RPM1

I put my fuel pump on today but I have some pressure issues. It starts out about 7 pounds at idle, 16 pounds at 1500 RPM, 18 pounds at about 2000 RPM. I took my wife down to a body shop to drop her car off, about 3 miles round trip. By the time I got back to the house it was at 3 pounds at idle, 7 pounds at 1500 RPM. I bled the air/water from my filter (Stock filter) nothing changed except this time I took it around the block and it was back to 3 PSI.

Can someone help me out on how to fix this, do I need to tweak the spring in the regulator? I called DTT at 4 PM west coast time but didn't get an answer. They must have gone home early. I need to fix this quick as I am down to one car.

RPM1

I figured it out. I am getting some debris in the regulator from the install. I have cleaned the spring actuated regulator out twice tonight.

I need to figure out what I can do in the long term. I was thinking about a small can type filter between the pump and tank for a while.

BarryG

That bypass can be a pain sometimes. I know when I originally installed my RASP (a pump DTT sold years ago) I had the same issue shortly after install and it was as you stated crud in the valve seat of the bypass. Once cleaned out it worked great for quite a while. The spring does fatigue at some point and I had to shim it and after that I replaced it with a new one. I have also found that the barrel valve seat or whatever you call it that is inside can and does pit after time. Which will affect its performance causing low pressure. I have found replacements from a place called Kinsler Racing
http://www.kinsler.com/Cat_31_Web_HT..._screen35.html hopefully that link will appear correctly it has the kinsler jet cans, secondary bypass valves as well as shim kits etc on that page. They actually hand lap the valve seat on the jet cans. The secondary bypass valve I think uses a rubber type seal on the end of the barrel for the seal. I have used both types over the years and both types work but both types have worn out as well.(this is over approx 200k of use). It sure is frustrating to have spent all the money on a seemingly bullet proof type pump and to still have a problem whether right away as you had and me as well or later down the road. For me the mechanical type pump disadvantages were less than the electric pumps disadvantges. The mechanical pump is not going to stop pumping fuel without some sort of catastorphic failure of which I have never heard of happening. The belt drive is a non issue and a $5 belt for insurance in the glove box resolves that which really only leaves the bypass valve as an issue. Even if the bypass is not fully seating and you are getting low pressure more than likely you are still getting good flow so the vp is not starving for fuel

Fortunately they are not hard to take apart and clean out but depending on what type of crud and the mileage on the valve a replacement may be necessary. So a spare could be a nice thing to have. You can rebuild the old one and then use it as the spare if needed. One member used two of them inline. You could also put an inline filter just before the bypass to catch the crud.

While I am unfamilar with thier new version the rasp pump did have one failing and that was the front seal. It would last about 25k before mine would start leaking. It would just collect dirt and as time went by it would work its way into the seal and tear it up. Not a big deal to replace it but nonetheless. So on a lark after about the third time I tried something and it sure worked for me. I took the pulley off the shaft and found the fattest tightest rubber oring I could get on the shaft and moved it flush up against the housing. I never had a seal go out again after I did that. My thinking was it would act as a filter or a barrier to keep the road grime etc from getting to the seal in the first place. This is assuming the belt wasnt too tight to begin with which mine was not (some people felt the belt need to be tight and in reality it need to be fairly loose (say at least an inch of deflection though DTT could tell you the proper amount for their new pump).

Hope some of this info helps sorry about being long winded.

RPM1

I may consider one of those Kinsler valves in the future. I bought a small can filter and put it inline. So far so good, I drove it around all yesterday afternoon, and when I turned the corner for home, the pressure began to fluctuate. I cleaned it out, and there were two small pieces of rubber from the install in it. My wife drove it today and she said it was fine. I guess I will find out how things go soon, as I am pulling the trailer 600 miles to Yellowstone next week.

In hindsight I should have put the filter just prior to the regulator. And not right after the sump.

At some point I am going to ditch the stock filter and get a Donaldson inline water separator and filter setup. I just can't quite get over giving up the stock filter with a heater. I know there are a lot of guys running remote filters without a problem over a lot more severe winters then I have in Colorado.