Need help diagnosing fuel pressure problem.

[Ronnie]

Found this photo of what I believe is a Reatta fuel tank. Are the lines normally disconnected in the area circled in blue, or red? I'm thinking the answer is blue. If blue I assume the tank will need to be dropped down part way to get to those connections?

 

[2seater]

The blue area is where the hard lines from the tank connect. There is some room to access but it is why I cautioned to be sure the fitting was held firmly when disconnecting. It is sort of by feel.

[Ronnie]

7 minutes ago, 2seater said:

There is some room to access but it is why I cautioned to be sure the fitting was held firmly when disconnecting. It is sort of by feel.

Do you recommend dropping the tank down some first or try to disconnect the lines first?

[2seater]

6 hours ago, Ronnie said:

Do you recommend dropping the tank down some first or try to disconnect the lines first?

Any additional room is beneficial. The lines to the front of the car have a flexible section which are permanently crimped to the hard lines. Only you can judge if it will be necessary. I looked through my photos from last year and can't find anything specifically relevant🤨

[Ronnie]

Thanks for all the help and suggestions so far.  I've decided to get my friend Donnie Turpin to do it for me at his garage if he has time but I'm making plans on the best way to do it myself if he can't get to it.

[Ronnie]

I spent some time under my Reatta looking at the gas tank today. Looks like dropping the sway bar will be easy.  The filler tube and vent hose clamps were turned for easy access so don't see a problem there. If I'm looking at it right the fuel lines appear to be out in the open and just held to the inside of the frame rail with a clamp as shown in. If so that would make the connections be in the area circled in red in the photo above. Is that right or am I looking at it wrong?  I should have taken a photo while I was under there...

 

With the rear as high as my jack stands would go all I could do is get my head and shoulders under the area where I would be working on getting the tank out. As big as I am I'll need both ends up as high as I can get them for me to do it. Hard part will be jacking it up all the way around and getting up and down to get wrenches a few dozen times.  Bad knee that will need replaced eventually didn't like me getting up and down a half dozen times today. Brain is saying do it. Body is saying no. 🙂

[2seater]

I am not 100% sure on this now but I think what you are referring to may be the end of the flex lines where the attach to the hard line going forward? I don’t remember them being separable and even though the red car is here, I had to modify a bunch due to rust. 
 

The clearance underneath is why I suggested ramps for the very heavy front end and jack stands at the rear. Seems more stable for doing a little tugging. Also why I don’t use a creeper, just an old carpet remnant. A tray for expected tools will be a plus, also for the removed fasteners. Old baking pan😉

[Padgett]

I have a pair of these for changing oil.

[ship]

Good luck, Ronnie.  You're a better man than me.  Be careful under there.

[Ronnie]

1 hour ago, ship said:

Good luck, Ronnie.  You're a better man than me.  Be careful under there.

Thanks. I'm not committed to doing it yet. Still gonna see if I can get someone to do it for me.

[Ronnie]

I decided to slide back under the car today and take some photos. The first photo shows the fuel line connections looking toward the back wheel. The other photo shows the connections straight on from under the car. They are right in your face and easy to get at if I'm looking at the right connections. Is my '88 model fuel line connections different from other years that are harder to get at?

 

[Padgett]

Dunno, just did on my '88 before had a lift so did on large jackstands. AFAIR I just let the sway bar swing down but was a decade or so ago.

[2seater]

That looks good Ronnie. You are indeed correct about the connections; in the red area they can be disconnected. In my defense, the red 89 had already been repaired several times before I got it and the donor can lines were just repaired without accessing the tank area on the donor car. My 90 is completely different. Should be a piece of cake on a rust free car.

[Ronnie]

Another update on my fuel pump problem that I have drug out for a couple of months now. I know this should have been fixed long ago but it's not been done yet.

 

My intention was when I got back from vacation (last week) I was gong to start on it. Only having one set of jack stands and needing two, I went to Harbor Freight to get a set of the aluminum ones. I've been wanting some of those for a while now. Just my luck they were out of stock. I didn't want another set of steel stands so I was willing to wait until they got the aluminum stands back in stock. That worked out pretty good. I saw my friend Donnie Turpin, (who I originally wanted to change the pump for me) at the Cracker Barrel Saturday night. He asked if I had got my fuel pump installed yet. I told him no. He said he was covered up with work but if I would bring it over to his garage when he opens next Monday morning at 9 o'clock he would do it for me. That made me very happy because I was dreading doing it laying on my back without a lift.

 

If all goes well I should be driving next week just in time for the leaves to start changing in the mountains. Fall is my favorite time of year for driving my Reatta. Just goes to show that sometimes a little patience pays off. 🙂

[DAVES89]

You mean "procrastination"? Right? 

 I'm a "crastinator" I haven't reached the PRO status you have...

[2seater]

"If all goes well I should be driving next week just in time for the leaves to start changing in the mountains. Fall is my favorite time of year for driving my Reatta. Just goes to show that sometimes a little patience pays off. 🙂"

 

Maybe it's just me but it sounded more like procrastination, of course when retired, that is standard for many thing😬 Not pickin' on ya, I have an S/C engine to put together that has been on the back, way way back, burner for a couple years. Probably a smart move if not entirely confident and this ranks right up with Dave's friends. Glad to hear it.

 

Edit: I must have forgotten to click the submit button a few hours ago so I guess Dave beat me too it :((

 

[Ronnie]

I decided it would be good idea to make sure my Reatta would still start and run so I could take it to get the fuel pump replaced Monday. If it wouldn't run I was going to call Donnie to bring his roll-back truck and get it. I think Hagerty would pay for it so he wouldn't be doing it for free.

 

Before trying to start it I put the fuel pressure tester on the fuel rail to see how much pressure it had. I turned the key on and off 3-4 times and then looked at the tester. Fuel pressure was 30 psi and held steady. When I tried to start the engine it had to spin over a long time before it finally started running . When the engine is running the tester bounces rapidly between 31-29 psi. When I open the throttle quickly by hand the pressure will drop to about 27 psi but the engine seems still to run smoothly.

 

After letting the engine idle for a while I took the tester off. The engine started right back up like it normally would. I was really surprised at that. I was expecting it to spin for a long time before starting again. I drove it on the street close to home in case it might quit on me. Then I headed out down the highway. I drove it six miles down the road and back, stopping a few times to see how it would accelerate. I can tell it is sluggish taking off from a stop and if I mash the gas pretty hard it will bog just a little. It's definitely not it's old self.  I'm really surprised it will run as good as it does with just 30 psi.

 

I'm thinking the engine has to spin a lot on the first start to get any air out of the fuel rail out that might have accumulated in it as the fuel drained back to the tank over time. Normally, if the pump puts out full pressure the regulator would open and circulate any trapped air in the fuel rail back to the tank through the return line. My pump isn't capable of putting out enough pressure to open the regulator so air is trapped in the fuel rail until it gets purged through the injectors opening. Does that theory sound plausible and make sense?.

[Padgett]

Certainly possible. I'd expect over 38 psi at all times. With no load is probably enough to rev. I'd be a bit concerned for the transition from open to closed loop.

Edited October 15, 2021 by Padgett

[2seater]

I think the only reason yours will actually start with that low pressure is the fact that it does hold pressure so there is something there for the priming shot. In my case the pressure bled off immediately leaving nothing to squirt into the port. My experience says this will only get worse and driving any distance is likely to leave you stranded. I am not sure where actual air would be in the rail but it takes quite a bit to pressurize that large diameter rail and nothing will go through the injector without a decent amount of pressure, and that would likely be a dribble rather than atomized fuel. If you look at the fuel rail of an L27 TPI engine, the rail is about 1/4 the volume or even less.

[Ronnie]

Got the fuel pump replaced this morning. I got there a little before 9:00 and Donnie and his 3 workers showed up about the same time. We had to eat Hardee's biscuit & gravy he brought before he went to work. He got it on the lift about 25 after 9:00. He wouldn't let me help. He said his insurance had been on him about not letting anyone in the work area so he got one of his crew to help him. I just stood at the door and talked to him while he worked. At 10:36a he was letting the lift down. That is what I call QUICK! It would have took me at least 2 days laying on my back to do it.

 

He turned the key three times and it started after a few turns. After that it started as it should so he pulled it outside.  He put his pressure tester on it and it idled at 36 psi which I thought was a little low but he said that wasn't too unusual with a regulator that old. When you hit the throttle and vacuum drops pressure jumps UP to about 41 psi. Before replacing the pump it would drop to about 27. He said he wouldn't replace the regulator as long as it is working as good as it is. He said he doubts I would be able to tell the difference in the way the engine would run if I replaced it. What do you guys think? Would you replace the regulator?

 

Driving home I could tell it ran as it should and accelerates much much better. When I got home I put my tester on it and hooked up the jumper to the prime connector. It will hold a steady 47 psi without the engine running so the pump is capable of putting out plenty of pressure. I feel safe about driving now without fear of being stranded on the side of the road.