Last summer I threw a new overflow valve from Larry's (style with the little ball in top. original has thread plug on top) into my 97 (mods in sig) since I was having a hazing at idle symptom, loss of mileage and it has 208k on it and since I owned it at 125k I have never replaced it. Well last month I finally installed a fuel pressure gauge and find I only have around 8-9 psi at idle and 15 psi at 2500. Put original overflow back in and had around 10 at idle and same 15 at 2500. Figured would start on easy things and removed fuel heater, no change. Tonight actually brought it in shop and replaced the fuel suction hose and then had a friend watch gauge as I pinched off return hose. Gauge hit 50 psi so figure lift pump must be ok. Took original overflow and took apart and stretched spring and re-installed it. Now I have a shaky 38 psi at idle, 33 psi at 2500 no load, and only drops to 20 under heard acceleration. The new overflow must be bad? Thinking of ordering one of the adjustable overflow valves now???

 

Check out Tork-tech. quality OFV's

 

When is the last time you changed your fuel filter? That makes a big difference on your pressures.

 

Replaced fuel filter and cleaned screen 1-2 months ago.

 

Get Tork technology overflow valve. Adjustable and much better quality than Bosch. I've bought a couple so far with good results.

 

Call Larry and he'll give you a new OF valve.
Since he now sells TorkTec maybe he'll even give you one of those instead, or at least a discount.
Larry told me he was having quite a few failure complaints with the old OFV he was selling.

 

I just shot him an email, thanks for the info.

 

Ended up paying the difference and have an adjustable OF valve on the way. Great CS.

 

Got new valve and all in spec. Thanks guys.