Fuel accumulator removal / bypass

[AugustneverEnds]

I was just looking through some plumbing stuff I have laying around and a 3/8" compression nut on a toilet fill line fits like a glove. Wonder if the 7/8" end will fit on a fuel filter

Looks DMC was prepared for cheapass owners trying to use plumbing supplies to keep their cars running

[Helirich]

Not at all I know you can remove the old one, breaking clips in the process, and it will be bent out of shape. Getting the new one in place and in usable condition will be likely not possible.

I haven’t looked at it, but if it can’t be replaced in the stock location, it would seem like it can’t be that hard to run a line in another location. Of course, I’m not a “factory only” kind of guy.

[AugustneverEnds]

I haven’t looked at it, but if it can’t be replaced in the stock location, it would seem like it can’t be that hard to run a line in another location. Of course, I’m not a “factory only” kind of guy.

I will probably end up using some type of alternative to the hard line routed slightly differently to the way it is. I'm not concerned with originality here just need a leak free connection.

[Coppertank]

Hello!

Sorry that this is a bit of a necro post, but I'm curious if this will benefit my car.

I'm running a TEC-II ECU for EFI on a 3.0L Eagle Premier engine in #2860. I cannot pin any sort of pattern down, but the car will sometimes outright refuse to prime. I've checked all the wiring and relays and haven't come across anything sketchy. I've hooked a multimeter up to right where the TEC-II runs to the fuel pump. When it's not priming, there is no power at all. I've basically narrowed it down to the ECU itself thinking it needs replaced or re-tuned, but lately I've been thinking maybe the pump won't prime if theres too much pressure in the accumulator? I can hear what I think is the accumulator making a sound when the pump primes and sometimes when I turn the engine off.

[Ron]

(Assuming you confirmed that the ECU is getting the signal to prime during failures...)

I'd say that the ECU is the better bet since normal D rest pressure is less than 50psi [3.3 Bar], and, the PPR will keep it <= 75.4 psi (5.2 Bar).
Next time it fails to prime, you might try jumping 12V to the ECU pump terminal...

[FABombjoy]

When it's not priming, there is no power at all. I've basically narrowed it down to the ECU itself thinking it needs replaced or re-tuned, but lately I've been thinking maybe the pump won't prime if theres too much pressure in the accumulator?

I'm not familiar with this ECU but there may be some control over priming when the engine is warm vs cold.

It's also possible there is a fuel pressure sensor that's part of the pump control but this is less common.

EFI cars do not need an accumulator but this isn't the source of your situation, and removing it won't change anything.

the PPR will keep it <= 75.4 psi (5.2 Bar).
Next time it fails to prime, you might try jumping 12V to the ECU pump terminal...

The PPR is likely on another car Should be closer to 45psi (less when engine running).

Don't put 12v at this terminal. EFI ECUs almost always are switched ground.

[Ron]

The PPR is likely on another car Should be closer to 45psi (less when engine running).

Don't put 12v at this terminal. EFI ECUs almost always are switched ground.

LOL - Yeah, I guess the PPR wouldn't have anything to do with since it's eliminated along with the FD.

I think I'll ban myself from the EFI section...

[Coppertank]

I'm not familiar with this ECU but there may be some control over priming when the engine is warm vs cold.

It's also possible there is a fuel pressure sensor that's part of the pump control but this is less common.

EFI cars do not need an accumulator but this isn't the source of your situation, and removing it won't change anything.


The PPR is likely on another car Should be closer to 45psi (less when engine running).

Don't put 12v at this terminal. EFI ECUs almost always are switched ground.

I very much appreciate input from both of you! It's great to hear input that basically validates what I've been headed towards. This has been an uphill battle for the last half of a year. I just bought a Windows XP with a built-in serial port off of ebay so that I can talk to the damn thing (I did get it running with a modern laptop and a serial-to-usb adapter, but didn't feel like lugging my main laptop around). Yesterday, I was able to run a "datalog" file which basically shows that the idle starts bouncing between 700-800 once the coolant reaches about 140F. Definitely worth investigating if it's a setting that adjusts based on the temp. After I ran the datalog, I turned the car off and tried priming it a few times. The pump would kick on and then stop more abruptly than usual. Normally it primes for about 15-20 seconds or so before it stops.

Today, I took a look at the car without starting it. I disconnected the fuel pump relay and hooked in a multimeter. When I turn the key on, power runs through it every single time. Forgive me if this sounds silly, because I am a computer guy and not a mechanic; Is there anything that could be telling the ECU that there's "enough gas" and so it just doesn't prime? If I jump the relay, the pump kicks on without fail. But it won't start if I don't have the relay in.

[FABombjoy]

A fuel pressure sensor combined with ECU fuel pump driver module or solid-state relay. This is really not common at all on basic EFI conversions.

There are a host of reasons that the idle would oscillate but the fuel pump isn't likely one of them. You should start a new thread and post some data or a recording of the car & gauges visible on the laptop.

[Coppertank]

A fuel pressure sensor combined with ECU fuel pump driver module or solid-state relay. This is really not common at all on basic EFI conversions.

There are a host of reasons that the idle would oscillate but the fuel pump isn't likely one of them. You should start a new thread and post some data or a recording of the car & gauges visible on the laptop.

Good thinking! Sorry to momentarily hijack your thread. It's good to know that deleting the accumulator wouldn't resolve it. It's still something I may do down the road if it's not needed for EFI anyway. Thanks again!