How did I kill my 044 in less than 2k miles?

[dos531]

So I just finished replacing my 044 that died a few of days ago. I had just finished the fuel pump wiring mod and made it a couple blocks from home when it blew the front pump fuse and started running like crap. It immediately blew the spare fuse I swapped in as well. Limped it home and figured I must have messed up some wiring, but after quadruple checking my work I couldnt find any faults.

Luckily I ordered my 044 through Amazon and they warranty all automotive items for 1 year so after a short live chat I had a new one on the way. They told me the used unit was now hazardous material and couldn't be shipped back to them so I could keep it. Big props to Amazon customer service.

I just finished swapping in the replacement pump and it works like a charm. What I'm trying to figure out is what caused it to go in the first place? Maybe debris in the fuel tank? I didnt drain the tank the first time so I went ahead and did that this time. There was a little debris in the bucket I drained out of the tank, but the screen came out clean with no debris. Could that kill the pump that fast? Defective pump?

Also, I bench tested the one I removed and it seems to spin, but I dont have the setup to determine if it is flowing properly.

[krasuskyp]

if it wasn't mfg'd in Czech Republic, it's a Chinese knockoff known for early failure

[dos531]

Yeah I read up on all of that before I bought it and figured Amazon is a pretty good bet for genuine items. It was made in czech republic and shows no signs of being counterfeit.

Also I should note that there is a screen in the inlet on the pump and there is absolutely no debris on it...

[JFairman]

FWIW, the pump you got to keep would probably work fine with EFI. EFI runs at less than half the fuel pressure 930 CIS needs and the fuel pump draws much less current and has an easy life because of it.

You're lucky you didn't have to return it. I've always had to return them to where I bought when they were too noisy and I did.

[zcoker]

You might want to check your system pressure after you installed the 044. I had to lower my system pressure back to a normal range after I installed my 044. The pressure went sky high thus putting a lot of strain on the 044 pump. Seems okay now after I re-shimmed the regulator.

[dos531]

Originally Posted by zcoker

You might want to check your system pressure after you installed the 044. I had to lower my system pressure back to a normal range after I installed my 044. The pressure went sky high thus putting a lot of strain on the 044 pump. Seems okay now after I re-shimmed the regulator.

That's a good idea. I havent checked pressures, but my afrs are unchanged so it couldnt have changed too much. I'm leaning towards it just being a defective pump.

[JFairman]

Originally Posted by dos531

That's a good idea. I havent checked pressures, but my afrs are unchanged so it couldnt have changed too much. I'm leaning towards it just being a defective pump.

If your car is an '86 and it has the original aluminum lambda fuel head in stock or modified form your system pressure is around 98 psi. It should be anyway, because the lambda fuel heads are designed to run at higher system pressure than the older cast iron fuel heads that ran at around 86psi.
You can raise and lower system pressure and adjust the spring tension in the upper chamber differential pressure valves to work around that for more top end fuel delivery.
My car has a CIS Flowtech modified fuel head with the lambda system removed and upper chamber fuel meterng orifices enlarged. When I removed the stock fuel pumps and replaced both of them with Bosch 044 pumps made in Czech Republic there was no change in system pressure. It remained at 98psi.

[dos531]

Originally Posted by JFairman

If your car is an '86 and it has the original aluminum lambda fuel head in stock or modified form your system pressure is around 98 psi. It should be anyway, because the lambda fuel heads are designed to run at higher system pressure than the older cast iron fuel heads that ran at around 86psi.
You can raise and lower system pressure and adjust the spring tension in the upper chamber differential pressure valves to work around that for more top end fuel delivery.
My car has a CIS Flowtech modified fuel head with the lambda system removed and upper chamber fuel meterng orifices enlarged. When I removed the stock fuel pumps and replaced both of them with Bosch 044 pumps made in Czech Republic there was no change in system pressure. It remained at 98psi.

Yeah mine has the original fuel head with the lambda system removed. I replaced the pump because it was leaning out above 5500 regardless of adjustments to the WUR. The pump solved the problem so I think the stock pump couldn't maintain the fuel pressure at the higher volume needed at high rpm. I looked into raising the system pressure, but since my AFRs are correct now, I dont see the need. It is my understanding that the pump shouldn't affect the fuel pressure since that is controlled at the regulator, but rather allows for a higher volume of flow when needed.

[JFairman]

Originally Posted by dos531

It is my understanding that the pump shouldn't affect the fuel pressure since that is controlled at the regulator, but rather allows for a higher volume of flow when needed.

Exactly... the regulator controls pressure by returning fuel to the tank,
..and just like modern ball bearing turbochargers with billet compressor wheels, pressure and volume are two different things.

[zcoker]

It is my understanding that the pump shouldn't affect the fuel pressure since that is controlled at the regulator, but rather allows for a higher volume of flow when needed.[/QUOTE]

Anytime you change anything in the CIS fuel system, a gauge-check should be performed, regardless of what it did before, opinions or otherwise. And if all checks out, then good. If not, you can go from there and make the necessary adjustments. Do not "assume" that your system pressure is correct just because your AFR's are the same.

[krasuskyp]

digging this one up from last summer

one of my 2 new made in Czech Republic 044's is acting up nearly exactly a year to the day from purchase, and maybe 2-3k mi (?)

WTF?

and I'd confirmed with all the known 'tells' (packaging, etc.) that these were genuine not knock offs

making loud 'dry' noise now, and car won't take any throttle w/o running like CRAP

oddly enough, the next day the pump was back to sounding normal and the car drove great

tried it again today, back to loud and crappy

just ordered another one via Amazon, and will return this one - so hopefully just annoying and no $ lost

but yeah, friggin annoying tho - guess it's better the rear vs. the front from a PITA to swap perspective, but it's not like the rear one is a particular treat to swap either

and guess I should be happy it didn't outright fail, and this is all "local" and not on a roadtrip - but makes me now worry about the front pump - grrrrrrrrr

QUESTION: I thought I'd read here these cars would run on only ONE 044? Why does the car run like crap w/ 2 pumps but one acting up?

curious

most annoying tho is the timing of the failure - this literally happened like 12hrs after (finally!!!) fixing my horn, and 1/2 way fixing my sunroof - as is always the case w/ this car... fix 2 things, break another... argh!

[JFairman]

I've been through around 5 of these f....... donkey piss pumps... genuine ones yeah.
Rear 044 is quiet and smooth and front one makes a lot of buzzing noise. Directly wired to battery with relays and individual blade fuses.
I don't know and I gave up on them a year ago. I just live with the buzzing front pump now and hope it keeps working.
I guess they're made for EFI and not the high pressure needs of aluminum CIS fuel heads and my front one is going to always buzz.

[krasuskyp]

oy

I don't mind audible buzz, this sounds dry and strained and is affecting the delivery

grrrrr

[Roby466]

I found a while back that when one of the pump's relay was bad, the other pump would cavitate and sound dry. Maybe they can run on only one pump but if one is dead, it's restricting the flow. However their design should be pretty free flowing but that little bit of resistance could be enough.

[JFairman]

I don't know... at least you have a new one coming for free.
Have you made sure the rubber fuel line isn't pinched where it crosses over the steering rack? If you have steering rack bump steer spacers installed there's a chance of that.
Is the metal fuel return line inside the gas tank flowing freely? It's skinny and for some reason some people have had it clog up inside the gas tank.

[Tippy]

Paul, trying to push through the second will strain the pump even further than it is under normal working conditions.

[JFairman]

Correct, because these are close tolerance roller pumps. Kind of like a roller bearing and if the rear pump stops the front one will have an extremely hard time trying to push fuel around stationary rollers in the race they run in.

Peel a dead one apart sometime so you can see how they work.

[krasuskyp]

thanks, and yes I plan to just out of queriousity

[Ronnie's.930]

Originally Posted by krasuskyp

I don't mind audible buzz . . .

[JFairman]

"thanks, and yes I plan to just out of queriousity"

Yeah I peeled a part a dead bosch one from an L jetronic BMW 7 series years ago out of curiosity.
The two curved magnets inside them are strong and make killer refrigerator magnets.