New fuel pump?

My engine is throwing two codes - one for running lean and one for random cylinder misfires. Seems clear they are related. I took it to my mechanic to figure out what was going on and after three days he said my fuel pressure was 25 when it should be 50. I need a new fuel pump, he says. I asked if he tried replacing the fuel filter, checked the voltage to the pump or checked the fuel lines for clogs. He said he didn't. So now I'm annoyed. Shouldn't a thorough diagnosis have checked those things?

Fuel filters are tough to check, rarely have dirt in them and easy to replace. They can trap a good bit of water depending on your fuel habits. And if he's replacing the pump the filter should be replaced anyway as well.

Unless there is physical evidence to the contrary (kinks, dents, corrosion) the fuel lines are not likely to be clogged. Does not mean don't check them, just means it's rare.

Thanks for the feedback you've been providing, albertj. I'm feeling my way with this mechanic, trying to decide if I can trust him.

Don't forget the fuel pressure regulator as well. Fuel pressure testing gauge kits are cheap on Ebay. If you pull the vacuum line off the pressure regulator, the pressure should jump up.

If you have to replace the fuel pump, take a look at it by taking the inspection plate off in the trunk. It isn't uncommon to have significant rot of the tabs that hold the pump down. There are ways to deal with that, but if your mechanic sees that, he may tell you that the tank needs to be replaced. That's a big job on the Riviera.

LARRY70GS wrote:

Don't forget the fuel pressure regulator as well.  Fuel pressure testing gauge kits are cheap on Ebay.  If you pull the vacuum line off the pressure regulator, the pressure should jump up.

If you have to replace the fuel pump, take a look at it by taking the inspection plate off in the trunk.  It isn't uncommon to have significant rot of the tabs that hold the pump down.  There are ways to deal with that, but if your mechanic sees that, he may tell you that the tank needs to be replaced.  That's a big job on the Riviera.

Don't we know all about that Wizard

71stagegs wrote:

LARRY70GS wrote:

Don't forget the fuel pressure regulator as well.  Fuel pressure testing gauge kits are cheap on Ebay.  If you pull the vacuum line off the pressure regulator, the pressure should jump up.

If you have to replace the fuel pump, take a look at it by taking the inspection plate off in the trunk.  It isn't uncommon to have significant rot of the tabs that hold the pump down.  There are ways to deal with that, but if your mechanic sees that, he may tell you that the tank needs to be replaced.  That's a big job on the Riviera.

Don't we know all about that Wizard

Yes we do. Good old Northeast salt on the roads.

71stagegs wrote:

LARRY70GS wrote:

Don't forget the fuel pressure regulator as well.  Fuel pressure testing gauge kits are cheap on Ebay.  If you pull the vacuum line off the pressure regulator, the pressure should jump up.

If you have to replace the fuel pump, take a look at it by taking the inspection plate off in the trunk.  It isn't uncommon to have significant rot of the tabs that hold the pump down.  There are ways to deal with that, but if your mechanic sees that, he may tell you that the tank needs to be replaced.  That's a big job on the Riviera.

Don't we know all about that Wizard

There is an old thread on this site dealing with that rusty locking tab thing - -and I think new ones are available from RockAuto.com

...so if you don't mess up the opening getting the old one out, you're golden...

https://www.rockauto.com/en/catalog/buick,1997,riviera,3.8l+v6+supercharged,1022050,fuel/air,fuel+tank+lock+ring,10325

Tank's plastic.

Albertj

No, the tabs on the tank rot off, so there is nothing for the locking ring to attach to.

https://rivperformance.editboard.com/t10875-rusty-fuel-tank-tab-repair?highlight=rusty+fuel+tank

LARRY70GS wrote:

No, the tabs on the tank rot off, so there is nothing for the locking ring to attach to.

https://rivperformance.editboard.com/t10875-rusty-fuel-tank-tab-repair?highlight=rusty+fuel+tank

Thanks for the reminder.

Didn't the thread you referred to include something on making a repair plate for the tank?

albertj wrote:

LARRY70GS wrote:

No, the tabs on the tank rot off, so there is nothing for the locking ring to attach to.

https://rivperformance.editboard.com/t10875-rusty-fuel-tank-tab-repair?highlight=rusty+fuel+tank

Thanks for the reminder.  

Didn't the thread you referred to include something on making a repair plate for the tank?

Yes, Ken Lisk made a number of rings that replaced the tabs. You had to affix that ring to the tank with 4 screws. It worked fairly well, but it didn't quite push the pump down enough to seal it completely. I used some windshield urethane to help that out. If I ever have to replace the pump again (doubtful), I'll have to use a razor blade to cut it out.

I'm grateful for the feedback I get from the good people here. My feeling that I was being given an inadequate diagnosis of my fuel pressure issue has been proven accurate. Two separate highly regarded shops told me I needed a new fuel pump, but each time I was not happy with the effort they put into that diagnosis. Finally, I found a shop that rolled up their sleeves and did a proper diagnosis. Turns out the fuel pump is fine. It's the fuel pressure regulator that is failing. I'm really glad I stuck to my guns and demanded thoroughness. I've finally found a shop I can trust. Will be getting my Riv fully sorted over the next few days.

Steve98 wrote:

I'm grateful for the feedback I get from the good people here. My feeling that I was being given an inadequate diagnosis of my fuel pressure issue has been proven accurate. Two separate highly regarded shops told me I needed a new fuel pump, but each time I was not happy with the effort they put into that diagnosis. Finally, I found a shop that rolled up their sleeves and did a proper diagnosis. Turns out the fuel pump is fine. It's the fuel pressure regulator that is failing. I'm really glad I stuck to my guns and demanded thoroughness. I've finally found a shop I can trust. Will be getting my Riv fully sorted over the next few days.

When you replace that regulator don't cheap out.

I replaced my original FPR with a Standard, and had to replace it again in about a year -- I kid you not -- I replaced it with a FPR from the local junkyard, off a Park Ave Ultra and "have not had to talk to it since." The only FPR I'd look at would be the GM OE p/n 24506988. I would not want the GM/Delco 19236423, it's the Standard. I mean, it does work and I would not throw it back, and maybe they have improved the design, but the first one I got did not work correctly for all that long and I would not want another. YMMV.

Thanks for the advice, albertj. I'm not sure which FPR my shop is using, but they do guarantee it for two years. I'll ask them about it.