IP fuel lift pump

Mitsubishi Pickup
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strada-caster
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Vehicle: Mitsubishi Strada 1992
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Location: Thunder Bay, Ontario

IP fuel lift pump

Post by strada-caster »

Hello, I believe my lift pump is acting up and making it hard for the IP to perform its job.
-lack of power (have to climb in third when forth would have done it a year ago)
-lower fuel economy (approx 15% worse, have seen this trend since last winter)
-bumping and chugging idle when I first start, idle is fine after warm up
-white/grey smoke on start up when bumping and chugging

-no IP leaks that I can see
-glow plugs are good
-injectors have new nozzles and reset pressures..
-recently replaced timing/balance belt and tensioners, water pump, thermostat and IP shaft seal. had timing proffesionally checked afterwards.
-air/fuel filter are new enough...
-in tank filter is good, saw that a year ago when I repaired my tank.

engine was bumping and chugging before all this work was done.


I plan on testing this with an inline fuel pump to keep the fuel lines pressured.
Does anyone know what pressure the lift pump generates?
what pressure pump should I look at getting?

Thanks,
Devin
yojimbo
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Re: IP fuel lift pump

Post by yojimbo »

You have a lift pump? I've never noticed having one, is it original?
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strada-caster
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Re: IP fuel lift pump

Post by strada-caster »

yojimbo wrote:You have a lift pump? I've never noticed having one, is it original?
the lift pump is built into the IP, from what I understand.
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Strada 92
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Re: IP fuel lift pump

Post by Strada 92 »

There's no lift pump on Strada.Your problem is the IP shaft seal.You will not see any leak of fuel most of the time.The air pass thru the seal causing air in the fuel system.
On a Strada or any 4d56,you can fit a lift pump,not the best solution but will solve the problem for a time.On a 4m40,don't do that cause the old seal of the IP breathe air and crankcase oil,so you have
oil in your fuel system, eventually burning this oil.A good indication of this problem is a fuel filter with black (oil) inside.(4m40).

Change your IP shaft seal.It's the same seal that everyone change on Spacegear and Pajero (4m40).
Mitsubishi Strada Ralliart 1992 (sold)
Mitsubishi L400 Spacegear
Mitsubishi I-MiEV 2012
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Strada 92
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Re: IP fuel lift pump

Post by Strada 92 »

Sorry,i've just seen that you have already change the seal.

If you really want a lift pump,ford ranger turbo-diesel from 1985 to 1987 with a Mitsubishi 4d55 was equipped with electrical lift pump.
The specification from the fuel filter outlet is minimum 1 psi at 4000rpm no load.Pressure at the pump outlet should not differ by less than 3.5 psi.Standard operation pressure is 4 psi or less.Never exceed 15 psi for fuel supply lines.
Lift pump capacity should be minimum 1 pint in 30 second.
Mitsubishi Strada Ralliart 1992 (sold)
Mitsubishi L400 Spacegear
Mitsubishi I-MiEV 2012
strada-caster
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Re: IP fuel lift pump

Post by strada-caster »

Strada 92,

Thanks for the info. Hopefully I get to test this out in the next 2 weeks.
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Strada 92
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Re: IP fuel lift pump

Post by Strada 92 »

Check for corrosion under the fuel filter adapter-lift pump primer,exactly where the filter gasket contacts the adapter.
Over time, the aluminum corrode and there is a loss of seal.
When you starts the engine, after a night,there is a bit of air in the system.

Mine was like that. I removed the adapter, remove corrosion and apply a little grease on the surface of
contact before putting the filter in place.

Soon, I will replace the adapter-lift pump primer.

Hope this help.
Mitsubishi Strada Ralliart 1992 (sold)
Mitsubishi L400 Spacegear
Mitsubishi I-MiEV 2012
strada-caster
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Location: Thunder Bay, Ontario

Re: IP fuel lift pump

Post by strada-caster »

I was able to put some clear lines on my fuel system. In doing so I noticed that the IP lift pump is working perfectly.
Also noticed there is no air leak/entrainment in to the fuel lines atleast not from teh fuel filter to the IP, in my eyes, the most important part.

hit the RPM higher, the fuel draws through the lines solid, no air whatsoever.
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Strada 92
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Re: IP fuel lift pump

Post by Strada 92 »

I've order an electrical lift pump from ebay.I will try this soon.I know it's not the best but i 've heard about some good point about electrical lift pump.
One of those is that the fuel is always circulating in the system allowing some kind of cooling.
Also,improved cold start.

To be continued ...
Mitsubishi Strada Ralliart 1992 (sold)
Mitsubishi L400 Spacegear
Mitsubishi I-MiEV 2012
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Strada 92
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Re: IP fuel lift pump

Post by Strada 92 »

Ok,I've passed winter with the lift pump to compensate for wear of the rotor head of the injection pump and i could say that
a lift pump make no difference.The best way to resolve many of the smoking,chugging,bumping,etc... is to rebuild the IP with new seals and rotor head.

I don't know why it is not mentioned anywhere to replace the rotor head when the IP is in need of a rebuild.
Chugging cold start is the fault of this piece.And it seems quite common to replace this rotor head in Japan.

So lift pump is not really a good thing on a 4D56.
Mitsubishi Strada Ralliart 1992 (sold)
Mitsubishi L400 Spacegear
Mitsubishi I-MiEV 2012
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