Possible bad FPR?

[shippy8907]

Could a completely failed fuel pressure regulator cause a no start? I bought the car essentially non running. It would only start if you sprayed a shot of starting fluid into the intake, then it would hold idle but run very rough and miss. I've replaced the pump and the filter at this point. I know I am getting fuel to the rail, but I have not confirmed with a gauge the actual pressure. And I also do have spark coming out of my coil going into the opti, so it is not a spark issue. I just didn't know if the regulator failed completely, if it would allow all or most of the pressure to go through the return line back into the tank.

[englundjd]

you have spark going to the opti, have you verified spark coming out? Also you need to check pressure at the fuel rail. If you suspect a bad FPR then pull one of the vacuum hoses off and see if there is gas in it or if it smells like gas. Also would not hurt to scan the pcm for codes. Some codes do not set off the SES light.

[96LT1355Z28]

Yes, a bad FPR can cause no start and dying while driving. Most auto parts stores will rent you a fuel psi gauge for free. I'd check for psi at the rail before you buy anymore parts. Post up your results along with some info on the car ie year, mods, etc and we'll go from there!

[shippy8907]

No I haven't verified spark coming out yet I still need to do that. I pulled the rail up out of the intake and cranked and didn't get a drop of fuel from any of the injectors. I was going to remove the feed line to verify I had pressure there, but I couldn't find my tool to release the line. The regulator does not smell like fuel either. I'm trying to line up a pressure gauge in the next couple days. The previous owner said he checked and the opti sending signal to the injectors, but I still need to verify that. Its probably highly unlikely that all 8 injectors would be bad? The car is a 94 z28 by the way pretty well bone stock as well.

[shippy8907]

Also I can't check the codes at the moment. Someone was nice enough to remove the cigarette plug power source so the scanner wouldn't connect.

[SwampWS6]

I have a brand new one thats adjustable if you need it

[shippy8907]

Okay I hooked a gauge up to the rail and couldn't get a reading. I think the gauge was faulty though because it didn't work on my truck either. I unhooked the feed line and I have pressure there while cranking

[96LT1355Z28]

Try and find a fuel psi gauge that you know works and get an actual psi. There may be fuel at the rail that sprays from the schrader valve but until you know what the actual psi is it doesn't mean much. Check all the fuses in the car to make sure none of them are blown/missing?

If you have fuel psi (around 43 psi when the pump primes) then check for spark. Easiest way is to put an inductive timing light on a plug wire and crank the engine.

If you have no spark start back tracking to the coil and check for spark, then check for power to the coil.

You can also check for power to the injectors (pulsing) with a noid light available at most parts stores. The opti sends the signal to the pcm to fire the coil and injectors so a bad opti can cause issues in the fueling or spark or both.

Another easy thing to check that's pretty common is the opti harness. On the passenger side you'll see a harness that plugs into the opti and then connects to the main engine harness on the passenger side of the intake. It's not uncommon for this to become corroded where it connects to the opti. That can cause multiple issues since the pcm is not getting the info it needs to fire the engine leaving you chasing your tail switching out parts that work. For a good explanation on how the opti works and what info it gives the pcm click HERE (http://shbox.com/1/4th_gen_tech2.html#opti_test).

As you can see there's several "possibilities" for your no start issue that can lead to hours of frustration and confusion. It's easiest to do one test at a time and post up the results so we can figure out what direction to go next.

[shippy8907]

Yeah ill probably just end up buying me a gauge to use. I never thought to check the harness connection, ill for sure do that. I'll get a hold of a set of noid lights also. I'll check into all those areas and let you know. I appreciate all the responses guys!

[BALLSS]

OP

you pulled up fuel rail and cranked and no fuel came out of injectors, right?

This suggests a fuel delivery issue. Something EASILY verified by a FP gauge. Like this one

http://www.summitracing.com/parts/hyp-4004?seid=srese1&gclid=CJiK1fyehcQCFVFhfgodpT8Aow

I would stop pulling parts and get a gauge to confirm wtf your FP is first.

[shippy8907]

Well I did attempt to use a pressure gauge yesterday, but the gauge is faulty. I have to get a hold of a gauge that actually works so I can see exactly how much pressure I have.

[shippy8907]

Okay, I bought a pressure gauge from harbor freight yesterday. Primed the pump twice, gauge showed right around 40 psi. But as soon as the pump stopped priming, it started to bleed down really really fast. I had the rail unbolted and over a catch pan to make sure the injectors weren't leaking the pressure and they were not. This is sounding more and more like an issue with the regulator.

[blackbirdws6]

How old is the pump? Pump issues can cause the same problem with pressure bleeding. Reg is easier to get to obviously. You are positive no fuel is coming out of the vacuum line on the reg?

Edit - you mentioned earlier on that you pulled the rails with injectors and while cranking, none of them sprayed fuel? If this is correct?

[shippy8907]

Pump is brand new, zero miles on it. I had the rail unbolted and laid over a pan so I had the vacuum line off the regulator when I checked the pressure and nothing was coming from it. It doesn't have any obvious fuel smell to it either.

[blackbirdws6]

So nothing was coming from the injectors with them plugged into the pcm and you turning the engine over?

[shippy8907]

No, nothing that I could see anyway. I just popped them up enough to where they were sticking out of the intake and there wasn't a drop from any of them when cranking. Previous owner had checked and the computer was pulsing ground on the injectors. I still need to confirm that though, but I'm assuming that's true considering it will continue to run after the initial start on starting fluid.

[Spartan7]

Pump is brand new, zero miles on it.

This is an instant red flag to me. What brand pump, and who installed it?

[shippy8907]

Its an airtex pump and I installed it. I just removed the old pump from the basket and installed this one, it was the exact same pump that was already in there. I blocked off the return line last night and primed the pump, pressure still dropped. So I primed the pump and quickly clamped the feed line, still bleeding down. I then noticed after a couple minutes, the injector for cylinder 8 was dropping some fuel from the o ring in the rail. But there is no way that's where all the pressure is going considering how quickly it leaks down.

[96LT1355Z28]

I'm wondering if there is a leak inside the tank. The fuel psi should bleed down but over a decent amount of time, not instantly when the pump stops running. If you've blocked the feed line and it's still doing it that kinda eliminates the FPR.

I have a friend who bought a car in a similar situation as you. Crank no start, had spark but no fuel psi. We could hear the pump prime and get some fuel from the schrader valve but not alot. Turns out someone had used standard rubber fuel line inside the tank from the pump to the housing. It's not rated to be submersed in fuel and had swollen and blown out the side. The pump was working but it was just cycling fuel inside the tank. Obviously this isn't the case with yours but the concept's the same.

[shippy8907]

Yeah that would make sense. All the hoses in the tank looked good, no swelling or splits that I could see or feel. I'm just stumped at this point. Unless I'm somehow having a leak on both the feed and return line?

[shippy8907]

I probably need to pop the pump back out and double check all my connections.

[96LT1355Z28]

Have someone turn the key on and prime the pump while you can see it, keep it in gas or coarse! If there's a leak, you'll see it!

[shippy8907]

I'll have to have my buddy help me this weekend and see if I can find a leak when its priming. I'm just so ready to get this thing on the road. I've always wanted a 6 speed so bad. And now I have one...that doesnt run. lol

[Spartan7]

What do you mean by "blocked" the return line? Capped it or tried pinching it? If you actually capped it and pressure still bled down, the only things it can be are an external leak or an internal pump leak.

[shippy8907]

Just used a set of locking pliers with washers on the teeth to put equal pressure on it. That's the only way I had to try and block it at the time. I do have a very slight drip from the back of the fuel filter at the quick connect, but that would have to be gushing considering how quickly the pressure drops. What would be the best way to completely cap the lines to be sure?

[Revolutions]

In case you are not aware of it there is a fuel pump prime connector (gray wire) on the passenger side near the PCM if you supply 12v to it the pump will run continuously.
31996

[shippy8907]

Yeah I knew that was there, I just forgot about it while I was messing with the car the last few times and used the key. Thank you for the info though!

[96LT1355Z28]

Thinking about what Spartan7 said where did you pinch the fuel line at? I ask because there's only steel and plastic lines and if you pinched the plastic lines that's not good. It's not part of your current problem but you might have created a new issue for your self once this is fixed.

[shippy8907]

I did just pinch it with locking pliers about 3-4 inches back from the connection to the rail, which I realize isn't the best option. Is there any special tool to use to cap the lines? I don't think I have any other way to block it really.

[Spartan7]

The only thing I can think of is getting some A/N fittings and adapters to cap it off. Are you sure it's the quick connect at the filter leaking and not dribbling down the hose from higher up, closer to the sending unit? I would fix that first just to be sure. You'd be surprised how much pressure a small leak can vent (especially on higher pressure stuff).

Did you cut an access hole for the fuel pump? I'm doubting its integrity since it's been the most recent change to your fuel system. Or did you have this problem before the fuel pump swap?

[shippy8907]

I haven't taken a really good look at the filter leak yet. I just know its got a small dribble at the quick connect side. It very well could be coming down the line from the sending unit. I need to take a better look at it just to see exactly where its coming from. Yes I did do a trap door. I bought the car and it already had this issue, only starting with starting fluid then will start afterwards on its own.

[shippy8907]

Well I threw an extra fuel rail with injectors and regulator on it and it still bled down, so its somewhere on the feed side. Most likely in the tank. I'm gonna pull the pump and probably just put a fresh piece of fuel injection line in place of that factory style plastic line to be sure. If that doesn't do it, looks like I'm in the market for a new pump.

[96LT1355Z28]

I'm sure you will but check it before you replace any more parts, this way you know what you fixed and are certain it's actually fixed!

[shippy8907]

Oh I will check before I actually buy a pump. I'm on a married man budget, so I have a limited spending amount on it anyway. Lol

[shippy8907]

Update; the car is now running on its own. Turns out the pump did have a bad check valve. I defected the old pump out, threw this one on and it fired right up. I also got the plugs changed and the previous owner was nice enough to use 3 different kinds of spark plugs including one accel plug that was a good 3/4 an inch too short. Now I just have to track down a vacuum leak and bleed my clutch and she will be on the road. Thanks for all the help guys!

[96LT1355Z28]

Carb cleaner or brake clean help a ton in finding vacuum leaks, why do you think it' got a vacuum leak? The clutch shouldn't need bleeding, why are you thinking it needs to be bled? Just trying to make sure your not making more work for yourself!

[shippy8907]

The clutch master was bone dry when I bought the car, so it was a completely separate issue. Sorry if that was confusing. Lol. I'm pretty sure it does because it is idling at 2k rpm. I'll probably pop the idle control valve out to see if its all gunked up just to be sure. Probably could use a cleaning anyway.