Possible new breakthrough in Rough Idle fix?

[t14abrunson]

I'm one of the many that have the rough idle issue with the 05-09 LGT. Mine is a 2005 LGT to be exact, 5spd. I have done the following to fix my idle issue;

 

-MAF Clean

-Replaced Intercooler

-Replaced TB Hose

-Boost Leak Test

-Smoke Test

-Zip Tied vac lines

-Swapped injectors

-Swapped coils

-Fuel System Cleaner

-New Plugs

-New Air Filter

-MAF Re-scaling

-Tune

-Raised Idle from 750 to 800-900-975 - No fix.

 

Now for what actually fixed my issue about 95%, and how I will try to fix 100%.

 

The fuel pump housing o-rings. In the fuel pump housing there is a feeder pump line hose that tee's into the return hose, and clips into the built in filter on the fuel sending unit. Then you have the pressure side hose that comes out of the filter and into the top of the housing to feed the engine.

 

Here is what my high pressure side o-ring looked like;

 

http://abrunson.smugmug.com/Other/Random/i-4XD5VdT/0/XL/oring-XL.jpg

 

This will cause idle issues because the fuel is bleeding off instead of holding steady pressure to the rail. Luckily for me I work in one of the biggest sport compact distributors in the usa and have access to the full Deatschwerks line. So I used the filter and o-rings for the Dw65C fuel pump kit on my stock filter (the sock) and the o-rings on the housing. I also snagged a set of side feed o-ring kits from Deatschwerks as well and re-orings all my injectors.

 

Final result, about 95% of my stumbling issues at idle gone. I have a periodic one every now and then. So my idea to get to 100% smooth idle is to double up on all the o-rings on the fuel housing to try and eliminate ALL pressure bleed-off inside the tank.

 

I'll keep you guys posted, I'm going to beat this damn idle issue. I swear.

[06silvarubiLGT]

Hmmm. interesting. that could explain why I have a really long crank when the car sits for a day or 2. Maybe I should toss the STi pump in there and see if that fixes it.

[t14abrunson]

It's not a pump issue. So putting in a different pump isn't going to do anything.

[BarManBean]

Did you lube the new o-rings? If not, I doubt you have to "double up" on the rings, just grease them prior to install. I believe that DW supplies superlube for this.

[06silvarubiLGT]

It's not a pump issue. So putting in a different pump isn't going to do anything.

 

I realize that, but I would replace the O-rings while I was there. just and excuse to do something else to it.. lol

[t14abrunson]

They are lubed, but they actually supply two o-rings to double up on the feed end of the pump and the factory only has one. I'm going to double up on all to insure no bleed off. Did the same on my 500+whp STi, but didn't have any idle issues prior. I only did it on the STi because I was running a ton of base pressure and the pump is hardwired.

[BarManBean]

They are lubed, but they actually supply two o-rings to double up on the feed end of the pump and the factory only has one. I'm going to double up on all to insure no bleed off. Did the same on my 500+whp STi, but didn't have any idle issues prior. I only did it on the STi because I was running a ton of base pressure and the pump is hardwired.

 

Cool

[DezzIsh]

I had this exact issue on my DW fuel pump. After install it was rough, went back and realized the O-ring wasnt exactly perfect. The fuel pumps seem to be very touchy.