Vapor Lock???

[Sieg]

Scott,

First off a disclaimer that I have little knowledge of 2nd Gens.........

I had a similar experience with drop off in fuel pressure and in my case a new pump solved it.

> If the cap isn't vented how does the fuel tank vent?

Another connection I spotted that concerned me on my car was the connecting hose between the tank hard line and the chassis hard line in this pic:

I replaced it years ago, but it felt soft enough that I was concerned about it collapsing under heavy demand so I replaced it.

First guess is a venting issue as the tank has to vent for the oneway system to work. The car sat for a while right? Bug debris effecting venting?

[protour73]

Originally Posted by Sieg

Scott,

First off a disclaimer that I have little knowledge of 2nd Gens.........

I had a similar experience with drop off in fuel pressure and in my case a new pump solved it.

> If the cap isn't vented how does the fuel tank vent?

Another connection I spotted that concerned me on my car was the connecting hose between the tank hard line and the chassis hard line in this pic:

I replaced it years ago, but it felt soft enough that I was concerned about it collapsing under heavy demand so I replaced it.

First guess is a venting issue as the tank has to vent for the oneway system to work. The car sat for a while right? Bug debris effecting venting?

Back in the day, venting lines ran from three vents off of the tank to the charcoal canister in the engine compartment. Hence, no vented cap. I ditched that whole charcoal canister system back when I started the build.

I have that same connecting hose basically on the 2nd Gen. Mine seems fine, and since I have a brand new pump installed, I've eliminated that possibility.

The car has been out including track time. There is always the possibility that the ethanol fuel around here has compromised the sock filter on the pickup of the sending unit in the tank. So I may have to drop the tank

[Rick D]

Originally Posted by protour73

Back in the day, venting lines ran from three vents off of the tank to the charcoal canister in the engine compartment. Hence, no vented cap. I ditched that whole charcoal canister system back when I started the build.

I have that same connecting hose basically on the 2nd Gen. Mine seems fine, and since I have a brand new pump installed, I've eliminated that possibility.

The car has been out including track time. There is always the possibility that the ethanol fuel around here has compromised the sock filter on the pickup of the sending unit in the tank. So I may have to drop the tank

Um you don't want to look under there

Did you try to run it with the gas cap off like I said yesterday?? If it doesn't drop then you know it's a vent issue? If it still drops then it may be the pickup in the tank.

[protour73]

Originally Posted by Rick D

Um you don't want to look under there

Did you try to run it with the gas cap off like I said yesterday?? If it doesn't drop then you know it's a vent issue? If it still drops then it may be the pickup in the tank.

Before I even talked to you I ran it with the gas cap off, still dropped.

Originally Posted by Vegas69

Liquid filled fuel pressure gauge in the engine compartment?

Yes, it is a liquid filled fuel pressure gauge in the engine compartment.

[Vegas69]

Originally Posted by protour73

Before I even talked to you I ran it with the gas cap off, still dropped.

Yes, it is a liquid filled fuel pressure gauge in the engine compartment.

A liquid filled gauge will become innaccurate with heat. Been there, done that. Order a non liquid filled or a universal gauge and verify before you spend any more time or money.

[Ron in SoCal]

Thoughts...

Scott are there any starting/performance issues?

I'd verify you're getting good fuel pressure readings. You can check this may ways.

[intocarss]

Todd is right, liquid filed gauges can be inaccurate due to heat or altitude change. Some gauges have a vent screw on top. Make sure not to let any of the liquid out. Now, turn the screw two or so turns out to equalize inside gauge pressure(NOTE.. some gauges have a little rubber plug that you maybe able to remove insted of a screw).

This will allow the gauge to release un-wanted pressure and self adj to different altitudes or temperature. I used to have to do this at different race tracks with my gauges. Oil filled is good for vibration but can suck for accurate readings.

Ron Sutton is also right, It could be your regulator. I have had the diagram ones lose pressure and you have to adjust accordingly. You said you replaced the fuel pump so I doubt its the bypass (if any) in your pump.Some pumps have an adj pressure screw..is that set right?

Another thing... are your hoses old? Maybe they are coming apart inside and tiny bits of rubber are in your regulater. This is just my 2 cents..Hope you find it

Also..For safety sake... I do not like to run a fuel pressure gauge under my hood they can leak JMOHO

[Vegas69]

Originally Posted by Vegas69

A liquid filled gauge will become innaccurate with heat. Been there, done that. Order a non liquid filled or a universal gauge and verify before you spend any more time or money.

Not a bad idea......

Just giving you hell Scott.

[protour73]

Originally Posted by Vegas69

Not a bad idea......

Just giving you hell Scott.

HA, Todd I have a pretty thick skin after years of hanging out on these cars sites!! LOL

Originally Posted by Vegas69

Liquid filled fuel pressure gauge in the engine compartment?

But when you posted this I went, OH CRAP, he knows something and that's just the teaser!!