2.5 Liter YJ Sputtering issue

burrellsjeep

burrellsjeep

Breaking Stuff...
Joined
Nov 19, 2008
Location
Morganton NC
My neighbor got a YJ a few months ago. I think a 92. It has a 2.5 liter 4 banger.

The issue he is having is that it idols well, But as soon as you give it any fuel it sputters and cuts out. He has already check all the plugs (There firing well) and cleaned the throttle body, I asked him to check the fuel filter, well the PO had removed the filter. So he is putting it back on. I haven't had a chance to help him look at, Just hoping for some help.

Any Ideas, Like I said it idols fine, But sputters out when fuel is applied.

Thanks For the Help
 
The missing fuel filter may be the issue. Depends on how long it was out. Also does the check engine light work? If so you can pull the code by turning the ignition on and off five times, and leaving it in the on position on the fifth time. The light should flash once, pause and then twice. That indicates a code 12 meaning the diagnostic system is functioning correctly. Any stored codes will flash after that. Any chrysler guys please respond to this as I dont exactly remember if you cycle it five or seven times. This trick works on the early OBDI or the OBDII systems. A 2001 Dodge for instance will display your codes right on the odometer display. Anyways it sounds like you are leaning out really bad, so I would check your codes if there are any, and go from there with the fuel system, injectors, and so on.
 
CarolinaTruggies said:
Had one just like that and the cat was clogged. Take the exhaust off before the cat and see what it does.
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I told him mine did the same thing years back (i have a 2.5 also). But I for the life of me could not remember what I did to fix it, Until you posted that. That is exactly what mine was. Gutted the cat and never had the issue again.

Thanks for the help guys, I will pass this along and report back the results.
 
Well it was not the CAT, removed it and it still does it.

We have checked for vac leaks, spark on all plugs, injectors spray fine, checked for leaks around the intake. cleaned the intake

What else, Timing, O2 Sensors?

This all started just driving in town, Stop at a light and it started when pulling away, The check light does come on and will stay on until the jeep is turned off and then back on.
 
could be the fuel pump. put a gauge on it while on and check the leak down as well. i had one where a piece of the sock had broken off and was floating around and would suck up into the pump and choke it out. pita to diagnose.
 
Mine used to do that and periodically still does. Every other time I fill it up I put a can of sea foam in and drive it hard til it straightens out. This Jeep is driven by my college student step-son and he like to let the fuel level get low for long periods of time creating condensation inside the tank. The Sea Foam helps dissipate the water.
 
I had him unplug the TPS sensor on the throttle body and it made no diff in the sputter, Should it not have caused it to run worst, See how it didn't make a change, I am leaning toward this being the issue.

Does anyone know if the Throttle Body from a 97 2.5 will swap on to a 92 2.5?? I am considering swapping mine for testing or just the TPS sensor.
 
What is the fuel pressure? The TPS works like a accelerator pump on a carb when throttle is applied it tells the PCM to add fuel. Most times it is fuel pressure related sounds like the pressure is low a quick check could be see if there is any difference with the fuel pressure regulator disconnected.

If you turn the key on and off three times it should flash any trouble codes.
 
rob92xj said:
What is the fuel pressure? The TPS works like a accelerator pump on a carb when throttle is applied it tells the PCM to add fuel. Most times it is fuel pressure related sounds like the pressure is low a quick check could be see if there is any difference with the fuel pressure regulator disconnected.

If you turn the key on and off three times it should flash any trouble codes.
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Flash the Check light???
 
****Update*****

Alright we reset the computer and then drove it see what codes it would throw and here is what we got.

13 - Manifold Absolute Pressure (MAP) Sensor Vacuum
23 - MAT sensor or circuit
24 - Throttle Position Sensor (TPS) sensor or circuit
55 - End of Codes

Checked to three times, same codes each time to be sure.

So any Ideas what cause these to come up?
 
Probably set the tps code cause you unplugged it with it running. That goes for any sensor you unplug while its running.
 
I had the same problem with my 97 2.5 mine was speratic one day it would be fine then out of the blue it would idle fine but would stall when I gave it the gas. I replace the fuel pump and have not had an issue with it since.

One other thought my 98 ram would do this same thing and it turned out to be corroded battery terminals don't know if 92 jeep could have the same problem. They are both chrylser porducts though.
 
31 at idle is fine, what is the pressure with the fuel pressure regulator disconnected? With it disconnected it should be 40psi +/- 2psi.

The TPS codes would possibly be wiring, PCM, grounds. The battery cables can cause problems make sure they are in good condition.
 
Working with it today to trace wires for shorts and vacs for leaks, We found that the CPS plug to the harness if moved or wiggled it cause the engine to die, Could this cause the issues that the jeep is having? The CPS was replaced a couple months ago, due to a no crank issue.


Edit: does not seem to be grounding out, possibly losing connection in the plug.
 
rob92xj said:
31 at idle is fine, what is the pressure with the fuel pressure regulator disconnected? With it disconnected it should be 40psi +/- 2psi.
The TPS codes would possibly be wiring, PCM, grounds. The battery cables can cause problems make sure they are in good condition.
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41 psi is the reading with the vac unhooked from the Fuel Pressure Regulator.

Can't figure out the 30 psi at idle, 40 psi half peddle, 30 psi full peddle. With the peddle all the way down there should be zero to little vac just like with the vac off the FPR.
 
burrellsjeep said:
41 psi is the reading with the vac unhooked from the Fuel Pressure Regulator.
Can't figure out the 30 psi at idle, 40 psi half peddle, 30 psi full peddle. With the peddle all the way down there should be zero to little vac just like with the vac off the FPR.
Click to expand...
You might have an injector or 2 opening too much which will drop the pressure at WOT, or the TPS is not reading right at the TPS and the PCM is not adjusting the pulse width of the injectors at WOT.
 
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