Blowing smoke from exhaust

I put a fuel pressure gauge on the Schrader on the fuel rail. Read 0 after cycling the key 5 times without cranking. I had my wife crank it, and pressure only got up to 10 psi while running.
How do I diagnose from here? Probably the ancient fuel filter, I would assume.


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Some of it to fix isn't bad. The fuel pressure regulator is on the rail and you have a fuel filer on the frame rail but, the fuel pump is in the tank.

I haven't read of it yet, but your fuel level is determined by a float. If this is damages or not functional, it could explain this gauge issue. This combine with your fuel pressure lacking is odd. 5 gallons should be enough to read 1/4 tank.
Try key on to run about 5 times, do not start the vehicle. This should prime enough through repetition to get a reading from the fuel rail. At this point note your reading and then start the jeep. Get an idle reading and watch the fuel pressure gauge as you open the throttle plate slowly to increase rpm.
This will give you a good idea as to weather the fuel pump is toast, or a check valve has failed.


Otherwise , yes bad wiring could be an issue, but I doubt it unless you have good reason to suspect this.


To me it sounds like someone drove your rig into zombie status lol.

I would be tempted to Jack it up high at the back, remove the pump/ filter. Get a decent container and dump some fuel into. Chances are it probably has crap in the tank anyhow,
Fine filter the fuel and repeat as needed. Test the fuel pump whilst out. Carefully but!
Maybe use deisel? Bit less flammable..
Disconnect all your fuel injectors, and perhaps blow some air pressure up the line and parts cleaner.
Correct me guys if there is any valves/etc that can be damaged. Old school way.

So, I was able to build about 15 psi through a few starts. The pressure bleeds off very quickly to 0 once the engine is turned off. Maybe injectors failed open? I can't imagine that a failing tps or iac would cause this.

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Also a that test was done with a new fuel filter

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I believe a 1992 still has the fuel pump ballast resistor on the fender. Check that it's not messed up or broken. You can eliminate the resistor and connect the wires together, as the resistor was added to reduce the voltage while running for noise reasons. If you have a meter, check that you're getting voltage to the fuel pump. To me the bleeding down quickly points to the fuel pressure regulator, fuel pump, or a badly leaking injector (which could contribute to your sludge and/or smoke). I'd maybe unhook the fuel filter and key-on to see if it's flowing well.

You probably have a heap of knock on symptoms. Great info coming in to help you, and we all learn from it.
Pretty sure you guys over there can get parts heaps cheaper than us here.
Consider a 2nd hand head, get it decked and cleaned up etc,.
Then later get your original one done up in time when cash available.
Or swap for exchange head.
A lot can be fixed with your own time without spending big bucks.

The in-tank fuel pump has a check-valve to hold pressure & fuel in the line to the injectors. When the in-tank fuel check-valve fails, fuel flows back into the tank and empties the fuel line and fuel pressure can't build-up. This happened on my 88XJ. You can replace the in-tank fuel pump/check valve assembly OR you can just install an inexpensive aluminium check-valve downstream of the fuel filter. I added an external check-valve on my 88XJ and the problem was solved. The fuel regulator, on the fuel rail only regulates fuel pressure, it is NOT a check-valve.

Best regards,

CJR

Could my smoking problem have messed up an injector? Does that happen?

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I doubt it very much.

rain164845 said:

So, I was able to build about 15 psi through a few starts. The pressure bleeds off very quickly to 0 once the engine is turned off. Maybe injectors failed open? I can't imagine that a failing tps or iac would cause this.

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You don't want to start it a few times, just key on to run like 5 times, then on the 6th start it.

If your injectors are leaking it'll start in flood mode and a bit rough.

What color smoke?

*correction, if injectors are leaking it'll start flooded. Starting in flood mode, if the same on your year, would be by holding the gas pedal down all the way, then starting.



Tps/iac hasn't anything to do with starting fuel pressure. Only check valve/pump or injectors, Other wise ide think there would be fuel leaking under your ride....ha


You could pull the rail and prime 5 times like I said earlier, then see if an injector leaks. Just don't try starting it.

4x4JeePmaNthINg said:

*correction, if injectors are leaking it'll start flooded. Starting in flood mode, if the same on your year, would be by holding the gas pedal down all the way, then starting.



Tps/iac hasn't anything to do with starting fuel pressure. Only check valve/pump or injectors, Other wise ide think there would be fuel leaking under your ride....ha


You could pull the rail and prime 5 times like I said earlier, then see if an injector leaks. Just don't try starting it.

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Based on that I'm thinking Fuel pump. Preferred one today along with iac and girl pump relay. If that doesn't fix it then I'll do injectors

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Are you getting a lot of condensation at the exhaust

Down under said:

Are you getting a lot of condensation at the exhaust

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I did notice condensation, yes.

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rain164845 said:

I did notice condensation, yes.

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Some condensation while warming up or cold out is normal. A lot after it warms up on a warm dry day is not, and could indicate a head gasket issue. I suspect your current problem is a fuel problem.

Pretty sure when an injector has pooped itself, they stay in an open position (constant fuel feed).
Thus emitting access condensation and a cloud of smoke (un-burnt fuel), commonly mistaken for blown head gasket.
But with your previous posts, I would not fit new injectors just yet until you replace the fuel filter and flush etc.
Inspect the sump oil for water contamination. (Blown head gaskit)
Could be all of the above.

Great news, the Jeep is up and running!!!!
Replaced fuel tank, pump, filter, iac. Took off valve cover and degunked the baffles and snorkels. Also did the front shocks, rotors and pads once it was drivable.
If imgur starts working again, I'll load videos. I think the billowing smoke was oil getting sucked into the intake manifold due to the baffles in the valve cover being gunked up. I think that it just so happened that the fuel pump died at the same time.

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Good stuff! A friend of mine who i had just rang was about 2 minutes from getting a 2nd hand motor put in, because of a smoke cloud coming out of the exhaust on a newish car he bought.
And this problem started not long after he did an oil change and using an engine oil flush treatment.
Thought he had stuffed the motor.
So I told him to disconnect the breather line to the intake, and take it for a good blat.
Sure enough the smoke slowly faded.
Went to his house, ripped off the cover..... Sure enough his looked like yours did.
The engine flush loosened all the crap on the cover and around the baffle, and was getting sucked up through the breather.
Saved him $5 grand!
Cleaned it up, put a $15 catch can in the line. A few cans of cleaner, and new plugs.
Presto!
Good chance you will have some soot and gunk in your manifolds and around the valves and in the exhaust pipe.
Give it 100kms, then pop your plugs out, dump a full can of cleaner down the throttle, let it sit for a minute, crank to move valves, as some will be closed and not get a soak etc , then give it another full can . Then get a friend to crank it for you whilst you use an air pistol down the throttle and cover the gap with a rag to stop the air getting out past it. Then do the same into the pots, give each pot a spray/soak, crank , blast into pot, don't put the tip of the air pistol to far in!
Refit your plugs , run till warm, then use the cleaner down the throttle in the standard way,.
Go for another blat to spit it all out of your exhaust system.