[Formulajones]

Originally Posted by JLMounce

I spent the day working on the car and doing some testing. I wish I had a complete log but for some reason the log function in the procal software or on my handheld is not functioning. Might be something with the laptop I’m using.

Anyhow here are my findings.

Fuel pressure is running at 50psi at idle, it should be 58psi. On a quick rev it’s dropping to 40 psi. That’s definitely a problem.

Replaced the fuel filter and I honestly can’t say that the old one looked terrible. That clearly wasn’t the issue.

I verified all injectors are firing at idle and through the rpm range.
Verified timing has not moved. It’s still in sync with the computer.
Changed the plugs, two of them showed signs of the porcelain cracking. Most of them read hot and lean, which makes some sense.
Inspected the cap and rotor. Both look good with no indication of ionization issues. The adjustable rotor has not moved from where it was originally set.
Removed the valve covers and inspected each spring. No outward indication of the outer springs and what can see of the inner springs being broken. None of the polylocks have moved.
Finally also conducted a compression test. Engine at 190 degrees, full charge on the battery, throttle wide open.

1: 183
2: 180
3: 190
4: 182
5: 183
6: 180
7: 191
8: 192

What I was able to accomplish today made no difference in behavior.

There’s still way too much fuel in the tank to drop it, so I’ll need to drain some of the fuel. I also went ahead and ordered a genuine bosche fuel pressure regulator. I should be able to get to those next week. Hopefully there will be a positive result.

If not I’ll move on to checking the springs and inspecting the lifters.

That's kind of what I suspected, there is some sort of fuel delivery issue. That would have been visible in the tune as the unit tries to cover up the fuel deficiency. If it's dropping to 40 with just a quick free rev, it's probably plummeting fast under a WOT load.
Sounds like a possible fuel pump issue. What kind of pump setup are you using?

Edit: never mind I see you mentioned dropping the tank so you have an in tank setup. That's good news. Just make sure you get a genuine walbro. Not the cheaper stuff advertised as walbro on ebay. Those seem to have problems and I suspect they are reboxed garbage. I always just order directly from Walbro, I pay more but I know what I'm getting in the box. It's the same stuff all the OEM's use.
A trap door would have that swapped out in about 15 minutes, even with a full tank of gas Just sayin.