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Old 6th June 2006, 12:54   #1
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Default Mechanical to electric conversion of fuel pump, help please.

Guys i've bought a UCAL electric fuel pump, not the in tank variety. It's for my M800. This pump comes after the inline fuel filter. It's made for a 1.8liter Contessa i guess. I've installed the pump, the pump comes on while the ignition is in the on position. I've taken the power wire that goes to the coil to power the pump. The pump is working and the it's pumping well. But there is a problem:

Once i revv the engine hard while i overtake or just go fast it the engine dies. It simply dies and the batt & oil lamps comes up inside the meter console.

What could be the problem?

I have 3 doubts:
1) The fuel pressure is too high, the engine might be getting flooded.
2) The fuel pressure is too low.
3) Taking the pump connection from the wire going to the ignition coil could be the problem.

But 1 can be ruled out (i think) coz if the engine gets flooded starting it would be difficult. In this case the engine can be started easily after it kills itself.
2) Electric pump often give more pressure than mech pumps, so it couldn't be. Also what are the symptoms for fuel starvation?
3) This one could be the culprit. Power for the coil & the pump is from a single lead... it could be.

Guys please help me with your valuable inputs, ideas, thoughts...

cheers. crank.
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Old 6th June 2006, 16:29   #2
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It could be No.2. The pump will be working at full action (maximum pumping) when the car is revved and there just might be a slow air leak into the fuel pipe due to the suction effect of the pump,(through either of the fuel filter connector sides or the pump inlet connection) leading to insufficient pumping of fuel. Check to see if your connections to the filter inlet and outlet and the inlet of the pump are secure and totally airtight.
Used to have this problem on my contessa. Was rectified only after i changed the hose clips of the fuel plumbing.
One way to say for sure is to check the sound of the pump when your engine goes off. Turn off the ignition and stop immediately when your engine dies. Switch on the ignition. If your pump works with a lound clicking noise it means that there is low fuel presuure in the line. If it works with a muted clicking, then it means that there is sufficient pressure in the fuel line.

Last edited by jyobeb : 6th June 2006 at 16:33.
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Old 6th June 2006, 16:41   #3
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Jyobeb, thanks for the information. I'll check my fuel connections once again. But when i restart the clicking sound is not there. The pump is getting fuel, that should be the reason. Did your contessa have the UCAL fuel pump and did it have a pressure regulator?

I'm worried about the pressure being too much or too less. Do you know what's the pumping pressure of the contessa fuel pump?

Thanks.
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Old 6th June 2006, 17:00   #4
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Is that fuel pump meant for the MPFI Isuzu engine? If so, its probably putting out too much pressure for a carb. M800 engine to deal with.

After the engine stalls and you go to start it up again, how easy or difficult is it to start?
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Old 6th June 2006, 19:31   #5
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No, the conti didn't have a pressure regulator.
RTech: The pump he is talking about is a regular electric pump. It's pretty much used on everything from conti's, Ambassador, Mm540's and on Petrol & Diesel cars. There is no pressure regulator or cut off switch on it. It just keeps pumping when it is switched on, hence not a good idea to keep your ignition on without starting the engine.
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Old 6th June 2006, 19:36   #6
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Hi,

If your car is an MPFI 800 that pump wil never work for your car. You need a high pressure pump which will cost you approx Rs1850 upwards. Please make sure to specify to the shopkeeper/mechanic you want it for a MPFI car.

The problem you are facing is low pressure and fuel pump heating up and cutting supply. This is common in these pumps.

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Old 6th June 2006, 22:08   #7
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@Rtech: As i've said in the first post the engine is easy to start after it died. So no flooding.

@Jyobeb: Is the pump capable of sustaining the fuel need of carb amby's and conti's at high engine speeds. Is this type of pump reliable? It's a square type pump. Is this a high volume low pressure pump?

@viper:It's not a mpfi engine, it's a carb 800. I just wanted to get rid of the mechanical pump and go the electric way. For this application the ideal pump would be a high volume low pressure pump, 4psi is enough.

Updates:

This evening i reconnected the electrical pump (was using mechanical) and the power for the pump was given directly off the batt with a switch. Took the car for a round and it performed fine. Didnt take it for a high speed run as dad was with me. Will do a proper test run tomo and post the results.
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Old 7th June 2006, 01:25   #8
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Is it required that the pump be mounted closer to the fuel tank? Or is the engine bay okay for installation. It's a Facet type solid state pump (was able to get this info from net).

In the contessa where is the fuel pump located?
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Old 9th June 2006, 11:26   #9
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Problems ironed out. Electrical pump working just fine and now i've got to fit a relay to the circuit to switch the pump on when the ignition is turned on. And then to take out the mechanical pump and close the opening in the head with a plate seen on the mpfi 800.

Don't know if the plate is available, otherwise will have to get one made.
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