wd21 vg30i how do i lean out?

[Scaramoche]

Ok,

 

back at it...I thought the AB valve would fix my issue, but nope, im still backfiring at 3k. From what ive read this is a result of running rich

 

help

 

note; i have the throttle body

[MY1PATH]

well I know the ecu changes conrol over from maf to o2 @ 2800 rpms. (the o2 is supposed to be more accurate)

is the pop when coming down thru the rpms or accelerating?

 

Higly experimental but I placed a piece of electrical tape across the inside of one of the vents in my injector cap. these vents feed your maf, pulg them and your truck will shut off fuel and die.(try it)

The tape initially leaned it enough to make my exhaust smell proper but also killed my power. then I made it block less and less of the passage untill (2 tanks per try) my power was back and my MPGs were @ a peak.

 

this was a bandaid to deal with my custom cams but Kingman also tried this after me and I think he had decent results too.

Edited June 26, 2010 by MY1PATH

[Scaramoche]

well I know the ecu changes conrol over from maf to o2 @ 2800 rpms. (the o2 is supposed to be more accurate)

is the pop when coming down thru the rpms or accelerating?

 

Higly experimental but I placed a piece of electrical tape across the inside of one of the vents in my injector cap. these vents feed your maf, pulg them and your truck will shut off fuel and die.(try it)

The tape initially leaned it enough to make my exhaust smell proper but also killed my power. then I made it block less and less of the passage untill (2 tanks per try) my power was back and my MPGs were @ a peak.

 

this was a bandaid to deal with my custom cams but Kingman also tried this after me and I think he had decent results too.

thanks my1path

 

Actually i figured out how to fix backfire issues. Seems when i cleaned out my ab valve it worked for 2 days, but i believ i loosened some material the clogged the litle hole inside the diaphram. So i went to nissan...again...and they are going to order one for me.

 

Either way, my pathy is my only car, so i had to find a way to get it to run.

 

I experimented by placing about 1ft of hose where the ab valve enters manifold. I then (with help from wife) put my finger over the hose(so no air would enter it) then had her rev engine to 2.5krpm, as expected it began backfiring. I slowely moved my finger of the top of hose allowing air in, and wham it cleared up backfires. So i had verified that it was the AB causing my issue.

 

I also knew that if i left it open, then at idle it would run like hell, or not idle at all. So using my rocket scientist type brain i came up with a simple solution. I put a cap on the end of the hose(those rubber ones you pick up to terminate vaccum lines, and hoses at auto store). I then tested, and it idled fine, but my backfire still occured.

 

I then took my drill with a small bit, and drilled a hole into the cap(very small), it still idled fine, and my "backfiring" improved. I slowely widened the hole, and bingo, i found the "sweet spot", where idle was fine, and NO MORE BACKFIRES.

 

In hindsite it works just like the ab valve, but relies on a simpler solution. From what i can figure out, at low rpm's the hole want's to "self seal" allowing very little air in. but at higher rpm's the vaccum created help's open the hole allowing fresh air in, allowing a more complete combustion. I may completely off, and full of shate, but it works lol

 

Hope this helps you all

Scara

[Kingman]

I did what MY1PATH tried and it really worked. Before my exhaust smelled horrible at idle and now it smells basically like I have a catalytic converter on there. Backfires were cut down as well which I've almost always had a problem with on this engine. It seemed to have a little better throttle response and didn't bog down quite as easy but I didn't really have long enough before the motor blew to figure out what it did to my gas mileage. I capped off one entire slot on the injector cap, I tried more but as soon as I started messing with the other one it would barely run.