Hi all,

I converted my factory pressure regulator into an adjustable one and must have messed up the reassembly because when I prime the fuel lines and then remove power to the fuel pump the pressure dropped off very quickly to 0psi. So I took it apart and put it back together again and applied power and the pressure jumped quickly to 42psi. I cut power to the pump and it took 10 seconds to drop down to 35psi. After 5 minutes it had dropped to about 18psi. Is this an acceptable drop off rate or do I really need to get a new pressure regulator?

 

It sounds like the disc is not seating properly. Your rate of fuel leakage is not too high, and it should work with no problems. Eventually, the disc and seat may lap back together and seal a little better, but holding 18# after 10 minutes is not a problem. At that rate, it would be difficult to determine if the pressure drop is from the FPR, pump, or an injector. Did you test the pressure drop rate prior to the conversion?

 

It was actually 18psi after 5 minutes, not that it probably makes any difference. I don't know how long it took to drop to 0psi as I didn't stay round to watch it, except to say that by the time I went to work it had reached 0. I know it's not the injectors because I had them tested and they all flowed good with no leaking. Before I reassembled my modified regulator I did crimp off the pump feed to see where the leakage was occuring and it still leaked rather fast, making the regulator the problem, and the pump came from a working car anyhow. No, I didn't test the regulator prior to conversion. It simply didn't occur to me to do that before I ripped the whole engine apart.

 

You might not notice any problems, except if you go instantly to start your car, it might take a few revs longer to start. Other than that, it won't make a difference at all. If you come across another free regulator and are bored, fix it. Otherwise, I'd probably just live with it (unless it's for a paying customer).

 

Ah that's OK then. I think I can live with it. It comes up to pressure within the two seconds that the ECM primes the pump for when you turn the key but don't start it. I just needed to get reassurance from someone. Thanks.