Stupid fuel accumulator question

[at88mph]

I KNOW I should know this, but does the fuel accumulator assist in any way with the cold starting of the car? Since I did the engine swap to the Chevy motor, (way back in 2000) I of course removed the accumulator b/c I figured it was no longer necessary. I've been drivin the D a lot more lately, and when I FIRST go to start the car, it takes quite a few seconds or tries to start it (If I keep the key engaged, it takes about 8-15 seconds to start....or if I just crank it giving it a rest, it take about 2-3 tries at about 5 seconds each) Just curious if the accumulator was also a mid-point location so pressure wouldn't have to be built up from the fuel pump. Once the car is started for the first time for the day, it starts up just fine.

Thanks for any input! :)

[Chris 16409]

Yes the accumulator keeps the fuel pressure up. When this part goes bad on a stock DeLorean, starting the car becomes an issue.

[Bitsyncmaster]

If your running a carb you don't need the accumulator. EFI holds pressure for most cars but with injectors that electrically open the hot start problems are not like our stock systems.

[content22207]

Gasohol is more evaporative than pure gasoline (non-water portion is -- water just separates out and sits on the bottom of the tank). Your bowl(s) will evaporate within a week. Depending upon your pump arrangement, you may well need to spin the engine for a protracted period of time to fill the bowl(s) after the car has been sitting.

What kind of carburetor are you running? Carters do not like to sit (Edlebrocks are Carter AFB's, now manufacturered by Weber).

Bill Robertson
#5939

[Kenny_Z]

Isn't a 4.3 Vortec a throttle body injection engine? Unless of course you swapped it to a carb. My stang will do the crank and die after a few hours of sitting. The fuel pressure has dropped in the lines but the carb is holding some fuel in the bowls. I can get her to stay running if I apply a little gas but most of the time I forget to do this. Will yours crank faster with a few pedal pumps?

[at88mph]

Isn't a 4.3 Vortec a throttle body injection engine? Unless of course you swapped it to a carb. My stang will do the crank and die after a few hours of sitting. The fuel pressure has dropped in the lines but the carb is holding some fuel in the bowls. I can get her to stay running if I apply a little gas but most of the time I forget to do this. Will yours crank faster with a few pedal pumps?

Yep, it is TBI, not carbed. :) Thanks to everyone for the responses. I guess I'll put the fuel accumulator back into the car. Its not really a big deal, but it does kinda irritate me when people are around and the car is cold and its kinda embarrassing waiting so long for it to start when its COMPLETELY cold. :) Granted, it seems to only be a REAL issue when I go w/o starting it for a couple of days or more.

Thanks again!!

[lorentbj]

I am new to the D site.Did you replace the acc.?I would think this might not have been your problem?It sounds more like a fuel pump leaking back.
How was it putting in a 4.3?What year was the 4.3? thanks,bob

[Ron]

I'm with Bob, something isn't adding up here...

There is no need to put the accumilator back on.

Not a lot of info to go on, but-
The symptom you described is usually caused by a bad ECT sensor (especially if no engine light). It is VERY common for these sensors to be 'off ' but not out of the 'valid range'. So it does not set a P code and kick the engine light on. (It simply 'thinks' the engine is warmer than it is.) (I've replaced dozens of them and it the only problem!)

ECT- (E)ngine (C)oolant (T)emperature. The sensor mounts just in front of the throttle body and if you remove the plug and look in the cavity, it will resemble a mushroom. Swap or buy one -It's relatively cheep. Make sure you tell the parts guy it is NOT for a gauge or light.

FYI- A 4.3 with TBI should have 62-90 kPa (9-13 psi), with key on-engine off. it may be worth mentioning that the stock DeLorean pump is multiples higher and will ruin the TBI pressure regulator in no time, so I doubt it is still installed, if so search for fuel pump mods here for ideas.

If none of this helps, give us more details...

[David T]

The accumulator does 2 things in the Bosch K-Jet fuel system.
1) It smooths out the pulses from the fuel pump
2) It hold up "Rest Pressure" to help the K-Jet start when hot-warm. In a TBI system it will have no effect on hot or cold starting.
Sounds to me like the motor isn't starting cold because it needs *some* pressure in the system and from a cold start the pump can't get the pressure up fast enough. Try turning the key on and off a couple of times to run the fuel pump before cranking the motor. If it starts up faster then that is the problem. BTW how are you running the pump, through the RPM relay? If so you may need to find another way to run the fuel pump.
David Teitelbaum

[content22207]

RPM relay closes during cranking. It's reset interval is about 1.5 seconds.

Bill Robertson
#5939

[Ron]

David's comments reminded me that a stock TBI setup has a fuel pump check valve, a likely candidate.
(Most TBI relays run the pump ~4 seconds to prime.)

Since it has been working for 10+ years, I don't see how it is wired would be a problem all of a sudden. But if it is wired through the rpm relay, I'd sure test the output or try another one.

Pop the lid off of the air cleaner and see if it is getting fuel the first time you turn the key that day to kill 200 birds with one stone!

What kind of pump?

[David T]

Many TBI systems have a transfer pump in the fuel tank that makes a low pressure, enough to get the fuel out of the tank and up to the next pump which creates the high pressure to run the system. Even with a check valve, if the system sits long enough it will lose any residual pressure. The key is to have a pump that can bring the pressure up quickly so the motor can start very soon after you start cranking it over. The check valve is mainly so all of the fuel in the system doesn't drain back into the fuel tank. If it does then not only does the pump have to pressurize the system, it must fill it first. That takes a little longer. On most systems there is a pressure valve on the return to keep that from draining back to the tank too. In doing the engine swap all of these kind of little things are not always done right. And even if they were, something may have gone bad.
David Teitelbaum

[Ron]

Many TBI systems have a transfer pump in the fuel tank that makes a low pressure, enough to get the fuel out of the tank and up to the next pump which creates the high pressure to run the system. Even with a check valve, if the system sits long enough it will lose any residual pressure. The key is to have a pump that can bring the pressure up quickly so the motor can start very soon after you start cranking it over. The check valve is mainly so all of the fuel in the system doesn't drain back into the fuel tank. If it does then not only does the pump have to pressurize the system, it must fill it first. That takes a little longer. On most systems there is a pressure valve on the return to keep that from draining back to the tank too. In doing the engine swap all of these kind of little things are not always done right. And even if they were, something may have gone bad.
David TeitelbaumI'm with you here.
I can't think of a 4.3 TBI that used 2 pumps off of the top of my head (several fords tho)...not saying there wasn't, but can't see why with ~10psi, to the injectors. And in this case...well, any case, 15 seconds is a looooooog time to wait on ~10psi, especially if it starts and runs ok for the rest of the day.
Agreed!, this being an engine swap there is no telling -- we're just grasping at straws w/o more info.