Write-Up: Fuel Pump/Sending Unit (NA Series II)

moldymac wrote:

Riveting a ring to the tank might work, just gotta seal the rivets somehow. I can press in threaded studs on that ring here, thats not a problem.

There are rivets made that don't leave the blind side open and nothing falls into the hole you are riveting. Blind Rivets.
They can be used with a regular rivet gun as well.
Would need to find a supplier for these, but before you do anything you need to determine the grip length of the fastener, whether it is a Rivnut or a Blind Rivet.
The grip length equals the thickness of the material's you want to fasten. The stacked height.
So, in this case it would be the thickness of the plastic tank and the thickness of any ring you are going to manufacture and a little more for sealant.
The above is assuming you are going to rivet a ring to the tank. If you are going to drill the holes in your ring of the same diameter or slightly larger than the O.D. of Rivnut and then adhere your manufactured ring with adhesive / sealant then the grip length will only be the thickness of the tank and I believe the Rivnuts I have will be more than adequate for that purpose.
But you will want to do a sample test with one of these Rivnuts into a piece of material the same thickness as the tank to determine if they will capture properly.
I will be sending you enough of them to waste a couple testing them.

I just remembered watching one of those car restoration shows on TV (not an infomercial) quite a while back and they were showing how to use a product that is a combination sealant and adhesive on a plastic / poly gas tank to a metal filler tube that was bolted to a round inlet on the tank. Sound familiar.
They used a product made by Norton that came in a caulking gun size tube. The product was guaranteed and certified by SCCA for use on fuel cells.
Norton makes a lot of products for the Body Shop industry. So I would say you could find some of this stuff at a Body Shop Supply Store, where you would go for paint and sandpaper and all other shop supplies. If they didn't have it in stock it can be ordered.
Maybe a search on the internet will help identify a product name and number for you.
I'll bet that would be the stuff to use without worrying about leaks and it will help build up the area on the existing tank that may be uneven and provide a good seal as well as helping to adhere these rings and sealing the threads of the fasteners so they don't leak, etc.

Sorry I forgot about this product, it is exactly what you need for a leak free uneven joint.

Billy Mays' Mighty Putty?

Eldo wrote:

Billy Mays' Mighty Putty?

Hey if it works like Oxiclean it must be good...

GMFreak8 wrote:

Eldo wrote:

Billy Mays' Mighty Putty?

Hey if it works like Oxiclean it must be good...

And hopefully NOT like the single-frequency Jupiter Jack...

None of this infomercial stuff is helpful.
I don't want anyone to be afraid of using the correct products and I think this Norton product should be used or at least it's equivalent.
Probably isn't inexpensive, but you are trying to restore an uneven surface as well as adhere and seal all of these pieces without the car catching on fire.

EDIT: NAPA used to carry Norton products and still might. It would be worth asking at your local NAPA store

Rick, I'll be P'ming you. I have an idea on how to do this, but its always good to have a backup. My idea is to make a "ring" thats larger than the opening in the tank with studs protruding on both sides. One side will be bolted into the tank, and the top ones will be used to secure down either another ring or some sort of anchors to put pressure on the sending unit. I gotta see how that turns out, we don't have the tooling large enough to punch a round hole as big as I want it for the sending unit so a lot is going to be cut by hand. I'm thinking it might be simpiler to make several tabs for the very top that will press on the sending unit. My truck's tank uses those and it has not leaked yet.

The pump did arrive today, I left the sending unit at work so didn't have a chance to install it. The new pump is much different from mine and am wondering how to make it work. The old pump has 2 ports on the bottom, one with a screen, and the other fit into the bottom of the cup where the other screen is. And there is one on the top that goes into the plastic hose. My new pump just has one on port on the bottom where the screen goes, and nothing else there. The top has an output to go to the plastic hose, and a small brass fitting that came with black plastic line to attach to it. I assume the brass fitting with the plastic hose replaced the second connection on the bottom that went to the screen on the bottom of the cup, but what do I do with it? The last pump I replaced was in my 87 lesabre and it didnt have anything like this!

There are some Write Ups on here that show the venturi tube installed. The small black plastic one.
That helps provide additional fuel into the canister at all times so the pump won't starve for fuel during cornering or on steep hills, IIRC.

Can someone who knows where these reference sites are point them out or provide a LINK please.

Also, try doing a search and an advanced search on here for Fuel Pump and see what you come up with.
There have been some recent write-ups with good photo's on replacing the just the pump in the plastic canister with the sending unit.

Regarding your above mention of your truck holding up well to the tabs modification, I would just caution you that the Riv's tank / pump access is not very easy if you encounter a leak on the road or god forbid a leak turns into a fire. That can be a difficult area to reach quickly with an extinguisher. Where as the truck has much more room between the tank and chassis. Correct me if I'm wrong.

Your right on access to the tank Rick. I looked in the write ups and saw one for installing a walbro pump. There were some pics of a pump with the venturi tube connecting at the bottom of the cup. Does the venturi suck fuel?

moldymac wrote:

Does the venturi suck fuel?

YES
I would continue to look for other write ups as there is one if i remember correctly where someone dealt with the same issue you are dealing with. I just don't know where the topic is hidden.

As long as the pump will mount properly and attach to the filter-sock inlet on the bottom of the cup, you should be OK. As far as the extra black tube, you don't have a venturi jet in the bottom of a normally aspirated fuel module cup... Just attach it to the brass fitting and use a zip-tie to hold it facing down into the cup. It will help keep the cup full of fuel, to keep the pump cool & quiet.

As far as the ideas for tank repair, I have another point that makes the deeply discounted $200 tank a better choice: Remember that the computer runs tests of the EVAP system by pulling a vacuum and measuring the fall at the pressure sensor on the top of that fuel pump module. A tiny leak that might be "acceptable" as far as fuel leakage would likely keep throwing a code and lighting the SES light... If you live in a smog-check area, you'll be disqualified, too.

Eldo wrote:

As far as the ideas for tank repair, I have another point that makes the deeply discounted $200 tank a better choice: Remember that the computer runs tests of the EVAP system by pulling a vacuum and measuring the fall at the pressure sensor on the top of that fuel pump module. A tiny leak that might be "acceptable" as far as fuel leakage would likely keep throwing a code and lighting the SES light... If you live in a smog-check area, you'll be disqualified, too.

Our suburban had the same exact issue as what is going on in this thread, and the exact thing you describe happened. Wasn't enough of a problem to cause a gas leak, but would set the SES light off. Couldn't pass inspection until the tank was replaced. The repair jobs just didn't do it.

GMFreak8 wrote:

Eldo wrote:

As far as the ideas for tank repair, I have another point that makes the deeply discounted $200 tank a better choice: Remember that the computer runs tests of the EVAP system by pulling a vacuum and measuring the fall at the pressure sensor on the top of that fuel pump module. A tiny leak that might be "acceptable" as far as fuel leakage would likely keep throwing a code and lighting the SES light... If you live in a smog-check area, you'll be disqualified, too.

Our suburban had the same exact issue as what is going on in this thread, and the exact thing you describe happened. Wasn't enough of a problem to cause a gas leak, but would set the SES light off. Couldn't pass inspection until the tank was replaced. The repair jobs just didn't do it.

Thanks for the confirmation, Kyle! See the burden of responsibility I have that comes with being omniscient?

Yes, you all are correct. I totally forgot about the EVAP tests being run periodically by the system.
A gas cap air leak can trigger the light, so nothing less than a perfect seal at the gas tank - fuel pump joint will cause a problem.
Either a very well made connection and a lot of sealant or a new tank. Which will cost less in the long run or even the short run.?
If you consider your time as valuable as well as manufacturing parts and pieces, it may be less expensive to get the $200.00 tank. IDK, it's your call David.
I hate to seem like I'm flip flopping on this but I value my time as much as I enjoy making parts and finding a fix and having it work out perfectly.
But, when your not sure if the fix is going to work correctly and the known solution is available for $200.00 it's almost a no brainer at this point.

Eldo wrote:

The suburban had the same exact issue as what is going on in this thread, and the exact thing you describe happened. Wasn't enough of a problem to cause a gas leak, but would set the SES light off. Couldn't pass inspection until the tank was replaced. The repair jobs just didn't do it.
Thanks for the confirmation, Kyle! See the burden of responsibility I have that comes with being omniscient?

Oh Potentate, you abandon us in our hour of need.

I didnt even think of the EVAP system! My friend's explorer would throw a code for that because of a gas cap, but the chances of this leaking are a lot higher. I think I might try contacting the guy on CL with a tank again and hope he gets back to me. My truck (which is an 85) barely has an emissions system and a good but not excellent seal probably doesn't matter there.

moldymac wrote:

I didnt even think of the EVAP system! My friend's explorer would throw a code for that because of a gas cap, but the chances of this leaking are a lot higher. I think I might try contacting the guy on CL with a tank again and hope he gets back to me. My truck (which is an 85) barely has an emissions system and a good but not excellent seal probably doesn't matter there.

The stuff from Napa that RIck talked about, or butyl caulk (as for windshields) would give you the seal you want provided the surfaces are clean when cemented and the o-ring seals right. Be advised that clean does not mean simply wiped off. It means cleaned with appropriate solvents and cleaners. If it was me I'd use a little "safe on plastic" brake cleaner on a rag, then dry gas (alcohol), then Windex or similar.

I'd say fabricating a ring is a very good plan B, plan A being to get a tank reasonably priced. Actually, getting a tank and then repairing the old one seems like a good bet if you can store or sell the repaired tank.

Don't forget to call/write Ed Morad at moradpartscompany.com to see about a tank, I think a good one would come in around $70-100 shipped--but contact him don't take my word for it.

Albertj

David, does it look like this pump is going to physically fit? When this little project began, I didn't know what the Delco numbers were for the fuel module assy's. I found out now that the N/A unit is MU33 and the S/C unit is MU35, which is what your kit is for. If they're the same size, I'm wondering just how different they can really be...

The only thing that bothers me is that someone was obviously paranoid about keeping the S/C pumps cool. My Chevy counterman couldn't believe it when I told him that they added that split off of the pump output and the venturi jet-pump, on top of the fuel from the return line, to keep that cup full of fuel, PLUS the speed-control module in the trunk of S/C cars to run those pumps at partial power until Enrichment Mode is reached...

I was thinking that if necessary, I'd buy your kit and you could buy the right kit, but I've been looking all over eBay and so far I can't seem to find a pump kit for the MU33.

As long as it's in the same vein, I should mention to everyone that I did find replacement fuel senders on eBay for only $38 shipped... The list price in the GM computer yesterday for just a fuel level sender was $199!! Anybody know if the S/C and N/A modules use the same sending units?? If they do, I'll buy a new one myself this time...

albertj wrote:

moldymac wrote:

I didnt even think of the EVAP system! My friend's explorer would throw a code for that because of a gas cap, but the chances of this leaking are a lot higher. I think I might try contacting the guy on CL with a tank again and hope he gets back to me. My truck (which is an 85) barely has an emissions system and a good but not excellent seal probably doesn't matter there.

The stuff from Napa that RIck talked about, or butyl caulk (as for windshields) would give you the seal you want provided the surfaces are clean when cemented and the o-ring seals right.

I'd say fabricating a ring is a very good plan B, plan A being to get a tank reasonably priced. Actually, getting a tank and then repairing the old one seems like a good bet if you can store or sell the repaired tank.

Don't forget to call/write Ed Morad at moradpartscompany.com to see about a tank, I think a good one would come in around $70-100 shipped--but contact him don't take my word for it.

Albertj

Attempting your repair scheme on the old tank would be a good exercise for the cause if you have the time. Don't think it would cost that much and my offer on the fastener's still stand.
If you are able to make a good leak free seal and install a good used pump assembly, it would be prepped for sale and when someone on here needed a tank due to a rotted tank they would gladly pay you for a well repaired tank.
Look at it this way, a properly repaired tank would be much better than used and should be almost as good, if not, as good as new.
So someone that knows about all the work that goes into making a proper repair wouldn't hesitate to buy it from you. I would document the work by taking pic's so you could advertise it elsewhere if necessary.
You could even advertise on EBay as we are not the only Riviera owners or Park Ave owners, etc having fuel tank issues.
Just something to think about.

I still plan to try my repair, just been a bit busy and didn't get the parts I need put together yet. I figure I don't really have anything to loose, the tank is "bad" and I gotta try this. Otherwise I will be wondering "what if..." I'll keep you all updated!

Ok guys..
I got the pump in a few days ago and took some pics of what the new one looks like compared to my old one. I didn't get a chance to install it, but I'll pass this info along to everyone here. First off, it is a delco pump. The odd thing is it says made in china on the box. I thought all delco parts were US made. The AC part number is BGV00248, the GM number is 19239667. The delco number is stamped on the pump body along with a delco logo, and it matches what is on the box. The kit came with all the parts shown there, including the tank O-ring! The only thing I didn't get was a small length of hose to connect the pump to the input line where the old pump connected to. I suppose I could just connect the flexable nylon line directly to the pump, but with it fit up against the inlet, it appears to be the same overall length of my old pump.
The new pump is much smaller than my old one. Now that I see the new one, it looks almost identical to the one I installed in my 87 lesabre, except this one has a venturie part on the top.
It looks like aside from the small piece of fuel line to connect the pump to the sending unit, everything is provided to make this work in my sending unit. It came with a wire harness that will need to be spliced into the sending unit.

Complete Kit


New pump next to old one (l36)



Side of box


Once I get it all installed in the sending unit I'll try to get to my friend's house where the car is parked and drop it in and see if the car starts. I'll try to remember my pressure gauge too. When I get some time to, I do still plan to try a repair on the tank. If the pump works out well, this is a hell of a deal and I plan to stock up on a spare or 2 for my L67, beats the hell out of a crappy $300 aftermarket that probably wont last.

Delco does not mean made in USA, I am not sure they actually make anything at this point, they hand out specs and rebox.

As someone that just had the module apart yesterday I really am interested in the repair tubing and how it feels or acts different then the original. Watch out for brittle plastic nipple where the tube attaches to the housing/outlet, I used a lighter to soften it up to not damage things.

Remember when you could just slap a fuel pump on the side of the engine, and one size fit many? Sighhhhh...

Between Delco & GM numbers, MU33 & MU35, or possibly MU1623 & MU1742, individual pumps vs kits vs modules,
it's enough to make you fire a Very pistol into the tank!

If both of the nipples on the bottom of your old pump aren't used, this pump looks to be a lot closer... the only
one I've found with that special clip/cover on the top:
LINK

Keep in mind that shipping a used gas tank can be difficult. A lot of shippers won't touch it because even though it's empty it's still classified as 'hazardous'.

i seen a tank today for $999...