"RacinBob" (racinbob)
09/01/2019 at 14:10 • Filed to: None
2
5|
"RacinBob" (racinbob)
09/01/2019 at 14:10 • Filed to: None | 2
| 5 |
I for about 2 years have been getting an intermittent low fuel pressure light on my ‘74 Spider. It would be fine when cold in the morning, but driving home at noon the light would flash. I believe the car has a light to protect you from running the Spica mechanical injection system dry which I would presume would damage it.
I diagnosed it through some intuition. I noted the rear electric fuel pump is silent when cold, but sounds gravely/rough when the light is on, I pinched off the discharge hose and noted no difference in sound. I pinched off the supply hose and it got worse. My theory, pump is starving and I am hearing cavitation or vapor from flashing fuel going through the pump. I turn on my air compressor and wrap a rag around the air chuck and put it in the tank, A quick hit of air and the pump quiets and the light shuts off, diagnosis confirmed
Since the tank was full, I squeezed off the line upstream of the filter and pulled the filter, I rapped the filted on the ground and you can see all the stuff that came out, I blew brake cleaner through it and got more of a fine gritty material. I re-installed the filter and it is good as new,
I’ll wrap this up with a mention of some of my favorite tools. First is my 20 year old or so track mat mechanics mat. It makes laying in the ground a lot more tolerable. One of my best presents ever. Also, I love my Showa gloves. Protects your hands and keeps them clean, Beat of all is they are so sensitive you can pull a dim out of your pocket with them on, They really are nice.
MKULTRA1982(ConCrustyBrick)
> RacinBob
09/01/2019 at 15:07 |
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I’m having similar noise from my fuel pump and I also have mechanical fuel injection, is yours Bosch too by any chance? I will be coming back here to copy your diagnosis, thanks! Any tips you would give now that you’ve done the job?
RallyDarkstrike - Fan of 2-cyl FIATs, Eastern Bloc & Kei cars
> RacinBob
09/01/2019 at 15:29 |
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Yay! See people? Old Italians aren’t that hard to keep on the road! :P
Urambo Tauro
> RacinBob
09/01/2019 at 18:11 |
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Neat trick with the coins to keep the jaws from biting into the hose.
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RacinBob
> MKULTRA1982(ConCrustyBrick)
09/01/2019 at 18:21 |
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Yes , I have a spica mechanical fuel injection and a new (2 year old) bosch electric fuel pump. The original pump started leaking when I switched from gasohol to pure gasoline. So I would say if you have been running gasohol, you might as well continue as the pump seals do not like the change.
Second, I would drain the tank as much as possible and then let the remainder go into a bucket. so that you can change all the hoses back there. One of my 7/16 hoses
was so brittle that it cracked when I pinched it off. I have replaced every rubber line on the car. I have concluded old hoses are why
old cars
burn down.
You might as well get a new filter. S o do it on a day that the parts store is open as you will probably not be able to size the filter and lines while on the car. Ps I would not touch the front filter. It is so oversized that I cannot imagine it getting plugged. Also if you take it apart, you will discover that it is a SOB to reassemble in place.
One last thing, I noted that all the line size changes from tank to filter and filter to pump. A handy adapter of large fuel lines are those breass pex fittings you can get from plumbing supply houses. I found a 3/8 to 7/8 adapter that worked great.
Send pictures, good luck.
CaptDale - is secretly British
> RacinBob
09/02/2019 at 23:09 |
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I have a new filter for my Vette.... need to finally do that