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

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

Brian,
If you can't find exactly what your looking for just ask.
What year is your car and is it Supercharged.?
This makes a difference on pump selection as well as installation procedure.

You need to fill out your signature so we can better help you.
just look at the FAQ's for instructions on how to fill out that info also.

Wow, the SC sending unit is much different from the NA one I am working on. I manged to get the pump in the can and try it out in the car. Heres a couple pics of the finished unit (sorry, no pics of the inside). The new pump is much smaller, which is why I opted to take the elbow off that use to connect between the old pump and the flexible hose. This way, the pump sits right in the bottom and this hose puts tension on it. The screen sock on the bottom of the pump does a good job of keeping the pump in place from moving. And I just put the venturi hose pointing in the bottom of the can (mine didnt have a place to attach it).


The wiring was easy, I popped the contacts out of the connector that went to my old pump and put them right into the connector clip for the new one that came with the kit, no splicing required. I got the pump in the car, and it read 55psi with the car off (the car has other issues and won't start for me yet).

How about the new clear tube, how did that fit? just pushed on?

When I made my unit I was using a NOS 99 tahoe hanger as a donor the factory really made those hoses a pain to service .

The hose was the absolute worst part. I managed to get the hose onto the top part of the sending unit by heating it wtih a lighter, and eventually it made its way on. The other end went onto the pump with a bit of force, but I did not need to heat it. Thats part of the reason why I removed the elbow that use to connect to the old pump. I could not get that hose onto it, and I would have needed a piece of line to connect the new pump to the part of the elbow that went into the top of the old pump.

I also used the lighter to loosen the hoses but they never were quite the same after that, so I got everything back as best as possible and added 2 zip ties, one at each "rib" of the fitting .

Fuel pressure holds for a good amount of time after shut off so it must be sealing.

Good point, I think I'll either add some zip ties or maybe some small hose clamps. I still have to work on securing the unit into the tank (my original problem). That will wait until I get the engine running though

Do not use hose clamps, they will deform the thin nylon tubing, dont ask how I know!

Does the bottom of the pump in your application suck from inside the bucket like mine (the 3rd photo above, that was an accidental duplicate at first...) Or does it pass through bottom of the bucket into the external filter sock?

98inSFl wrote:

Do not use hose clamps, they will deform the thin nylon tubing, dont ask how I know!

Zip ties it is then!

Eldo wrote:

Does the bottom of the pump in your application suck from inside the bucket like mine (the 3rd photo above, that was an accidental duplicate at first...) Or does it pass through bottom of the bucket into the external filter sock?

It sucks from inside the bucket like yours. The kit came with a sock for the bucket which I installed even though I don't think it needs it now.

You have the same problem my Bonneville had. The rings themselves had corroded when fuel pump time came. I ditched that car though. I have a bad float in my tank that gives inaccurate readings so...its time to change the entire unit.

The sending unit is shot on mine too I found out. Still haven't fixed my broken tank yet either.

I had quite an unpleasant experience with getting bad fuel readings on my old Grand Prix and Im not taking a chance on that again so first chance I get, Im going back to the junkyard and getting a whole pump assembly.

KillaKeninaRiv wrote:

I had quite an unpleasant experience with getting bad fuel readings on my old Grand Prix and Im not taking a chance on that again so first chance I get, Im going back to the junkyard and getting a whole pump assembly.

You'll find lots of entries on this site about the fuel pumps and senders, including how to fix the existing senders, or purchase new ones without having to buy the whole "fuel module" assembly...

Fortunately its easy to access and swap out. I know one guy who had to have his exhaust dropped, then the tank removed just to access his fuel pump.

True, except for rusty lock rings in salty areas. I was mainly referring to $$$...