I am having a really weird fuel pump problem'¦ I am currently running dual Bosch 044 fuel pumps'¦ The other day I noticed the fuel pumps making some funny noises.. Fuel pressure was moving and my A/F was leaning out.. Got it home and noticed that one of the pumps was not getting power (I may have been running on 1 pump for a while)'¦ well today the car lost all fuel pressure while driving.. it stalled and I pulled over.. went back checked the relays.. and everything seemed fine (nothing lose and the pumps didn't seem to be to hot.. but the relays were really warm!) well the car started up and fuel pressure once again dropped and the car stalled'¦ well I pulled one of the relays so only one pump was running'¦ and it built pressure and drove it home'¦ I got home and put both relays back in and went driving'¦ about 30 minutes into the drive it did it again.. I pulled the same relay and it worked and got me home'¦ WTF!?

When I got home I put both relays back in and fuel pressure held steady... its almost like its when they get warm or something'¦

So do you think that one pump is done?.. how can I test it?.. is there a certain voltage they are supposed to get?.. any help would be much appreciated!.. I also put new relays in after the first deal.. Does this sound electrical?..

 

Bypass the relays and run the pumps directly to the battery. Run for a while and see if you are ok - relays could be getting hot(too much amp draw) And as you get hotter resistance builds.

Mike

 

Problem is it seems to only be when I am driving the car for a while that it does it... You saying to just bypass the relays and drive the car like that?... The other problem I was thinking it could be is the relay at the DFI... If I am not mistaken they have one dedicated relay for the fuel pump?... I have had a few problems with relays going out on the DFI in the past (I have had two go out on me and the DFI was getting no power.. crazy time thinking it was the computer, grounds, etc etc... to find out it was the relay on the DFI harness)..

But thoses damn relays seemed really warm.. if not border line hot (but the pumps didn't seem that warm at all)'¦ That is what seemed to me as the problem'¦ they are 30 AMP relays'¦ you think I need larger?.. I have never heard but is there in initial voltage spike like on the Taurus fans etc?..

 

Yes just wire the pumps up directly - the relays are there to use the ignition ON as a switch to run the fuel pumps. If they are getting HOT then you might have an issue however, warm is normal as you have a good amount of amps going through it with two pumps. I am not sure on the amperage of the pumps. If they draw more than the relay is designed for then you are creating more resistance (less voltage to the pumps as the contacts get hotter.)

 

I will give that a shot.. and remember each bosch pump has its own relay I just splice the key hot fuel pump wire (from the DFI) to both relays..

 

So today I hard wired the pumps (from the relay base I jumped 30 and 87 12v straight to the pump) which took out all the relays in the system and drove it'¦ well not one problem all day!... drove a good 50-60 miles.. to work etc etc'¦ well on my way home tonight.. guess what.. I start to here the pumps making noise again'¦ and then it lost fuel pressure and the car died'¦ I pulled over and pulled one of the jumpers'¦ and I could not get the pumps to prime (I tried both pumps and one at a time) '¦ I tried for about 10 minutes and it would not get above like 10 psi of pressure'¦ and then out of now where it decided to prime and start up (I only had one relay in '¦ so only one pump which was the same relay that worked for me the other day)'¦ drove it half way home and decided to switch the relays to see if it was really the other pump'¦ drove home fine'¦ WTF?!?!?!?!?!?... Are both pumps going out?.. Am I just losing prime because of cavitation??.. I also opened the fuel door and there was no pressure..
Someone help here?!?!...

 

What location are the pumps?? They don't self prime too well...

 

What size wire are you running. I believe the max amps for those pumps is 15 amps a piece. As always check your grounds.

 

I have the pumps mounted on the fuel tank cover and about level with the sump... (And keep in mind I have been running this same setup for close to a year and not one problem until now)... and the grounds are all running to the bolt on the fuel tank strap and everything is 10 gauge.. And I have a 10 gauge wire running from the negative battery terminal to that same bolt so I can make sure it's a really good ground!... This is really starting to get frustrating!..

 

This is a quick picture of the pumps and how they are mounted... (the only thing that has changed is the -8 going in and out into the Y block have been shortened quite a bit for clearance)

 

Just my little 2 cents. Those pumps are supposed to be able to push or pull so it shouldn't really matter where there mounted for priming. The A1000 pump is a gravity fed pump.

 

What kind of pickup is being used? And I know you said that you had this running for a year but use a dedicated clean(bear metal) ground. You could be having ground issues at your bat/motor and its now surfacing and killing your grounds to the body when it feels like it.

Mike

 

Well I think I found the problem!!... I had my tail pipes welded up a few weeks back'¦ Well he was next to the gas tank and did not want to get sparks in the tank so he put a GOLF TEE in my vent tube and forgot to take it out!!.. I am 99 percent sure that is what the problem was!... It was not the pumps or the damn relays'¦ the whole time it was not cooling the pumps or the relays it was cooling the fuel from cavitating'¦ Crazy!..

 

Well.. I went driving the car today.. all day was good... until..... It did it again... did great all day (a good 50 miles just driving around)... then out of know where the fuel pressure just dropped off... would not start... and I pulled both relays and jumped them.. and I did one at a time and the most it would see is about 10 pounds of fuel pressure... then after about 5-10 minutes it built pressure (this time with both relays in) and drove a good ways back home with no problems!!! So... back to square one!! DAMNIT!!!... So back up top for some help'¦ Is this just two bad pumps?!!?!... Do I need to put one pump on a hobs switch and only run one pump until boost comes on?..

 

I had the same prob a couple of years back with a 2.3t with the f150 inline pump and it was the pump in my situation.
It acted the same exact way you are experiencing,but it would be hard for me to swallow that both pumps are bad at the same time.
hope you get it figured out soon

 

So you ended up with two new pumps and it fixed the situation?...

And I am curious if anyone else out there is driving on these 044's as much as me... I am talking a good long ways (50-75 miles at a time)... and I am wondering if I should hook one up to the hobs switch in the DFI so both are not running all the time??... I was advised against this because it is one more thing to go wrong with the electric system and should not be needed'¦

 

bump

 

Well, since no one else has chimed in, I will add my 2 cents worth...My take on the Bosch 044 pumps are they should provide OEM reliability as I believe they were originally designed for and used on stock high output Porches. Therefore, daily driving shouldn't be a problem for them as long as they are mounted correctly, fed ample power and not run dry excessively. That's my take on them. I use the one step down on my daily driver, it's rated at slightly less flow. I think it's rated the same as a Walbro 255lph. Can't remember the number at the moment. Been working good for over 2 years at 43psi.

 

So what you are saying is that it is probably not the pumps?...

Well just as an update I pulled the filters and the 100 micron pre filter had junk in it (looked like RTV copper and other stuff weird) and the red 10 micron filter was dirty... I blew through both of them and the 10 micron almost had no air go through it.. I bought a new paper 10 micron and I can blow through it like nothing... I was talking with tech over at Aeromotive and they said that definitely could be my problem (Very knowledgeable guys on fuel systems I might add! ).. So I am going to put it all back together with the new paper 10 micron post filter and clean out the 100 micron filter and see if it does it...

O and I pulled the regulator and took it apart and the diaphragm looks brand new (because it is... I have only had the regulator on the car for less than 1000 miles).. So I think I can rule out that as the problem as of now...

 

http://forums.bimmerforums.com/forum/showthread.php?p=14557718
Just a heads up
https://www.theturboforums.com/smf/index.php?topic=120441.0
The 044`s in the pic look like "real" Bosch pumps , I have been running dual Bosch 044`s for over a year now on the E85 side of my fuel system with no problems. A single 70 AMP relay from McMaster Carr is used with #10 wire powering the relay and #12 powering the pumps.
http://www.aeroelectric.com/Mfgr_Data/Relays/McMaster_p865.pdf

Let us know if the blockage was the problem. BTW your fuel system looks very clean.