help!

**gtiupb2002** · 06-03-2011 07:57 PM

Originally Posted by orttauq

I can't complain, this s4 has been uncharacteristically reliable! I might have to go with used OEM to get it going quickly then just move on to an 044. Thanks for all your help!

you can get a wahlboro for about $100, I went with one instead of oem and it works flawlessly. only problem I am having is I have a long crank. I need to check some this out though I don't think its the pump.

**orttauq** · 06-03-2011 08:35 PM

Thanks for the input. I wouldn't mind the walbro. Seen them in many applications. Just read some issues in B5 S4's and was a little apprehensive.

**NishadJoshi** · 06-03-2011 09:23 PM

I'm going OEM... that 044 sounds nice but I just nerd this done as costly and quickly as possible... it's kinda weird how we all have this issue at the same time.

**orttauq** · 06-03-2011 09:33 PM

Crappy fuel quality? Most likely a coincidence though..

**gtiupb2002** · 06-03-2011 10:39 PM

Originally Posted by orttauq

Thanks for the input. I wouldn't mind the walbro. Seen them in many applications. Just read some issues in B5 S4's and was a little apprehensive.

I have seen some people with issues, maybe I'm having an issue with mine but I have been reading and just think I need into put in a inline check valve? We shall see.

**goohead** · 06-04-2011 10:08 AM

I got a working used pump w less than 45k on it for $40 lmk, can priority mail it to u for like 10$ to cali will be there in 3 day. Can also send u the basket tool, to take the pump out, its real easy to change can help u w that too

**NishadJoshi** · 06-04-2011 10:24 AM

Originally Posted by goohead

I got a working used pump w less than 45k on it for $40 lmk, can priority mail it to u for like 10$ to cali will be there in 3 day. Can also send u the basket tool, to take the pump out, its real easy to change can help u w that too

Where and why'd you pickup a B5S4 fuel pump with 45k?

**goohead** · 06-04-2011 10:44 AM

Its mine cause i upgraded to a 044 back in 08

I got plenty of feedback selling to people on here, audiworld, supraforms, my.is, ebay heatware, etc.

Edit: when hooking up if i remember correctly the leads are reversed, red on neg black on positive from the factory just fyi

**obijohn22** · 06-04-2011 11:13 AM

I have had similar issues with other cars....do you have any codes? I had something like this happen and it was an intermittent ground connection from the alternator. any terminal 30 codes in the ECU? just another thought to put in form consideration. good luck

**orttauq** · 06-04-2011 01:07 PM

Originally Posted by obijohn22

I have had similar issues with other cars....do you have any codes? I had something like this happen and it was an intermittent ground connection from the alternator. any terminal 30 codes in the ECU? just another thought to put in form consideration. good luck

Not a single code. Although I am going to check grounds.

**NishadJoshi** · 06-04-2011 05:34 PM

Originally Posted by Alex818

WMS did it today. I haven't looked at the bill yet. (i kinda don't want to lol)

oh and i upgraded to an 044.

LOL, well.. when you do decide to take a look at the bill, which I hope is soon, please let me know cause I'm having a shop take a look next week and would like to know around how much it's gonna come out to before I get quoted.

**NishadJoshi** · 06-04-2011 05:41 PM

Originally Posted by goohead

Its mine cause i upgraded to a 044 back in 08

I got plenty of feedback selling to people on here, audiworld, supraforms, my.is, ebay heatware, etc.

Edit: when hooking up if i remember correctly the leads are reversed, red on neg black on positive from the factory just fyi

Haha, I wasn't doubting your legitimacy or anything like that, just simply wondering.

**orttauq** · 06-04-2011 09:03 PM

Doesn't seem to be a grounding issue. Does anyone know for certain if the fuel pump primes before key turn? There doesn't seem to be any clear cut info on this. But I do know that my pump is not priming, yet the cars starting fine right now.

**NishadJoshi** · 06-05-2011 12:06 PM

Wow, having no car is the worst shit a person can go through...

**goohead** · 06-05-2011 10:25 PM

Its really to change urself, it shouldnt cost more than 30-40 labor to do, as i can do it w/o proper tool in 20min.

**NishadJoshi** · 06-06-2011 02:08 PM

Well, it happened again, I took it to a close by shop today and they ran codes, I had like 5 different faults but I didn't get a chance to take a pic or print them out :/ wish I had. They told me it's probably the Engine Speed Sensor (G28? $80?)... And that it's $600 total, then I mentioned the idea of it being the Fuel Pump, he said it'd be $600 total with labor... and that if it were the Fuel Pump, and if it died, it wouldn't come back and work again- that once it's gone, it's gone. He cleared the codes and told told me to let it happen again and come back Wednesday so he could see which codes reappear.

I got home, I sat in my driveway and let it idle expecting it to happen again, sure enough it died... there was this really weird sound so I grab my camera. There is this really odd sound, it's like a "WOOSH" sound right after the crank... anyone know anything about it?
0:06 to 0:08
0:11 to 0:12
0:17 to 0:19
0:36 to 0:38
0:40 to 0:42
You get the point... appreciate the feedback.

**ThirdStrike** · 06-06-2011 03:16 PM

Originally Posted by NishadJoshi

Well, it happened again, I took it to a close by shop today and they ran codes, I had like 5 different faults but I didn't get a chance to take a pic or print them out :/ wish I had. They told me it's probably the Engine Speed Sensor (G28? $80?)... And that it's $600 total, then I mentioned the idea of it being the Fuel Pump, he said it'd be $600 total with labor... and that if it were the Fuel Pump, and if it died, it wouldn't come back and work again- that once it's gone, it's gone. He cleared the codes and told told me to let it happen again and come back Wednesday so he could see which codes reappear.

$600 to change a crank position sensor, and fuel pump? :smdh:

Is the pump engaging when you turn they key to start the car? If yes, it very well could be your crank sensor. The ECM uses the crank sensor to time injector cycles/fuel pump pulse rates. When that sensor dies your car randomly shuts off and the ECM never tells the pump to engage to the correct voltage when you crank the motor.

**NishadJoshi** · 06-06-2011 03:34 PM

Originally Posted by ThirdStrike

$600 to change a crank position sensor, and fuel pump? :smdh:

Is the pump engaging when you turn they key to start the car? If yes, it very well could be your crank sensor. The ECM uses the crank sensor to time injector cycles/fuel pump pulse rates. When that sensor dies your car randomly shuts off and the ECM never tells the pump to engage to the correct voltage when you crank the motor.

Very helpful, thanks. But how exactly would I go about discovering if the pump engages when I try to start it up?

**orttauq** · 06-06-2011 04:46 PM

That noise is the starter winding down. The bendix is winding down and retracting.

You should hear a hum coming from the back seat area, that would be the fuel pump priming.

Now, I FINALLY got some damn codes to go by! Engine speed sensor G28 implausible signal, and no signal intermittent. Also got a terminal 30 voltage supply too low. Picked up a crank sensor today, but unfortunately that is not something to be done without a lift/jack stands, so I'll have to drive the hour to work tomorrow and hope my car doesn't die in a spot where I can't pull over!