Problem With Duel Fuel

[kieranmorris1987]

Hi Everyone,

I am looking for some help in diagnoising a problem I have.

I have a Nissan Patrol 1991 GQ 4.2ltr petrol/lpg. The Lpg runs perfect but the petrol does not. If I put my foot down when it is on petrol it stutters quite alot and have no power. I can still drive in on petrol as long as I take it really easy.

I thought it might be dirty fuel so I have replaced the fuel filter and left the petrol run out and then filled it up again but problem is still there.

I would very much apprieciate any advice.

Cheers

[Winnie]

MAF sensor? Is it EFI?

[threedogs]

Hi mate really should pop over to intro section first before asking questions, just something asked of all Newbies.
Hard to get 4x4 to run well on both, sometimes carby dries out causing flat spot

[Bigrig]

Don't forget to slip over to the introductions section mate and let us know a bit about yourself and the truck. Something we request of all new members - no harm done, but please ensure it happens.

The injectors can become gummed up from lack of use with dual fuel and can absolutely cause the issue you're mentioning - essentially they'll be fine under low pump/throttle pressure but apply the right pedal and the injectors don't atomise the fuel properly and it sort if just dribbles in causing stuttering, hesitation and loss of power ...

Probably a good spot to start and check the regulator, pump/fuel line pressure (about 40psi on idle - from approx 70psi up to 90+psi on throttle) and the TPS ... and the MAF if efi ...

[97_gq_lwb]

If it is a carb model.
Sounds like it could be the plunger in the carb to me what it does is give a squirt of fuel when you hit the pedal.
Run it on petrol so the bowl is full take the aircleaner lid off look down into the throat and see if it is squirting fuel when you open up the throttle.
You don't need the engine running.
Or it could be the typical blockage or air leak loose bolts etc.

[kieranmorris1987]

Hey sorry for not introducing myself, its all done now..

My Patrol is a carb model. I will have a look and see if its squirting fuel when I open the throttle. Can a carburetor become cloged should I give it a good clean.
I am new to fixing car and still learning so excuse me if I come out with stupid questions here and there...

[kieranmorris1987]

Hi mate really should pop over to intro section first before asking questions, just something asked of all Newbies.
Hard to get 4x4 to run well on both, sometimes carby dries out causing flat spot

How can I resolve this if this is the problem?

[mudski]

On the older engines it is quite hard to get the engine to run good on both as the engine requires slightly different timings for gas and then petrol. If it was fine before and now not my guess would be the carby needs an overhaul, all the seals and the plunger is probably dried up from the gas. Once you get it sorted I would advise to instal one of those lube kits which intravenously drip feed a lubricant into the intake to prevent the gas from drying anything out.
Years ago my dad had issues with his Crumpydore gas system, he got it fixed up and put one of these systems in and the car ran really good and even was better on fuel.

[patch697]

How can I resolve this if this is the problem?

In some cases if you run it on Petrol before you shut it down for the night & leave it, the petrol will soak into all the dry gaskets & pot thinks right again..... "But" this is a hit & miss type of deal & is not alway successful.

If you do try this be sure to check all around the carby in the morning before trying to start it just in case fuel has leaked out though the night & if it has clean it up first before you try starting it.

As I said this method is very hit & miss but it has worked for me in times passed & I thought it worth a mention.