P0141

Well, sounds to me like the FP is dying/dead. That valve should have pressure on it all the time (if you drive it daily). If it doesn't, it means you have a leaky Injector, bad Regulator, or dying/dead FP.

Get a gauge and check it. AutoZone (or equivalent) has them for rent.

I'll get a pressure gauge and get new readings.

Is there an easy place where I can check for voltage going into the fuel pump?

Thank you.

Mikel wrote:

I'll get a pressure gauge and get new readings.

Is there an easy place where I can check for voltage going into the fuel pump?

Thank you.

Not really, no. The best place to check is at the pump connector itself inside the trunk. It's actually the best starting point too. If you don't have the proper voltage at the pump, then you start moving towards the fuse block. May as well test the entire circuit first....

And now that we're talking about Fuel Pumps, a failing one will cause "misfires" and bad running conditions under a load. Maybe your FP has been slowly going bad?

Possibly. The interesting thing is that fuel pressure is one of the first things I checked and it never fell below 40PSI. But this was done in Park. I guess under load the fuel needs are much higher.

Thank you.

Mikel wrote:

Possibly. The interesting thing is that fuel pressure is one of the first things I checked and it never fell below 40PSI. But this was done in Park. I guess under load the fuel needs are much higher.

Thank you.

Well, when primed, the Fuel Pressure should spike to about 55psi, and drop to a steady ~40psi when the car is started. Once it's running, it will vary anywhere from ~35psi to 55psi depending on throttle position.

Abaddon wrote:

Oh Jesus. I'm so sorry. I was thinking of the other post (digi's jerks under load thread) relating to misfires apparently. God dammit I'm an idiot. Again, I apologize.

If a valve/cylinder is bad enough, it'll do exactly as you're describing. I think you might just want to throw a new head on there though instead of a new engine. Do you know anybody that has an air fitting that'll go into the spark plug hole with shop air? If you pull the Valve Covers and the Rockers off, you will literally hear air rushing past the bad valve on that cylinder with air introduced to that cylinder. Right now, you know exactly which one to test. This way, you can get away with actually fixing the problem.

The '98 GP engine will work, but you'll have to strip it of all it's brackets and mounting hardware, and transfer almost EVERYTHING from the Riv to it. Basically, you'll need to strip is down to a bare block.

Can the '98 or later GP or bonneville transmission also be mounted? That is, can I put in the powertrain? Reason for asking - I have over 300K on my Riv, if I need to replace engine/transmission would like to know my options instead of being held thrall to somebody pushing something or other.

It ended up not being the fuel pump. Pressure seemed normal once I got it running (up to 55 PSI driving, depending on load).

I unplugged the MAF sensor and the engine kept running, so I borrowed one from the other engine and it runs far better than before. I still have a small miss (I keep getting a P0301 code). I wonder if the cheapo Duralast plug wires I bought may be causing it. Plugs are new.

How does the computer sense a misfire in an individual cylinder?

Certainly a big improvement.

Thank you.

I would change the wires out with some nice ACDelco ones.

KnottyEagle wrote:

I would change the wires out with some nice ACDelco ones.

Taylor wires are also pretty good. Either set will last you a nice long time. If you have a scantool and can tell which cylinder has the miss, try swapping around the wires to see if the miss moves around to confirm that it is the wires causing it.

https://rivperformance.editboard.com/t26-faq-which-spark-plugs-ignition-wires-should-i-use?highlight=wires

Cheap wires comes back to this site over and over and over again as causing problems. DO NOT use cheap wires on the supercharged motor.

Personally, I prefer not to use Duralast anything anymore. I got tired of replacing crappy parts, lifetime warranty be damned. Doing a job more than once (or twice or even more) is not worth the few bucks saved. I drive right past Autozone to my local Advance or NAPA now. If they don't have a "good" brand of part, I will order one. It's not worth it to use cheap parts.

Well, some good luck at last!

My random misfire code eventually turned into a fairly repeatable "cylinder 1 misfire". I replaced that one coil pack (I had already replaced the wires and plugs) and the engine now runs beautifully!

I really had forgotten how nice these cars are to drive.

Thank you all.