To Dream the Impossible Dream (Redwing's Z cars)

[SteveJ]

I'll be giving Jai's car a once over tomorrow. I'm about to load up my car to make sure I have all of my diagnostic tools.

[Patcon]

Good travels Steve. I think you will get it sorted quickly.

 

Blue, I was not sure whether that was rich or some oil deposits. I didn't look at them that close on Sunday because we were shot and a huge thunderstorm rolled through.

Like the avatar, have you ever used a blue M&M character?

[Redwing]

Lumens

"But at some point" .... what???

[siteunseen]

Lumens

"But at some point" .... what???

They have to be opened up and new internals put in. Rings, timing chain kit, new valve seals and gaskets. Short list.

[Patcon]

I believe her 280z is a low mileage car. Her 240z has the 256,000 on it but it has bigger issues than miles

[SteveJ]

Okay, I'm back from looking over Jai's car.

 

My overall impression is that the car is not in bad shape. The AC needs work. At a minimum it will need new hoses and a dryer. I'm not sure if the compressor is in good shape, though. The system has been disconnected for a while now.

 

I drained the tank. There was a little rust, but it didn't seem that bad. If I could ever figure out how to manipulate my borescope, I could have gotten a better idea of the condition of the tank. I replace the hose between the tank and fuel pump and added an inline fuel filter in case the rust is worse than I thought. I had trouble manipulating the fuel pump because there wasn't a lot of room and, it's not very comfortable working on gravel. I also replaced the fuel filter in the engine compartment, though the old one didn't seem that bad.

 

When we tried running it after replacing the fuel line and putting in the filters, it was slow to fire. I expected that with the lack of fuel pressure. Then it came to life and seemed to run fine.

 

Thinking that I might have resolved the issue, I tried to clean up the battery before the corrosion built up enough to drop the voltage to the car. I had issues with the nut on the negative cable, (No, I'm not referring to me.) so I just cleaned it the best I could. There was no battery hold down bracket, so I tried to use one of the generic types from the parts store. That didn't work out for me. So, I decided to wrap up the work.

 

Unfortunately, the car didn't want to run again. It just seemed fuel starved. I talked to my friend, Chet Wittel, and he confirmed that I couldn't diagnose squat on the fuel starvation without a fuel pressure gauge.

 

With the prevailing heat wave, I knew I couldn't keep working on the car and thinking clearly. The heat was getting to me, and I didn't want to cause more problems than I solved.

 

So, I plan to go back in a couple of weeks. Now that have a better sit-rep, I can bring along tools to help me work on the car better. I am thinking of fabricating a battery bracket on-site next time, as well as finding the cause of the fuel starvation.

 

My key suspects:

1. Fuel pump.

2. Fuel pressure regulator

3. EFI relay/ECU.

 

Number 3 is the long shot, and I hope that isn't the case. I found a fuel pump on Amazon for $46, but I didn't find a specific FPR for her car, just universal types. RockAuto has an FPR, but it will be over $70 shipped.

 

So, my questions to the group:

1. Does anybody have a good fuel pressure gauge that will go up to 50 or 60 PSI to loan me for my return trip?

2. Had anybody used a universal FPR with good results? If so, what was the cost, and what was the part number?

[Zed Head]

One universal FPR might be a pair of locking pliers on the return line.  If you have a gauge you can probably get it dialed in enough to make the engine run.

 

Many of the inexpensive adjustable regulators will leak down rapidly with no pump pressure. Creating a whole new issue.  I would stick with an OEM supplier since they're designed to hold pressure.  The aftermarket FPR's are for adjustability and bling.

 

Unfortunately for us, in general,, the 2.5 bar spec. has been superceded by 3.0 bar.  So there aren't many options to make work.  You might find an old BMW, or VW, or other Euro brand that would work.  1970's to 1980's would be the range.

 

There is an adjustable Bosch FPR that I've seen on eBay but it doesn't have the vacuum adjustment.  Has to be modified.  Bought mine for $34.

Edited July 25, 2015 by Zed Head

[Zed Head]

Here's a VW option that could be used.  Still spendy, but it's available at OReilly Auto.  1979 Super Beetle.

 

http://www.oreillyauto.com/site/c/search.oap?year=1979&make=Volkswagen&model=Super%2BBeetle&vi=1423189&keyword=fuel+pressure+regulator

[Zed Head]

Here's the OReilly 76 option.

 

http://www.oreillyauto.com/site/c/search.oap?year=1976&make=Nissan&model=280Z&vi=1209226&keyword=fuel+pressure+regulator

 

You can make almost any 70-80's era FPR work with some hose and clamps.

[Patcon]

Where is the FPR located on a 280z?

[Zed Head]

It's right in the middle of the rail.  The fuel enters from one side, travels through two loops then exits n the middle at the FPR.  Rigging up a non-stock FPR would take a little ingenuity but it's doable.  On a 76 you can replace the stock FPR with a T fitting, and mount the non-stock FPR remotely on the return line.  

[FastWoman]

Steve, the fuel pressure can actually be off a bit without dramatically affecting the running condition, so even a cheap pressure gauge can probably tell you what you need to know.  A number of us have installed cheap pressure gauges permanently under the hood for diagnostic purposes.  Usually the little gear mechanisms in these gauges wear out.  However, the gauge will be good long enough to get the engine sorted out.  The way I did mine was to fit two nipples with 1/8" MPT threaded ends into a 1/8" FPT tee fitting.  (The 1/8" is nominal, and the bore is really much larger than that -- fits a 5/16" hose nicely).  On the third leg of the tee, screw in a cheapo, hardware store variety of pressure gauge, sold for measuring water pressure -- usually in the water pump isle.  Total parts will be about $10-15.  Insert the gauge inline between the fuel filter and the fuel rail.  Again, if it's inaccurate by a couple of psi, it's not that big a deal.  It should still give you a good idea whether the rail is up to pressure, and it's always present in the system, ready to yield useful info in the event of another breakdown.

 

With regard to the FPR: It seems a very simple and robust design to me.  People sometimes say they have trouble with these things, but I've owned three, and they are all square on 36.4 psi w/o vacuum -- no problem ever.  Pressure is given by spring pressure minus vacuum, so it is unlikely one would be inaccurate.  (Dunno...  maybe spring fatigue?  But I've not seen it.)  I would think the only ways for it to fail would be leak-down of fuel pressure after shutdown or rupture of the diaphragm (dumping raw fuel into the intake via the vacuum line).

 

To stress-test the fuel pump, I would hook up a gauge, connect a long hose (clear PVC is fine) to the fuel rail return line, and put the other end in the tank filler neck.  Then hotwire the pump to run with the ignition off.  You can periodically measure flow rate, while keeping an eye on pressure.  These pumps often run fine when they're cool and then fail once they warm up.  You'll see the pressure hold steady, with a gradually diminishing return flow rate.  Then when the pressure drops below 36.4, return flow will cease.