hey all,

want to upgrade my fuel pump to a deatschwerks 300 which comes with an installation kit. haven't been able to find any detailed instructions on how to do the install, but presume its the same as the walbro 255

question I got is that with the walbro, most ppl recommend re-using the stock fp sock ...for those that run the deatschwerks fp...did you use the sock that came with the installation kit or did u reuse the old one?

btw car is a my99 gc8 - replacing the fp coz my car tends to hesitate/bog in 1st & 2nd gear at lower rpm (2500-3000rpm) if I do moderate launches or powering out of corners. car still had 3/4 tank of fuel

1. existing or new sock- depends on condition, size, and fit. I think the stock sock is bigger than the Walbro so preferred.
2. Hesitating at low rpm, why would you think this is a fuel pump problem?

sounds more like afm issues, not running a k&n oiled filter are you?

no, standard airbox and OEM filter. will give the sensor a clean with contact cleaner and see if that helps

doesn't do it on full boost at high revs...only when going WOT from low rev and car is a bit jerky on decel

yeah more of a hesitation feeling coming onto boost is caused by faulty afm, cleaning it may help it but it may need to be replaced, pretty common problem on my99 models

MAF sensors on MY99 are notorious for failing. In my early days of Subaru ownership I lost two engines to this. On an MY99 UK Turbo 2000 which was a watered down WRX.

You're showing classic signs of a failing maf.

As others have said reuse the standard sock from your OEM pump. Don't forget the little clip that holds it to the fuel pump body and press it inplace with a small flathead screw driver. They tend to bend and not clamp once you remove them once. The DW300 may be a little different but I've just done mine on a Walbro 460 so its pretty fresh in my mind what needs doing.

__________________
605whp
Quarter Mile in 10.9 seconds @ 135mph /217kph
0-100 kph 3.2 seconds

Be careful when buying a replacement as there are a lot of non genuine MAFs around that don't have the same electrical calibrations.

Check out Japanparts.com for good value. I ordered a new one for my 08 the other day and it came to approx $180 landed.

thanks heaps guys ...will def get a new afm before I drive the car again. lucky its not my daily

bit worried now that I took my car to the track like that ...and thought that since it was only doing it on hard corners that it was a fuel pickup issue.

learnt my mistake...will get the replacement afm and a wideband 02 gauge just so I can see it happening sooner next time