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-   -   front 044 - 2nd failure... diagnosing fault? (http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/893180-front-044-2nd-failure-diagnosing-fault.html)

krasuskyp 11-30-2015 07:26 AM

front 044 - 2nd failure... diagnosing fault?
 
Last we left our fearless Stuper Hero here, I'd had a newish front 044 fail and Amazon credited me for a new one upon return.

The replacement suffered the same fate this fall :rolleyes:. Don't think it's an issue with the part / source (being a knockoff, etc.) as all the "real deal" tells have all been present on all the 044's I've gotten from this source via Amazon. Besides, the rear 044 from same source has been fine, so...

Prevailing wisdom back when I'd first mentioned this failure was that the fuel tank inlet screen was clogged and some of the clog was making its way thru and chewing up the pump. Symptoms began as the front pump not coming on and causing the rear one to audibly strain. Get under, literally 'touch' the front pump - zing - zipped to life.

This would eventually devolve into needing to literally wail the piss out of the pump to get it to spring back to life. Limped it home this fall via a series of about 97 pull-over Chinese fire drills w/ my passenger turning it over when it cut out while I got under and smacked the fukker. "Fun".

Sooooooooooo...

Finnnnnnnnnnally drained the tank this weekend, and pulled the tank plug which has the inlet screen attached. Was disappointed to find a relatively clean screen. Sure, it had 'some' trace debris @ the lower corners, hair, grit, etc. - but not the "ah ha" magic moment I'd hoped for. Damn.

That said... what now is the likely culprit?

One recent suggestion was wiring. I *DID* extend the +/- OE harness wires to the FP with crimped on 2" extenders after creating about 47 new swear words fighting to get the "exaaaaaaaactly the right fukking length not a c-hair to spare extra!" OE wires affixed to the pump a few installs ago. The crimps I'll add are strong enough that I was able to dangle the FP from the wires upon removal this time (not too smaht, I know - but they're apparently solid connections?).

Might my crimp connectors be causing some voltage issue, and thereby nuking the front pump?

Should I consider running fatter gauge wire with a relay straight from the battery or fuse block?

Any insight appreciated as always - TIA gentz! New 044 arrives from Amazon tomorrow and I'd like to tackle the install stat - try and get some seat time in before the f'n snow flies. Sigh.

pkabush 11-30-2015 09:52 AM

I'd start by checking the connections. Just b/c the connectors can hold the weight of the f/p doesn't insure they're good. Perhaps solder and shrink wrap them. Before the new pump is hooked up you can put a voltage tester on it to verify full voltage, then check it under load. Another idea would be to bench test your old pump by attaching some leads to it and hooking it directly to 12V pwr. Although, if it works after smacking it around (not unlike what Ronnie pays strange men to do to him) I'd suspect the unit. Anyhoo, I'm sure others will chime in with better advice, I hate auto electrical problems. Good luck, I'm sure you'll get it sorted.

Ronnie's.930 11-30-2015 10:40 AM

How dare you, Mr. 70'sbush - I've never had to pay for the smacking! :eek:

Paul, maybe the pumps wouldn't fail so quickly if you resisted "bothering" them prior to install?! That said, have you verified that your fuel return line has good flow (unlike you) back to to the tank - not obstructed in any way?


Quote:

Originally Posted by krasuskyp (Post 8897431)

Might my crimp connectors be causing some voltage issue, and thereby nuking the front pump?

Highly unlikely - unless the crimp is done totally improperly, that method is just as sound as soldering. Also, the wire is only going to pass as many amps as the pump asks of it (given no shorts to ground, etc.), so voltage/amperage problem is likely caused by the pump itself.

Quote:

Originally Posted by krasuskyp (Post 8897431)
Should I consider running fatter gauge wire with a relay straight from the battery or fuse block?

Nope.

Norm K 11-30-2015 10:45 AM

Quote:

Originally Posted by krasuskyp (Post 8897431)
wail the piss out of it to get it to spring back to life.


Fluffers, I hear, are fare more gentle. Try it next time you experience this "issue".



_

Ronnie's.930 11-30-2015 10:50 AM

^^^

Or . . . .

http://educafinanzas.org/styles/imag...xhLWF6dWwuanBn

turbo owner 11-30-2015 12:25 PM

Quote:

Originally Posted by Ronnie's.930 (Post 8897776)


Quite the stash you have there, Ronnie

pkabush 11-30-2015 01:08 PM

How dare you, Mr. 70'sbush - I've never had to pay for the smacking!
Cant beat a free beating

Ronnie's.930 11-30-2015 01:49 PM

Quote:

Originally Posted by turbo owner (Post 8897915)
Quite the stash you have there, Ronnie

Yes indeed - helps with those disturbing, worse-than-double-bagger, situations!

klefroid 11-30-2015 02:03 PM

Same thing happen to me. but mine did not work at all :-) Strange thing was, there are two electric connectors on the fuel pump... (round ones) a small M5 and a bigger M6, so I connected the wires without checking the positive and negative because it was impossible to put them on in the wrong way... turned out to be wrong so I connected negative to positive and positive to negative and fuel pump was death... also a 044 btw

pkabush 11-30-2015 10:32 PM

Quote:

Originally Posted by klefroid (Post 8898044)
Same thing happen to me. but mine did not work at all :-) Strange thing was, there are two electric connectors on the fuel pump... (round ones) a small M5 and a bigger M6, so I connected the wires without checking the positive and negative because it was impossible to put them on in the wrong way... turned out to be wrong so I connected negative to positive and positive to negative and fuel pump was death... also a 044 btw

Wow! Good to know, thx

Bucketlist 12-01-2015 04:01 AM

I just drilled out the m5 connector to make it fit the m6 post and skipped the wiring rework.:)

reclino 12-01-2015 05:04 AM

Maybe the outlet screen in the fuel tank is too small for the flow of the 044 pump and the pump is cavitating. So how could we rig up a longer screen with twice the surface area....
David

bpu699 12-01-2015 05:27 AM

Could there be a blockage down stream? Fuel filter, etc? Is the rear pump ka-puut and the front is try to work past it?

Go buy an inline amp meter ($20 at a lot of online sites for radiocontrol cars, etc. Called a Watt-Meter)... And solder it up inline, and see what your amp draw is. That tells you how hard the pump is working...

klefroid 12-01-2015 06:17 AM

If there was any blockage in the return then your wcp would go up and she would not be running well.
I would never put a 044 up front unless the rear pump has the same or more flow rate... your 044 is pushing the other one forward? Maybe I'm wrong... my 0000.2 cents

JFairman 12-01-2015 07:00 AM

Quote:

Originally Posted by reclino (Post 8898769)
Maybe the outlet screen in the fuel tank is too small for the flow of the 044 pump and the pump is cavitating. So how could we rig up a longer screen with twice the surface area....
David

The fuel tank screen that screws out of the bottom of the tank is big and would not restrict flow if it wasn't clogged. I remember it being around 3 to 4 inches long and around an inch wide.
When I removed my gas tank to restore and paint it the internal filter was clean with just a few little specs of dirt on the screen.
Water in the bottom of the gas tank from todays E10 gasoline phase seperation in humid climates is a more of a problem than dirt in the gas these days.

I've been through 3 different 044 pumps trying to find one that would not buzz loudly after a half hour when mounted in front. One was a little quieter than the the other two but after 3 of them I gave up trying.
I think the 044 pump is the wrong pump for a CIS 930 in the front position because maybe they flow too much fuel volume for the tiny little CIS fuel head system pressure regulator and return line system.
If the car sits for a long time gas can leave varnish deposits inside the skinny return line inside the gas tank and clog it too. That's a fun one to diagnose and requires gas tank surgery to fix but some people have been there and done that.

Bosch fuel pumps have an internal pressure release valve that opens and recirculates fuel round and round inside the pump to keep it from laboring too hard and overheating and burning out if the fuel flow it's pumping is restricted.
Fuel flows through the pump motor all around the armature, brushes, and everything else while it's running and the pump is lubricated and cooled by the fuel flowing through it.
The pump rollers are in the exit end of the pump so the fuel flowing around the motor armature, bearings, and brushes so before it reaches the spinning rollers it is not under pressure yet. It's under suction at that point so that increases the chance of cavitation.
I know this because I took a seized Bosch fuel pump apart years ago. Had to cut and peel the aluminum casing apart with a couple pairs of vise grips but I wanted to see the insides. I still have the curved armature motor magnets from inside it.

If the pump overheats after 30 minutes of gasoline recirculating around and around inside the pump the pump and gasoline inside will get very hot and could start to vaporize inside the pump and then you have cavitation bubbles whirling around and around with the gas in between the pump rollers inside the roller chamber in the exit end of the pump and then it makes a nasty loud buzzing noise and the pump eventually burns out.

That's my theory and maybe I'm wrong.
I still say from my experiences the 044 pump may pump too much fuel volume for the stock 930 CIS system pressure regulator in the front pump position and the original stock fuel pumps are better.
For whatever reason the rear 044 pump I put in my car has always been relatively quiet.

A couple pics of different front 044 fuel pump installations I've done on my car trying to find one that doesn't drive me nuts with the loud buzzing noise after 30 minutes of driving.

First one using the original front fuel pump mount.

http://forums.pelicanparts.com/uploa...1448982903.jpg

Second or third 044 pump installation with the two piece rubber cover Porsche used in the 964 and 993. It fits the 044 pump like a glove and does muffle some of the buzzing noise. It definately helps. Chris at Turbokraft turned me on to the part number for it. It was around $25 from Sunset Porsche in Oregon. They had to order it from Germany but they get big shipments of parts from Porsche in Germany every week so they didn't charge me for the shipping from Germany.
I used the larger wire eyelets and rubber covers Bosch supplies with the pump. I crimped and soldered them to the wires.

http://forums.pelicanparts.com/uploa...1448983317.jpg

krasuskyp 12-01-2015 07:21 AM

other than some audible buzzing tho Jim - you are still running the dual 044 setup with no running issues right?

So doubting that is what my issue here is then. A number of others here do as well IIRC.

Car runs great when the front pump runs. First one lasted a few thousand miles. 2nd one maybe a couple thousand. So doubting it's a flow issue, bubbles, etc. Just my gut based upon those datapoints of running great for miles.

My fuel filter is newish (miles-wise). I'll do some current / draw testing tonight when the new pump arrives and SC/Alfa John up the road here arrives w/ his expertise.

thanks for the thoughts - please keep them coming

I'm getting damn good @ FP R&R 8-/... grrrr...

reclino 12-01-2015 07:25 AM

I have googled around a bit more today and roller cell pumps like the Bosch 044 are very sensitive to cavitation due to restriction on the inlet side. One way to put it is these pumps don't like to suck. Looking at my inlet strainer I just don't think it's large enough to support the flow. One other contributing factor is the vapor pressure of ethenol is lower than gas. This means gas/ethenol blends are more prone to cavitation. Cavitation on the inlet side of pumps will kill the pump.
David

krasuskyp 12-01-2015 07:49 AM

thanks David - if this one packs the fudge (like Ronknees), I'll replace with something more conventional

Ronnie's.930 12-01-2015 08:12 AM

^^^

Paul, is that a packing request?!?! :eek:

reclino 12-01-2015 08:16 AM

Does anyone have a fuel tank outlet screen that they have replaced. I would like to experiment with fitting a larger strainer to the brass fitting but don't have a spare.
David

Ronnie's.930 12-01-2015 08:25 AM

Quote:

Originally Posted by reclino (Post 8898915)
One way to put it is these pumps don't like to suck.

So in other words, the pumps are NOT Paul?!

JFairman 12-01-2015 09:53 AM

Quote:

Originally Posted by reclino (Post 8898915)
I have googled around a bit more today and roller cell pumps like the Bosch 044 are very sensitive to cavitation due to restriction on the inlet side. One way to put it is these pumps don't like to suck. Looking at my inlet strainer I just don't think it's large enough to support the flow. One other contributing factor is the vapor pressure of ethenol is lower than gas. This means gas/ethenol blends are more prone to cavitation. Cavitation on the inlet side of pumps will kill the pump.
David

Good points you posted that are good to know.

Before I removed my gas tank to restore it a few years ago I had to drain it best I could.
I removed the fuel inlet line at the fuel head and stuffed it into a 4 foot long hose and put the other end of that hose into a 2.5gallon jug and turned on the 044 fuel pumps.

An approximately 14mm diameter stream of gas came shooting out of that hose like a garden hose. It filled the jug quickly so I don't think the original fuel strainer in my '87 gas tank restricts the fuel flow too much for 044 fuel pumps.

That information may have been aimed at the guys with hot rodded Asian 4 cylinder cars. A lot of those guys use Bosch 044 pumps and the gas tank fuel pick up strainers are probably smaller in those cars than the one in a 930 tank.

Alexm930 12-02-2015 04:08 AM

Paul, just my 2 cents here but I would not use crimp connectors without soldering & heat shrink at the connection.

pkabush 12-02-2015 09:14 AM

Quote:

Originally Posted by Alexm930 (Post 8900164)
Paul, just my 2 cents here but I would not use crimp connectors without soldering & heat shrink at the connection.

Agreed. As Ronnie pointed out, it's probably not the problem. It's likely to turn into one down the road though. I was pulling my hair out chasing an intermittent wiring issue on my Dodge truck. Turned out to be a ****ty crimp connection by the p/o at the f/p.
Solder and s/w are pretty bomb proof.
Good luck. LUK the outcome.

Jeff NJ 12-02-2015 09:36 PM

When done correctly, crimping is a more reliable, better conducting method for connecting wires compared to soldering . It is also considerably easier to do correctly than soldering.

Marine Wire and Cable: Crimping vs Soldering Marine Cable and Wire Connectors

Ronnie's.930 12-02-2015 10:00 PM

^^^

I used to solder everything, but never got very good at it and always hated how slow the process was (for me), so gave that up many years ago after reading about the superiority of good crimped connections, and of course, it is much easier and quicker. Now I only solder large cable connections (like car battery cables). I don't like crimped insulators however, so always use heat shrink instead.

Paul, this is how a real man crimps and insulates - getcha suuuummmmm!

http://forums.pelicanparts.com/uploa...1449125876.jpg

http://forums.pelicanparts.com/uploa...1449125917.jpg

http://forums.pelicanparts.com/uploa...1449125960.jpg

WinRice 12-05-2015 11:51 AM

Paul,

I haven't been on in awhile, work is consuming my life, but here's my 2 cents.

Good (non knockoff) pumps die from a couple of things, too much heat on the motor, and debris through the pump section. Sounds like your problem fits in the overheat category. JFairman outlined the pump function nicely, so to summarize:

1. Not enough fuel flow, motor isn't cooled and dies.
2. Restriction on the suction side the pump works too hard and overheats.
3. Restriction on the pressure side, pump works too hard, starts to bypass, cavitate and overheats.
4. Wiring problem that keeps the pump from getting full voltage, causing the motor to strain and overheat.


An overloaded fuel pump pulls more amps than when it's operating normally, and that's what causes the heat. When you install the new pump, buy or borrow an ammeter and hook it in series with the new pump. Put a volt meter across the pump. Fire the car up and let it run, monitoring the amp draw and voltage drop, and see what it's running cold and warm. From memory, the pump would draw about 11-12 amps under constant load. Maybe JFairman has better numbers. Measure the voltage across the battery and compare it to the voltage across the pump.

WinRice 12-05-2015 12:04 PM

Quote:

Originally Posted by Jeff NJ (Post 8901640)
When done correctly, crimping is a more reliable, better conducting method for connecting wires compared to soldering . It is also considerably easier to do correctly than soldering.

Marine Wire and Cable: Crimping vs Soldering Marine Cable and Wire Connectors

I'm not saying one is superior to the other, that's about as a bad as the oil wars, but that article has a few fallacies.

1. No matter how perfect the crimp is, the solder will wick through the voids.
2. Most terminals already have a lead/tin coating on them to start with, and if you crimp and solder, the solder only fills in the voids and doesn't add resistance.
3. Every good solder joint starts with a good mechanical connection.
4. Anybody can solder well, but most start with a cheap 40 watt Radio Shack soldering iron when you really need a 200 - 300 watt gun so it heats fast and flows well.

krasuskyp 12-06-2015 06:29 AM

thanks Win - will try those suggestions hopefully today when John comes by

WinRice 12-06-2015 07:51 AM

One thing I forgot to add, a high load on the pump and the amp draw usually goes up, when a pump cavitates, it's moving air and vapor and the amp draw usually goes down. YMMV


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