Fuel Injected Issue

[Tin Medic]

3 times today I ended up on the side of the road due to what I think is vapor lock. The engine is getting to hot and then shutting down but not overheating. It stutters before it dies and then I have to wait about 15 min before it will start again. I will check my fan clutch and thermostat tomorrow but I am open to any other ideas.

 

[Saddle Tramp]

Vapor lock is caused by liquid gasoline heating to the point it turns to a “vapor”. I would check the gas line and make sure it isn’t too close to a heat source such as the exhaust system or motor block, any place that generates heat hot enough to boil the gas.

PS: Maybe the fuel pump is starting to fail?

 

[Tin Medic]

I was already thinking about the fuel pump. I will be running the fuel lines tomorrow to check for any issues.

 

[Tin Medic]

Fuel pump looks to be the culprit. Sometimes it doesn't come on when I turn the ignition on.


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[Torxhead]

I would think you would be getting a code sent informing you of low fuel pressure. How long has the pump been in? I am assuming that it is externally mounted and not located in the fuel tank.

 

[Big G 86 Cj KrAwLeR]

I'm having the same issue. But it wasn't fuel pump. Ran my rig all day on trail get on road back home then sputter sputter and DEAD. I've got 4.3 vortex fuel injected any new ideas would be great. Oh yea also when I removed gas cap sounded like my gas tank had imploaded

 

[Tin Medic]

I would think you would be getting a code sent informing you of low fuel pressure. How long has the pump been in? I am assuming that it is externally mounted and not located in the fuel tank.

Where would these codes be coming from? Externally mounted and has been there longer than I've owned the jeep.

 

[bondo258]

You need a functioning vapor purge/ charcoal canister setup for FI to function correctly.

Just the constant recirculation of fuel to and from the tank causes excessive vapor pressure.

Without a vapor release (some off road guys run only vented fuel caps which pushes fuel out of your tank on steep climbs....not my idea of ideal)
or a charcoal canister to release excess pressure (or in rare cases vacuum) FI can't work well. CJ tanks return lines are at the top of the sender unit. fuel drips out while vapor is forced up to the regulator. Vapor-locked regulators can be notoriously difficult to purge, since it bypasses pressure when vapor-bound. Full bypass equals no fuel.

Check to make sure you have a fuel return capable of keeping up with a FI pump. Usually the stock return line is waaay undersized for the task. The carb sytem fuel pressure peaked around 5-6 PSI. Fuel injection runs much greater pressures and GPH.

 

[Tin Medic]

From my fuel tank the line goes to a filter to the fuel pump and then to a black canister then the fuel lines run to the front. What is the black canister? About 5 inches long and 2-3 inches in diameter.

 

[bondo258]

Not sure what fuel injection setup you have, but the typical setup is as follows...

Fuel outlet from tank, filter, pump, Fuel pressure regulator.

The FPR feeds the injection setup.

The return line goes directly back to the tank. Nothing else should be connected to it.

The vapor line goes from the top of the tank, to your rollover /liquid check valve(s). Different years have slightly different check valve arrangements.
These valves keep liquid gas from being drawn into your canister when at extreme angles

From there it goes to your charcoal canister. The charcoal canister will gets a seperate vacuum line for a signal to purge, and vapors are drawn (through yet another line) into the throttle body to be burned in the engine.

 

[priceg]

Before you rebuild your entire fuel system, buy a cheap fuel pressure gauge and tape it to your windshield so you can verify this as your problem. It would suck if all you needed was a ignition module. Just saying...

 

[Tin Medic]

I am running the Mopar Performance MPI setup. I dont seem to have any return lines anywhere. Will take a better look today.

 

[Tin Medic]

Ok, the problem is back. I have replaced the fuel pump and lines. Is there anything electrical that could be causing this. I am leaving tomorrow morning for South Dakota so I need to fix this tonight.

 

[Sasquach]

I am running the Mopar Performance MPI setup. I dont seem to have any return lines anywhere. Will take a better look today.

My Mopar system has a return line directly off the fuel pressure regulator that is located just down stream the filter, all of which is located in front of the fuel tank.
Bondo has the system described perfectly in terms of process.

 

[Sasquach]

I thought I may have mentioned this to you before but Hesco has a forum devoted to the Mopar system that they developed and sell.
Jeep MPI Kit - Hesco Forums - Page 1

 

[Torxhead]

You stated that there was some stuttering prior to the engine stalling, i'm thinking fuel starvation. If so, I would think the fuel pump would be hot to the touch. Another thing that could be causing this is poor fuel tank ventalation. A way to check this would be to after a long drive or engine stall out, would be to remove the gas cap and listen for air rushing in since an unvented fuel tank will create a vacumn as the fuel is used up. It was already mentioned that a fuel pressure check is advised. I would think if it were an electrical problem there would be an immediate stalling and no stuttering.

 

[Tin Medic]

My return line is in place. My pressure test was right around 30 psi.

 

[Sasquach]

My return line is in place. My pressure test was right around 30 psi.

Does it read 30 when the problem exists?

 

[Tin Medic]

I dont have a regulautor in the line, I tested it in the shop so I dont know if it's reading 30 psi when it stalls. I see people refering to the fuel regulator as a possibilty but I cant seem to find one on mine. I was on the HESCO forum but there are way to many topics to read to find one refering to my problem. I did read the regulator topic and that is what got me looking for mine.

 

[Sasquach]

If you follow the line from the pump to the rail you see nothing in line?
Not sure what the early Mopar systems consisted of but I know there was a change prior to the system I have and it envolved the reg if I remember correctly.

As a side note I just built a heat sheild for my filter/pump/reg. because my exhaust passes so closely that I had a problem boiling the fuel and having pump cavitation, funny thing was it ran fine just made the pump noisy. I also wrapped the tail pipe with header heat wrap and that stopped the problem so my new heat sheild is more insurance. The Cavitation only occured in 90+ heat on long uphill grades at high elevation.
Just some food for thought.