flypfi

Hi... Does anyone know of a thread that lists the steps and level of tear-down needed to access and replace the fuel pressure regulator? I know I just need to get in there and start disassembling, but if there are any shortcuts or gotcha's I need to know about it would be greatly appreciated! I'm planning on digging into it this weekend.

Someone mentioned in an old post there is a way to do it without removing the intakes, but provided no details. Anyone know about this?

Thanks!

Rocket Rob

The fuel pressure regulator is at the end of the engine in the far back of the engine compartment. You will need to remove some or all of the intake manifold. You will want to have a set of flare nut wrenches. As for tips or advice? What is the problem you are trying to solve? While you are working on the regulator, be sure to inspect your fuel lines. My C2's fuel lines were very hard and one had puffed up like a balloon. I ended up replacing all of them, just to be safe.

JasonAndreas

With the engine running, remove the fuel pump fuse (not the DME relay). The engine will die shortly and the remaining fuel will be under a lot less pressure which you will appreciate when you break the lines open.

flypfi

Thanks Rob... I know where it is located. I pulled the the manifold pressure/vacuum line off to confirm the problem - gas spewed everywhere, so a large defect in the diaphragm. I have the replacement in hand, I was just wondering if there was any advice from someone who had done it like "You don't need to remove the throttle body" or "Only remove the left side intakes" etc.

I guess I just don't want to dig deeper than I need to!!

flypfi

Thanks Jason - Since the problem I am experiencing is a loss of fuel pressure - it drops to zero within 3 seconds of turning the pump off - discovered it is going back through the vacuum line, hence the need to replace the FPR - do you think there might still be residual pressure on the return side?

Vandit

The FPR is actually attached to a bracket at the bottom of the throttle body, and the 24mm nut that attaches it to the bracket is kind of a beat down to remove. It's best to disconnect the return line so that you can get the closed end of the wrench on the 24mm nut rather than the open end.

flypfi

Thanks Vandit... that's the advice I was looking for! So to be clear, does the throttle body come out first, or they come out together?

onceover

What lead you to try removing the FPR vacuum line? I've been having cold start issues where the engine will need to crank for a good 5-10 seconds before it fires up.

Thinking its a fuel pressure problem, and I've picked up a fuel pump check valve in hopes that it's that, but could it potentially be the FPR?

Vandit

The fuel side and the vacuum side of the FPR are separated by a diaphragm. Getting fuel through the vacuum side is a sign the diaphragm is failing. As a result, the fuel will be sucked through the vacuum line and into the intake and mess w/ the a/f mixture and can cause the car to run poorly. Additionally, if the FPR is bleeding fuel pressure while parked, then it makes for hard starting since the system needs to repressurize the next time you turn on the car.

jpar

I did it last year without removing the intake manifold, but I don't remember exactly every step. Basically I removed the airbox/afm and the blower motor and kinda felt my way around with a mirror, it was a pain in the ***, but it can be done.
If you have the time, I would pull the intake manifold and change the breather gasket, the o-ring for the oil pressure console and the check the oil pressure/temp sensors aren't leaking if they've never been done. My breather gasket and that o-ring were leaking a lot, the only reason I didn't pull the intake was because I knew I'd be doing a reseal the following winter.

Here's what it looks like back there. You need to undo the 3 fuel lines, and then the 24mm nut in the center. You can also see how bad the leaks were.

flypfi

onceover- I was having warm start problems and a mixture of other weird power issues - small occasional backfire when accelerating, random power loss, etc. Progressively got worse. I changed or checked everything, ISV, O2 sensor, DME relay, DME reset, MAF sensor, codes, etc. Then I attached a fuel pressure gauge and noticed the pressure dropped to zero with a couple seconds when I shut the pump off - it should stay up for 20-30 minutes. I pinched off the supply line at the pump and the pressure still dropped - indicating the check valve in the pump was not the problem. Then I pinched off the return line on the FPR and it still dropped. That meant it had to be draining into the vacuum line - and sure enough, when I pulled it off, fuel leaked out. Then I turned the pump on and got a geyser out of the small vacuum port on the FPR! That was my diagnostic process, for what it is worth!

flypfi

Thanks jpar - great photo. I wish my engine was out! So it looks like the phillips screws attach the bracket to the throttle body (or is it the center manifold?), so the fuel lines will need to be removed with the throttle body in place. Looks like a bitch.

jpar

No problem, the screws and bracket stay, just undo the lines and that center nut and it comes out. I think I also undid the clamp and moved the breather hose out of the way.

JJ964

I did all this in Feb. Since I've got lots of oil leaking, I cheated and pulled the engine.

I had the same "problem" with the fuel lines. Yes the lines are hard because it turns out they are not hose. They are rubber sleeved hard nylon formed lines. I had one bulged line and it turned out to be only the rubber sleeve. I also had lines that turned on the fittings, but didn't leak. I also ordered new lines from Sonnen (x$450) for peace of mind.

Flypfi, this was hard with the engine out, I think at the least you will need to pull the intake manifold as an assembly. Disconnect all electrical connectors, vacuum lines, throttle cable, fuel lines, ect. There is a hidden connector and vacuum line on the back of the AFM. Loosen the hose clamps on the rubber connectors and it should come off. I had a torn rubber connector so I would replace them.

The FPR is mounted on a bracket connected to the chimney assy. Disconnect the vacuum line, 3 fuel hoses and Big nut.

Assembly is just the reverse! Do a search on BigMikeAtl, he had a thread with pictures.

flypfi

Thanks JJ964 - exactly the "inside info" I was hoping for!