afpr adjustment

[i8av8]

i was adjusting fuel pressure cause i was getting a popping/backfire noise. went down to 34-35 from 38-39 psi. the pop/backfire went away but i was burning fuel like crazy and it wasn't running rich. "rich" as in it wasn't burning my eyes or smelled real bad of gas. according to my a/f gauge it was fluctuating back and forth as it should, i guess?

after adjustment to 34-35 psi i took it on a test drive and now my bov got really quiet. :rant: WTH!, just from messing with the afpr? is this possible or a coincidence? before, it was one tone at any speed/rpm just louder at higher speed/rpm. now, it sounds muffled (low tone) at low speed/rpm but high (normal) at higher speed/rpm.

i adjusted it w/key forward and the jumper wire w/fuse at firewall. my digital gauge shows adjustment in increments of 4 psi

 

[Osmosis]

Re: afpr adjustment

Sounds like you have some issues that may need to be fixed.

Start with the basic's. Spark, fuel, air. Vacume @ idle? Compression test, ohm test injectors.

I had a 91Z28 that was supercharged and my fuel pressure regulator was bad which caused similar problems. The diaphram on my fuel pressure regulagtor had a tiny pin hole in it that caused excessive fuel to dump in the engine when I would increase the fuel pressure. I would watch yoru fuel pressure as you increase it. Irratic fuel pressure will be a dead give away. also finding excess fuel in the cylinders will tell you if the fuel is passing the regulator and into the cylinders. When I did put my fuel pressure regulator on my Ty, I noticed I had a similar problem when I hit 53psi. After some tuning and chip burning, it went away.

Keep us in formed as posting your end results helps everyone

 

[i8av8]

Re: afpr adjustment

Sounds like you have some issues that may need to be fixed.

Start with the basic's. Spark, fuel, air. Vacume @ idle? Compression test, ohm test injectors.

I had a 91Z28 that was supercharged and my fuel pressure regulator was bad which caused similar problems. The diaphram on my fuel pressure regulagtor had a tiny pin hole in it that caused excessive fuel to dump in the engine when I would increase the fuel pressure. I would watch yoru fuel pressure as you increase it. Irratic fuel pressure will be a dead give away. also finding excess fuel in the cylinders will tell you if the fuel is passing the regulator and into the cylinders. When I did put my fuel pressure regulator on my Ty, I noticed I had a similar problem when I hit 53psi. After some tuning and chip burning, it went away.

Keep us in formed as posting your end results helps everyone

thanks for the reply

i was having a problem with the afpr. it was passing gas through the vacuum lines so i replaced it w/one from sytyperformance. i put the new one on and used clear vacuum lines to see if gas was passing through. problem fixed. i re-readjusted the fuel pres. and the pop/bf has gone away again. i'm keeping an eye out on my gas mileage and everything else. no gas on the plugs either.

i know this is a big no-no but i am doing this w/o a tune, datamaster, wideband and all the other stuff required. don't have access really.

 

[Osmosis]

Re: afpr adjustment

Ah, that's right. I remember when my Z's afpr went bad. I had fuel in the vacume line which is a dead give away that the diaphram is bad.

 

[i8av8]

Re: afpr adjustment

culprits top plug is #3 and bottom plug is # 5

also (not shown) were some badly damaged wires. when i bought the ty i did a tune up but never replaced the wires cause i thought they were still good.

 

[Osmosis]

Re: afpr adjustment

compression check
Check ignition wires
Check fuel pressure
see if you have a vacume leak

 

[dpw41285]

Re: afpr adjustment

sounds like a vacum leak

 

[i8av8]

Re: afpr adjustment

wires were hideously bad. found that out upon close insp.

fuel press. is at 38 idle and holds.

fixed vacuum leaks when i pulled the upper intake to paint it and when i purchased the engine tie down. torque of motor from boosting caused the brake booster vacuum line grommet to go bad. a discontinued item so i had to make my own.

comp. check: i'll have to look/learn that one

also i went with the tr6 (colder plug) from the tr55. can and have been in excess of 20psi boost so thought it (tr6) would be better