signs of bad fuel pressure regulator?

[cgmtboarder]

what are signs of a bad fuel pressure regulator?

 

[Auto RS T]

Fuel in the vacuum line.

 

[steve]

what are signs of a bad fuel pressure regulator?

Rather than give you all the possible cases why don't you think about what a fuel pressure regulator does and how it might go bad. Then think about how you might test or check each of those.

 

[millertime6009]

Before owning my current 91 AWD Talon I had an 87 RX7. Let me tell you the guys at RX7 club are a hell of a lot more helpful. The responses to the OP's original question are pitiful. He wouldnt make a post if he knew the specifics of an FPR and what it does and what it wouldnt do if it went bad. So to answer your question there can be fuel in the vacuum lines mainly the FPR vacuum line. Next, if the diaphragm in it goes bad it can destroy your idle because it is no longer functioning as a regulator. A bad diaphragm will cause massive amounts of fuel flowing all the time... at least as much as what it would send at WOT if it was good except ALL THE TIME! This causes you to get about 160 miles per tank of gas, crazy idle surge, engine dying if you let the RPMs drop too far, and also effects the boost/vacuum. When mine went bad I was searching for a massive boost leak somewhere but couldnt find one. My boost gauge would read about -3 at idle and shoot up like crazy under part and WOT but i was getting NO BOOST. The turbo which is normally very loud i did not hear spooling at all. Hope this helped. Oh and while your at it replace your injectors o rings, grommets, and the seals that go on the intake manifold.

 

[kenamond]

Before owning my current 91 AWD Talon I had an 87 RX7. Let me tell you the guys at RX7 club are a hell of a lot more helpful. The responses to the OP's original question are pitiful. He wouldnt make a post if he knew the specifics of an FPR and what it does and what it wouldnt do if it went bad. So to answer your question there can be fuel in the vacuum lines mainly the FPR vacuum line. Next, if the diaphragm in it goes bad it can destroy your idle because it is no longer functioning as a regulator. A bad diaphragm will cause massive amounts of fuel flowing all the time... at least as much as what it would send at WOT if it was good except ALL THE TIME! This causes you to get about 160 miles per tank of gas, crazy idle surge, engine dying if you let the RPMs drop too far, and also effects the boost/vacuum. When mine went bad I was searching for a massive boost leak somewhere but couldnt find one. My boost gauge would read about -3 at idle and shoot up like crazy under part and WOT but i was getting NO BOOST. The turbo which is normally very loud i did not hear spooling at all. Hope this helped. Oh and while your at it replace your injectors o rings, grommets, and the seals that go on the intake manifold.

Do the RX7 club guys judge as quickly as you do? Just curious. Nice description, nevertheless.

OP: you can replace the fpr without removing the rail, so if you don't have boost leaks at the injector insulators, I'd leave the rail on the head and just change the fpr and o-ring. Or you could take the opportunity to upgrade the fpr (if you plan on going to a big fuel pump, for example, you'd need to upgrade to an adjustable fpr). But that's if the fpr is bad in the first place.

You might want to post the symptoms that led you to suspect the fpr. It might be completely unrelated. Or perhaps you were just curious.

 

[shaunallenallen]

miller time is right. I have learned when your there replace them so later down the road you will not have to question that part you replaced.

 

[Team Addiction]

Another common test is to pull the vaccum line off fuel pressure should jump 8-12 psi typically. If not it may be bad.