Parts Quality

Fredrick Owner Suwanee, Georgia Posted   Latest   Edited  
Question
Parts
New Fuel Pump

I am curious what you think about the quality of this new AM fuel pump. I would love to hear from an electrical engineer on how much this matters. This Ram Truck had a new fuel pump put in it a few weeks ago. I was there to diagnose an intermittent no start and took this capture of the pump. Now I realize there is nothing wrong with this capture, and this pump is not causing the issue (It was a poor connection under the truck at a bulk connector. ) I am surprised how inconsistent the current draw is across the commutators. I rarely get to see "Fixed" captures as a mobile tech, but I do remember years ago when working in a shop that new electrical motors were usually very smooth and consistent. Sometimes it was even difficult to count the number of commutators because the signatures were all so similar. 

Is this inconsistency a result of cheap manufacturing? Not taking the time to polish the brush contact surfaces evenly? Does it even matter? Will this have any effect on the longevity of this pump? Do OE pumps look the same these days? or is this just aftermarket pumps that look like this? I am used to seeing inconsistencies in old worn pumps with a lot of miles on them, but it surprised me to see this out of a new pump. Maybe I just have not looked at a new electric motor in a long time, but I do remember new electric motors being much more consistent than this. 

0
William Owner/Technician
Surrey, British Columbia
William Default
 

That is about normal for a new pump AM or OE until it has gone a couple of weeks. At least in the thousands I have looked at. NA pumps. Japanese and German are usually a bit better . Doesn't seem to cause any problems. Usually smooths down after about 2 weeks. When I first seen this I would warrantee them as bad pumps. Then I realized this is what you get now.

0 Default Ð Bounty Awarded
Fredrick Owner
Suwanee, Georgia
Fredrick Default
   

I considered that the would probably be a break in period but after that things should smooth out some. This truck had been gone about 3 weeks and had about 380 miles on it according to the invoices I saw in the truck. They had put the fuel pump in BEFORE I was called out to look at it. Like I said, it's been a while since I scoped a new electric motor, I just remember them being better than…

0 Default Ð Bounty Awarded
Jamey Owner/Technician
Ventura, California
Jamey Default
 

I am no engineer, but the pump does not have many armature segments. You have plenty of RPM. The pattern is a little wonky, but nothing I wouldn't expect from an AM pump.

0 Default Ð Bounty Awarded
Paul Mechanic
Harvey, Illinois
Paul Default
 

I think you shorted you measurement by half, but I'm looking at it on my phone. I think it has 10 commutator bars not 5.

0 Default Ð Bounty Awarded
Jamey Owner/Technician
Ventura, California
Jamey Default
 

The signiture repeats every 5 humps.

0 Default Ð Bounty Awarded
Fredrick Owner
Suwanee, Georgia
Fredrick Default
   

Look again Jamey. It's 10, not 5. This pump probably has 2 brushes on opposite sides of the motor, so you are looking at 2 commutators at once. That makes it appear like it repeats every 5, but if you look closer, it is actually every 10. That is because even though we see the same commutator pair every 5 pulses, they are on opposite brushes as before so the signature is slightly different.

0 Default Ð Bounty Awarded
Paul Mechanic
Harvey, Illinois
Paul Default
 

Yes, you really have to look hard to see the difference, but there are 180 degrees apart, but one of the valleys has a slight ripple where the opposite is straighter, that an the rpm is too high to be moving anything but air in my opinion and experience. The current draw tells me the pump is moving fuel. I was also taught/measured- most fuel pumps have 8, 10 or 12 commutator bars.

0 Default Ð Bounty Awarded
Michael Technician
Amherst, Massachusetts
Michael Default
 

OEM fuel pumps usually last a very long time in my experience. When you install a new or aftermarket fuel pump it takes a few miles for it wear in to get a good waveform capture.

0 Default Ð Bounty Awarded
Fredrick Owner
Suwanee, Georgia
Fredrick Update
 

Just to be clear, I am not suggesting this is a bad pump in any way. I have scoped thousands of electric motors, and this one looks fine. I am just curious about the inconsistency in a pump that only has about 400 miles on it. I'd like to see a new OEM pump with similar mileage, or even brand new out of the box. Perhaps it is no big deal, or maybe it speaks to the quality of the build of this…

0 Update Ð Bounty Awarded
Sean Technician
Cincinnati, Ohio
Sean Default
 

This was a brand new Delphi out of the box maybe 3 min run time

0 Default Ð Bounty Awarded
Fredrick Owner
Suwanee, Georgia
Fredrick Default
 

Looks a lot smoother than the one I posted.

+1 Default Ð Bounty Awarded
William Owner/Technician
Surrey, British Columbia
William Default
 

don't forget you are comparing Pico detail to another smaller screened and unknown quality scope.

0 Default Ð Bounty Awarded
Sean Technician
Cincinnati, Ohio
Sean Default
 

The u scope is a very good quality scope. I have compared them back to back and saw the same pattern. I wasn' trying to say "this one's smooth that's better" had it thought it would be worth sharing. That is all.

0 Default Ð Bounty Awarded
Mike Mechanic
Chagrin Falls, Ohio
Mike Default
 

Not trying to hijack your thread, or change the subject, but I had a situation with DELPHI I thought I'd share. I had a 1996 Buick Roadmaster come in, 230,000 miles, barely ran. Had low fuel pressure. Replaced fuel pump with a DELPHI. 3 weeks later, it set P0171, P0174 codes. Also had a hard start condition. Had 15 psi fuel pressure. Pulled pump back out, found the rubber hose from the pump had…

0 Default Ð Bounty Awarded
Rex Technical Support Specialist
Alliance, Ohio
Rex Default
 

Mike, that is crazy! A whole new wrinkle. Wonder if Arvin Meritor and others are doing the same. Until now I always assumed (Iknow) that if the part # was the same the part was the same. Wow

0 Default Ð Bounty Awarded
Fredrick Owner
Suwanee, Georgia
Fredrick Default
 

I've seen that with Delco brake pads for a Corvette. OE pads from the dealer were over $200. The pads with the same part number from Johnson Industries were $40. I worked at a shop at the time and the shop manager would not believe me that they were different parts as he lambasted the dealer for price gouging. I had him order both sets...same part number. The difference was OBVIOUS just by…

0 Default Ð Bounty Awarded
Rex Technical Support Specialist
Alliance, Ohio
Rex Default
 

Mike, could you ask the Delphi guy what you would get if you ordered from a GM dealer under a GM part#? If the numbers are different. Sourcing quality parts has been getting harder. What you are posting moves this problem to a whole new level.

0 Default Ð Bounty Awarded
Fredrick Owner
Suwanee, Georgia
Fredrick Update
 

My opinion on it is this. I do think the quality of the electric motor is of lower quality, and while this pump will probably not last as long as a higher quality AM or an OEM pump, that is not because of anything we see on this capture. I think the same low quality finishing of the brushes/commutator carries over to all parts of the pump and its death will more likely be mechanical in nature…

+1 Update Ð Bounty Awarded
David Mobile Technician
Rimforest, California
David Default
 

I heard a story in a “what’s in the box” class. Name brand cordless drill. One from Lowe’s and one from Wally World. Same box, same part #. took both apart. One had ball bearings, the other had bushings. You guess which.....

0 Default Ð Bounty Awarded
Rex Technical Support Specialist
Alliance, Ohio
Rex Default
 

That is what bothers me. I understand the post by Frederick above. Different manufacturers same part # different parts. That I get. But same name on the box i.e. the drill or the Delphi part, same part # but the parts are different depending on the distribution channel. Years ago I got an education on belts. This was v belt days but I believe it to be still be true, especially now. Company X…

0 Default Ð Bounty Awarded
Fredrick Owner
Suwanee, Georgia
Fredrick Resolution
 

Just closing this one out.

-1 Resolution Ð Bounty Awarded