So…I’ve been working on my L98, and now the fuel pump has failed.

Saw some interesting stuff, arguing that the pulsator should be eliminated, and frankly, I’m not a fan of eliminating it.

All the pulsator is is an accumulator. It’s job is to even out pressure spikes as the fuel injectors are opening, and closing.

Most every post I see mentions it’s main job is “noise” elimination, but I see a far more important role it plays long term.


The source of the additional noise with the pulsator eliminated are the pressure spikes…but that’s why I’m thinking it’s better to leave one in the system.

Each one of those pressure spikes places an additional momentary load on the fuel pump. Since TPI injectors fire in “batches”, this is a considerable spike as each bank of injectors fire.

It’s my contention that while the pump is certainly able to handle this additional momentary load, over time, this is putting unnecessary wear and tear on the pump, shortening pump life, compared to a much steadier load with the pulsator in place.

Thoughts?

 

The damper is to eliminate pressure spikes from the old school style rotary vane/roller pumps. Pressure spikes from the injectors are hardly even noticeable on a scope trace of the fuel pressure. And with modern turbine pumps the pulses from the pump are vastly reduced due to many more and much smaller turbine blades instead of like 4 roller vanes on the old junk..... so there's really not much use for the dampers. I have a Walbro 450 turbine, 1050cc injectors and no dampers anywhere in my system. My junk runs just fine and indeed we build a lot of cars at my shop and very few of them have dampers in the fuel system (other than the fuel filter, which itself is an expansion chamber / damper). You can get really nice dampers tuned to the fuel pressure you are going to run from Radium (www.radiumauto.com). But the reality is that if you use a turbine pump there's very little need. We don't see failures of the turbine pumps or injectors really at all - despite there not being any pulse dampers in most hot rod fuel systems.

GD

 

Precisely the sort of discussion I’d hoped for.

Thanks for the good information.

 

Fantastic information! I'm getting ready to replace my OEM pump and I've wondered if I should replace the (often prone to failure) pulsator as well.

 

Never used one in my TPI G20 van. Never noticed an issue from it not being there either.

 

Well…I’m converted.

When I replaced the fuel pump, I insisted on also replacing the pulsator. Bought a brand-new pulsator from RockAuto ($27), and all was well for a little over 3 weeks.

Fuel pressure dropped to 30 PSI, and I barely got my L98 IROC back home. First thought was the fuel pressure regulator, since I had no idea how old it was, so I bought a Holley adjustable FPR….no change.

The problem was the pulsator…lasted less than a month before it failed. Eliminated the pulsator, and now pressures are normal again. The only positive I can report is I now have a nice adjustable fuel pressure regulator.