Is this what a bad exhaust manifold gasket looks like? I have been having an issue with stalling for some time now. Generally happens when the Jeep is well warmed up, not when it's on the cooler side. Could this be a contributing factor to that condition if not the root cause itself?

 

Does the valve cover leak oil at all? Could be oil from that burning up on the exhaust. If not, then it does look like you have an exhaust leak, but don't think that would be the root to your stalling issue. It would have to be leaking bad enough that it would impact compression and be running extremely rough to cause stalling I would think.

 

With the engine cold some morning, beginning in the middle and working out toward the ends, snug up the intake manifold fasteners.

 

You can test to see if exhaust is leaking there. Once it warms up, just hold a small piece of tissue near it. If you see nothing at idle, reach over to the throttle cable and rev the engine a bit.


I doubt if that leak (if it is a leak) would cause engine stalling. When it stalls, will it start right back up?

 

Ok I will do that. Yes, it does start right back up after it stalls. Any ideas would be greatly appreciated

I have done that just not sure if I did it while the engine was cold. I will do it again.

I'm not exactly certain but it is a possibility that it is leaking a tiny bit and has accumulated over time. I will delve further into it.

Thanks guys and Happy New Year!

 

So I'm still having a stalling issue:
1) It happens when the car is good and warmed up.
2) Always at idle
3) Sometimes I get a drop in RPM when I press the accelerator, followed by a surge forward. (This is much rarer than it used to be and could have been more due to loose transmission mount bolts)
4) Truck starts right back up after it dies
5) Can avoid stalling by keeping the RPM's up via my other foot on the gas pedal ever so slightly at a stop.

Where should I be looking besides vacuum lines? Any sensors that I can test? What is a good way to test vacuum lines, soapy water spray? I've looked them over quite a few times but haven't found anything. My brake booster sounds like it's leaking, even though I just put in a salvaged one, but before that it was noisy since the day I got it and had no effect.

 

I would pull out the IAC valve and see if its dirty. Probably wouldnt be a bad idea to just yank the throttle body off and clean the whole thing.

 

Test the TPS on the engine side.

 

I checked the TPS, and there didn't seem to be any fluctuation when I wiggled the wiring harness. What should be the baseline read on the meter?

My alternator was going bad, it had begun squeaking and I noticed a drop on my gauge yesterday. Tested it with the multimeter and it was charging at about 12.8. I always keep an extra on hand as I usually have to change it once every one or 2 years. After replacing it, the stalling seems to have increased. It stalled 3 times on the way back from the store which is about a mile or less away from home. I'm wondering if I have a bad ground somewhere.....

 

TPS ADJUSTMENT FOR ENGINE ISSUES

Both Renix manual and automatic transmission equipped XJs and MJs have a flat three-wire connector to the TPS which provides data input to the ECU. The three wires in the connector are clearly embossed with the letters A, B, and C. Wire “A” is positive. Wire “B” is ground. DO NOT UNPLUG THE CONNECTORS!

1. KEY ON, measure voltage from “A” positive to “B” ground by back-probing the connectors. Note the voltage reading–this is your REFERENCE voltage.
2. KEY ON, back-probe the connector at wires “B” and “C”. Measure the voltage. This is your OUTPUT voltage.
3. Your OUTPUT voltage needs to be seventeen percent of your REFERENCE voltage. For example: 4.82 volts X .17=.82 volts.
4. Loosen both T-20 Torx screws attaching the TPS to the throttle body and rotate the TPS until you have achieved your desired output voltage.
5. Tighten the screws carefully while watching to see that your output voltage remains where it is supposed to be. If you can’t achieve the correct output voltage, replace the TPS and start over.

Sometimes, after adjusting your TPS the way outlined above, you may experience a high idle upon starting. If that happens, shut the engine off and reconnect your probes to B and C. Start the engine and while watching your meter, turn the TPS clockwise until the idle drops to normal and then rotate it back counterclockwise to your desired output voltage.

 

So the TPS was bad and I replaced it. I cleaned the throttle body and the IAC. Made a huge difference in overall operation.

Took it out for a cruise tonight and it stalled again.

When it shudders, the dash lights dim a little bit. I also noticed something else. I'm not sure of the exact term for the part, but I have a set of 5-90 cables. There is a plastic box that has a fuse in it inline on the positive cable to the battery. It has looks like its melted a bit including a hole on one edge of the cover.

 

Give us pic of that.

 

So as you can see in the above pictures my fuse holder is FRIED. The terminal melted through the base and I am guessing is the source of my electrical issues. I picked up another one tonight, only issue is it's not the post style like my old one. This means I will have to remove the terminals from my wires and insert it directly into the big shiny gold block (bottom picture) and then tighten it. I feel that this may be less secure, although I was assured that this is the way to go and that the old style is crap, that's why most places don't stock them anymore. I am on the fence right now about installing it. Anyone have experience using one of these for their battery cables?

 

Ok so new fuse block installed, MASSIVE improvement in a lot of areas.

But it still will stall just not as easily/frequently.

I just installed a brand new fuel tank which turned out to have a leak, so there may be a fuel pressure issue because of that. Parts supplier is supposedly sending me a new one. Regardless the stalling was happening before the tank, so I don't believe it's the root cause.

I still think it may be something electrical.Before it shudders/stalls the lights dim on the dash and the RPM's dip. The car also obviously idles a little rougher when it dips.

 

There had to be a reason the fuse fried. It's between the alternator and battery. I'm wondering about that alternator.