Fuel Pressure Build Up

[Ricker]

Is it possible to jumper the relay so that the fuel pump runs whenever the key is turned on but the engine is not running? Will this burn up something? I'm tired of hitting the switch over and over again to run the pump 20 - 30 times to pressurize the fuel system after the car sits for 2 weeks. I have replaced the fuel pump, check valve, accumulator, and O-rings in the pressure regulator. Not sure if there is anything else to try. I can't find the minute pressure leaks. Once the pressure is built up, the car starts fine hot or cold.

[Bitsyncmaster]

Is it possible to jumper the relay so that the fuel pump runs whenever the key is turned on but the engine is not running? Will this burn up something? I'm tired of hitting the switch over and over again to run the pump 20 - 30 times to pressurize the fuel system after the car sits for 2 weeks. I have replaced the fuel pump, check valve, accumulator, and O-rings in the pressure regulator. Not sure if there is anything else to try. I can't find the minute pressure leaks. Once the pressure is built up, the car starts fine hot or cold.

You could jumper the RPM relay socket but it would put a heavy load on the key on circuit and prevent the safety measures of the RPM relay. It only takes about 2 seconds of the pump running before the PPR regulator starts to feed return fuel. So any further priming would do nothing.

[Helirich]

I?ve been driving mine less recently. Like once a month. I don?t have to switch it multiple times. Something wrong there.

[Ricker]

You could jumper the RPM relay socket but it would put a heavy load on the key on circuit and prevent the safety measures of the RPM relay. It only takes about 2 seconds of the pump running before the PPR regulator starts to feed return fuel. So any further priming would do nothing.

But I don't understand why, after the car sits for a week or so and only on long idle times, does it take 20 - 30 primes of the fuel pump to get gas to the engine fuel injection system? A day or two there is no issues, it holds pressure and fuel. It is like the fuel in the line from the front fuel pump to the engine goes empty.

[Bitsyncmaster]

But I don't understand why, after the car sits for a week or so and only on long idle times, does it take 20 - 30 primes of the fuel pump to get gas to the engine fuel injection system? A day or two there is no issues, it holds pressure and fuel. It is like the fuel in the line from the front fuel pump to the engine goes empty.

Do the cold start valve test. Put the CSV into a jar and pull the white/yellow wire off the resistor block so it won't start. Crank the engine and see if you get any fuel in the jar.

My car does need the CSV working after it sits for a week or more. Otherwise it starts right up without needing it.

[Ricker]

Do the cold start valve test. Put the CSV into a jar and pull the white/yellow wire off the resistor block so it won't start. Crank the engine and see if you get any fuel in the jar.

My car does need the CSV working after it sits for a week or more. Otherwise it starts right up without needing it.

I let the car sit for a week or so to make sure it would not start right off that way I could do the checks. Wouldn't you know it, it started right up. Try again next week.

[Ricker]

I let the car sit for a week or so to make sure it would not start right off that way I could do the checks. Wouldn't you know it, it started right up. Try again next week.

So, I tried to start the car again today as it has set for a few days. It did not start so I then took the grey plug from the warm-up regulator and put it at the blue plug on the cold start valve. It started right up. Not sure what that means? Could it be the termo time switch or could it be the engine temperature senor? How would you check both? Thanks!

[Ron]

So, I tried to start the car again today as it has set for a few days. It did not start so I then took the grey plug from the warm-up regulator and put it at the blue plug on the cold start valve. It started right up. Not sure what that means? Could it be the termo time switch or could it be the engine temperature senor? How would you check both? Thanks!

Swapping the two plugs is one of the tests to check the TTS. (It sends power to the cold start valve.) The engine temperature sensor has nothing to do with the cold start valve (its for the gauge only).
Sounds like the termo time switch (TTS) might be bad. Do a search to find other tests you can perform before purcha$ing one...

[AugustneverEnds]

If you do need a thermotime switch they are not too pricy (https://store.delorean.com/102125-th...me-switch.html) $56.12 plus $8.99 for the adapter to make it fit (https://store.delorean.com/102122-screwed-adapter.html). If you have to have an OEM one then that's a more difficult and expensive matter.

[Ricker]

Well, I got out today and tested the Thermo Time Switch. With the engine as ground, the one pin read 0 ohms, the other 30 ohms. It doesn't look like that is the problem. And since the car has only sat for a day, it started right up. I'll wait a week and try something else. Any ideas? It still seems like the fuel in the line from the fuel pump to the engine goes away. Where, I don't know. No marks on the garage floor or gas smells.