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Engine runs fine for a while then quits
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Author:  johnnyZ [ Thu May 14, 2020 6:13 pm ]
Post subject:  Re: Engine runs fine for a while then quits

After taking another test run a couple of weeks ago and having the car quit on me once again :roll: and having it flat-bedded back home again I seemed to be back at square one.

I removed the tank again and had Rich ( yellow Z No. 777) take a look inside the tank as well as having my son's younger eyes peer into it with a flashlight and mirror to ensure that the pick-up tube was not cracked or being temporarily blocked, All checked out fine, we blew out the suction and return lines, checked the fuel vapor return valve function and made sure the fuel vapor and air make-up lines were clear. All checked out fine. After replacing the tank, installing my third new fuel pump, removing and inspecting the SU carbs again and making all the proper connections I got her running again. I took her out for over an hour around town yesterday (Wednesday) and she ran fine.

Here is one thing that bothers me though :?. I ordered 4 new WIX #33087 fuel filters which are made for this Z. They have the clear chamber which allows you to clearly see the gas and filter element. When the car runs the filter develops an air pocket at the top of the filter which at times seems to extend down close to the bottom of the filter element. Hmmm, that can't be good! Also, when idling, you can see the fuel pulsing out from the filter's top discharge tube. I kind of remembered that this was always the case with my car even when using other OEM and Fram filters. So I called Rich and Vinny B who both confirmed that this is normal. Frank T also confirmed it as well. What puzzles me is where does this air come from? Why doesn't the air get sucked out of the filter? I would think that the filter unit should eventually become completely full of fuel without air pockets at the top. This even happened during an earlier "test" I did when I had the fuel filter sucking fuel directly out of a separate container full of fuel. This eliminated the possibility of any air getting sucked in from a faulty tank or line connection.

Has anyone else experience this? I don't like the fact that it appears the fuel pump is sucking both fuel and air. Anyway, the car seems to be running fine now, although I do plan a few more test runs before traveling any great distances with it. I also contacted WIX whose engineering department is now looking into this phenomenon for me. I'm running out of hair on my head to pull out.

Author:  Frank T [ Thu May 14, 2020 6:18 pm ]
Post subject:  Re: Engine runs fine for a while then quits

The silver lining is that these stupid little things bond you with your car (or in Paul's case, his fleet of cars) and makes you aware of the entire machine. Like a good GP doctor who cares for you all your life, being the primary mechanic on your Z gives you an advantage when something goes wrong and gives you a feel for the car's general health as you drive it. I feel there is an actual persona about my Z, which I am aware of on trips. I know it's not alive, but I can feel a certain spirit of the car and I can tell when things are good or not-so good with it. My Z can sometimes "tell" me when it needs something.

That's probably not just true for Zs, but for any of the pre-computer cars we grew up with.

As we get older we don't get the same degree of fun and adventure from hanging upside down under the steering wheel or dropping a fuel tank for the 3d time, that we got when we were younger. But the satisfaction of successfully slaying gremlins and dragons is still rewarding.
AND, you get to talk about it with your Z-buds.
There are costs to owning a classic Z, but the rewards are higher.

Frank

Author:  johnnyZ [ Fri May 15, 2020 8:22 am ]
Post subject:  Re: Engine runs fine for a while then quits

I couldn't agree more :)

Author:  Frank T [ Tue May 19, 2020 5:03 pm ]
Post subject:  Re: Engine runs fine for a while then quits

HaHa! John, you're contagious.

Tried to start the Z today, no go.
Tank is full, fuel filter is dry :lol:

Time for another pump.

Author:  FM6 [ Tue May 19, 2020 9:50 pm ]
Post subject:  Re: Engine runs fine for a while then quits

John at this point it sounds more and more like a lost cause . . . . . tell ya what I'll give ya 5k for it right now. :shock:

Author:  Frank T [ Wed May 20, 2020 12:39 pm ]
Post subject:  Re: Engine runs fine for a while then quits

I'll give $5,0001 if he throws in a spare fuel pump!!!

Author:  FM6 [ Wed May 20, 2020 4:52 pm ]
Post subject:  Re: Engine runs fine for a while then quits

:shock: $5015 and I will get my own pump . . . .
he buy's cheap ones apparently :P :P :P

Author:  johnnyZ [ Thu May 21, 2020 2:41 pm ]
Post subject:  Re: Engine runs fine for a while then quits

Add another "0" to the end of the number and we can talk..... and I'll throw in 2 fuel pumps. :wink:

Author:  Frank T [ Thu May 21, 2020 5:03 pm ]
Post subject:  Re: Engine runs fine for a while then quits

Gee Karl, and here I thought he was our buddy....... :?

Author:  johnnyZ [ Sun May 24, 2020 6:48 pm ]
Post subject:  Re: Engine runs fine for a while then quits

OK guys, I think the plot gets thicker in this long story.

After my Z quit on me while backing it out of the garage last Wednesday, my son Mike and I tried swapping out the new Delphi pump with another identical pump labeled GMB. We bench tested the Delphi and found that when manually operating the actuator arm, it did not suck or blow out properly from the respective ports. The same scenario with the GMB pump. I called MSA and asked them if they have had any issues with returns or complaints on these pumps and they said they had a few, but not enough to flag concerns :roll: . They were gracious enough to send me another pump which I am currently waiting on. In the meantime, I had attempted to order a different style pump from Rock Auto, a Spectra Premium pump that was similar to an old replacement pump I had on the car for years right up to and including my last trip to Rochester. I only replaced it because it had that chinsey looking gold colored stamped metal cover and I thought the Delphi looked more OEM. Of course I ended up thowing away the chinsey pump :oops: .

My Rock Auto pump came in today and when I opened the shipping box the pump package had a nice picture of the gold top pump I was waiting for. Yeee Ha! I could hardly wait to get it on the car. I opened the pump box and what do you know! Another Delphi style pump with a stamp on the screwed on cover labled "Spectra" :evil: Crap! The same pump again!

Mike in the meantime was on Facebook (I'm not a member) and happened to discover a couple of other Z owners experiencing the same fuel starvation issues. One guy just replaced his original Datsun OEM pump after 46 years because it finally started to leak. He put in a Delphi and had to have the car flat-bedded home for the very first time.

So I believe we are having a real issue with these aftermarket "Delphi style" pumps and I feel that the issue is with the internal, non-repairable inlet and outlet check valves. Installing this last "Spectra" clone is not giving me warm fuzzies and I don't think the MSA pump that is on it's way is the solution either. Same pump, different label. I'm still checking my options and will have a "discussion" with Rock Auto after the weekend. This story isn't over yet.

Author:  Frank T [ Sun May 24, 2020 7:13 pm ]
Post subject:  Re: Engine runs fine for a while then quits

I wonder if the valves in so many pumps are all failing due to a bad reaction to present day Springtime hi-test fuel available here?

OR ~

Our cars might be catching the dreaded Coronapump Virus! :shock:

Author:  johnnyZ [ Mon May 25, 2020 10:45 am ]
Post subject:  Re: Engine runs fine for a while then quits

Yep, I've been wondering about the effect of Ethanol in our gas for a while now. I cannot say that I've seen any corrosion in my fuel pump or carbs, but I still wonder about how compatible these fuels are with these fuel pump diaphragms and check valve discs.

See attached link.

https://www.enginelabs.com/news/what-ev ... e85-fuels/

Author:  Frank T [ Mon May 25, 2020 1:30 pm ]
Post subject:  Re: Engine runs fine for a while then quits

OK, that was a well-camouflaged commercial but full of very important information. I intend to change out my fuel pump and, once detached, I want to open it and examine the interior. Pumps are really simple items; basically a diaphragm and 2 one-way valves. If the diaphragm perforates or if either of the valves fails, fuel won't flow as needed. That's so dirt-simple even I should be able to detect a defect.

Author:  johnnyZ [ Mon May 25, 2020 3:59 pm ]
Post subject:  Re: Engine runs fine for a while then quits

I removed the top 5 screws and removed the top cover off of the Delphi pump which reveals the two check valves on the pump currently installed (see pic) The bottom set of screws allows you access to the top of the main actuation diaphragm. Yes, it's simple but it's pretty hard to see how the check valves operate and they cannot be removed in my pump.

Frank, is yours a Delphi also? The name is usually stamped on one side of the pump under the diaphragm. GMB and Spectra also put their labels on the identical pumps. As I said earlier, I am waiting for delivery of the "sealed" pumps to see if they work better.

Attachments:
File comment: Datsun "Delphi" fuel pump internals
Datsun Delphi fuel pump.jpg
Datsun Delphi fuel pump.jpg [ 31.22 KiB | Viewed 14550 times ]

Author:  Frank T [ Sun May 31, 2020 2:25 pm ]
Post subject:  Re: Engine runs fine for a while then quits

So, what's the outcome on this?

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