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Weird Bosch 044 noise, only when engine is running.

Scott Y

Well-known member
Joined
May 8, 2001
Messages
482
Location
Lakewood, Colorado, USA
Summary:
Fuel pump operates normally when started via DSMlink with the engine not running, but starts making strange noises after engine is started. I put about 1000 miles on this configuration, and one day out of the blue the noise started. At first I thought it was something loose in the exhaust.

Fuel System
- intank Jay Racing uberBosch 044
- rewired with 8gauge
- 6an line to stock rail, Aeromotive AFPR, stock return line
- full tank of E85
- tank is spotless inside

Electrical Info:
Voltages
Engine not running, pump engaged via DSMlink
V(battery) = 12.14VDC
V(pump) = 11.86VDC
V(pump running) = 11.39VDC

Engine running
V(battery, engine@idle) = 14.39VDC
V(battery, engine@4000rpm) = 14.45VDC
V(pump) = 14.10VDC
V(battery, engine@idle) = 25.8mVAC
V(battery, engine@4000rpm) = 29.7mVAC

ECU caps replaced in 2000.

Troubleshooting steps already performed:
- Return line removed from tank and fuel directed to jerry can: No change
- Fuel pressure adjusted via AFPR as high as 60 @ idle: No change
- Power line run external to car from battery to fuel pump: No change
- Power line plus new ground from sending unit independent of car harness: No change
- Different known good battery: No change
- Known good battery sitting on floor, connected to (+) & (-) of pump, car harness disconnected from pump: pump runs perfectly! Of course, the pump cannot be controlled via the ECU. The pump was running while connected to the 2nd battery , then the engine was started.

Video of the behavior
Ignore the low fuel warning light, I probably hurt the sensor as I've had the sending unit in and out of the car at least 10 times and it's a wrestling match every time . The tank is known full.

I've been fighting this one for weeks and it is putting the hurt on me.
 

onesickcrx

Well-known member
Joined
Jun 3, 2007
Messages
1,076
Location
NY
Sounds like a bad pump /ubbthreads/images/graemlins/dunno.gif
 

Scott Y

Well-known member
Joined
May 8, 2001
Messages
482
Location
Lakewood, Colorado, USA
The pump is ok. This behavior has happened for 2 different 044 pumps that have been installed in the car. And the pump works fine if the engine is not running.
 

Do you still have the pump wired up as a stock pump would be? It is my understanding when the ignition is turned on all the pump does is prime the system and then shut back off till you start the engine. Hence the reason for no noise until the car is started. The pump only pumps for a split second to build pressure before you turn the key the rest of the way. It doesn't just keep pumping without the engine running. As far as the noise...as long as you have fuel pressure you're ok.
 

bazeng

Well-known member
Joined
Feb 6, 2003
Messages
2,520
Location
Melbourne, Australia
The only things that change from non running to running are:

- injector pulse
- voltage

I have an external 044 and they are noisy pumps!

So when you pulled the return line, was it flowing ok?
What reg are you running?
 

Scott Y

Well-known member
Joined
May 8, 2001
Messages
482
Location
Lakewood, Colorado, USA
Pump is rewired with big wire through a relay, just like all the vfaqs say. It's been like that for years. The afpr is the Aeromotive unit that tons of people use.

Whether the pump is using the stock wiring, the rewire, or some combo of both, the symptoms remain: engine off = pump running smoothly and perfectly, engine on = pump making strange noises and being erratic. By powering the pump completely externally (2nd battery outside of car on the floor, wired directly to + and - of the pump, it runs fine whether the engine is running or not.

Barring any tokens of wisdom from the masses, I think my next step is to replace the alternator even though the electrical measurements shown in the original post show that it is functioning normally.
 

curtis

Well-known member
Joined
May 4, 2003
Messages
11,892
Location
Clarksville TN
Ok disconnect the wires from the car and run straight from a 2nd battery and start car. See if it does it or not. Those are noisy pumps but it kind of sounds like my buddies external when the sump runs out of gas. His is about half way up the car and if he noses down a hill and sits there for more than a few seconds with anything less than 1/2 a tank it gets like that but you said yours is full. Which leads me to think the drive on the pump shaft is slipping and yes is pumping but I bet not to the point its suppose to. Maybe 3/4 of the volume or 1/2. You can get that pump from Auto Zone or Advance. There in the early 90's audi. a100's and late 80's 5000 quattros from the factory also the 2.3 powered cars. Can't remember which is which.....sorry..... but there is a 040 thats an intank with sock filter thats the same volume and pressure rating as the 044. Just do some number research and go in there and see what they have or research ebay. I've seen the 044's sell on there to people that know which cars to buy for for under 50 shipped.
 

Scott Y

Well-known member
Joined
May 8, 2001
Messages
482
Location
Lakewood, Colorado, USA
I've already run the pump via the 2nd battery, and it's fine that way. The problem isn't the pump. It made this noise with an 044 (not a chinese clone) and I replaced it with a new JayRacing 044. The symptoms remain, I refuse to believe that 2 044s are bad. Plus it runs fine when the car is not running. Perhaps I need to make a better video that illustrates the problem more clearly.

Thanks, though.
 

brisvr4

Well-known member
Joined
Feb 13, 2004
Messages
955
Location
brisbane australia
Have you thought about pulling the whole pump and sender unit out of the tank and run it in external container full of fuel?
The noise sounds almost like the pump assembly in the tank is vibrating against something once the pump gets more voltage after you start the car.
Does the sound change when you dial in more fuel pressure?
 

Yao

Well-known member
Joined
Mar 6, 2001
Messages
810
Location
Denver, CO
Scott, I've the same noise in my vr4 and gsx. At first I was concerned, but the vr4 is a daily driver for the last year with this noise and pump. NO Problems! just noisy, especially if the tank is low on fuel. If everything checks out fine and the car is running good, don't worry about it. Run it and see what happens.
 

chucklesas

Well-known member
Joined
Feb 14, 2003
Messages
1,895
Location
Dayton, OH
One of the changes from a running car and non-running car is the vacuum on the FPR... maybe try disconnecing the vacuum tube on the FPR and see if that changes the noise? Good luck.
 

14u2nV

Well-known member
Joined
Jul 22, 2004
Messages
9,398
Location
Agency/St. Joe, MO
If you turn the pump on via the laptop, is it pressure regulated at all, or does it simply flow up to the engine then dump back to the tank? I'm not sure exactly on that, BUT I think that when you are running the pump by itself, it is just pressurizing the system. This in turn, would make the pump push against the pressurized fuel, slowing the pump down. NOW, when the engine is running, the fuel is being used, thus making the pump try harder to keep the pressure up,, and thus making it more noisy. You can try it with a box fan. Run the fan on high, and listen to the noise, then hold a piece of cardboard in front of it (so it is pushing against it) and then listen. Lower rpms = less noise.

That's just what I'm thinking. /ubbthreads/images/graemlins/cool.gif
 

jb4

Well-known member
Joined
Sep 7, 2009
Messages
46
Location
Hampton Roads
The pump is cavitating. I have had the same problem with the 044 in my 2g for a while now. I tried so many different things to fix it and nothing worked permanently. My pump is inline. I have since giving up on solving it. It is very annoying but I have not seen any adverse effects while making pulls, idling, or cruising. There are a couple of threads on the Link forums about this also.

Did you try lowering the fuel pressure ?
 
Last edited:

Scott Y

Well-known member
Joined
May 8, 2001
Messages
482
Location
Lakewood, Colorado, USA
Cavitation, that's interesting.
Here is a link of the thousands that are out there. Based on what Fuellab talks about, I wouldn't want to run a pump under these conditions for very long.

I have the sending unit out, as I am redoing the 12V feedthrough. My work schedule hasn't allowed me to find the right fittings yet, but I am sure I will end up with a homegrown nylon bolt/stud solution.

I'm starting to wonder if the Bosch044 pump is too much for a -6an line & stock return? Initially I don't buy it, due to the large number of folks running big pumps on reasonably small lines on DSMs. Plus the fact that the car ran fine for a few months and then the problem started occurring out of the blue.
 
Last edited:

bazeng

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Joined
Feb 6, 2003
Messages
2,520
Location
Melbourne, Australia
My 044 gets noisy when it is low on fuel or when the fuel gets hot (hot day).

I'm running a walbro 255hp feeding a surge tank...
 

Scott Y

Well-known member
Joined
May 8, 2001
Messages
482
Location
Lakewood, Colorado, USA
Solved!

It's the stupid fuel sock on the pump. It's the JayRacing sock, and everything was groovy for a month before this problem just came out of the blue.

If the pump is seeing less than 12V, it runs fine. If it's seeing >12V, then the sock creates a restriction and causes the pump to make the noise. I would never have guessed, but it came down to trying anything because we ran out of things to try electrically. When we put the pump back in the tank without the sock and it ran perfectly I was speechless.

I guess that it's safe to say that the sock is not E85 compatible, it must have melted /decomposed / fused to the point where it became useless. I haven't emailed JayRacing yet, but plan to shortly. Visually it looks fine.

So, I still have to redo the electrical connection through the sending unit because I tore it out thinking that was the problem. But at least I know the car will be running soon.

Stupid sock.
 

jb4

Well-known member
Joined
Sep 7, 2009
Messages
46
Location
Hampton Roads
I tried two different socks and once with no sock , in my case noise always returned. I hope you have better luck than I did. The noise in my 044 happens with both pump gas and e-85.
 
Last edited:
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