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

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...

brians74x wrote:

i seen a tank today for $999...

OUCH!

I had a little time tonight (before it started raining) to try out my new pump in the riv. I dropped the pump in the tank (just dropped in, not secured down yet, still gotta work on that). I primed it about 10 times, and she wont start. Every few cranks you get either a pop or something that sounds like it might start, but it won't go. Checked the pressure, shows 55 psi and holds it, on, off, or cranking. I didn't have much time to muck around, so I only had a chance to pull one plug wire off and confirmed there is spark on at least one cylinder. I guess this weekend I am going to try to get over to my friends, where the car is stored, and put a noid light on the injectors and see if anything is happening.
Does anyone know if basic diagnositcs between an l67 and an l36 is similar? I only have a shop manual for a 99, which doesnt do this car much good.

David, please add the year/engine of your riv at minimum to your signature so I don't have to reread the entire thread looking for info.

The no-start troubleshooting shouldn't be very different amongst the Series II 3800s.

Woops, sorry about that! Gets a bit confusing being both of my rivs are the same year. The old pump was showing about 10-12 psi when I pulled it. Is it possible for the car to have run on that pressure? I ask because the PO over the car had an intermittent no start condition.

10-12 Wow it may or may not start but driving it likely will not

moldymac wrote:

The old pump was showing about 10-12 psi when I pulled it. Is it possible for the car to have run on that pressure?

FP should be around 50. FP should be measured with the engine running and vac line removed (and plugged) from the FP regulator.

I would think it would not run on 10 PSI, but it may chug along with crappy performance. Some computer scans would help here - we could see if the Injector Pulse Width and LTFTs have increased drastically to compensate for the low fuel pressure.

Im in the same boat some what with my Rivi. Could you give me a link for that fuel pump you got off ebay. I looked for it and i couldn't find it...... thanks

The LINK was on page one of this thread.
Here it is, good luck:

http://cgi.ebay.com/ebaymotors/ACDELCO-FUEL-PUMP-REPAIR-KIT-1997-BUICK-RIVIERA-MU1742_W0QQitemZ360227353710QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item53df39346e

Make sure you get the correct one for your year car. It makes it much easier and it makes a difference if it's SC or non- SC., if you didn't already know that

How hard was it to put this together? Im not exactly a master machanic

This thread may not have good pictures of actually replacing the pump into the canister and in and out of the car itself, etc.
Do a search on here for Fuel Pump and see if you can find a more user friendly write up for pump only change.
I know there is at least one buried in the bowels of this vast data base.

Thanks again