I guess this is my various query thread? (formerly "Fuel pump won't stop..)

1995 Riviera, SC, 205,000 miles. No (known) mods.

Hey everyone! I'm pretty sure my fuel pump died on me this past Friday (fuses and relays good, going to check fuel pressure later today to confirm). I've noticed that, since the moment I bought it, the fuel pump primes itself for way longer than normal (about 1 minute before I shut it off one time) and also when the driver's door is opened and no key in the ignition. I'd also notice a strong fuel odor from this. I'm pretty sure all this extra running burned out my fuel pump. So I have a couple of questions I haven't found answers to yet:
1) What would cause my fuel pump to run incessantly? I really don't want to burn out another $210 part.
2) What's the fuel pressure supposed to be at the rail? I've found numbers ranging from 35-55psi.

Do you have a copy of the factory service manual? With these cars at their age, you will need a set, even with us here.

Fuel pump priming long can have many causes, including failed pressure regulator at the fuel injector rail, or a rusted fuel line under car that is now leaking.

I have no idea why the fuel pump is running at all when driver's door is opened and no key in ignition.

I have no idea why you're paying $210 for a fuel pump, if you are installing it yourself. (if you are paying to have one installed I have a good idea why, it's - ahem - involved... I've done it twice to fix the fuel level sender)

Words to the wise:

1) when you smell fuel, the *first* thing you check on an ICE car, no matter which car and before you even post a question on a web site, is the fuel lines in the engine compartment and under the car.

2) The SC Rivieras had/have higher fuel pump pressure from the factory. I don't think you'll find one spec, but there is a BIG BIG hint - the Bosch fuel pressure regulator on the fuel rail is set on the SC Rivieras to 3.8 bar (55.11 PSI). If you have an original regulator, that spec is *printed* on the can. If you're getting thirty something something at the rail then you're getting a new regulator and/or a new pump from somewhere, and/or fixing at least one fuel line. As for the regulators, my experience is a junkyard Bosch regulator is better than a new Standard. I've had 2 new Standard regulators, neither has lasted more than 2 years. The JY Bosch's I've pulled and installed have run at least 7 years each (for me).

3) When the fuel pressure regulators fail, one mode is the internal diaphragms give out and then they won't let the fuel pump build real fuel pressure. They will make the pump act like it is failing.

Kindly post an update after you've checked your fuel lines for leaks, and after you've removed the fuel pressure regulator to see if it's loaded with gasoline (take it off the rail and check to determine if it is retaining gasoline).

albertj wrote:

Do you have a copy of the factory service manual? With these cars at their age, you will need a set,  even with us here.

I'm waiting until payday to order one, I saw one for $100+ on eBay this morning. I'd kinda hoped I could skate until then to start wrenching (registration fees, etc), but, life.

albertj wrote:

Fuel pump priming long can have many causes, including failed pressure regulator at the fuel injector rail, or a rusted fuel line under car that is now leaking.

Fuel lines seem okay, ran out of daylight before I could finish getting the fuel pressure regulator off. It's on the back driver's side, right by the SC, right? Great tips on Bosch, I'll remember that.

albertj wrote:

I have no idea why the fuel pump is running at all when driver's door is opened and no key in ignition.

Previous owner replaced the window motors but didn't do everything properly, so it's probably something to do with that. My trunk button and lock switch don't work, but my fuel door release and the window switches do. That's gonna need to be fixed.

albertj wrote:

I have no idea why you're paying $210 for a fuel pump, if you are installing it yourself.

AutoZone.com. I see that's not the greatest idea though.

I forgot to mention, the previous owner mentioned something about the fuel pump acting funny, but he wasn't clear in his explanation. I can't remember if he said he replaced it or not. I'll post a proper update in the morning, and seriously, thanks.

Okay, I got the FPR off (and a pox on the house of the person who put both tabs straight up, on either side of the nipple). It's definitely not stock (2.7bar). There was fuel in the space behind it but I didn't see any come out of the canister itself, so I guess that's my real problem? Also, looks like some crud on the side (varnish?) Guess I'll start looking for an original. Do you think one from a PA Ultra would work?

Also, fuel lines seem to be in good shape.
This hose was disconnected and I have no idea where it's supposed to go.
https://i.servimg.com/u/f50/20/37/40/09/20210914.jpg
And I've never seen a PCV port bolted off before. Is that normal?
https://i.servimg.com/u/f50/20/37/40/09/20210915.jpg

StellaRae95 wrote:

albertj wrote:

Do you have a copy of the factory service manual? With these cars at their age, you will need a set,  even with us here.  

I'm waiting until payday to order one, I saw one for $100+ on eBay this morning. I'd kinda hoped I could skate until then to start wrenching (registration fees, etc), but, life.

albertj wrote:

Fuel pump priming long can have many causes, including failed pressure regulator at the fuel injector rail, or a rusted fuel line under car that is now leaking.  

Fuel lines seem okay, ran out of daylight before I could finish getting the fuel pressure regulator off. It's on the back driver's side, right by the SC, right? Great tips on Bosch, I'll remember that.

albertj wrote:

I have no idea why the fuel pump is running at all when driver's door is opened and no key in ignition.  

Previous owner replaced the window motors but didn't do everything properly, so it's probably something to do with that. My trunk button and lock switch don't work, but my fuel door release and the window switches do. That's gonna need to be fixed.

albertj wrote:

I have no idea why you're paying $210 for a fuel pump, if you are installing it yourself.

AutoZone.com. I see that's not the greatest idea though.

I forgot to mention, the previous owner mentioned something about the fuel pump acting funny, but he wasn't clear in his explanation. I can't remember if he said he replaced it or not. I'll post a proper update in the morning, and seriously, thanks.

You should be able to get a factory manual set for more like $30 - look at the "sold" listings on ebay for context.  

FP regulator is a little metal can at the end of the fuel rail on an SC motor. The second picture down on this page at the following link shows it, a little silver can at the left end of the fuel rail.  https://www.fiero.nl/forum/Forum4/HTML/065100.html

Replacing the window motors does not require any wiring whatsoever.  They should plug right in unless the PO used motors off/for something other than a GM car about the same age. Something else is wrong - like, your car was in a wreck and the tech who wired it back up was partly colorblind (happens).  

The fuel pumps are repairable, although getting the plastic hose on requires magic or a really bad attitude, and the sender units can be hard to get, they might be only NOS at this point, not sure.   If you have an SC car you might want to repair your pump so you can put a high enough flow cartridge in.  *Especially* with your planned mods.  There should be more info on that elsewhere on this site.

So you think it's the pump instead now?
If it's the FPR, do you think I could get away with a 41psi one for now, just to get back on the road? Uber is killing me. I'm talking about the Standard one, from O'Reilly's. https://www.oreillyauto.com/detail/c/standard-ignition/fuel---emissions/fuel-injection/fuel-pressure-regulator/0ce0f00c815f/standard-ignition-fuel-injection-pressure-regulator/std0/pr140/v/a/2695/automotive-car-1995-buick-riviera?q=fuel+pressure+regulator&pos=0

StellaRae95 wrote:

Okay, I got the FPR off (and a pox on the house of the person who put both tabs straight up, on either side of the nipple). It's definitely not stock (2.7bar). There was fuel in the space behind it but I didn't see any come out of the canister itself, so I guess that's my real problem? Also, looks like some crud on the side (varnish?) Guess I'll start looking for an original. Do you think one from a PA Ultra would work?

Also, fuel lines seem to be in good shape.
This hose was disconnected and I have no idea where it's supposed to go.
https://i.servimg.com/u/f50/20/37/40/09/20210914.jpg
And I've never seen a PCV port bolted off before. Is that normal?
https://i.servimg.com/u/f50/20/37/40/09/20210915.jpg

"The space behind it" being the fuel rail, yes you should have had fuel there. I hope you relieved the pressure in the rail at the Schraeder valve before you popped the regulator . Other than that - no wonder you've got issues, 2.7 bar isn't enough fuel pressure for the SC engine to get the injectors dosing the cylinders sufficiently when fired, unless the PO edited the fuel maps (NOT likely). Your car would constantly starve and misfire (no, really?!?!?).

Yes, one from a PA ultra should work fine. The one I am running ATM, I pulled off a PA Ultra some years ago. I think you will find other cars (Chevies, Pontiacs) with the 3800 motor have the same rated and shaped FPR. Just look for the printed '3.8 bar' spec on the little can and the hose nipple with the flare on the end. Or just get one from a parts store, try a NAPA and just ask for the FPR spec'd for your supercharged engine. I've had two Standard FPRs. In my experience they work for about 18 months reliably, and neither lasted me more than ~23 months.

Near the FPR you should find a tee on the main vacuum harness that you just pop onto the FPR. Hopefully someone else reading this can post a snapshot, I can't ATM. And, there is info and maybe a drawing in the service manual. It might be that some work done for the prior owner of the car affected the harness. They should still be available from GM (they are an emissions item) and from either Intense or ZZP, I forget which. Problem with the GM one is the parts counter person has to know to look at the vac harness for the 3800 in the Chevy Lumina/Monte Carlo if they can't find the cross reference for the Riviera in the system.

Oh and the PCV - there are internal passages in the supercharger for that.  If you are curious just open up the plate and have a look.  You might need a pair of needlenose pliers to actually get it out.  It is a little can like GM has been using since the 1960s.  Pull it, make sure it rattles and if so you can put it back.  Or just replace it, they are not much $. For instance, RockAuto lists them for less than $2.00 each.

albertj wrote:

"The space behind it" being the fuel rail, yes you should have had fuel there.  I hope you relieved the pressure in the  rail at the Schraeder valve before you popped the regulator .   Other than that - no wonder you've got issues, 2.7 bar isn't enough fuel pressure for the SC engine to get the injectors dosing the cylinders sufficiently when fired, unless the PO edited the fuel maps (NOT likely).  Your car would constantly starve and misfire (no, really?!?!?).

Haha, funny you mention misfires, she started doing that REAL bad right before she died. I'm not heavy on the throttle typically, but even the lightest touch and she was protesting. So yeah, looks like the PO had the right diagnosis but put in the wrong part because he didn't know any better.
I'll let you know how everything goes! And I'm ordering a FSM when my paycheck drops at midnight

Just buy a new one, they aren't expensive,

https://www.rockauto.com/en/catalog/buick,1995,riviera,3.8l+v6+supercharged,1022016,fuel+&+air,fuel+injection+pressure+regulator,6124

LARRY70GS wrote:

Just buy a new one, they aren't expensive,

https://www.rockauto.com/en/catalog/buick,1995,riviera,3.8l+v6+supercharged,1022016,fuel+&+air,fuel+injection+pressure+regulator,6124

Yeah, but nobody seems to know the psi for them.

Finally got a new FPS on there (BWD 22855 at Advance Auto) rated at 53psi. She fired up on the first turn...!
...then died within 30 seconds. Three times. Also, now there's smoke coming from the firewall side of my engine. I'm very disappointed.

Full service manual is ordered, but she's going to a shop Monday. As of today this car has been laid up for half the time I've owned it. I bit off more than I can chew here.....

StellaRae95 wrote:

LARRY70GS wrote:

Just buy a new one, they aren't expensive,

https://www.rockauto.com/en/catalog/buick,1995,riviera,3.8l+v6+supercharged,1022016,fuel+&+air,fuel+injection+pressure+regulator,6124

Yeah, but nobody seems to know the psi for them.

Finally got a new FPS on there (BWD 22855 at Advance Auto) rated at 53psi. She fired up on the first turn...!
...then died within 30 seconds. Three times. Also, now there's smoke coming from the firewall side of my engine. I'm very disappointed.

Full service manual is ordered, but she's going to a shop Monday. As of today this car has been laid up for half the time I've owned it. I bit off more than I can chew here.....

You're not so much disappointed as you're not really done troubleshooting...

As far as that smoke goes, could be oil leaking onto the exhaust manifold from somewhere.  Regasketing the top end, if that's what's needed, will run a several hundred bucks to have it done, less than $150 I think in gaskets to do it yourself.   Involves throttle body, supercharge plenum, lower intake manifold, and valve covers.  All of the 3800s have to have this done at some point, I was more than 300,000 miles in before mine but I think typical is more like 10-15 years and/or 100 - 150 thousand miles. SO... you're definitely there on a 'years' basis.

Yeah, you're right, I'm not done. My first thought was valve cover gasket, there's seepage on the front bank too.

What about the throttle position sensor? I had mine go out on my 92 PA (also an 85 Fleetwood Brougham), and both times the car either wouldn't start, or start and stumble until it died.
Like I said, I did get the car to start, briefly, Friday. Idle seemed to be mostly stable (around 1100 I think), for a few seconds before it steadily drop down.

StellaRae95 wrote:

What about the throttle position sensor? I had mine go out on my 92 PA (also an 85 Fleetwood Brougham), and both times the car either wouldn't start, or start and stumble until it died.
Like I said, I did get the car to start, briefly, Friday. Idle seemed to be mostly stable (around 1100 I think), for a few seconds before it steadily drop down.

Throttle position sensor can be checked with a scanner, like Torque Lite - shows the TPS readout, then you just have to ask yourself if what's displayed makes sense compared to where your foot is (how hard you press) on the loud pedal.

You can also check it with a multi meter. There are 3 wires. Reference, Ground , and Signal wires. The PCM supplies the TPS with a 5 volt reference voltage, the TPS sends back a voltage via the signal wire, based on throttle opening. At closed throttle idle, voltage should be ~.40 volts, Full throttle, about 4.5 volts. As you slowly open the throttle, the voltage should smoothly increase from .40 - 4.5 volts or so. If it gets erratic, or displays abnormal voltages, it's bad.

So I owe you folks an update!
It turns out, all I needed was a $40 coil to fix a misfire on #2 & 5. I was running myself crazy (I also ordered the wrong FSM, Electrical & Chassis, oops) so I sent it to a mechanic who fixed it the same day. She runs well now, and (so far) I haven't smelled any fuel!
But there is one symptom that has still bugged me, the 3-5 minute hum from the rear passenger side whenever I open the driver's door, even without the key in the ignition. Took me forever to realize it, but I think the hum is probably my suspension system being bad. There's a pretty significant sag in the rear, and it stopped when my weight shifted to the front. Another item for the list.
I don't regret what I did though; at the very least, I replaced the FPR before it could become a problem!

StellaRae95 wrote:

So I owe you folks an update!
It turns out, all I needed was a $40 coil to fix a misfire on #2 & 5. I was running myself crazy (I also ordered the wrong FSM, Electrical & Chassis, oops) so I sent it to a mechanic who fixed it the same day. She runs well now, and (so far) I haven't smelled any fuel!
But there is one symptom that has still bugged me, the 3-5 minute hum from the rear passenger side whenever I open the driver's door, even without the key in the ignition. Took me forever to realize it, but I think the hum is probably my suspension system being bad. There's a pretty significant sag in the rear, and it stopped when my weight shifted to the front. Another item for the list.
I don't regret what I did though; at the very least, I replaced the FPR before it could become a problem!

That is the Automatic level control system. You are hearing the air compressor. The system is a common problem. The best solution is to use coil over shocks and disable the compressor by pulling the fuse or Relay under the rear seat.

https://www.rockauto.com/en/catalog/buick,1995,riviera,3.8l+v6+supercharged,1022016,suspension,suspension+conversion+kit,13000

https://www.rockauto.com/en/moreinfo.php?pk=2215718&cc=1022016&pt=13000&jsn=458

Are the rear shocks bad? If the compressor stops on its own, eventually, that sounds like it is struggling to air up leaky shocks. Like you've got a slow leak - the compressor can get them into an acceptable range and the pressure will hold for a while, but the air leaks out overnight.

If that is the case I'd replace with the original style air shocks.

Jack the R wrote:

Are the rear shocks bad?  If the compressor stops on its own, eventually, that sounds like it is struggling to air up leaky shocks.  Like you've got a slow leak - the compressor can get them into an acceptable range and the pressure will hold for a while, but the air leaks out overnight.  

If that is the case I'd replace with the original style air shocks.    

If the shocks are leaking the compressor stops after ~45 seconds.

As inexpensive as the Monroe MA822 shock are, I'd just replace them. You don't even have to jack up the car to do that if you can reach the bottom bolts (I would jack up the rear end, though). The shocks are less than $100/pair. Only $65/pr plus tax & shipping from rockauto for instance.

LARRY70GS wrote:

That is the Automatic level control system.  You are hearing the air compressor.  The system is a common problem.  The best solution is to use coil over shocks and disable the compressor by pulling the fuse or Relay under the rear seat.

I pulled the fuse as soon as I figured it out, because it's been a parasitic draw on my battery. Also, thanks for the link, I can't wait until payday!

Jack the R wrote:

Are the rear shocks bad?  If the compressor stops on its own, eventually, that sounds like it is struggling to air up leaky shocks.  Like you've got a slow leak - the compressor can get them into an acceptable range and the pressure will hold for a while, but the air leaks out overnight.  

If that is the case I'd replace with the original style air shocks.    

I don't think they're leaky, I think they're just bad. No matter how long the compressor runs, the car still sags.

albertj wrote:

If the shocks are leaking the compressor stops after ~45 seconds.

As inexpensive as the Monroe MA822 shock are, I'd just replace them.  You don't even have to jack up the car to do that if you can reach the bottom bolts (I would jack up the rear end, though).  The shocks are less than $100/pair. Only  $65/pr plus tax & shipping from rockauto for instance.

That's delightfully affordable! I was scared they were gonna be $200 a pop!

I just noticed Rock Auto has a front strut on closeout for $10.76! - Link

It may not be the best one, but it's a screaming deal for a car that's on its last legs.

Jack the R wrote:

I just noticed Rock Auto has a front strut on closeout for $10.76! - Link

It may not be the best one, but it's a screaming deal for a car that's on its last legs.  

That's a wicked deal!

She died again.
This time, though, I know it's an electrical problem. I checked my battery voltage with a multimeter and it was down to 11.8V. The battery is only 1yo so I got it charged at my local auto store, who confirmed the battery is totally good. Checked the terminals and cables (in good shape) so now I'm looking at the alternator. The last time she wouldn't start the mechanic just charged the battery and she started, but he didn't investigate further, plus I had noticed a small intermittent noise from that side of the car when driving recently, so I'm decently certain. Gonna go get it tested today, I'll let you know how it goes!

StellaRae95 wrote:

She died again.
This time, though, I know it's an electrical problem. I checked my battery voltage with a multimeter and it was down to 11.8V. The battery is only 1yo so I got it charged at my local auto store, who confirmed the battery is totally good. Checked the terminals and cables (in good shape) so now I'm looking at the alternator. The last time she wouldn't start the mechanic just charged the battery and she started, but he didn't investigate further, plus I had noticed a small intermittent noise from that side of the car when driving recently, so I'm decently certain. Gonna go get it tested today, I'll let you know how it goes!

The fast charge at your auto store will get you started but won't really charge the battery. If your alternator etc. are working, it does not matter all that much. Seems like you're on the right track.