Mechanical pump pressure regulator

[RustyPile]

If I bought a mechanical pump that was spec'd at 4 - 6# and it actually put out 10#, I'd be returning it.. If the 2nd pump did the same, I'd be be getting a refund, not throwing more money into a "band aid fix".....

 

[kenny78]

Spanky, how did you resolve the high fuel pressure?

 

[spanky55amg]

Sorry guys, Ha. I havent been on much. Work has me pegged out at 100% duty cycle right now and then the misses does too when I get home.

I havent. Haha. I drive the thing, and I have it running ok. I had to do 3 whole turns out of the idle mixture screws and in gear idles at 900 but 1200 when in P or N. But Im getting a solid 10mpg city and hwy driving.

I did buy a Holley fuel pressure regulator but that only made the issue worse, so I ripped it off. I am also running 91 octane instead of 87. That seemed to help a lot. Im running 4* timing and that sucks.

I tried adjusting the fuel mixture screws and that turned into a nightmare. So back to the 3 whole turns out.

 

[spanky55amg]

I need to return the pump. I think Im just going through all the pumps they have till I find one that works within the range. Sadly, I do not know of a way to test it without actually installing the sob. Now that I have the 22's off, that should be an easier job.

 

[spanky55amg]

Ok. So I did end up returning the pump. I didnt measure the new pump but I could tell that it was lower because it ran better. And I havent been on in a hot minute has work has kept me very busy, but, there were a lot of issues with the carb. Some have been fixed, there has been a band aid or two, and waiting to install a part.

Most of this has been because of a lean miss while cruising and under load. Example, highway speeds and a hill. It would back fire one time through the carb and ruin my day.

So I replaced the pump that I knew was making it run a little rich. Backed off the high speed idle till it didnt matter. Set the base idle to 650 rpm's while in gear (about 900 out of gear). Set the idle mixture screws to 3 turns out. That is GM's spec on bench rebuilding. With that set, it would be ok till it was hot. Secondaries were still a bitch and acted up. One day it back fired and left me almost stranded. Out of a fit of rage, I was under the hood and revving the engine but wasnt seeing the secondaries open up. I couldnt figure out why the secondary pull off wasnt allowing to open the secondaries. I ripped off the vaccum hose (I carry vaccum plugs with me) and let the engine cool down. Now, still some backfiring but I could drive with the load. I got home and sprayed some WD-40 on the accelerator pump. Well sure as ****, the backfiring has stopped if it do that every 3rd day. I do have a acc pump from Cliffs sitting on my tool box.

So there you go. Im getting between 16-20 mpg with my Quadrajet. Problem solved... sorta.

 

[1987 GMC Jimmy]

New wheels! Noice.

 

[spanky55amg]

New wheels! Noice.

Thanks!

I bought them around Dec and repainted them. They have been on but still had spring spacers on the truck and the centers arent bolted on. I need to pick up the screws for those still. So I hung them on for a new pic since the pulled the spacers and replaced both front calipers and brake lines. It made it easier with the lines off. I could actually get in there with my BigAzz pliers. It stopped raining for a bit, so I cleaned her up and took a pic.

 

[theblindchicken]

Ok. So I did end up returning the pump. I didnt measure the new pump but I could tell that it was lower because it ran better. And I havent been on in a hot minute has work has kept me very busy, but, there were a lot of issues with the carb. Some have been fixed, there has been a band aid or two, and waiting to install a part.

Most of this has been because of a lean miss while cruising and under load. Example, highway speeds and a hill. It would back fire one time through the carb and ruin my day.

So I replaced the pump that I knew was making it run a little rich. Backed off the high speed idle till it didnt matter. Set the base idle to 650 rpm's while in gear (about 900 out of gear). Set the idle mixture screws to 3 turns out. That is GM's spec on bench rebuilding. With that set, it would be ok till it was hot. Secondaries were still a bitch and acted up. One day it back fired and left me almost stranded. Out of a fit of rage, I was under the hood and revving the engine but wasnt seeing the secondaries open up. I couldnt figure out why the secondary pull off wasnt allowing to open the secondaries. I ripped off the vaccum hose (I carry vaccum plugs with me) and let the engine cool down. Now, still some backfiring but I could drive with the load. I got home and sprayed some WD-40 on the accelerator pump. Well sure as ****, the backfiring has stopped if it do that every 3rd day. I do have a acc pump from Cliffs sitting on my tool box.

So there you go. Im getting between 16-20 mpg with my Quadrajet. Problem solved... sorta.

Good to hear the new pump helped it out a ton as well as some issues with the carb.

Kinda jealous of your mpg!

 

[spanky55amg]

Good to hear the new pump helped it out a ton as well as some issues with the carb.

Kinda jealous of your mpg!

Thanks, its just been one big kick in the dick.

But Ill take it. Its made this thing enjoyable. I was seriously contemplating selling the sumbitch. Now, if I could just get the shimmy/shake to go away above 65. Thats a whole nother post.

 

[Camar068]

back to your Post title, between fittings regulator and such I had about $60 in a Mr. Gasket regulator with gauge. The part that pissed me off was how bouncy the gauge was. Do I tweak using the peak/low/or middle line? I ended up taking it off frustrated that I couldn't find much info on it and had wasted the money lol.

Now that I think about it, I could have maybe put air fittings on it and "calibrated" to the pressure I wanted with an air compressor or air compressor/fluid tank jig. This could eliminate the pulses from the mechanical pump that I'm guessing causes the gauge to bounce.

Mentioning only to add to the original post title in case someone else is in the same boat....that and curiosity.

Glad you figured out your issue btw.